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Decline of the world's saline lakes
Nature Geoscience
Abstract
Many of the world's saline lakes are shrinking at alarming rates, reducing waterbird habitat and economic benefits while threatening human health. Saline lakes are long-term basin-wide integrators of climatic conditions that shrink and grow with natural climatic variation. In contrast, water withdrawals for human use exert a sustained reduction in lake inflows and levels. Quantifying the relative contributions of natural variability and human impacts to lake inflows is needed to preserve these lakes. With a credible water balance, causes of lake decline from water diversions or climate variability can be identified and the inflow needed to maintain lake health can be defined. Without a water balance, natural variability can be an excuse for inaction. Here we describe the decline of several of the world's large saline lakes and use a water balance for Great Salt Lake (USA) to demonstrate that consumptive water use rather than long-term climate change has greatly reduced its size. The inflow needed to maintain bird habitat, support lake-related industries and prevent dust storms that threaten human health and agriculture can be identified and provides the information to evaluate the difficult tradeoffs between direct benefits of consumptive water use and ecosystem services provided by saline lakes.
... Farmland and associated water consumption expanded steadily in the basin since the 1850s, until farm area stabilized in the 1980s (Wurtsbaugh et al., 2017). Natural fluctuations in rainfall and streamflow have caused the GSL to rise and fall over annual and decadal periods, but in absence of anthropogenic water consumption the long-term trend in the lake level since the 1850s would have been flat with a natural mean elevation of 1282 m (4206 feet) (Wurtsbaugh et al., 2017). ...
... Farmland and associated water consumption expanded steadily in the basin since the 1850s, until farm area stabilized in the 1980s (Wurtsbaugh et al., 2017). Natural fluctuations in rainfall and streamflow have caused the GSL to rise and fall over annual and decadal periods, but in absence of anthropogenic water consumption the long-term trend in the lake level since the 1850s would have been flat with a natural mean elevation of 1282 m (4206 feet) (Wurtsbaugh et al., 2017). The lake's water balance has been in deficit (i.e., more losses than inputs) for most of the past century but a period of abnormally large snowmelt inflow during the 1980s and 1990s temporarily obscured the long-term decline in lake levels (Fig. 2). ...
... Sustainable water management has proven to be challenging for endorheic (i.e., closed basins lacking outflow) saline lakes around the globe, given that they are typically situated in arid environments with limited opportunity for large-scale water extraction without pushing water balances into deficit (Wurtsbaugh et al., 2017). Water development has resulted in dramatic reductions in surface area and volume in many saline lakes including the Aral Sea in Kazakhstan and Uzbekistan, Lake Urmia in Iran, Owens Lake in California (US), and many others. ...
... As a group, terminal lakes span the broadest ranges of water chemistry characteristics among inland waterbodies, creating diverse habitats that support varied ecosystem services (Herbst 2001 ). Most terminal lakes lie in arid or semiarid regions (Wurtsbaugh et al. 2017, Wang et al. 2018, and therefore are highly sensitive to changes in water availability. In response to growing human populations and associated water use demands, coupled with extended drought and climate change, the spatial extents and water quality of terminal lakes have declined globally (Messager et al. 2016, Gross 2017, Wurtsbaugh et al. 2017, Wurtsbaugh and Sima 2022. ...
... Most terminal lakes lie in arid or semiarid regions (Wurtsbaugh et al. 2017, Wang et al. 2018, and therefore are highly sensitive to changes in water availability. In response to growing human populations and associated water use demands, coupled with extended drought and climate change, the spatial extents and water quality of terminal lakes have declined globally (Messager et al. 2016, Gross 2017, Wurtsbaugh et al. 2017, Wurtsbaugh and Sima 2022. Worldwide, agricultural (Williams 1996, Micklin 2007, Moore 2016) and urban (Wurtsbaugh et al. 2017 ) water use increased by approximately 175% between 1960 and 2010 (Wada and Bierkens 2014 ), and around the same time terminal lakes and their basins experienced an extensive water loss of 106.3 gigatons per year between 2002 and 2016 (Wang et al. 2018 ). ...
... In response to growing human populations and associated water use demands, coupled with extended drought and climate change, the spatial extents and water quality of terminal lakes have declined globally (Messager et al. 2016, Gross 2017, Wurtsbaugh et al. 2017, Wurtsbaugh and Sima 2022. Worldwide, agricultural (Williams 1996, Micklin 2007, Moore 2016) and urban (Wurtsbaugh et al. 2017 ) water use increased by approximately 175% between 1960 and 2010 (Wada and Bierkens 2014 ), and around the same time terminal lakes and their basins experienced an extensive water loss of 106.3 gigatons per year between 2002 and 2016 (Wang et al. 2018 ). Rising temperatures increase plant evapotranspiration rates, water requirements, and irrigation rates for extensive agricultural areas, ultimately reducing stream flow in many regions where terminal lakes exist (Li et al. 2019, Doede and DeGuzman 2020, Donnelly et al. 2020, Schulz et al. 2020, Rad et al. 2022. ...
Terminal lakes are declining globally because of human water demands, drought, and climate change. Through literature synthesis and feedback from the resource and conservation community, we review the state of research for terminal lakes in the Great Basin of the United States, which support millions of waterbirds annually, to prioritize ecological and hydrologic information needs. From an ecological perspective, research priorities include measuring the underlying differences in waterbird resource selection and distribution, migratory connectivity, abiotic factors that interact with prey densities to affect prey availability, and waterbird fitness or demography. Integrated links between water availability, water quality, and food webs are lacking in the literature. Scarce water availability data hinder the current knowledge of water extraction and evapotranspiration rates. Research that can address these priorities would help advance our understanding of how the Great Basin terminal lakes function as an interrelated system and support conservation efforts to reverse the decline of these critical lakes.
... This challenge is exacerbated by Utah's steady population growth. Increased anthropogenic water withdrawals, especially in the agricultural sector, have resulted in continued reductions in flow into the GSL, causing the lake to be approximately 50% smaller than when settlers arrived in 1847 [22][23][24]. The disappearance of a saline lake can trigger a sequence of environmental and economic damages that are nearly impossible to reverse [22,25,26]. ...
... Increased anthropogenic water withdrawals, especially in the agricultural sector, have resulted in continued reductions in flow into the GSL, causing the lake to be approximately 50% smaller than when settlers arrived in 1847 [22][23][24]. The disappearance of a saline lake can trigger a sequence of environmental and economic damages that are nearly impossible to reverse [22,25,26]. ...
... Irrigated agriculture is causing the demise of saline lakes on nearly all continents [22,25,42]. We have demonstrated that achieving the annual water conservation goal of 581 million m 3 -necessary for restoring the GSL to a healthy elevation within 30 years-is feasible within the agricultural sector alone. ...
Conserving agricultural water resources is crucial for sustainable development, yet, developing effective policies is challenging due to limited site-specific information. We present a framework combining economic models and remote-sensing data to spatially explicitly assess willingness-to-accept payments to irrigators and unit water-saving costs. Applied to three major tributary watersheds of the Great Salt Lake, this framework identifies areas with the highest conservation potential and cost-effectiveness. We find that an annual water conservation goal of 581 million m³, necessary to restore the lake within 30 years, can be met by fallowing irrigated alfalfa fields. With 95% certainty, this goal would be fully achieved with annual payments of US376 million under county-level payments, or at least 84% achieved with US$341 million under watershed-level payments. This framework can be applied to explore policy priorities and the economic viability of land-based natural resource protection, informing funding decisions and achieving conservation goals in various contexts.
... Across the globe, saline lakes and their peripheral wetlands are rapidly being lost due to water diversions, prolonged droughts, and rising temperatures (Wurtsbaugh et al., 2017). Because they often occur in already waterstressed regions, saline lakes provide rare concentrations of water in otherwise arid landscapes, and their declines have outsized effects on the health of species reliant on these ecosystems (Moulton et al., 2018;North American Bird Conservation and Initiative, 2022;Saccò et al., 2021). ...
... Colonial waterbirds that rely on saline lake ecosystems are particularly at risk of population declines as saline lakes shrink. Many of these species are welladapted to saline habitats, and rely on saline lakes and their peripheral wetlands as stopover, breeding, and foraging sites (Wurtsbaugh et al., 2017;Sacco et al., 2021). Globally, shrinking saline lakes have been tied to population declines or local extirpation of numerous colonial avian species, including greater flamingos (Phoenicopterus roseus) in Iran's Lake Urmia (Sima et al., 2021), and at least 10 species in central Asia's Aral Sea (Joger et al., 2012). ...
... Great Salt Lake is the largest saline lake in North America, and its location in the arid Great Basin, Utah, makes it an irreplaceable resource for migrating and breeding birds in the western hemisphere (Wurtsbaugh et al., 2017). The lake and peripheral wetlands harbor large invertebrate and fish populations that feed up to 10 million birds annually (Baxter & Butler, 2020). ...
Shrinking saline lakes provide irreplaceable habitat for waterbird species globally. Disentangling the effects of wetland habitat loss from other drivers of waterbird population dynamics is critical for protecting these species in the face of unprecedented changes to saline lake ecosystems, ideally through decision‐making frameworks that identify effective management options and their potential outcomes. Here, we develop a framework to assess the effects of hypothesized population drivers and identify potential future outcomes of plausible management scenarios on a saline lake‐reliant waterbird species. We use 36 years of monitoring data to quantify the effects of environmental conditions on the population size of a regionally important breeding colony of American white pelicans (Pelecanus erythrorhynchos) at Great Salt Lake, Utah, US, then forecast colony abundance under various management scenarios. We found that low lake levels, which allow terrestrial predators access to the colony, are probable drivers of recent colony declines. Without local management efforts, we predicted colony abundance could likely decline approximately 37.3% by 2040, although recent colony observations suggest population declines may be more extreme than predicted. Results from our population projection scenarios suggested that proactive approaches to preventing predator colony access and reversing saline lake declines are crucial for the persistence of the Great Salt Lake pelican colony. Increasing wetland habitat and preventing predator access to the colony together provided the most effective protection, increasing abundance 145.4% above projections where no management actions are taken, according to our population projection scenarios. Given the importance of water levels to the persistence of island‐nesting colonial species, proactive approaches to reversing saline lake declines could likely benefit pelicans as well as other avian species reliant on these unique ecosystems.
... Saline lakes globally account for 44% of the volume and 23% of the surface area of lakes 13 and are frequently desiccating due to consumptive water uses. 14 As salinity is not strongly correlated with dry-flux rates, 11 it is likely that desiccating saline lake beds feature GHG fluxes as high as those reported from freshwater systems. However, as littoral saline lake sediments are often chronically desiccated (i.e., sediments are not seasonally inundated), seasonal changes in temperature and moisture, the most important drivers of dry fluxes, 11 , likely produce intraannual emissions patterns that would not be captured by studies focusing on brief or intermittent periods of desiccation. ...
... One particularly iconic saline lakes is Great Salt Lake (GSL; Figure 1), a hypersaline lake in Utah (United States), and the eighth-largest saline lake in the world. 14 Since the late 1800s, water diversions in the GSL catchment (predominantly associated with local agricultural activities 15 ) have substantially lowered its water levels, exposing roughly half of the lake bed to the atmosphere by the time of our study. 14,16 The lake is on course to become fully desiccated by as early as 2030 without immediate measures being implemented to halt its desiccation. ...
... 14 Since the late 1800s, water diversions in the GSL catchment (predominantly associated with local agricultural activities 15 ) have substantially lowered its water levels, exposing roughly half of the lake bed to the atmosphere by the time of our study. 14,16 The lake is on course to become fully desiccated by as early as 2030 without immediate measures being implemented to halt its desiccation. 17 To date, the alarm being raised around this issue has focused on the social, economic, and environmental consequences of losing the lake but not on the impacts of generating new GHG emissions to the atmosphere. ...
... Its causes are well understood and its implications in terms of environmental degradation, loss of biodiversity, destruction of livelihoods, and human health well documented (Glantz et al., 1993;Peterson, 2019). Yet, many terminal lakes of endorheic basins worldwide have experienced, or are currently experiencing, a similar fate (Wurtsbaugh et al., 2017;Hassani et al., 2020), amid a general feeling of hopelessness and the display of catalogues of insufficient or flawed conventional measures. These include prominent lakes such as the Dead Sea in Jordan/Israel, Utah Lake or the Salton Sea in the US, Lake Poopo in Bolivia, or Poyang Lake in China. ...
... Considerable work has been devoted to documenting the shrinking of lakes and its dire consequences (Wurtsbaugh et al., 2017). Although, largely limited to distinguishing between natural/climatic and anthropogenic/human use factors, research on the underlying causes has identified an 'Aral Sea syndrome ' (AghaKouchak et al., 2015) that includes 'technological optimism' (Wine & Laronne, 2020), upstream competition, water resource overdevelopment and the expansion of irrigated agriculture expansion, 'the primary driver of desiccation of global lakes' according to Wine and Laronne (2020). ...
... Like the GSL, terminal saline lakes worldwide have been impacted by the effects of climate change and human activities including unsustainable irrigation practices. (9,10) The Aral Sea saw a loss of 90% of its water volume from the 1960's to the 2000's, (11) leading to devastating health and economic impacts. (12,13) Other examples include Owens Lake and the Salton Sea in California. ...
... This study shows that GSLD and regional dusts contribute to PM 2.5 and PM 10 based on current EPA and Utah Department of Air Quality standards. If the GSL were to continue to lose water, additional sediments would become exposed, potentially increasing dust burden in the local airshed.(51) ...
Background: Climatological shifts and human activities have decimated lakes worldwide. Water in the Great Salt Lake, Utah, USA is at near record lows which has increased risks for exposure to windblown dust from dried lakebed sediments. Formal studies evaluating the health effects of inhaled Great Salt Lake dust (GSLD) have not been performed despite the belief that the dust is harmful. The objectives of this study were to illustrate windblown dust events, assess the impact of inhaled dust on the lungs, and to identify mechanisms that could contribute to the effects of GSLD in the lungs.
Results: An animation, hourly particle and meteorological data, and images illustrate the impact of dust events on the Salt Lake Valley/Wasatch front airshed. Great Salt Lake sediment and PM2.5 contained metals, lipopolysaccharides, natural and anthropogenic chemicals, and bacteria. Inhalation and oropharyngeal delivery of PM2.5 triggered neutrophilia and the expression of mRNA for Il6, Cxcl1, Cxcl2, and Muc5ac in mouse lungs, was more potent than coal fly ash (CFA) PM2.5, and more cytotoxic to human airway epithelial cells (HBEC3-KT) in vitro. Induction of IL6 and IL8 was replicated in vitro using HBEC3-KT and THP-1 cells. For HBEC3-KT cells, IL6 induction was variably attenuated by EGTA/ruthenium red, the TLR4 inhibitor TAK-242, and deferoxamine, while IL8 was attenuated by EGTA/ruthenium red. Inhibition of mRNA induction by EGTA/ruthenium red suggested roles for transition metals, calcium, and calcium channels as mediators of the responses. Like CFA, GSLD and a similar dust from the Salton Sea in California, activated human TRPA1, M8, and V1. However, only inhibition of TRPV1, TRPV3, and a combination of both channels impacted cytokine mRNA induction in HBEC3-KT cells. Responses of THP1 cells were partially mediated by TLR4 as opposed to TRP channels and mice expressing a “humanized” form of TRPV1 exhibited greater neutrophilia when exposed to GSLD via inhalation.
Conclusions: This study suggests that windblown dust from Great Salt Lake and similar lake sediments could pose a risk to humans via mechanisms including the activation of TRPV1/V3, TLR4, and possibly oxidative stress.
... Additionally, warming not only affects evaporation from the lake, but also streamflow via decreasing runoff efficiency. It has been suggested that upstream water diversions for agricultural, industrial, and residential purposes have played a leading role in the decline (Great Salt Lake Policy Assessment, 2023; Wurtsbaugh et al., 2017). However the role of different contributors to declining streamflow are complicated by the fact that warming induced evaporation would also reduce streamflow. ...
The Great Salt Lake reached the lowest water volume in its entire 170+ year record in 2022. To explain this record low we develop and apply a lake mass‐balance model and perform four simulations: one where all input and output variables are fixed to their mid‐20th century average resulting in an equilibrium lake volume, and three others where one of the input variables (precipitation or streamflow) or the output variable (evaporation) follows observations while the other two are fixed to their mid‐20th century average. Results show anomalously low streamflow accounting for the largest proportion of the lake volume departure from the equilibrium state by 2022, resulting in about three times the additional water loss over 1950–2022 as increasing evaporation, which played the second largest role. Precipitation changes played a minimal role. Though streamflow had a greater effect, the lake would not have reached the record low volume without increasing evaporation.
... Crucial factors include the dose and duration of exposure and the presence/absence of specific chemicals (e.g., metals, PAHs, etc.), pathogens, and physical characteristics. While the adverse effects and mechanisms associated with GSLD inhalation are unknown, studies of similar lakebed dusts (e.g., dust from the Salton Sea and Owens Lake in California, Lake Urmia, the Aral Sea and others) imply the potential for both acute and long-term adverse health effects including respiratory effects such as asthma-like hypersensitivity, increased rates of infections and other malaise [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53]. ...
Background
Climate change and human activities have caused the drying of marine environments around the world. An example is the Great Salt Lake in Utah, USA which is at a near record low water level. Adverse health effects have been associated with exposure to windblown dust originating from dried lakebed sediments, but mechanistic studies evaluating the health effects of these dusts are limited.
Results
Monitoring data and images highlight the impact of local crustal and Great Salt Lake sediment dusts on the Salt Lake Valley/Wasatch front airshed. Great Salt Lake sediment and derived PM< 3.1 (quasi-PM2.5 or qPM2.5) contained metals/salts, natural and anthropogenic chemicals, and bacteria. Exposure of mice via inhalation and oropharyngeal aspiration caused neutrophilia, increased expression of mRNA for Il6, Cxcl1, Cxcl2, and Muc5ac in the lungs, and increased IL6 and CXCL1 in bronchoalveolar lavage. Inhaled GSLD qPM2.5 caused a greater neutrophilic response than coal fly ash qPM2.5 and was more cytotoxic to human airway epithelial cells (HBEC3-KT) in vitro. Pro-inflammatory biomarker mRNA induction was replicated in vitro using HBEC3-KT and differentiated monocyte-derived (macrophage-like) THP-1 cells. In HBEC3-KT cells, IL6 and IL8 (the human analogue of Cxcl1 and Cxcl2) mRNA induction was attenuated by ethylene glycol-bis(β-aminoethyl ether)-N, N,N′,N’-tetraacetic acid (EGTA) and ruthenium red (RR) co-treatment, and by TRPV1 and TRPV3 antagonists, but less by the Toll-like Receptor-4 (TLR4) inhibitor TAK-242 and deferoxamine. Accordingly, GSLD qPM2.5 activated human TRPV1 as well as other human TRP channels. Dust from the Salton Sea playa (SSD qPM2.5) also stimulated IL6 and IL8 mRNA expression and activated TRPV1 in vitro, but inhibition by TRPV1 and V3 antagonists was dose dependent. Alternatively, responses of THP-1 cells to the Great Salt Lake and Salton Sea dusts were partially mediated by TLR4 as opposed to TRPV1. Finally, “humanized” Trpv1N606D mice exhibited greater neutrophilia than C57Bl/6 mice following GSLD qPM2.5 inhalation.
Conclusions
Dust from the GSL playa and similar dried lakebeds may affect human respiratory health via activation of TRPV1, TRPV3, TLR4, and oxidative stress.
... The mineral composition of surrounding soils is crucial for the lake's alkalinity, with sodic soils contributing Na⁺ and CO₃ 2 ⁻ ions through weathering and erosion [19,23,24]. Sodic soils, which are alkaline and rich in Na⁺ and CO₃ 2 ⁻, affect soda-saline lake's chemical properties [24,25]. The geological formations beneath lake basins play a key role in influencing lake water chemistry, which can vary based on the area's geological characteristics [26][27][28]. ...
... Although beautiful, dry salt lakes produce mineral-rich dust through erosion (Klose et al., 2019;Prospero, 2002), which is detrimental to air quality and human health and a major source of uncertainty in modelling climate sensitivity (Kok et al., 2023). Changes in water use policy and climate are exacerbating these problems worldwide, as marginal saline lakes like the Dead Sea or Great Salt Lake are receding, leaving salt flats behind (Wurtsbaugh et al., 2017). In this context, Owens Lake is seen as a case study for developing remediation strategy and dust control at dry lakes, given its situation as a man-made dry lake that was at one time the largest source of hazardous aerosols (PM-10) in the United States (Bertenthal, 2021). ...
Geological materials are often seen as the antithesis of soft; rocks are hard. However, during the formation of minerals and rocks, all the systems we shall discuss, indeed geological materials in general, pass through a stage where they are soft. This occurs either because they are at a high temperature -- igneous or metamorphic rock -- or because they are at a lower temperature but in the presence of water -- sedimentary rock. For this reason it is useful to introduce soft-matter concepts into the geological domain. There is a universality in the diverse instances of geological patterns that may be appreciated by looking at the common aspect in their formation of having passed through a stage as soft matter.
... Aquatic ecosystems, irrespective of their type (e.g., inland wetlands, natural mountain lakes, and seasonal and permanent rivers), play a crucial role in hydrological and biogeochemical cycles (Pekel et al. 2016;Pi et al. 2022;Rodell et al. 2018). This is because they underpin the functioning and various services of other terrestrial ecosystems (Rodell et al. 2018;Wurtsbaugh et al. 2017). Many studies have examined the effects of both climate change and human activities on these vital arteries of the planet (Karim et al. 2023;Sarkar et al. 2020). ...
Khuzestan province in Iran is facing serious water challenges due to the development of agriculture, industries and urbanization. These challenges differ between surface water (SW) and groundwater (GW) resources. Failure to pay attention to water tensions has exacerbated environmental and social crises, therefore, it is very important to investigate the impact of climatic and human factors on Khuzestan’s water resources. This study explored the effects of climate change and human activities on the water resources of Khuzestan province by collecting and analyzing comprehensive data on Precipitation (P), Evaporation (E), Land Surface Temperature (LST), Evapotranspiration (ET), SW, and groundwater storage (GWS) using remote sensing data, meteorological data, and CMIP6 reports. Pearson’s correlation coefficients were used to examine the effects of parameters on water resources. The findings of the research show trend in LST (0.04 °C/yr), P (1.04 mm/yr) and E (1.1 mm/yr) during the period 2000–2021 and GWS (− 23.02 mm/yr) during the period 2003–2021. The highest water stress was observed in 2008 and 2010. Among climatic factors, GWS exhibited a significant positive relationship with ET (R²: 0.5, p-value < 0.05) and a significant negative relationship with LST (R²: − 0.6, p-value < 0.05). These significant relationships were confirmed by Pearson’s correlation coefficients at the 95% confidence level. These results highlight the necessity of paying more attention to the consumption of groundwater and planning for better management. It is suggested that the processes of population spatial changes and the impact of climatic parameters on water resources be further investigated to identify the influencing factors over both long and short-term periods.
Graphical abstract
... Currently, our knowledge of microbial distribution patterns and biogeochemical functions is limited between sediment and water columns in saline lakes (with salinity above that of seawater) [9,10]. Saline lakes are widespread worldwide and account for almost half of the total area of all lakes on Earth [11,12]. Therefore, studying the differences in microbial community structures and metabolic functions between sediment and water of saline lakes are crucial to improve our understanding of microbial ecology in lake ecosystems. ...
Climate change and human activities have led to frequent exchanges of sedimentary and aquatic microorganisms in lakes. However, the ability of these microorganisms to survive in their respective habitats between saline lake sediment and water remains unclear. In this study, we investigated microbial sources and community composition and metabolic functions in sediments and water in Yuncheng Salt Lake using a combination of source tracking and Illumina MiSeq sequencing. The results showed that 0.10–8.47% of the microbial communities in the sediment came from the corresponding water bodies, while 0.12–10.78% of the sedimentary microorganisms contributed to the aquatic microbial populations, and the microbial contributions depended on the salinity difference between sediment and water. Habitat heterogeneity and salinity variations led to the differences in microbial diversity, community composition, and assembly between sediment and water communities. The assembly of sedimentary communities was mainly controlled by stochastic processes (>59%), whereas the assembly of aquatic communities was mainly controlled by deterministic processes (>88%). Furthermore, sediments had a higher potential for metabolic pathways related to specific biogeochemical functions than lake water. These results provide insights into the survival ability of microorganisms and the mechanisms of microbial community assembly under frequent exchange conditions in saline lakes.
... A combined increase in evaporation with a decrease in precipitation can significantly reduce the quantity of water within a lake and in turn negatively affect its ecosystem functioning (Finger Higgens et al. 2019;Tal 2019). For instance, depleting water levels can limit access to drinking water, food transportation, fisheries, and energy generation, significantly influencing the economy particularly of regions that highly depend on the ecosystem services that lakes provide (Bergmann-Baker et al. 1995;Gronewold et al. 2013;Gownaris et al. 2017;Wurtsbaugh et al. 2017;Yao et al. 2023). ...
Lakes represent a vital source of freshwater, accounting for 87% of the Earth’s accessible surface freshwater resources and providing a range of ecosystem services, including water for human consumption. As climate change continues to unfold, understanding the potential evaporative water losses from lakes becomes crucial for effective water management strategies. Here we investigate the impacts of climate change on the evaporation rates of 23 European lakes and reservoirs of varying size during the warm season (July–September). To assess the evaporation trends, we employ a 12-member ensemble of model projections, utilizing three one-dimensional process-based lake models. These lake models were driven by bias-corrected climate simulations from four General Circulation Models (GCMs), considering both a historical (1970–2005) and future (2006–2099) period. Our findings reveal a consistent projection of increased warm-season evaporation across all lakes this century, though the magnitude varies depending on specific factors. By the end of this century (2070–2099), we estimate a 21%, 30% and 42% average increase in evaporation rates in the studied European lakes under RCP (Representative Concentration Pathway) 2.6, 6.0 and 8.5, respectively. Moreover, future projections of the relationship between precipitation (P) and evaporation (E) in the studied lakes, suggest that P-E will decrease this century, likely leading to a deficit in the availability of surface water. The projected increases in evaporation rates underscore the significance of adapting strategic management approaches for European lakes to cope with the far-reaching consequences of climate change.
... Artemia is highly plastic across morphometric and morphological traits in both natural and laboratory conditions [6][7][8][9][10][11], and tends to exhibit accelerated molecular evolution very likely due to the mutagenic effect associated with ionic strength variance [12] and other stringent ecological conditions [13], combined with natural population expansion and contraction cycles. Additionally, natural salt lake ionic compositions, temperatures, and salinity heterogeneity, further affected by climatic changes and human perturbations [14][15], have left mitogenomic signatures in Artemia bisexual species [1], which are also re ected in private mitochondrial haplotypes [4,5,[16][17][18][19][20][21][22][23]. There is no classic "identi cation key" for the genus Artemia and taxonomic delimitation of sexual species and parthenogenetic lineages has been limited to reproductive mode [4,24], geographical distribution [25,26], and molecular markers [4,5,18,2127]. ...
The brine shrimp Artemia , a crustacean adapted to the extreme conditions of hypersaline environments, comprises nine regionally distributed sexual species scattered (island-like) over heterogeneous environments and asexual (parthenogenetic) lineages with different ploidies. Such sexual and asexual interaction within the genus raises questions regarding the origin and time of divergence of both sexual species and asexual lineages, including the persistence of the latter over time, a problem not yet clarified by the use of single mitochondrial and nuclear markers. Based on the complete mitochondrial genome of all species and parthenogenetic lineages, this article first describes the mitogenomic characteristics (nucleotide compositions, genome mapping, codon usage, and tRNA secondary structure) of sexual species and asexual types and, secondly, it provides a comprehensive updated phylogenetic analysis. Molecular dating and geographical evidence suggest that the ancestral. Artemia taxon originated in the Mediterranean area or South America in ca . 33.97 Mya during the Paleogene Period. The mitogenomic comparisons suggest that the common ancestor of diploid and triploid parthenogenetic lineages ( ca . 0.07 Mya) originated from a historical ancestor ( ca. 0.61 Mya) in the Late Pleistocene. Additionally, the common ancestor of tetraploid and pentaploid parthenogenetic lineages ( ca. 0.05 Mya) diverged from a historical maternal ancestor with A. sinica ( ca . 0.96 Mya) in the early Pleistocene. The parthenogenetic lineages do not share a direct ancestor with any sexual species. The Asian clade ancestor diverged more recently ( ca. 14.27 Mya, Middle Miocene). The mitogenomic characteristics, maternal phylogenetic tree, and especially divergence time prove that A. monica and A. franciscana ( time of divergence ) are two biological species.
... Similarly, other lakes, such as Bakhtegan [5], and Hamun [6][7][8], have experienced the same conditions due to climate change and anthropogenic activities [1,[9][10][11][12]). Furthermore, half of Iranians live close to the lakes' basins (According to estimation from dataset developed by Schiavina et al. [13]), which puts more pressure on local resources alongside climate change impacts [14]. ...
... Lakes are an essential component of terrestrial aquatic ecosystems and play a critical role in regulating regional climate [51]. Lake desiccation has been observed in recent years due to reduced precipitation caused by climate change or human activities [56,57]. The salinity and concentration of inorganic ions increase, and the freshwater lake gradually transforms into a saline lake (Geng and Hu, [18]). ...
Saline lakes, characterized by high salinity and limited nutrient availability, provide an ideal environment for studying extreme halophiles and their biogeochemical processes. The present study examined prokaryotic microbial communities and their ecological functions in lentic sediments (with the salinity gradient and time series) using 16S rRNA amplicon sequencing and a metagenomic approach. Our findings revealed a negative correlation between microbial diversity and salinity. The notable predominance of Archaea in high-salinity lakes signified a considerable alteration in the composition of the microbial community. The results indicate that elevated salinity promotes homogeneous selection pressures, causing substantial alterations in microbial diversity and community structure, and simultaneously hindering interactions among microorganisms. This results in a notable decrease in the complexity of microbial ecological networks, ultimately influencing the overall ecological functional responses of microbial communities such as carbon fixation, sulfur, and nitrogen metabolism. Overall, our findings reveal salinity drives a notable predominance of Archaea, selects for species adapted to extreme conditions, and decreases microbial community complexity within saline lake ecosystems.
... This Lake is an endorheic or terminal lake. Prime examples of drying terminal lakes in endorheic basins include the Aral Sea in Central Asia [9] Walker Lake and Great Salt Lake in the US [15] and Lake Urmia in northwestern Iran [7]. Lake Urmia exhibits high salinity due to the lake's water loss solely through evaporation. ...
In the late 1990s, Lake Urmia, located in northwestern Iran, was the largest saltwater lake in the Middle East. However, it has experienced severe shrinkage over the years, culminating in its division into two separate sections by 2008, with long-term consequences still uncertain. This study examines the changes in Lake Urmia from 2010 to 2020, focusing on various drought indicators such as Temperature Condition Index (TCI), Normalized Difference Vegetation Index (NDVI), Vegetation Condition Index (VCI), Palmer Drought Severity Index (PDSI), and Standardized Precipitation Index (SPI). We monitored evolving drought patterns in the lake's watershed and applied machine learning techniques to classify agricultural lands within the basin, assessing their transformations over time. Additionally, we analyzed the distribution of the UV Aerosol Index to understand dust storm occurrences caused by the exposed lakebed due to prolonged droughts. Our study presents statistical findings from modeling the interactions among these indicators, aiming to deepen our understanding of the drought impacts on Lake Urmia and its surrounding area. The research highlights the urgent need for measures to preserve the region's ecological balance. Given Lake Urmia's significance to neighboring countries and its historical and ecological value, international cooperation is essential. We employed Geographic Information Systems (GIS) and Google Earth Engine to enhance the clarity of our findings, providing a comprehensive view of the environmental changes. Our analysis of key indicators-VCI, PDSI, TCI, and SPI-reveals significant relationships that offer insights into the interplay between vegetation health and climatic conditions, which are crucial for effective resource management.
... Over recent decades, increases in lake salinity have occurred in lakes around the world, such as the Aral Sea in Central Asia [65], Urmia Lake [24], Great Salt Lake in the United States [66], and Daihai Lake in China [67]. Some lakes have shown decreased salinity, such as lakes on the Tibetan Plateau [5,55]. ...
Salinity is an essential parameter for evaluating water quality and plays a crucial role in maintaining the stability of lake ecosystems, particularly in arid and semi-arid climates. Salinity responds to changes in climate and human activity, with significant impacts on water quality and ecosystem services. In this study, Sentinel-2A/B Multi-Spectral Instrument (MSI) images and quasi-synchronous field data were utilized to estimate lake salinity using machine learning approaches (i.e., XGB, CNN, DNN, and RFR). Atmospheric correction for MSI images was tested using six processors (ACOLITE, C2RCC, POLYMER, MUMM, iCOR, and Sen2Cor). The most accurate model and atmospheric correction method were found to be the extreme gradient boosting tree combined with the ACOLITE correction algorithm. These were used to develop a salinity model (N = 70, mean absolute percentage error = 9.95%) and applied to eight lakes in Inner Mongolia from 2016 to 2024. Seasonal and interannual variations were explored, along with an examination of potential drivers of salinity changes over time. Average salinities in the autumn and spring were higher than in the summer. The highest salinities were observed in the lake centers and tended to be consistent and homogeneous. Interannual trends in salinity were evident in several lakes, influenced by evaporation and precipitation. Climate factors were the primary drivers of interannual salinity trends in most lakes.
... Great Salt Lake has been shrinking as water diversions for consumptive uses have increased (Null and Wurtsbaugh, 2020), a fate similar to other terminal lakes globally (Wurtsbaugh et al., 2017). Climate change pressures have reduced inflows, exacerbating the water loss (Wang et al., 2018;Meng, 2019;Baxter and Butler, 2020;Hassan et al., 2023). ...
The natural system at Great Salt Lake, Utah, USA was augmented by the construction of a rock-filled railroad causeway in 1960, creating two lakes at one site. The north arm is sequestered from the mountain snowmelt inputs and thus became saturated with salts (250-340 g/L). The south arm is a flourishing ecosystem with moderate salinity (90-190 g/L) and a significant body of water for ten million birds on the avian flyways of the western US who engorge themselves on the large biomass of brine flies and shrimp. The sediments around the lake shores include calcium carbonate oolitic sand and clay, and further away from the saltwater margins, a zone with less saline soil. Here a small number of plants can thrive, including Salicornia and Sueda species. At the north arm at Rozel Point, halite crystals precipitate in the salt-saturated lake water, calcium sulfate precipitates to form gypsum crystals embedded in the clay, and high molecular weight asphalt seeps from the ground. It is an ecosystem with gradients and extremes, and fungi are up to the challenge. We have collected data on Great Salt Lake fungi from a variety of studies and present them here in a spatial survey. Combining knowledge of cultivation studies as well as environmental DNA work, we discuss the genera prevalent in and around this unique ecosystem. A wide diversity of taxa were found in multiple microniches of the lake, suggesting significant roles for these genera: Acremonium, Alternaria , Aspergillus , Cladosporium , Clydae , Coniochaeta , Cryptococcus , Malassezia , Nectria , Penicillium , Powellomyces , Rhizophlyctis , and Wallemia . Considering the species present and the features of Great Salt Lake as a terminal basin, we discuss of the possible roles of the fungi. These include not only nutrient cycling, toxin mediation, and predation for the ecosystem, but also roles that would enable other life to thrive in the water and on the shore. Many genera that we discovered may help other organisms in alleviating salinity stress, promoting growth, or affording protection from dehydration. The diverse taxa of Great Salt Lake fungi provide important benefits for the ecosystem.
... Liu et al., 2021). Conversely, continued lake level decline in some areas can trigger regional water scarcity, international conflicts, etc (Pi et al., 2022;Rodell et al., 2018;Wurtsbaugh et al., 2017). These unprecedented lake-level changes are projected to continue, and even accelerate in the future. ...
Lake level changes are critical indicators of hydrological balance and climate change, yet long‐term monthly lake level reconstruction is challenging with incomplete or short‐term data. Data‐driven models, while promising, struggle with nonstationary lake level changes and complex dependencies on meteorological factors, limiting their applicability. Here, we introduce the Hydroformer, a frequency domain enhanced multi‐attention Transformer model designed for monthly lake level reconstruction, utilizing reanalysis data. This model features two innovative mechanisms: (a) Frequency‐Enhanced Attention (FEA) for capturing long‐term temporal dependence, and (b) Causality‐based Cross‐dimensional Attention (CCA) to elucidate how specific meteorological factors influence lake level. Seasonal and trend patterns of catchment meteorological factors and lake level are initially identified by a time series decomposition block, then independently learned and refined within the model. Tested across 50 lakes globally, the Hydroformer excelled in reconstruction periods ranging from half to three times the training‐test length. The model exhibited good performance even when training data missing rates were below 50%, particularly in lakes with significant seasonal fluctuations. The Hydroformer demonstrated robust generalization across lakes of varying sizes, from 10.11 to 18,135 km², with median values for R², MAE, MSE, and RMSE at 0.813, 0.313, 0.215, and 0.4, respectively. Furthermore, the Hydroformer outperformed data‐driven models, improving MSE by 29.2% and MAE by 24.4% compared to the next best model, the FEDformer. Our method proposes a novel approach for reconstructing long‐term water level changes and managing lake resources under climate change.
... Owing to consumptive water use and increased frequency and severity of droughts in arid and semiarid regions with climate change, some sandy lakes are shrinking at alarming rates, with subsequent changes in chemical (e.g., salinization) and biological (e.g., reduced biodiversity) characteristics, threatening the ecosystem services of sandy lakes and even leading to the disappearance of lakes, such as the Lop Nor and the Aral Sea [2][3][4] . Studying the structure and dynamics of lake ecosystems under multiple stressors, including warming, anthropogenic nutrient enrichment, and shrinkage, has increased fundamental understanding of how global change alters lake ecosystems, as well as how to save shrinking sandy lakes 1,5 . Many lake ecosystems experiencing warming reach a critical state in which slight increases in nutrient levels can trigger drastic ecosystem changes 6,7 . ...
Stressors endanger lake ecosystem biodiversity and networks, especially in sandy lakes of arid/semiarid regions, where impacts are poorly understood. Here, we investigate the changes in multitrophic biodiversity and ecological networks under increasing stress (temperature, nutrients, lake area) by using sedimentary DNA from a shrinking sandy lake in China over nearly 100 years. With increasing stress, species richness and stability increased, whereas species turnover decreased. Species synchronism decreased at high-trophic levels but increased at low-trophic levels. Empirical dynamic modeling showed network connectance and strength of species interactions decreased–increased–decreased over time, signaling a potential adaption–resistance–degradation change in ecosystem responses with increasing stress. Models also indicated network structure primarily depended on direct effects of nutrients and temperature under low/medium stress and on a diversity-mediated pathway under high stress. Thus, maintaining ecological network structure complexity and integrity in lake ecosystems is essential to mitigate the effects of multiple stresses.
... Rientjes et al., 2011;Vanderkelen et al., 2018;125 Wale et al., 2009) have estimated the water balance under the assumption that net water withdrawals are negligible. However, this may not be valid in the future due to changing climate conditions and increased competition over water use, which could result in a decrease in upstream inflow (Wurtsbaugh et al., 2017). For example, in Lake Urmia, Schulz et al. (2020) showed that net withdrawals for irrigation exacerbate the decline in storage caused by climate change. ...
This study estimates the water balance of a poorly-gauged large lake using an integrated modeling framework that accounts for natural hydrologic processes and net irrigation consumption. The modeling framework was tested on Lake Titicaca, located in the Altiplano of the Central Andes of South America. We used a conceptual approach based on the Water Evaluation and Planning System (WEAP) platform at a daily time step for the period 1982–2016, considering the following terms of the water balance: upstream inflows, direct precipitation and evaporation over the lake, and downstream outflows. To estimate upstream inflows, we evaluated the impact of snow and ice processes and net irrigation withdrawals on predicted streamflow and lake water levels. We also evaluated the role of heat storage change in evaporation from the lake. The results showed that the proposed modeling framework makes it possible to simulate lake water levels ranging from 3,808 to 3,812 m a.s.l. with good accuracy (RMSE = 0.32 m d-1) under a wide range of long-term hydroclimatic conditions. The estimated water balance of Lake Titicaca shows that upstream inflows account for 56 % (958 mm yr-1) and direct precipitation over the lake for 44 % (744 mm yr-1) of the total inflows, while 93 % (1,616 mm yr-1) of total outflows are due to evaporation and the remaining 7 % (121 mm yr-1) to downstream outflows. The water balance closure has an error of -15 mm yr-1. At the scale of the Lake Titicaca catchment, snow and ice processes, and net irrigation withdrawals had minimal impact on predicted upstream inflow. Thus, Lake Titicaca is primarily driven by variations in precipitation and high evaporation rates. The proposed modeling framework could be replicated in other poorly-gauged large lakes, as we demonstrate that a simple representation of natural hydrologic processes and irrigation enables accurate simulation of water levels.
İnsanın en temel ihtiyacı sudur. Dünya nüfusunun artması ve küresel iklim değişikliği nedeniyle dünya zorlu su yönetimi sorunlarıyla karşı karşıyadır. Kuruyan göllerin yanı sıra birçok gölde kuruma tehlikesi altındadır. Göller iklim değişikliklerinden en çok etkilenebilecek doğal kaynaklardır. Göllerdeki kurumanın nedenlerini sadece doğal değişkenlik ve iklim değişkenliğine bağlamak doğru değildir. Son zamanlarda Eğirdir göl havzası suyu çok fazla çekilmiş, göl özel hükümlerinde bahsedilen limitin de altına düşmüştür. Bu durumun basın yayın organlarında geniş yer bulması, ildeki kamu yetkilileri tarafından geniş çaplı araştırmalara yer verilmek istenmesi bu bilimsel çalışmanın yapılmasına dayanak oluşturmuştur. Bu doğrultuda il genelinde yayınlanan raporlar, süreli yayınlar, internet kaynakları ve tezler gibi ikincil kaynaklar kullanılarak literatür oluşturulmuştur. Elde edilen bulgulara göre gölün ciddi derecede kuraklık tehlikesi altında görülmektedir. Bunun için ildeki kamu kurum ve kuruluşların koordineli çalışarak, su arzını arttırıcı, talebini azaltıcı tedbirler alması, halkın bu konuda eğitilerek ve yasalarla su kullanımı sınırının çizilmesi, özellikle tarımsal alanda su israfını önleyici tedbirlerin alınması gerekmektedir.
Cases of water level decrease and lake shrinkage have been found in almost every freshwater ecosystem. In Indonesia, Laut Tawar Lake in Upland Gayo, Indonesia, allegedly has experienced the shrinkage of surface area and water level decrease. This study aimed to identify the shrinkage area and water level decrease, and its driving force. We make use of the remote sensing data, which is processed by ArcMap Geographic Information System to capture the lake shrinkage and the land use dynamic surrounding the ecosystem. Land cover were captured by interpreting Landsat data, which we further calibrated and validated with approximately 119 ground checkpoints on the lakeside. For the water level analysis, we conducted field measurements of the water line from 41 measurement points surrounding the lake area. To analyze rainfall and temperature, we use Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) data. Our study found approximately 2.4 percent or equal to 1.4 km ² of lake shrinkage in 35 years. Water level decrease occurs for 0.6 m and 1.3 m in 2022 and 2023, respectively. The shrinking was mainly caused by reclamation and sedimentation, while the water level decrease was mainly triggered by a massive reduction of water flow from rivers which reduced from 40 to 14 streams, accounting for 65% from previous years. These events were affected by land use change and temperature increase. This study offers a scientific finding to unravel the allegation of the shrinking of Laut Tawar Lake for lake conservation effort and environmental management in the future. Sustainable lake management was highly advised as part of conserving the study area as the biggest lake in Aceh Province.
Alkaline lakes hold significant biological, environmental, and economic importance, yet research on their deep-time formation remains limited. This study examines the sedimentary and evolutionary processes of the Permian Fengcheng Formation alkaline lake in the Mahu Sag, Junggar Basin, using seismic, well-log, core, mineralogical, and geochemical data. Results indicate that alkaline mineral formation primarily occurred in rift climax systems, where fan delta plains and lacustrine environments coexisted. Nahcolite (NaHCO3) formed as leafy crystals through evaporation on the outer fan margins, with nucleation at the bottom. Trona (Na2CO3·NaHCO3·2H2O) precipitated as raft-shaped crystals from saline water. Dark sediments interbedded with shortite (Ca2Na2(CO3)3) formed in deepwater environments under arid, cold conditions. The rift expansion facilitated evaporite deposition, and hydrothermal fluids contributed alkaline substances. Late Paleozoic glaciation increased chemical weathering, enhancing lake alkalinity, while arid conditions favored evaporite formation. An impermeable basement and semi-enclosed hydrology were critical for alkaline lake development. This study sheds light on the conditions for ancient sodium carbonate evaporite formation and provides insights into the sedimentary evolution of similar tectonic and climatic lake basins, offering a foundation for hydrocarbon exploration.
Grazing experiments were conducted for the zooplankton Artemia franciscana on three of its most common Great Salt Lake (Utah: USA) phytoplankton species (> 80–90% of phytoplankton biovolume: a chlorophyte, Dunaliella viridis; a cyanobacterium, Euhalothece sp., and a bacillariophyte, the pennate diatom Nitzschia epithemioides). For each Artemia developmental stage (nauplii, juveniles and adults), grazing rates (same phytoplankton abundances, temperatures, and salinities) are reported along with grazing preferences for the phytoplankton species in mixes of species pairs and all three species together. Each Artemia developmental stage exhibited different preferences for the phytoplankton species. Preferences measured for each species pair were consistent with preferences when all three species were together and were correlated with the phytoplankton’s survival value for each Artemia developmental stage. Survival values were positively related to the ingestion rate for each phytoplankton species (biovolume/individual/h), likely a function of cell size, and its nutritional quality treated as a function of phytoplankton N:P relative to Artemia developmental stage N:P.
Saline shallow lakes may play an important role in carbon exchange with the atmosphere, but their alteration may change carbon balance and greenhouse gas emissions patterns. This study investigated the relationship between carbon metabolic processes and environmental factors, focusing on alterations in salinity, hydroperiod length, and trophic status. The results revealed that disruptions to natural salinity patterns, driven by hydrological changes and ecological degradation, enhanced carbon greenhouse gas emitting metabolisms. In contrast, well-preserved lakes demonstrated significantly higher carbon retention and climate mitigation capacities (–188 ± 412 g C m⁻² yr⁻¹) compared to lakes with hydrological and trophic disturbances (–30 ± 141 g C m⁻² yr⁻¹). These findings emphasize the relevance of the metabolic activity of saline shallow lakes and highlight the need for targeted management and restoration efforts to maximize their climate regulation potential. The insights gained from this study may also be applicable to similar ecosystems in other regions.
Supplementary Information
The online version contains supplementary material available at 10.1038/s41598-024-79578-7.
Drying of Lake Urmia due to less water entry and evaporation leads to a rise in salt concentration as well as the saline water density. The declining saline water level and rising of its density have the opposite effect on the saltwater intrusion dynamic. In this study, based on the groundwater and lake water level fluctuations and density variation of Lake Urmia over two decades, the saltwater interaction in one of the coastal aquifers has been studied numerically using SEAWAT. The findings of the research have been approved by comparing the model results with the recorded data collected from the observation wells in the studied aquifer. The achieved results showed that in the case of constant lake water density saltwater wedge progresses slightly by the middle of the studied period and then recedes to the lakeside while considering the increasing density of the lake over 27 years showed that the length of the saltwater wedge in the field scale surprisingly has been expanded more than 250% during the shrinking period of the lake with more than 6 m dropping of water level. Overall, considering the behavior of the saltwater intrusion around the coastal area based on our findings would be conducive to the realistic management of the saline lakes and the implementation of any restoration program for drying lakes.
Shallow saline lakes in the La Mancha Húmeda Biosphere Reserve in Central Spain show diverse degrees of cultural and natural eutrophication, prompting urgent conservation measures. This study focuses on 17 representative lakes from the site to assess seasonal nutrient dynamics and their connection to plankton metabolism (photosynthesis and respiration) during two successive hydrological periods. Effect of environmental factors was evaluated on a combination of several response variables, demonstrating that source of the nutrient inputs (ranging from natural to anthropic) had the highest influence on the nutrients stoichiometry and metabolic rates. Regarding the source of eutrophication, the model demonstrated that effects of urban wastewaters exceed that of agricultural runoff, and moreover lead to more prolonged hydroperiods and contributes to desalination. Lakes affected by wastewater inputs or surrounded by volcanic lithology showed phosphorus enrichment in both water and surface sediments. Planktonic respiration rates in these cases closely correlated with photosynthesis, suggesting the utilization of algal-derived dissolved organic matter. Conversely, wastewater-free lakes, mainly fed by runoff, accumulated uncolored, likely recalcitrant dissolved organic carbon (DOC). These lakes exhibited a better-preserved condition, characterized by higher salinity, moderate metabolic rates, and lower production/respiration ratios compared to the previous state, implying a greater dependence on allochthonous organic matter. Enhancement of management strategies, which should consider salinity, volcanic lake vulnerability, and the multifaceted impacts of wastewater, will prove more effective in the conservation and restoration of these unique and fragile ecosystems.
Inland saline lakes play a key role in the global carbon cycle, acting as dynamic zones for atmospheric carbon exchange and storage. Given the global decline of saline lakes and the expected increase of periods of drought in a climate change scenario, changes in their potential capacity to uptake or emit atmospheric carbon are expected. Here, we conducted continuous measurements of CO2 and CH4 fluxes at the ecosystem scale in an endorheic saline lake of the Mediterranean region over nearly 2 years. Our focus was on determining net CO2 and CH4 exchanges with the atmosphere under both dry and flooded conditions, using the eddy covariance (EC) method. We coupled greenhouse gas flux measurements with water storage and analysed meteorological variables like air temperature and radiation, known to influence carbon fluxes in lakes. This extensive data integration enabled the projection of the net carbon flux over time, accounting for both dry and wet conditions on an interannual scale. We found that the system acts as a substantial carbon sink by absorbing atmospheric CO2 under wet conditions. In years with prolonged water storage, it is predicted that the lake's CO2 assimilation capacity can surpass 0.7 kg C m² annually. Conversely, during extended drought years, a reduction in CO2 uptake capacity of more than 80 % is expected. Regarding CH4, we measured uptake rates that exceeded those of well-aerated soils such as forest soils or grasslands, reaching values of 0.2µmol m⁻² s⁻¹. Additionally, we observed that CH4 uptake during dry conditions was nearly double that of wet conditions. However, the absence of continuous data prevented us from correlating CH4 uptake processes with potential environmental predictors. Our study challenges the widespread notion that wetlands are universally greenhouse gas emitters, highlighting the significant role that endorheic saline lakes can play as a natural sink of atmospheric carbon. However, our work also underscores the vulnerability of these ecosystem services in the current climate change scenario, where drought episodes are expected to become more frequent and intense in the coming years.
Study region
375 lakes across the East African Rift System
Study focus
East African Rift System lakes provide a critical region of freshwater biodiversity and support the livelihoods of millions of people. Since 2010, water levels have risen at many Kenyan Rift System lakes flooding settlements, destroying infrastructure and impacting biodiversity, whereas several Ethiopian lakes experienced declining water levels, threatening water availability. However, water storage changes have not been quantified and the drivers of hydrological change have not been assessed on a regional scale. Here, we used satellite Earth observation and open-access data products to quantify changes in lake water volumes, total catchment water storage anomalies and environmental drivers for 375 lakes across the East African Rift System from 2000 to 2023.
New hydrological insights for the region
Water storage increased across central East Africa and declined in the south of the Rift System, with lake surface areas increasing by a total of 71,822 km2 and water volumes increasing by 1375.2 km3. Increasing rainfall (Coef = 1.775, SE = 0.571, p = 0.002) and urban development (Coef = 6.270, SE = 2.260, p = 0.006) caused expanding lake surface areas, whereas population growth within catchments reduced both lake surface areas (Coef = −7.023, SE = 2.210, p = 0.002) and water volumes (Coef = −8.735, SE = 3.578, p = 0.020). Increasing rainfall trends (Coef = 4.454, SE = 1.733, p = 0.020) and the expansion of catchment forest cover (Coef = 11.284, SE = 5.263, p = 0.047) facilitated greater water storage within lake basins. With more extreme wet seasons and longer dry seasons predicted for East Africa under climate change, sustainable catchment management is required to mitigate both future flooding and drought events.
Soil salinization refers to the accumulation of water‐soluble salts in the upper part of the soil profile. Excessive levels of soil salinity affects crop production, soil health, and ecosystem functioning. This phenomenon threatens agriculture, food security, soil stability, and fertility leading to land degradation and loss of essential soil ecosystem services that are fundamental to sustaining life. In this review, we synthesize recent advances in soil salinization at various spatial and temporal scales, ranging from global to core, pore, and molecular scales, offering new insights and presenting our perspective on potential future research directions to address key challenges and open questions related to soil salinization. Globally, we identify significant challenges in understanding soil salinity, which are (a) the considerable uncertainty in estimating the total area of salt‐affected soils, (b) geographical bias in ground‐based measurements of soil salinity, and (c) lack of information and data detailing secondary salinization processes, both in dry‐ and wetlands, particularly concerning responses to climate change. At the core scale, the impact of salt precipitation with evolving porous structure on the evaporative fluxes from porous media is not fully understood. This knowledge is crucial for accurately predicting soil water loss due to evaporation. Additionally, the effects of transport properties of porous media, such as mixed wettability conditions, on the saline water evaporation and the resulting salt precipitation patterns remain unclear. Furthermore, effective continuum equations must be developed to accurately represent experimental data and pore‐scale numerical simulations.
The Aral Sea was once the fourth-largest inland water body in the world. However, the lake rapidly shrank over the past six decades, mainly due to the loss of inflow from one of its tributaries, the Amu Darya River. Lakes and reservoirs are traditionally characterized by static chemical and morphological parameters, leaving untouched a dynamic impact of phytoplankton changes. We used an integrated approach combining traditional microscopy and FlowCam-based imaging flow cytometry to study phytoplankton communities during the 2018 and 2019 expeditions in the Aral Sea remnant lakes system. The residual Aral Sea water bodies experienced different environmental conditions, forming hypersaline South Aral, North Aral Sea that is constantly getting freshwater, and brackish Chernyshev Bay and Tushchybas Lake with 2-8 times amplitude of salinity changes attributed to the variability in the precipitation and periodical influx of freshwater. The salinity fluctuations had an impact on the phytoplankton communities in Chernyshev Bay, making it similar to the phytoplankton of North Aral in 2018 while resembling the hypersaline South Aral phytoplankton assemblages in 2019. Multivariate analysis revealed that salinity, water temperature, ammonium, and nitrates were major contributors to explaining the variance in the sampling data. We conclude that drastic phytoplankton fluctuations occur in the two brackish water bodies in the middle of the former Aral Sea, reflecting changes in salinity.
Hypersaline Great Salt Lake’s (GSL: Utah, USA) pelagic food web is dominated by the herbivore, Artemia franciscana. Artemia demographic responses (survival, developmental transition, and reproduction) to GSL salinities, temperatures, common phytoplankton and yeast, and food levels were examined by factorial experiment. Survival across developmental stages was best at 90 ppt salinity, and decreased as temperature increased. Transition between life stages was best at 45 ppt salinity, and increased as temperature increased. Food was most important with both survival and transitioning responding similarly to food types and increasing with amount of food. Artemia reproduce in two ways (diapausing cysts – oviparity, live young – ovoviviparity): ovoviviparous and total reproduction were greatest at 90 ppt salinity and 20 °C, while oviparous reproduction was weakly affected by salinity and greatest at 20 °C. Oviparity was greatest at low food availability, while ovoviviparity and total reproduction increased with food availability, so reproduction shifted from oviparity to ovoviviparity as food increased. Maternal effects were observed for cyst hatchability, and ovoviviparous nauplii survival and transitioning to the juvenile stage. Combinations of salinity, temperature, food taxa and food amount strongly affect demography, making single factor studies of limited value. Results explain Artemia abundance in different parts of GSL and among years.
In light of the pivotal role of Artemia Leach, 1819 as food in larviculture and fisheries, it becomes imperative to continually reassess its resources and deepen our understanding of its species diversity. Such efforts are essential for the effective management of its commercial exploitation and the promotion of sustainable aquaculture activities. Here we present a comprehensive review of historical documents dating back to the 10th century and contemporary scholarly articles. The findings indicate the existence of 59 sites (natural resources and farming sites) across Iran where Artemia has been recorded. This is a significant increase from the 23 reported in the last checklist in 2016. The data indicate that regional A. urmiana Günther, 1899 occurrences warrant classification as “Critically Endangered” on the “Regional Red List” of Iran. Remarkably, apparently the Bazangan Lake has a natural population of Artemia, probably a consequence of climatic change. We highlight the threat posed to Artemia species diversity by the invasive American brine shrimp A. franciscana Kellogg, 1906, noting its presence in 12 locations compared to 7 in 2016. Preliminary studies suggest that the indigenous parthenogenetic Artemia lineages in Iran exhibit superior production potential when compared to both A. franciscana and the native A. urmiana. In light of these findings, the study recommends prioritizing the utilization of native parthenogenetic Artemia in aquaculture, to conserve Artemia biodiversity.
Lake surface temperatures are projected to increase under climate change, which could trigger shifts in the future distribution of thermally sensitive aquatic species. Of particular concern for lake ecosystems are when temperatures increase outside the range of natural variability, without analogue either today or in the past. However, our knowledge of when such no-analogue conditions will appear remains uncertain. Here, using daily outputs from a large ensemble of SSP3-7.0 Earth system model projections, we show that these conditions will emerge at the surface of many northern lakes under a global warming of 4.0 °C above pre-industrial conditions. No-analogue conditions will occur sooner, under 2.4 °C of warming, at lower latitudes, primarily due to a weaker range of natural variability, which increases the likelihood of the upper natural limit of lake temperature being exceeded. Similar patterns are also projected in subsurface water, with no-analogue conditions occurring first at low latitudes and occurring last, if at all, at higher latitudes. Our study suggests that global warming will induce changes across the water column, particularly at low latitudes, leading to the emergence of unparalleled climates with no modern counterparts, probably affecting their habitability and leading to rearrangements of freshwater habitats this century.
Saline and intermittent inland lakes play a key role in the global carbon cycle, acting as dynamic zones for atmospheric carbon exchange. Given the global decline of saline lakes and the expected increase of periods of drought in a climate change scenario, changes are expected in their potential capacity to uptake or emit atmospheric carbon. In this study, we conducted continuous measurements of CO2 and CH4 fluxes at the ecosystem scale within a saline endorheic lake of the Mediterranean region over nearly 2 years. Our focus was on determining net CO2 and CH4 exchanges with the atmosphere under both dry and flooded conditions, using the eddy covariance (EC) method. We coupled greenhouse gas flux measurements with water availability and analyzed meteorological variables like air temperature and radiation, known to influence carbon fluxes in saline lakes. This extensive data integration enabled the projection of the net carbon flux over time, accounting for both dry and wet periods on an interannual scale. We found that the system acts as a significant carbon sink by atmospheric CO2 uptake in wet conditions, with uptake ceasing in periods of drought. Moreover, increased air temperatures during wet phases slightly decrease the CO2 uptake efficiency. Regarding CH4, we measured uptake rates that exceeded those of well-aerated soils such as forest soils or grasslands. Additionally, we observed that CH4 uptake during dry periods was nearly double that of wet periods. However, the absence of continuous data prevented us from correlating CH4 uptake processes with potential environmental predictors. Our study challenges the widespread notion that wetlands are universally greenhouse gas emitters, highlighting the significant role that endorheic saline lakes can play as natural sink of atmospheric carbon. However, our work also underscores the vulnerability of these ecosystem services in the current climate change scenario, where drought episodes are expected to become more frequent and intense in the coming years.
Previous research has primarily focused on global annual CO2 emissions from drawdown areas. However, in drylands, which are highly vulnerable to global change, elucidating the spatial and temporal significance of drawdown areas in relation to CO2 emissions from water remains unclear. In this study, we aimed to characterize the relative importance of drawdown areas on waters (RIDW) in CO2 emissions at a spatio-temporal scale. We found that the total drawdown area of drylands was estimated to be 127,442 ± 18,474 km2 per year, which represents up to 22% of the waters area. Furthermore, the annual variation of drawdown areas (coefficient of variation: 0.64) was higher than that of waters (coefficient of variation: 0.22). Our findings suggest that the shrinking of drawdown areas in temperate lakes and reservoirs has been the main factor in the decline of the total drawdown area from 2004 to 2020. As a result, the mean total CO2 emissions from drawdown areas during 2013–2020 decreased by 18% compared with 2004–2012, particularly in North Africa and Middle Asia, which saw decreases of 35% and 34%, respectively. Meanwhile, the expansion of waters area led to a 29% increase in CO2 emissions from waters. Our research further reveals that the mean annual CO2 emissions from drawdown areas in drylands are as high as 132.3 ± 23.1 Tg C yr-1, equivalent to 61% of estimated CO2 emissions from waters, but its share of CO2 emissions of non-perennial waters shows a significant downward trend. These results have important implications for understanding the role of drawdown areas in CO2 emissions and the impact of global change on dryland ecosystems.
Remnants of cities and farmlands in China’s hyperarid Tarim Basin indicate that environmental conditions were significantly wetter two millennia ago in a region which is barren desert today. Historical documents and age data of organic remains show that the Loulan Kingdom flourished during the Han Dynasty (206 BCE–220 CE) but was abandoned between its end and 645 CE. Previous archaeological, geomorphological and geological studies suggest that deteriorating climate conditions led to the abandonment of the ancient desert cities. Based on analyses of lake sediments from Lop Nur in the eastern Tarim Basin and a review of published records, we show that the Loulan Kingdom decline resulted from a man-made environmental disaster comparable to the recent Aral Sea crisis rather than from changing climate. Lop Nur and other lakes within the Han Dynasty realm experienced rapidly declining water levels or even desiccation whilst lakes in adjacent regions recorded rising levels and relatively wet conditions during the time of the Loulan Kingdom decline. Water withdrawal for irrigation farming in the middle reaches of rivers likely caused water shortage downstream and eventually the widespread deterioration of desert oases a long time before man initiated the Aral Sea disaster in the 1960s.
In 2015, an emergency state was declared in Bolivia when Poopó Lake dried up. Climate variability and the increasing need for water are potential factors responsible for this situation. Because field data are missing over the region, no statements are possible about the influence of mentioned factors. This study is a preliminary step toward the understanding of Poopó Lake drought using remote sensing data. First, atmospheric corrections for Landsat (FLAASH and L8SR), seven satellite derived indexes for extracting water bodies, MOD16 evapotranspiration, PERSIANN-CDR and MSWEP rainfall products potentiality were assessed. Then, the fluctuations of Poopó Lake extent over the last 26 years are presented for the first time jointly, with the mean regional annual rainfall. Three main droughts are highlighted between 1990 and 2015: two are associated with negative annual rainfall anomalies in 1994 and 1995 and one associated with positive annual rainfall anomaly in 2015. This suggests that other factors than rainfall influenced the recent disappearance of the lake. The regional evapotranspiration increased by 12.8% between 2000 and 2014. Evapotranspiration increase is not homogeneous over the watershed but limited over the main agriculture regions. Agriculture activity is one of the major factors contributing to the regional desertification and recent disappearance of Poopó Lake.
Lakes are key components of biogeochemical and ecological processes, thus knowledge about their distribution, volume and residence time is crucial in understanding their properties and interactions within the Earth system. However, global information is scarce and inconsistent across spatial scales and regions. Here we develop a geo-statistical model to estimate the volume of global lakes with a surface area of at least 10 ha based on the surrounding terrain information. Our spatially resolved database shows 1.42 million individual polygons of natural lakes with a total surface area of 2.67 × 10⁶ km² (1.8% of global land area), a total shoreline length of 7.2 × 10⁶ km (about four times longer than the world's ocean coastline) and a total volume of 181.9 × 10³ km³ (0.8% of total global non-frozen terrestrial water stocks). We also compute mean and median hydraulic residence times for all lakes to be 1,834 days and 456 days, respectively.
The Aral Sea in 1960 was a huge brackish water lake (4th in the world in surface area) lying amidst the deserts of Central Asia. The sea supported a major fishery and functioned as a key regional transportation route. Since 1960, the Aral has undergone rapid desiccation and salinization, overwhelmingly the result of unsustainable expansion of irrigation that dried up its two tributary rivers the Amu Darya and Syr Darya and severely damaged their deltas. The desiccation of the Aral Sea has had severe negative impacts, including, among others, the demise of commercial fishing, devastation of the floral and faunal biodiversity of the native ecosystems of the Syr and Amu deltas, and increased frequency and strength of salt/dust storms. However, efforts have been and are being made to partially restore the sea’s hydrology along with its biodiversity, and economic value. The northern part of the Aral has been separated from the southern part by a dike and dam, leading to a level rise and lower salinity. This allowed native fishes to return from the rivers and revitalized the fishing industry. Partial preservation of the Western Basin of the southern Aral Sea may be possible, but these plans need much further environmental and economic analysis. This paper, mainly utilizing hydrologic and other data as input to spreadsheet (Microsoft Excel)-based hydrologic and salinity models, examines the current efforts to restore the Aral and looks at several future scenarios of the Sea. It also delineates the most important lessons of the Aral Sea’s drying.
INTRODUCTION Two types of saline water exist on Earth, namely marine waters, including brackish zones of mixing with fresh water, and epicontinental salt lakes. This chapter addresses the values, threats and likely future of salt lakes, which are here defined as permanent or temporary bodies of water with salinities >3 g per litre and lacking any recent connection to the marine environment (i.e. athalassohaline sensu Bayly 1967). While the use of 3 g per litre to demarcate salt lakes is somewhat arbitrary, it has come into general use and is, coincidentally, the ‘calcite branch point’; that is, the salinity at which calcite is precipitated as natural waters concentrate. The false dichotomy between marine and fresh waters embodied in the titles of institutions, textbooks and conferences obscures the fact that salt lakes are widespread and represent significant aquatic resources. They occur on all continents, including Antarctica (Fig. 7.1), under a range of climatic temperature regimes from the coldest to near hottest. Locally, they may be more abundant than fresh waters and, when they are, often dominate the landscape. While they are mostly confined to semi-arid (precipitation 200–500 mm per year) and arid (25–200 mm per year) regions of the world, these regions constitute about one-third of the Earth's total land area (Williams1998 a) and inland salt waters are not greatly lower in total global volume (85 000 km 3) than freshwater lakes (105 000 km 3) (Shiklomanov 1990).
Managing terminal lake elevation and salinity are emerging problems worldwide. We contribute to terminal lake management research by quantitatively assessing water and salt flow for Utah's Great Salt Lake. In 1959, Union Pacific Railroad constructed a rock-filled causeway across the Great Salt Lake, separating the lake into a north and south arm. Flow between the two arms was limited to two 4.6 meter wide rectangular culverts installed during construction, an 88 meter opening (referred to locally as a breach) installed in 1984, and the semi porous material of the causeway. A salinity gradient developed between the two arms of the lake over time because the south arm receives approximately 95% of the incoming streamflow entering Great Salt Lake. The north arm is often at, or near, salinity saturation, averaging 317 g/L since 1966, while the south is considerably less saline, averaging 142 g/L since 1966. Ecological and industrial uses of the lake are dependent on long-term salinity remaining within physiological and economic thresholds, although optimal salinity varies for the ecosystem and between diverse stakeholders. In 2013, Union Pacific Railroad closed causeway culverts amid structural safety concerns and proposed to replace them with a bridge, offering four different bridge designs. As of summer 2015, no bridge design has been decided upon. We investigated the effect that each of the proposed bridge designs would have on north and south arm Great Salt Lake elevation and salinity by updating and applying US Geological Survey's Great Salt Lake Fortran Model. Overall, we found that salinity is sensitive to bridge size and depth, with larger designs increasing salinity in the south arm and decreasing salinity in the north arm. This research illustrates that flow modifications within terminal lakes cannot be separated from lake salinity, ecology, management, and economic uses.
This article tells the epic tale of the fall and rise of Mono Lake—the strange and beautiful Dead Sea of California—which fostered some of the most important environmental law developments of the last century, and which has become a platform for some of the most potentially important developments in the new century. It shares the backstory and legacy of the California Supreme Court’s famous decision in National Audubon Society v. Superior Court, 658 P.2d 709 (Cal. 1983), known more widely as “the Mono Lake case.” Inspired by innovative legal scholarship and advocacy, the decision spawned a quiet legal revolution in public trust ideals, which has redounded to other states and even nations as far distant as India.
The Mono Lake dispute pitted advocates for the local ecosystem and community against proponents of the continued export of Mono Basin water to millions of thirsty Californians hundreds of miles to the south. The controversy itself spanned decades, but the story leading up to the litigation stretches back more than a hundred years, adding depth and dimension to the tale that is easily missed on a casual reading of the Audubon Society decision itself. It is a case study on the challenges and possibilities for balancing legitimate needs for public infrastructure and economic development with competing environmental values, all within systems of law that are still evolving to manage these conflicts. And at this particular moment in time, commemorating the hundredth anniversary of the Los Angeles Aqueduct that would threaten the lake and the twentieth anniversary of the State Water Board’s ultimate decision to save it, the Mono Lake story is especially worth revisiting.
Part II introduces the main cast of characters in the Mono Lake story, starting with the public trust and prior appropriations doctrines around which the legal controversy unfolds. Part III introduces the three places at the center of the drama—Los Angeles, the Owens Valley, and the Mono Lake Basin—in recounting the history of the Californian water struggles leading up to the Mono Lake case. Part IV discusses the Audubon Society litigation itself and its aftermath, reviewing the court’s conclusion and the subsequent decision by the California Water Resources Control Board implementing the judicial directive. After analyzing the most important doctrinal developments in the opinion, it discusses subsequent critiques and new developments in public trust law.
Part V concludes with parting reflections about important questions that the Mono Lake story leaves us to ponder, including whose interests count when we talk about the “public” trust, how they differ from aggregated private interests, and which to account for when balancing the economic, cultural, and environmental considerations in public trust conflicts. It considers the extent to which the doctrine creates substantive or procedural obligations, and the responsibilities of different legal actors and institutions in implementing them. The contested answers to these questions are what make the public trust doctrine so fascinating, so powerful, and so critical as we continue to confront the inevitable crises between competing natural resource values.
During the 1970s, Laguna Mar Chiquita (Argentina) experienced a dramatic hydroclimatic anomaly, with a substantial rise in its level. Precipitations are the dominant driving factor in lake level fluctuations. The present study investigates the potential role of remote forcing through global sea surface temperature (SST) fields in modulating recent hydroclimatic variability in Southeastern South America and especially over the Laguna Mar Chiquita region. Daily precipitation and temperature are extracted from a multi-member LMDz atmospheric general circulation model (AGCM) ensemble of simulations forced by HadISST1 observed time-varying global SST and sea-ice boundary conditions from 1950 to 2005. The various members of the ensemble are only different in their atmospheric initial conditions. Statistical downscaling (SD) is used to adjust precipitation and temperature from LMDz ensemble mean at the station scale over the basin. A coupled basin-lake hydrological model (cpHM) is then using the LMDz-downscaled (LMDz-SD) climate variables as input to simulate the lake behavior. The results indicate that the long-term lake level trend is fairly well depicted by the LMDz-SD-cpHM simulations. The 1970s level rise and high-level conditions are generally well captured in timing and in magnitude when SST-forced AGCM-SD variables are used to drive the cpHM. As the LMDz simulations are forced solely with the observed sea surface conditions, the global SST seems to have an influence on the lake level variations of Laguna Mar Chiquita. As well, this study shows that the AGCM-SD-cpHM model chain is a useful approach for evaluating long-term lake level fluctuations in response to the projected climate changes.
Saline lakes provide a prey-rich, predator-free environment for birds to utilize during migration and stopover periods. The Great Salt Lake (GSL), Utah is the largest salt lake in North America and is utilized by millions of migratory birds. It also is host to multiple commercial endeavors. Proposed expansion of commercial use of the GSL would result in increased impounded area and water extraction for mineral production, which may increase the GSL's salinity and negatively impact invertebrate abundance. I review previous literature and synthesize diets of avian species utilizing the GSL to determine the importance of each invertebrate species, including brine shrimp (Artemia franciscana) and brine flies (Ephydra spp.), and clarify the anthropogenic impacts on food sources and avian populations. Species considered are eared grebes (Podiceps nigricollis), northern shovelers (Anas clypeata), green-winged teals (Anas crecca), common goldeneyes (Bucephala clangula), American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), Wilson's phalaropes (Phalaropus tricolor), red-necked phalaropes (Phalaropus lobatus), and California gulls (Larus californicus). Brine shrimp and brine fly adults are consumed by all species considered. Alterations in prey abundance due to increased salinity may alter the ability of the GSL to support large avian populations.
In the 1990s, the western world became aware of the ecological disaster of what was once the fourth largest lake in the world – the Aral Sea. The drastic desiccation of the Aral Sea led to the intensive development of desertification processes in the region and the formation of a new desert, the Aralkum. In the last few decades, the Aralkum has become the new “hot spot” of dust and salt storms in the region. Dust storms and their source areas have been determined and analyzed by the NOAA AVHRR, TOMS and OMI data. An analysis of the land-cover changes in the dried bottom of the Aral Sea revealed that the north-eastern part of the Aralkum Desert is one of the most active dust sources in the region, responsible for high aerosol concentrations in the atmosphere. Dust plumes that sweep up from the dried bottom of the Aral Sea have become larger, and dust storms have become more powerful, since the bottom exposure. The main change that occurred in the land cover was the considerable reduction of vegetation and small water bodies, while the areas of solonchaks (salty pans) and sandy massifs increased significantly.
Saline lakes change in size and salinity because of natural climate variability and especially from inflow diversions, which threaten life in these waters. We conducted a microcosm experiment in 12 L containers using organisms from the Great Salt Lake to determine how salinities ranging from 10 to 275 g·L⁻¹ influenced the ecosystem. After 30 days, brine shrimp (Artemia franciscana) were nearly absent in salinities of 10 g·L⁻¹ (where fish survived) and >225 g·L⁻¹. As salinities increased from 75 to 225 g·L⁻¹, final masses decreased 60% and their total biomass decreased fourfold. Copepod and rotifer biomasses were negligible at salinities >50 g·L⁻¹. Brine fly (Ephydra gracilis) final biomass decreased 45% as salinity increased from 50 to 250 g·L⁻¹. When Artemia and other grazers were abundant, phytoplankton chlorophyll levels were near 4.0 μg·L⁻¹, but when grazing rates declined at higher salinities, phytoplankton chlorophyll increased to 130 μg·L⁻¹. Mean periphyton chlorophyll levels showed the reverse pattern. Denitrification decreased total N concentrations during the experiment, resulting in final N:P ratios indicative of algal nitrogen limitation. The microcosm experiment demonstrated the strong influence of salinity on the entire ecosystem and highlighted the need for careful management of salt lakes to maintain appropriate salinities.
The Bear River contributes more water to the eastern Great Basin than any other river
21 system. It is also the most significant source of water for the burgeoning Wasatch Front
22 metropolitan area in Northern Utah. Despite its importance for water resources for the region’s
23 agricultural, urban, and wildlife needs, our understanding of the variability of Bear River’s
24 stream flow derives entirely from the short instrumental record (1943-2010). Here we present a
25 1,200-year calibrated and verified tree-ring reconstruction of stream flow for the Bear River that
26 explains 67% of the variance of the instrumental record over the period from 1943-2010.
27 Furthermore, we developed this reconstruction from a species that is not typically used for
28 dendroclimatology, Utah juniper (Juniperus osteosperma). We identify highly significant
29 periodicity in our reconstruction at quasi-decadal (7-8 year), multi-decadal (30 year), and
centennial (>50 years) scales. The latter half of the 20th century was found to be the 2nd 30 wettest
(~40-year) period of the past 1,200 years, while the first half of the 20th century marked the 4th 31
32 driest period. The most severe period of reduced stream flow occurred during the Medieval
33 Warm Period (ca. mid-1200s CE) and persisted for ~70 years. Upper-level circulation anomalies
34 suggest that atmospheric teleconnections originating in the western tropical Pacific are
35 responsible for the delivery of precipitation to the Bear River watershed during the October-
36 December (OND) season of the previous year. The Bear River flow was compared to recent
37 reconstructions of the other tributaries to the Great Salt Lake (GSL) and the GSL level.
38 Implications for water management could be drawn from the observation that the latter half of
the 20th century was the 2nd 39 wettest in 1200 years, and that management for future water supply
40 should take into account the stream flow variability over the past millennium.
The Great Salt Lake is a closed basin lake in which level and volume fluctuate due to differences between inflows and outflows. The only outflow is evaporation, which depends directly on lake area and salinity, both of which depend on lake volume. The lake's level, volume, and area adjust to balance, on average, precipitation and streamflow inflows by evaporation. In this paper, we examine the sensitivity of lake volume changes to precipitation, streamflow, and evaporation and the interactions among these processes and lake area and salinity related to volume. A mass balance model is developed to generate representative realizations of future lake level from climate and streamflow inputs simulated using the k-nearest-neighbor method. Climate and salinity are used to estimate evaporation from the lake using a Penman model adjusted for the salinity-dependent saturation vapor pressure. Our results show that fluctuation in streamflow is the dominant factor in lake level fluctuations, but fluctuations in lake area that modulate evaporation and precipitation directly on the lake are also important. The results also quantify the sensitivity of lake level to changes in streamflow and air temperature inputs. They predict that a 25% decrease in streamflow would reduce lake level by about 66 cm (2.2 feet), while a +4°C air temperature increase would reduce lake level by about 34 cm (1.1 feet) on average. This sensitivity is important in evaluating the impacts of climate change or streamflow change due to increased consumptive water use on the level of the lake.
The population dynamics of Ephydra hians Say final instar larvae and pupae were compared over a two year period in rocky littoral habitats of two alkaline saline lakes in the western Great Basin. Relative abundance increased from 1983 to 1984 at Mono Lake (California), during dilution from ca. 90 to 80 g 1-1 TDS (total dissolved solids). In contrast, relative abundance decreased over the same period at Abert Lake (Oregon), accompanied by a dilution of salinity from ca. 30 to 20 g l-1 and a marked increase in the number and abundance of other benthic macroinvertebrate species. These observations are consistent with a hypothesis that proposes biotic interactions limit E. hians abundance at low salinity, and physiological stress limits abundance at high salinity.
Oviposition extends from early spring to early fall. Mixed instars present throughout this period indicates multivoltine population dynamics with overlapping generations. The standing stock biomass of final instars increases exponentially in late spring and peaks in late summer or early fall. Pupae increase in proportional representation and abundance from a spring minimum to a fall maximum. The body size of adults and pupae cycle seasonally from a spring maximum to a fall minimum, and may be related to either or both food limitation, or water temperature.
Satellite imagery has greatly influenced our understanding of dust activity on a global scale. A number of different satellites such as NASAs Earth-Probe Total Ozone Mapping Spectrometer (TOMS) and Sea-viewing Field-of-view Sensor (SeaWiFS) acquire daily global-scale data used to produce imagery for monitoring dust storm formation and movement. This global-scale imagery has documented the frequent transmission of dust storm-derived soils through Earths atmosphere and the magnitude of many of these events. While various research projects have been undertaken to understand this normal planetary process, little has been done to address its impact on ocean and human health. This review will address the ability of dust storms to influence marine microbial population densities and transport of soil-associated toxins and pathogenic microorganisms to marine environments. The implications of dust on ocean and human health in this emerging scientific field will be discussed.
The Great Salt Lake is a terminal lake whose level is determined by the balance between inflows and outflows. We examine the causes for multimodality in the distributions of lake level and hence volume and area that have previously been examined from a system dynamics perspective. We focus on the role of bathymetry in the dynamics of this system and show that some of the modes that are observed and that represent preferred system states are attributable to features of the bathymetry described using the topographic area-volume relationship. Being a terminal lake, the only “outflow” is evaporation, which depends directly on lake area, which adjusts (with stochastic fluctuations) to balance inflows. Where the topographic side slopes are relatively flat and the lake goes through a large change in area for a given increase in level, the outflux evaporation will go through a corresponding large change, tending to stabilize the lake at that point. Conversely, where topographic side slopes are relatively steep, the stabilizing effect is diminished. This effect was quantified using the derivative of the lake area–lake volume function determined from U.S. Geological Survey topographic and bathymetric surveys. We show how some of the observed modes that represent preferred lake volume states are attributable to peaks in this area-volume derivative, while a complete description of the observed distribution of lake volume requires combining the bathymetry represented by the area-volume derivative with a multimodal lake area distribution that may be connected to multimodality in the aggregate hydrological forcing.
Protecting the world’s freshwater resources requires diagnosing threats over a broad range of scales, from global to local. Here we present the first worldwide synthesis to jointly consider human and biodiversity perspectives on water security using a spatial framework that quantifies multiple stressors and accounts for downstream impacts. We find that nearly 80% of the world’s population is exposed to high levels of threat to water security. Massive investment in water technology enables rich nations to offset high stressor levels without remedying their underlying causes, whereas less wealthy nations remain vulnerable. A similar lack of precautionary investment jeopardizes biodiversity, with habitats associated with 65% of continental discharge classified as moderately to highly threatened. The cumulative threat framework offers a tool for prioritizing policy and management responses to this crisis, and underscores the necessity of limiting threats at their source instead of through costly remediation of symptoms in order to assure global water security for both humans and freshwater biodiversity.
To review the published literature examining the impacts of the Aral Sea disaster on children's health.
A systematic review of the English language literature.
The literature search uncovered 26 peer-reviewed articles and four major reports published between 1994 and 2008. Anemia, diarrheal diseases, and high body burdens of toxic contaminants were identified as being among the significant health problems for children. These problems are associated either directly with the environmental disaster or indirectly via the deterioration of the region's economy and social and health care services. While links between persistent organic pollutant exposures and body burdens are clear, health impacts remain poorly understood. No clear evidence for the link between dust exposure and respiratory function was identified.
While important questions about the nature of the child health and environment relationships remain to be answered, the literature unequivocally illustrates the seriousness of the public health tragedy and provides sufficient evidence to justify immediate action. Regrettably, international awareness of the crisis continues to be poor, and the level of action addressing the situation is wholly inadequate.
This study deals with effects of different salinities on the survival, growth, reproductive and lifespan characteristics of three Artemia populations from Urmia Lake and small lagoons at the vicinity of the lake under laboratory conditions. Experimental salinities ranged from 75 to 175 g L(-1). Salinity was proved to have significant impact on the majority of the characters studied in this survey. Growth and survival in bisexual A. urmiana and parthenogenetic Artemia from Lake Urmia were significantly higher with respect to the parthenogenetic Artemia from lagoons at most of the salinities tested. Reproductive characteristics such as total number of broods, total offspring number of offspring in each brood and number of offspring at each day of reproductive period reduced with increasing salinity. Moreover higher salinity prolonged the prereproductive period but shortened the total reproductive period. Higher salinities also affected the percentage of encystment and post-reproductive period, showing significantly higher values in parthenogenetic populations in comparison to bisexual A. urmiana.
Some of the world’s largest lakes have shrunk dramatically in the last few decades, while many more face serious pollution problems. A new global database of lakes may help to protect the water bodies that offer irreplaceable wildlife habitats and valuable ecosystem services. Michael Gross reports.
Absent local weather stations, a gridded weather dataset can provide information useful for water management in irrigated areas including potential crop evapotranspiration calculations. In estimating crop irrigation requirements and surface evaporation in Utah, United States of America, methodology and software were developed using the ASCE Standardized Penman-Monteith Reference Evapotranspiration equation with input climate drivers from the North American Land Data Assimilation System (NLDAS) gridded weather forcing dataset and a digital elevation model. A simple procedure was devised to correct bias in NLDAS relative humidity and air temperature data based on comparison to weather data from ground stations. Potential evapotranspiration was calculated for 18 crops (including turfgrass), wetlands (large and narrow), and open water evaporation (deep and shallow) by multiplying crop coefficient curves to reference evapotranspiration with annual curve dates set by summation of Hargreaves evapotranspiration, cumulative growing degree days, or number of days. Net potential evapotranspiration was calculated by subtracting effective precipitation estimates from the Daymet gridded precipitation dataset. Analysis of the results showed that daily estimated potential crop evapotranspiration from the model compared well with estimates from electronic weather stations (1980-2014) and with independently calculated potential crop evapotranspiration in adjacent states. Designed for this study but open sourced for other applications, software entitled GridET encapsulated the GIS-based model that provided data download and management, calculation of reference and potential crop evapotranspiration, and viewing and analysis tools. Flexible features in GridET allows a user to specify grid resolution, evapotranspiration equations, cropping information, and additional datasets with the output being transferable to other GIS software.
Although extremely important to migrating waterfowl and shorebirds, and highly threatened globally, most saline lakes are poorly monitored. Lake Abert in the western Great Basin, USA, is an example of this neglect. Designated a critical habitat under the Western Hemisphere Shorebird Reserve Network, the lake is at near record historic low levels and ultra-high salinities that have resulted in ecosystem collapse. Determination of the direct human effects and broader climate controls on Lake Abert illustrates the broader problem of saline lake desiccation and suggests future solutions for restoration of key habitat values. A 65-year time series of lake area was constructed from Landsat images and transformed to lake volume and salinity. "Natural" (without upstream withdrawals) conditions were calculated from climate and stream flow data, and compared to measured volume and salinity. Under natural conditions the lake would have higher volume and lower salinities because annual water withdrawals account for one-third of mean lake volume. Without withdrawals, the lake would have maintained annual mean salinities mostly within the optimal range of brine shrimp and alkali fly growth. Even during the last two years of major drought, the lake would have maintained salinities well below measured values. Change in climate alone would not produce the recent low lake volumes and high salinities that have destroyed the brine shrimp and alkali fly populations and depleted shorebird use at Lake Abert. Large scale withdrawal of water for direct human use has drastically increased the imbalance between natural runoff and evaporation during periods of drought in saline lakes worldwide but could be offset by establishing an "environmental water budget" to lay a foundation for the conservation of saline lake habitats under continued threats from development and climate change.
Protecting the worlds freshwater resources requires diagnosing threats over a broad range of scales, from global to local. Here we present the first worldwide synthesis to jointly consider human and biodiversity perspectives on water security using a spatial framework that quantifies multiple stressors and accounts for downstream impacts. We find that nearly 80% of the worlds population is exposed to high levels of threat to water security. Massive investment in water technology enables rich nations to offset high stressor levels without remedying their underlying causes, whereas less wealthy nations remain vulnerable. A similar lack of precautionary investment jeopardizes biodiversity, with habitats associated with 65% of continental discharge classified as moderately to highly threatened. The cumulative threat framework offers a tool for prioritizing policy and management responses to this crisis, and underscores the necessity of limiting threats at their source instead of through costly remediation of symptoms in order to assure global water security for both humans and freshwater biodiversity.
During the 1970’s, Laguna Mar Chiquita (Argentina) experienced a dramatic hydroclimatic anomaly, with a substantial rise in its level. Precipitations are the dominant driving factor in lake level fluctuations. The present study investigates the potential role of remote forcing through global sea surface temperature (SST) fields in modulating recent hydroclimatic variability in Southeastern South America and especially over the Laguna Mar Chiquita region. Daily precipitation and temperature are extracted from a multi-member LMDz atmospheric general circulation model (AGCM) ensemble of simulations forced by HadISST1 observed time-varying global SST and sea-ice boundary conditions from 1950 to 2005. The various members of the ensemble are only different in their atmospheric initial conditions. Statistical downscaling (SD) is used to adjust precipitation and temperature from LMDz ensemble mean at the station scale over the basin. A coupled basin-lake hydrological model (cpHM) is then using the LMDz-downscaled (LMDz-SD) climate variables as input to simulate the lake behavior. The results indicate that the long-term lake level trend is fairly well depicted by the LMDz-SD-cpHM simulations. The 1970’s level rise and high-level conditions are generally well captured in timing and in magnitude when SST-forced AGCM-SD variables are used to drive the cpHM. As the LMDz simulations are forced solely with the observed sea surface conditions, the global SST seems to have an influence on the lake level variations of Laguna Mar Chiquita. As well, this study shows that the AGCM-SD-cpHM model chain is a useful approach for evaluating long-term lake level fluctuations in response to the projected climate changes.
Assessing climate change risk to municipal water supplies is often conducted by hydrologic modeling specific to local watersheds and infrastructure to ensure that outputs are compatible with existing planning frameworks and processes. This study leverages the modeling capacity of an operational National Weather Service River Forecast Center to explore the potential impacts of future climate-driven hydrologic changes on factors important to planning at the Salt Lake City Department of Public Utilities (SLC). Hydrologic modeling results for the study area align with prior research in showing that temperature changes alone will lead to earlier runoff and reduced runoff volume. The sensitivity of average annual flow to temperature varies significantly between watersheds, averaging -3.8% 8F-1 and ranging from -1.8% to -6.5% flow reduction per degree Fahrenheit of warming. The largest flow reductions occur during the high water demand months of May-September. Precipitation drives hydrologic response more strongly than temperature, with each 1% precipitation change producing an average 1.9% runoff change of the same sign. This paper explores the consequences of climate change for the reliability of SLC's water supply system using scenarios that include hydrologic changes in average conditions, severe drought scenarios, and future water demand test cases. The most significant water management impacts will be earlier and reduced runoff volume, which threaten the system's ability to maintain adequate streamflow and storage to meet late-summer water demands.
We analyzed climatic and hydrologic data collected from the end of the nineteenth century to the present time from weather stations and hydro posts in the Teskei Ala Too and Kungei Ala Too mountain sites, around Issyk-Kul Lake, Kyrgyzstan, and Central Asia. These databases showed that the water level of Issyk-Kul Lake varied along with changes in climate indicators. Fluctuations in the Issyk-Kul Lake surface level were generated by an unbalanced water budget (volume) as a result of meteorological and hydrological processes, such as precipitation, evaporation, infiltration, and inflow and outflow conditions of rivers that fall into this lake. The impacts of each of these factors on the lake’s water balance are different, and the process usually has long temporal scales and effects. The quantitative measures of these factors and their actions are very important to considering the changes in water level of the lake surface. The data from the last 130 years indicated that the temperature in Issyk-Kul has changed over the years from 1880 to 2010. According to comprehensive analyses of these data, the water level has changed under the effects of global warming in this basin. The analysis of the weather station database over the last 130 years showed that approximately every 30 years there was an abrupt increase in air temperature during the hottest summer months that gradually decreased over that three decade cycle. These periods indicated an abrupt change in air temperature of 1–1.5 °C by the end of each cycle. And any change in air temperature influenced the amount of river runoff, glacier melt, and lake volume in this region. Depending on the interaction between water volume and air temperature and a reduction in irrigation, the lake’s water level also rose.
This study investigates the meteorological conditions associated with multidecadal drought cycles as revealed by lake level fluctuation of the Great Salt Lake (GSL). The analysis combined instrumental, proxy, and simulation datasets, including the Twentieth Century Reanalysis version 2, the North American Drought Atlas, and a 2000-yr control simulation of the GFDL Coupled Model, version 2.1 (CM2.1). Statistical evidence from the spectral coherence analysis points to a phase shift amounting to 6-9 yr between the wet dry cycles in the Great Basin and the warm cool phases of the interdecadal Pacific oscillation (IP0). Diagnoses of the sea surface temperature and atmospheric circulation anomalies attribute such a phase shift to a distinctive teleconnection wave train that develops during the transition points between the IPO's warm and cool phases. This teleconnection wave train forms recurrent circulation anomalies centered over the southeastern Gulf of Alaska; this directs moisture flux across the Great Basin and subsequently drives wet dry conditions over the Great Basin and the GSL watershed. The IPO life cycle therefore modulates local droughts pluvials in a quarter-phase manner.
Some grow and others shrink as changing climate patterns and human demands for scarce water resources reshape the ecology of the world's salt lakes.
In this work, we used the Regional Hydro-Ecological Simulation System (RHESSys) model to examine runoff sensitivity to land cover changes in a mountain environment. Two independent experiments were evaluated where we conducted simulations with multiple vegetation cover changes that include conversion to grass, no vegetation cover and deciduous/coniferous cover scenarios. The model experiments were performed at two hillslopes within the Weber River near Oakley, Utah watershed (USGS gauge # 10128500). Daily precipitation, air temperature and wind speed data as well as spatial data that include a digital elevation model with 30 m grid resolution, soil texture map and vegetation and land use maps were processed to drive RHESSys simulations. Observed runoff data at the watershed outlet were used for calibration and verification. Our runoff sensitivity results suggest that during winter, reduced leaf area index (LAI) decreases canopy interception resulting in increased snow accumulations and hence snow available for runoff during the early spring melt season. Increased LAI during the spring melt season tends to delay the snow melting process. This delay in snow melting process is due to reduced radiation beneath high LAI surfaces relative to low LAI surfaces. The model results suggest that annual runoff yield after removing deciduous vegetation is on average about 7% higher than with deciduous vegetation cover, while annual runoff yield after removing coniferous vegetation is on average as about 2% higher than that produced with coniferous vegetation cover. These simulations thus help quantify the sensitivity of water yield to vegetation change. Copyright (C) 2013 John Wiley & Sons, Ltd.
Two theoretical approaches to evaporation from saturated surfaces are outlined, the first being on an aerodynamic basis in which evaporation is regarded as due to turbulent transport of vapour by a process of eddy diffusion, and the second being on an energy basis in which evaporation is regarded as one of the ways of degrading incoming radiation. Neither approach is new, but a combination is suggested that eliminates the parameter measured with most difficulty-surface temperature-and provides for the first time an opportunity to make theoretical estimates of evaporation rates from standard meteorological data, estimates that can be retrospective. Experimental work to test these theories shows that the aerodynamic approach is not adequate and an empirical expression, previously obtained in America, is a better description of evaporation from open water. The energy balance is found to be quite successful. Evaporation rates from wet bare soil and from turf with an adequate supply of water are obtained as fractions of that from open water, the fraction for turf showing a seasonal change attributed to the annual cycle of length of daylight. Finally, the experimental results are applied to data published elsewhere and it is shown that a satisfactory account can be given of open water evaporation at four widely spaced sites in America and Europe, the results for bare soil receive a reasonable check in India, and application of the results for turf shows good agreement with estimates of evaporation from catchment areas in the British Isles.
Variability and unpredictability are characteristics of the aquatic ecosystems, hydrological patterns and climate of the largely dryland region that encompasses the Basin and Range, American Southwest and western Mexico. Neither hydrological nor climatological models for the region are suciently developed to describe the magnitude or direction of change in response to increased carbon dioxide; thus, an attempt to predict speci®c responses of aquatic ecosystems is premature. Instead, we focus on the sensitivity of rivers, streams, springs, wetlands, reservoirs, and lakes of the region to potential changes in climate, especially those inducing a change in hydrological patterns such as amount, timing and predictability of stream ¯ow. The major sensitivities of aquatic ecosystems are their permanence and even existence in the face of potential reduced net basin supply of water, stability of geomorphological structure and riparian ecotones with alterations in disturbance regimes, and water quality changes resulting from a modi®ed water balance. In all of these respects, aquatic ecosystems of the region are also sensitive to the extensive modi®cations imposed by human use of water resources, which underscores the diculty of separating this type of anthropogenic change from climate change. We advocate a focus in future research on reconstruction and analysis of past climates and associated ecosystem characteristics, long-term studies to discriminate directional change vs. year to year variability (including evidence of aquatic ecosystem responses or sensi-tivity to extremes), and studies of ecosystems aected by human activity. # 1997 by John Wiley & Sons, Ltd.
A common hypothesis is that federal water agencies pursue continued appropriations with little consideration of national economic
efficiency. In the mid-1980s, faced with a vote on a supplemental municipal and industrial water repayment contract on the
Bonneville Unit of the Central Utah Project, the Bureau of Reclamation confirmed this hypothesis. Through modifications in
cost allocation procedures, the bureau shifted costs from municipal and industrial water to hydropower and irrigation. The
result of this action was retention of the irrigation purpose in the Bonneville Unit, which would have been unjustified under
previous cost allocation procedures.
1. Introduction.- 2. Echosoundings.- 2.1. Introduction.- 2.2. Instrumentation.- 2.3. Preparations.- Working map.- Sounding tracks.- Pilot survey.- Calibration.- 2.4. Field-work.- 3. Bathymetric Map Construction.- 4. Morphometry.- 4.1. Optimization of lake hydrography surveys -the information value of bathymetric maps.- 4.2. The intensity of the survey.- 4.3. Practical use of the optimization model-manuals.- 4.3.1. Manual -unknown lake.- 4.3.2. Manual -already echosounded lake.- 4.4. Morphometrical parameters.- Maximum length.- Maximum effective length.- Effective length.- Effective fetch.- Maximum width.- Maximum effective width.- Mean width.- Maximum depth.- Mean depth.- Median depth.- Quartile depths.- Relative depth.- Direction of major axis.- Shoreline length.- Contour-line length.- Total lake area.- Lake area.- Volume.- Slope.- Mean slope.- Median slope ..- Shore development.- Lake bottom roughness.- Form roughness.- Volume development.- Islands, islets and rocks.- Insulosity.- Profiles.- The slope curve.- The hypsographic curve.- The percentage hypsographic curve.- The relative hypsographic curve.- The volume curve.- The percentage volume curve.- The relative volume curve.- The lake form.- The lake type.- 5. Acknowledgements.- 6. Appendix.- 7. References.
Comparison of bottom-water chemistry in the marine-limnic habitat gradient shows greater phosphorus availability in marine waters, primarily because of enhanced iron sequestration by sulfide. In the oxidative hydrolysis of iron and the concomitant precipitation of phosphate, a minimum of two iron atoms are needed to precipitate one phosphate molecule (Fe: P = 2). However, dissolved Fe: P < 2 predominates in anoxic marine waters, therefore leaving some phosphate in solution after oxygenation because of a shortage of dissolved iron for phosphate coprecipitation by iron oxyhydroxide. In contrast, anoxic bottom waters in most freshwater lakes show Fe: P > 2, allowing almost complete phosphate removal on oxygenation. This difference is a consequence of the high sulfate content of sea salt, and a main reason why nitrogen normally limits net primary production in temperate coastal waters, in contrast to the predominant phosphorus limitation of near-neutral lakes.
The Aral Sea is a huge terminal lake located among the deserts of Central Asia. Over the past 10 millennia, it has repeatedly filled and dried, owing both to natural and human forces. The most recent des-iccation started in the early 1960s and owes overwhelmingly to the expansion of irrigation that has drained its two tributary rivers. Lake level has fallen 23 m, area shrunk 74%, volume decreased 90%, and salinity grew from 10 to more than 100g/l, causing negative ecolog-ical changes, including decimation of native fish species, initiation of dust/salt storms, degradation of deltaic biotic communities, and climate change around the former shoreline. The population resid-ing around the lake has also been negatively impacted. There is little hope in the foreseeable future to fully restore the Aral Sea, but mea-sures to preserve/rehabilitate parts of the water body and the deltas are feasible.
Salt lakes have a variety of important uses and values, including especially both economic and scientific ones. These uses and values have been and are increasingly subject to degradation from a variety of impacts: diversion of inflows, pollution, agricultural practices, and introduction of exotic species are among the more important. Recognition of these impacts upon salt lakes has led to some international and national measures for their conservation, but considerably more effort in this direction is needed. Against this background, Mono Lake, California, USA, and the Aral Sea, central Asia, are discussed as two localities which bring into sharp focus the various matters discussed in the paper. Finally, attention is drawn to the need to conserve the Akrotiri Salt Lake, Cyprus.
Recklessly starving the world's fourthlargest lake to irrigate crops turned rich waters into a barren wasteland. Now the northern part, at least, is coming back
- Grimm N. B.
Salton Sea Ecosystem Monitoring and Assessment Plan Open
- H L I Case
- HLI Case
Case, H. L. I. et al. Salton Sea Ecosystem Monitoring and Assessment Plan Open-File Report 2013-1133 (United States Geological Survey, 2013).
As Great Salt Lake dries up, Utah air quality concerns blow in. Standard Examiner