No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Terrestrial biodiversity in Antarctica – Recent advances and future challenges
Abstract
Although its major components have been known almost since the earliest exploring expeditions, even today the terrestrial biota of Antarctica is surprisingly poorly described in detail. It is clear that most currently ice-free ground in Antarctica would have been covered and scoured by glacial advances at the Last Glacial Maximum or previous maxima. Exceptions to this generalisation include parts of the Victoria Land Dry Valleys and some inland nunataks and mountain ranges at altitude, which host their own largely unique biota. However, as new baseline survey data have become available, in combination with the application of techniques of molecular biological analysis, new evidence has been obtained indicating that long-term persistence and regional isolation is a feature of the Antarctic terrestrial biota whose generality has not previously been appreciated. As well as creating a new paradigm in which to consider the evolution and adaptation of Antarctic terrestrial biota, this opens important new cross-disciplinary linkages in the field of understanding the geological and glaciological history of the continent itself. Superimposed on this emerging historical template of Antarctic biogeography, this biota now faces the twin challenges of responding to the complex processes of climate change facing some parts of the continent, and the direct impacts associated with human occupation and travel to and between the spatially very limited areas of terrestrial habitat.
... Despite the fact that it remains remote, and its climate is harsh and inhospitable to human life, human presence on the continent has increased and the idea of it being undisturbed is no longer true (Brooks et al. 2019;Leihy et al. 2020;Cordero et al. 2022). Although most of the continent is ice-covered, we now know that the majority of terrestrial biodiversity is restricted to the few ice-free areas, which cover <1 percent of the continent and possess higher microbial diversity and abundance than thought by early explorers, even as late as the 1950s and 1960s (Convey et al. 2010;Chown et al. 2015;Wauchope, Shaw, and Terauds 2019). Along the coast and within the Southern Ocean there is extensive marine and bird life, but within the continent most of the fauna is microscopic (microbial flora and bryophytes, and microscopic invertebrates), and terrestrial flora is limited to algae, mosses, and lichens (Convey et al. 2014). ...
... Along the coast and within the Southern Ocean there is extensive marine and bird life, but within the continent most of the fauna is microscopic (microbial flora and bryophytes, and microscopic invertebrates), and terrestrial flora is limited to algae, mosses, and lichens (Convey et al. 2014). Much of the current biota, such as nematodes and arthropods, have high levels of species endemism (i.e., they have evolved in the extreme conditions on the continent and are specifically unique to Antarctica; Adams et al. 2014;Convey 2010Convey , 2011. Some of the microscopic species that form the current ecosystems are species that are thought to have survived glacial cycles and overcome significant environmental barriers, being previously protected by the isolation and harshness of the continent (Adams et al. 2014;Convey 2010Convey , 2011. ...
... Much of the current biota, such as nematodes and arthropods, have high levels of species endemism (i.e., they have evolved in the extreme conditions on the continent and are specifically unique to Antarctica; Adams et al. 2014;Convey 2010Convey , 2011. Some of the microscopic species that form the current ecosystems are species that are thought to have survived glacial cycles and overcome significant environmental barriers, being previously protected by the isolation and harshness of the continent (Adams et al. 2014;Convey 2010Convey , 2011. ...
The McMurdo Dry Valleys (MDV), Antarctica’s largest ice-free region, hosts unique terrestrial ecosystems, with biodiversity concentrated in the aquatic environments and surrounding soils. Despite being a scientific hub, the creation of the MDV Antarctic Specially Managed Area (ASMA) made significant steps toward protecting the environment from degradation from human usage. However, with sustained human presence within the MDV, increasing human activity across Antarctica, and aquatic ecosystems subject to environmental change, the effectiveness of current protections for biodiversity conservation requires evaluation. This study employs spatial analysis of MDV protected areas, streams, lakes, research camps, and tourist sites to assess the robustness of current protections, identify underprotected areas, and outline steps for future protection. Within the MDV ASMA, five smaller Antarctic Specially Protected Areas (ASPAs) exist. Only two ASPAs contain streams, and only one with a full hydrologic catchment. With roughly 6% of the lotic habitat area protected by ASPAs, the MDV fall short of global goals for freshwater protection. Past successful management of the MDV shows the effectiveness of collaboration and early action, and amongst calls for ASPA network expansion and restructuring, the MDV has the opportunity to be at the forefront again and increase the protection of Antarctic aquatic ecosystems.
... Temperature plays an integral role in the rate of tissue decomposition (Mann et al. 1990;Bass III 1996;Gill-King 1996;Megyesi et al. 2005;Vass 2011;Zhou and Byard 2011) as it impacts the activity of invertebrates (Pietro et al. 2001;Archer and Elgar 2003;Joy et al. 2006;Sharanowski et al. 2008;Voss et al. 2009), vertebrates scavengers (O'Brien et al. 2010Dabbs and Martin 2013;Young et al. 2014), and bacteria and fungi Hopkins 2008;Kasper et al. 2012;Lauber et al. 2014). Although extensive research has been carried out on the effects of abiotic factors on microbial diversity during carrion decomposition, no single study focuses on the decomposer diversity of Antarctica despite its relatively simple ecosystem (Convey 2010). ...
... Antarctica is constantly subjected to harsh climatic conditions such as limited organic nutrients, low humidity, frequent freeze-thaw and wet-dry cycles, low temperatures, fluctuating UV radiation, and katabatic winds which result in long periods of desiccation (Wynn-Williams 1990; Cowan and Tow 2004). Moreover, earlier studies recorded that few arthropod species in Antarctic soils were dependent on vegetation in the environment (Davis 1981;Usher and Booth 1986;Sinclair 2001;Convey 2010). When plant production is increased, food availability is enhanced and promotes greater populations of herbivores (Siemann 1998;Haddad et al. 2009; La Pierre and Smith 2016), supporting larger predator and parasitoid populations (Fretwell 1987;Langellotto and Denno 2004;Hairston et al. 2009). ...
Carrion decomposition contributes to the soil microbial community structure. This research aimed to identify the soil arthropod, nematode, bacterial, and fungal communities associated with penguin carrion on King George Island, Antarctica. Soil samples were collected around and beneath fresh (freshly killed penguins by the predators) and dried (decomposed more than a year) penguin carrion. Soil bacterial and fungal communities associated with the penguin carrion were analyzed using the 16S rRNA and internal transcribed spacer (ITS) gene sequencing, respectively. Arthropod identification was using Sanger sequencing and nematodes were determined using morphological identification. This study demonstrated no significant differences in arthropod and nematode, bacteria, and fungi communities between decomposition stages, soil location, and species of penguin carrion. This is the first study to identify soil arthropods, nematodes, bacterial, and fungal communities associated with penguin carrion, offering important insights into the initial documentation of the necrobiome communities in the polar region.
... Therefore, we examined the surface soils of Meseta, an ice-free plateau mountain crest of Fildes Peninsula, King George Island, far from the seashore, representing a soil developmental gradient in a glacier forefield (Boy et al., 2016). Being openly exposed to microbial colonization from outside Antarctica and connected to the much harsher and dryer ice-free zones of the continental Antarctic (Convey, 2010) makes Meseta of Fildes Peninsula a promising location to test those hypotheses. ...
... That principle concludes with the importance of aeolian transport in global-scale dispersal, which plays a significant role in the assembly of microbial communities over geological time periods. Air currents and migrating birds within Antarctica may be effective drivers for microalgae dispersal (Broady and Smith, 1994;Convey, 2010). The presence of specialist taxa suggests a unique adaptation to the particular combination of environmental conditions. ...
Introduction
Eukaryotic algae in the top few centimeters of fellfield soils of ice-free Maritime Antarctica have many important effects on their habitat, such as being significant drivers of organic matter input into the soils and reducing the impact of wind erosion by soil aggregate formation. To better understand the diversity and distribution of Antarctic terrestrial algae, we performed a pilot study on the surface soils of Meseta, an ice-free plateau mountain crest of Fildes Peninsula, King George Island, being hardly influenced by the marine realm and anthropogenic disturbances. It is openly exposed to microbial colonization from outside Antarctica and connected to the much harsher and dryer ice-free zones of the continental Antarctic. A temperate reference site under mild land use, SchF, was included to further test for the Meseta algae distribution in a contrasting environment.
Methods
We employed a paired-end metabarcoding analysis based on amplicons of the highly variable nuclear-encoded ITS2 rDNA region, complemented by a clone library approach. It targeted the four algal classes, Chlorophyceae, Trebouxiophyceae, Ulvophyceae, and Xanthophyceae, representing key groups of cold-adapted soil algae.
Results
A surprisingly high diversity of 830 algal OTUs was revealed, assigned to 58 genera in the four targeted algal classes. Members of the green algal class Trebouxiophyceae predominated in the soil algae communities. The major part of the algal biodiversity, 86.1% of all algal OTUs, could not be identified at the species level due to insufficient representation in reference sequence databases. The classes Ulvophyceae and Xanthophyceae exhibited the most unknown species diversity. About 9% of the Meseta algae species diversity was shared with that of the temperate reference site in Germany.
Discussion
In the small portion of algal OTUs for which their distribution could be assessed, the entire ITS2 sequence identity with references shows that the soil algae likely have a wide distribution beyond the Polar regions. They probably originated from soil algae propagule banks in far southern regions, transported by aeolian transport over long distances. The dynamics and severity of environmental conditions at the soil surface, determined by high wind currents, and the soil algae’s high adaptability to harsh environmental conditions may account for the high similarity of soil algal communities between the northern and southern parts of the Meseta.
... Simple intraspecific interactions and low taxonomic diversity allow for the consideration of terrestrial micrometazoan assemblages as models for ecology studies Wall et al. 2006;Heatwole & Miller 2019). This is especially important in the context of climate change and anthropogenic impact, both of which are dramatically affecting the components of Antarctic biota (Convey 2010;Chown et al. 2012;Convey & Peck 2019). ...
... The Antarctic terrestrial biota is commonly considered to be relatively poorly known (Convey 2010;Convey et al. 2014). Nevertheless, a number of genetic studies of micrometazoans have enhanced our knowledge of the diversity of particular groups (Velasco-Castrillón, Page et al. 2014;Velasco-Castrillón et al. 2015) and have revised earlier published data Velasco-Castrillón et al. 2018). ...
To elucidate poorly known aspects of the microscopic metazoan distribution in ice-free parts of the Antarctic, we examined samples of the multicellular terrestrial alga Prasiola crispa, collected over the last decade in different parts of continental East Antarctica and Haswell Island. We found that the micrometazoans inhabiting the algae consist of remarkably abundant bdelloid rotifers (subclass Bdelloidea), followed by tardigrades. We did not find nematodes. The rotifer assemblages were characterized by low diversity (only six species). Nevertheless, rotifer densities were extremely high: mean densities ranged from 75 to 3030 individuals per 100 mg of the dry sample weight and the maximum value numbered in excess of 8000 per 100 mg of the dry sample weight. These data show that terrestrial algae, along with mosses, are a very attractive habitat for rotifers and tardigrades in the Antarctic. The statistical analysis showed a lack of correlations between rotifer and tardigrade densities and nutrients (N, C, P, K and Na). Our findings are consistent with the patchy distribution of terrestrial micrometazoans in the Antarctic that has previously been found.
... Nielsen et al. (2011) similarly conclude that studies of the important soil faunal group, nematode worms, indicate responses to longer-term climate trends and rare 'extreme' events. However, basic survey and monitoring of the dominant cryptogamic and soil microbial communities of Antarctica and their associated fauna is lacking (Convey, 2006(Convey, , 2010Barrett et al., 2008;Wall et al., 2011). ...
... Given the limited biodiversity found within Antarctic terrestrial ecosystems and the slow rate of natural transfer and colonization by species from outside the region since the gradual improvement of conditions after the Last Glacial Maximum, it is thought there are low levels of functional redundancy in native communities, and not all niches are fi lled. Th is may provide opportunities for new colonists, irrespective of whether they are introduced by natural or anthropogenic means (Convey, 2006(Convey, , 2010(Convey, , 2011. In addition to this, native species, due to their long isolation and typically adversity selected life history characteristics, are generally poor competitors and vulnerable to competition from more aggressive colonizers (Kennedy, 1993;Convey, 1996a). ...
This book is part of the "CABI Invasive Series", which addresses all topics relating to invasive species, including biosecurity surveillance, mapping and modelling, economics of invasive species and species interactions in plant invasions. Aimed at researchers, upper-level students and policy makers, titles in the series provide international coverage of topics related to invasive species, including both a synthesis of facts and discussions of future research perspectives and possible solutions. This book specifically aims to examine the nexus of climate change and biological invasions, and the resulting impacts, and to identify means to reduce the vulnerability and increase the resiliency of managed and unmanaged ecosystems. It is divided into four parts: (i) the dimensions of the problem: background and science; (ii) case studies; (iii) management: detection and prevention; and (iv) management: control and adaptation.
... The biogeographic origins of the extant limno-terrestrial fauna of maritime and continental Antarctica, and the sub-Antarctic islands have been debated for more than a decade (e.g. Pugh and Scott, 2002; Barnes et al., 2006;Convey et al., 2007Convey et al., , 2008Pugh and Convey, 2008;Convey, 2010;Vyverman et al., 2010;Fraser et al., 2012). The current biogeographic distributions of Antarctic endemic or circum-Antarctic taxa could be the result of recent, ongoing dispersal in Antarctic regions (re-colonisation hypothesis; see Pugh, 2004) and/ or the consequence of relict Gondwanan taxa surviving the extreme, harsh conditions of Antarctica over the last 23 million years (My) (glacial refugia hypothesis; see . ...
... Antarctica formed a major component of the Gondwanan continent with a rich fauna and flora before geological and climate evolution isolated the continent and successive ice ages eliminated most plant and animal life. The extant biota that might have been associated with that period has been restricted to cryptogams and terrestrial meiofauna (Convey, 2010). Tardigrades, rotifers, and nematodes are major components of terrestrial Antarctic meiofauna in terms of diversity, number of specimens, distribution, and colonised substrates. ...
The origin of the Antarctic continental extant fauna is a highly debated topic, complicated by the paucity of organisms for which we have clear biogeographic distributions and understanding of their evolutionary timescale. To shed new light on this topic, we coupled molecular clock analyses with biogeographic studies on the heterotardigrade genus Mopsechiniscus. This taxon includes species with endemic distributions in Antarctica and other regions of the southern hemisphere. Molecular dating using different models and calibration priors retrieved similar divergence time for the split between the Antarctic and South American Mopsechiniscus lineages (32–48 Mya) and the estimated age of the Drake Passage opening that led to the separation of Antarctica and South America. Our divergence estimates are congruent with other independent studies in dating Gondwanan geological events. Although different analyses retrieved similar results for the internal relationships within the Heterotardigrada, our results indicated that the molecular dating of tardigrades using genes coding for ribosomal RNA (18S and 28S rDNA) is a complex task, revealed by a very wide range of posterior density and a relative difficulty in discriminating between competing models. Overall, our study indicates that Mopsechiniscus is an ancient genus with a clear Gondwanan distribution, in which speciation was probably directed by a cooccurrence of vicariance and glacial events.
... Global primary production is governed by higher plants, bryophytes and soil microbes (Kirchman and Kirchman, 2018). However, the simple trophic structure of Antarctic terrestrial ecosystems means that primary production in these cold deserts is predominantly regulated by soil microbes (Castro-Sowinski, 2019;Convey, 2010;Hogg et al., 2006). Microorganisms, being the dominant biota in the Antarctic soils, perform vitally important ecological roles in these deserts (Cowan et al., 2014). ...
Life at Robinson Ridge, located in the Windmill Islands region of East Antarctica, is susceptible to a changing climate. At this site, responses of the vegetation communities and moss-beds have been well researched, but corresponding information for microbial counterparts is still lacking. To bridge this knowledge gap, we established baseline data for monitoring the environmental drivers shaping the soil microbial community on the local ‘hillslope’ scale. Using triplicate 300-m long transects encompassing a hillslope with wind-exposed arid soils near the top, and snowmelt-sustained-moss beds at the bottom, we assessed the fine-scale heterogeneity of the soil environmental and microbial properties. Moist, low-lying, and vegetated soils exhibited higher soil fertility and unique biodiversity, with taxa adapted to thrive in moist conditions (i.e., Tardigrada, Phragmoplastophyta, Chloroflexi) and those that have previously demonstrated strong specificity for moss species (i.e., Fibrobacterota, Mucoromycota and Cyanobacteria) dominating. In contrast, elevated soils with limited moisture and nutrients were dominated by metabolically diverse phyla like Actinobacteriota and Ascomycota. Significant differences in microbial communities were observed at both hillslope (50–300 m) and fine spatial scales, as small as 0.1 m. Vertical heterogeneity was observed with higher abundances of Cyanobacteria and micro-algae in surfaces compared to subsoil, potentially indicating early biocrust formation. Stochastic and deterministic processes governing phylogenetic assembly were linked to soil positional groups and microbial domains rather than soil depth. Gradient Forest modeling identified critical environmental thresholds, such as ammonia, manganese, and sulphur, responsible for drastic community changes following level alterations. This reinforces the existence of strong niche preferences and distinct distribution patterns within the local microbial communities. This study highlights the need for finer-scale investigations considering site topography to better understand the relationship between environmental drivers and local microbiota. Ultimately, these insights enable us to understand environmental drivers and predict Antarctic ecosystem responses, helping safeguard this fragile environment.
... The extensive glaciation of Antarctica, with 99.6% of its surface being ice-covered (Convey, 2010), severely restricts the availability of terrestrial paleoenvironmental evidence of deglaciation history in the continent's limited ice-free areas. In this study, we combined direct surface exposure dating of polished surfaces and moraine boulders with lichenometry performed on the most recent moraine ridges to reconstruct the spatial and temporal patterns of glacial thinning and horizontal retreat on the Hurd Peninsula in Livingston Island. ...
... In its current state, terrestrial Antarctica's relatively simple trophic structure makes it an ideal system to study how soil microbial community composition responds to environmental change (Bottos et al., 2014;Convey, 2010). Hence, the application of gradient forest modeling to Antarctica's soil microbiota is timely, given the need to establish long-term monitoring systems. ...
Overgeneralization and a lack of baseline data for microorganisms in high‐latitude environments have restricted the understanding of the microbial response to climate change, which is needed to establish Antarctic conservation frameworks. To bridge this gap, we examined over 17,000 sequence variants of bacteria and microeukarya across the hyperarid Vestfold Hills and Windmill Islands regions of eastern Antarctica. Using an extended gradient forest model, we quantified multispecies response to variations along 79 edaphic gradients to explore the effects of change and wind‐driven dispersal on community dynamics under projected warming trends. We also analyzed a second set of soil community data from the Windmill Islands to test our predictions of major environmental tipping points. Soil moisture was the most robust predictor for shaping the regional soil microbiome; the highest rates of compositional turnover occurred at 10–12% soil moisture threshold for photoautotrophs, such as Cyanobacteria, Chlorophyta, and Ochrophyta. Dust profiles revealed a high dispersal propensity for Chlamydomonas, a microalga, and higher biomass was detected at trafficked research stations. This could signal the potential for algal blooms and increased nonendemic species dispersal as human activities increase in the region. Predicted increases in moisture availability on the Windmill Islands were accompanied by high photoautotroph abundances. Abundances of rare oligotrophic taxa, such as Eremiobacterota and Candidatus Dormibacterota, which play a crucial role in atmospheric chemosynthesis, declined over time. That photosynthetic taxa increased as soil moisture increased under a warming scenario suggests the potential for competition between primary production strategies and thus a more biotically driven ecosystem should the climate become milder. Better understanding of environmental triggers will aid conservation efforts, and it is crucial that long‐term monitoring of our study sites be established for the protection of Antarctic desert ecosystems. Furthermore, the successful implementation of an improved gradient forest model presents an exciting opportunity to broaden its use on microbial systems globally.
... Here, we use springtails (Collembola) as a study group because they are one of the most abundant groups in Antarctica (Convey, 2010), and its importance for soil functioning both above and belowground (Bardgett & van der Putten, 2014). In addition to this, springtails are a group highly dependent on environmental conditions, and especially soil moisture, for their survival (Chown, 2002;Teets & Denlinger, 2014). ...
The extreme low humidity and temperatures in Antarctica make it one of the harsher areas for life on our planet. In a global change context, environmental barriers that prevented the arrival of alien species in Antarctica are weakening. Deception Island, one of the four active volcanoes of Antarctica, is especially vulnerable to the impacts of alien species. Geothermal areas (GA) in this Island offer unique microclimatic conditions that could differentially affect native and alien soil arthropods. Here we explore the desiccation tolerance of a native (Cryptopygus antarcticus) and an alien (Proisotoma minuta) springtail (Collembola) species to these extreme environmental conditions. GA and non-geothermal areas (NGA) were selected to evaluate intra-and interspecific variation in desiccation tolerance. Populations of P. minuta from GA had greater desiccation tolerance than populations from NGA. However, desiccation tolerance of C. antarcticus did not differ between GA and NGA. This native species had greater desiccation tolerance than the alien P. minuta, but also greater body size. Our findings show that the alien P. minuta responds differently to environmental conditions than the native C. antarcticus. Furthermore, body size may influence desiccation tolerance in these two springtail species.
... Hoham et al. 2009, Leya et al. 2009 ), few have assessed responses to more realistic, multistressor conditions, nor potential inter-or intr aspecific r esponses. Researc h into other cryospheric terr estrial micr oor ganisms, including r ed snow algae (Segawa et al. 2018 ), has identified endemism (Vincent 2000, Conv ey 2010, Vyv erman et al. 2010, Segawa et al. 2017 ), but it is not y et kno wn if similar endemism exists across other snow algal species, nor the role of endemism in modulating responses to abiotic str essors. Her e, we assessed the growth, cellular stoichiometric, and photophysiological capabilities of two snow algal genera ( Microglena spp. ...
Snow algal blooms are widespread, dominating low temperature, high light, oligotrophic melting snowpacks. Here we assessed the photophysiological and cellular stoichiometric responses of snow algal genera Chloromonas spp. and Microglena spp in their vegetative life stage isolated from the Arctic and Antarctic to gradients in temperature (5-15 °C), nitrate availability (1-10 µmol L-1), and light (50 and 500 µmol photons m-2 s-1). When grown under gradients in temperature, measured snow algal strains displayed Fv/Fm values increased by ∼115% and electron transport rates decreased by ∼50% at 5 °C compared to 10 and 15 °C, demonstrating how high light can mimic low temperature impacts to photophysiology. When using carrying capacity as opposed to growth rate as a metric for determining the temperature optima, these snow algal strains can be defined as psychrophilic, with carrying capacities ∼90% higher at 5 °C than warmer temperatures. All strains approached Redfield C: N stoichiometry when cultured under nutrient replete conditions regardless of temperature (5.7 ± 0.4 across all strains), whereas significant increases in C: N were apparent when strains were cultured under nitrate concentrations that reflected in-situ conditions (17.8 ± 5.9). Intra-specific responses in photophysiology were apparent under high-light with Chloromonas spp. more capable of acclimating to higher light intensities. These findings suggest that in-situ conditions are not optimal for the studied snow algal strains, but they are able to dynamically adjust both their photochemistry and stoichiometry to acclimate to these conditions.
... Ice-free areas in Antarctica (coastal islands, inland mountains, nunataks), constituting less than 0.5% of the continental landmass, are among the most disproportionately affected by human activities (Brooks et al., 2019a,b). Supporting high ecological diversity ((substrate for bryophytes, lichens, microbiota) Convey, 2010), these areas serve as nesting grounds for iconic vertebrate species such as Adélie penguin Pygoscelis adeliae, open nesters (such as Antarctic petrel, south polar skua) and crevice-nesting species of pelagic seabirds (e.g., snow petrel and Wilson's storm-petrel- Harris et al., 2015). Given the sensitive nature of these ice-free areas, and their outstanding ecosystem values (Brooks et al., 2019a,b), seabird species breeding here need regular monitoring. ...
... One of the non-native species that would function as a model species in the analysis of the effect of climate change on growth, survival, and the type of interaction (facilitation/ competition) on native Antarctic plants is Juncus bufonius L. Juncus bufonius is a species whose propagules have been reported in soil samples from the vicinity of the Henryk Arctowski Polish Antarctic Station (Admiralty Bay, King George Is., South Shetlands), with a probable distribution area of approximately 300 m 2 (Cuba-Díaz et al. 2013. Additionally, this species has been reported to invading different sub-Antarctic islands (Frenot et al. 2005) and is considered one of the most dangerous species due to its high level of invasiveness (Convey 2010;Bazzichetto et al. 2021). J. bufonius is a cosmopolitan species, mainly associated with coastal areas and cool and temperate climates with moderately high precipitation, and it can also tolerate saline conditions (Heywood et al. 2007). ...
Anthropogenic pressure and climate change have generated important changes in the environmental conditions of Antarctic ecosystems. These changes include the introduction of non-native species, rising temperatures, changes in precipitation patterns, and the expansion of ice-free areas. These alterations can have adverse effects on the native flora. Therefore, our study aimed to assess the potential impact of the non-native plants: Poa annua and Juncus bufonius on native species Colobanthus quitensis and Deschampsia antarctica under climate change simulated conditions. Individuals of C. quitensis/D. antarctica and J. bufonius/P. annua were exposed to four different growth conditions: 6 °C/low water availability (LW); 8 °C/LW and 6 °C/high water availability (HW) and 8 °C/HW. We hypothesized that competition would be more intense at 8 °C/HW, whereas facilitation would be the predominant interaction at 6 °C/LW. The results revealed that under 8 °C/HW conditions, all species experienced a significant increase in biomass production. However, the mortality rate of native species shows the opposite trend. The Relative Interaction Index (RII) showed a competitive effect of both non-native species on D. antarctica, independent of temperature and water availability, while for C. quitensis competition is more intense at LW conditions. These findings demonstrate that the impact of climate change could exacerbate the effects of non-native species on native species in Antarctic ecosystems. This includes non-native species that have been reported but have not yet established stable populations in the maritime Antarctic.
... Future experiments could be expanded to include single or synergetic physical, chemical, and biological disturbances, predicted to become more frequent in the system due to climate change (Hughes and Convey 2010), to understand how these will impact ecosystem functions and resilience. Lastly, the human presence associated with fieldwork activities in the continent can leave long-lasting disturbances in the icefree soils affecting Antarctica's wilderness and aesthetic values as well as habitat suitability for its biota (Convey 2010;O'Neill et al. 2015). As such, efforts to develop infrastructure that enables remote and more sustainable research practices on ice-free regions should be encouraged and part of frameworks aimed to conserve and manage Antarctica's unique biodiversity and environment, one of the founding principles of the Antarctic Treaty. ...
Polar deserts contain unique and sensitive communities responsive to climate-associated habitat changes. However, unlike temperate desert ecosystems, characterizing and predicting the responses of polar ecosystems to environmental change remains a significant challenge due to logistical constraints. Here we aim to demonstrate the use of a custom-designed Polar Desert Environmental Chamber (PDEC) to perform off-continent experimental ecological research. We did so by characterizing the structure and composition of arid edaphic bacterial communities collected from the McMurdo Dry Valleys during a simulated wetting event. The results were discussed in light of previous field observations. Rapid structural and compositional changes were observed during wetting and re-drying treatments. Those were driven by changes in the relative abundance of coexisting taxa, which fluctuated asynchronously over time in response to the treatments. While selection was the main ecological factor influencing communities during dry conditions or the initial wetting, with prolonged exposure to wetness, neutral processes began to drive community assembly. Ultimately, these observations reflect different adaptative responses from microbial taxa to water stress, which can be argued as beneficial to increasing resilience in polar deserts. Our findings demonstrate that experiments conducted in PDEC provide valuable contextual data on community response to environmental change and can accelerate our ability to assess biological thresholds to change within polar desert ecosystems. We advocate that, with careful consideration of key emulated environmental attributes, laboratory-based Antarctic research can complement fieldwork to achieve a nuanced and evidence-based understanding of the ecology of Antarctica’s ice-free regions.
... org/ 10. 15468/ doyfzk). However, this inventory remains incomplete compared to those from both adjacent deeper waters and terrestrial habitats (Convey, 2010, Terauds et al., 2012, De Broyer et al., 2014. This review also highlighted an important bias in the geographic areas studied as well as a general lack of standardized and quantitative sampling approaches applied (e.g., Bick & Arlt, 2013, Waller, 2013, Aghmich et al., 2016. ...
The underexplored intertidal ecosystems of Antarctica are facing rapid changes in important environmental factors. Associated with temperature increase, reduction in coastal ice will soon expose new ice-free areas that will be colonized by local or distant biota. To enable detection of future changes in faunal composition, a biodiversity baseline is urgently required. Here, we evaluated intertidal faunal diversity at 13 locations around the Gerlache Strait (western Antarctic Peninsula), using a combination of a quadrat approach, morphological identification and genetic characterization. Our data highlight a community structure comprising four generally distributed and highly abundant species (the flatworm Obrimoposthia wandeli, the bivalve Kidderia subquadrata, and the gastropods Laevilitorina umbilicata and Laevilitorina caliginosa) as well as 79 rarer and less widely encountered species. The most abundant species thrive in the intertidal zone due to their ability to either survive overwinter in situ or to rapidly colonize this zone when conditions allow. In addition, we confirmed the presence of multiple trophic levels at nearly all locations, suggesting that complex inter-specific interactions occur within these communities. Diversity indices contrasted between sampling locations (from 3 to 32 species) and multivariate approaches identified three main groups. This confirms the importance of environmental heterogeneity in shaping diversity patterns within the investigated area. Finally, we provide the first genetic and photographic baseline of the Antarctic intertidal fauna (106 sequences, 137 macrophotographs), as well as preliminary insights on the biogeography of several species. Taken together, these results provide a timely catalyst to assess the diversity and to inform studies of the potential resilience of these intertidal communities.
... Low biological diversity and truncated food chains with a lack of high trophic levels are important characteristics of the freshwater ecosystems in the Continental Antarctic (Laybourn-Parry et al. 1997;Camacho 2006;Gibson et al. 2006;Laybourn-Parry and Pearce 2007). Consisting of communities of organisms that are adapted for existence in harsh conditions (Vincent 1988(Vincent , 2000Convey and Stevens 2007;Rogers et al. 2012;Laybourn-Parry and Wadham 2014), they can be considered models for evolutionary and ecology studies (Simmons et al. 1993;Laybourn-Parry and Pearce 2007;Camacho et al. 2012), which are becoming more important as the Antarctic environment is facing global changes (Convey 2010;Chown et al. 2012;Convey and Peck 2019). ...
Shallow waters, little-studied in Continental Antarctica, among other micrometazoans host bdelloid rotifers, which diversity, ecology, and distributional patterns in turn are poorly known. To address these issues, we analysed plankton samples collected during the 2018/2019 season in the Thala Hills oasis (East Antarctica), in shallow freshwater lakes and temporary ponds that formed during intense snow melting in December–January. Bdelloids were present in more than 90% of the sites with nine species revealed. The most frequent were Antarctic endemics [Philodina gregaria (P. gregaria), Adineta grandis (A. grandis), and Adineta coatsi (A. coatsi)], while some non-abundant bdelloids either provide characteristics of widely distributed taxa or require further taxonomy studies as they can be species new for the science. The abundance of bdelloids varied greatly across studied sites and localities, with a maximum of more than 700,000 ind m⁻³ and an increasing tendency to be more numerous in rock-basin temporary ponds, compared to larger lakes, with variability for different taxa. The environmental parameters strongly explain the bdelloid distribution (78.4% of the variation), with the most important factors being the type of bottom (9.9%), altitude (8.0%), TDS (6.6%), and salinity (6.5%). The cyanobacterial mats from the bottom didn’t contribute much to bdelloid distributional patterns, despite being known to be a preferred habitat for micrometazoans including rotifers. These results shape a perspective to study the processes of the formation of Antarctic seasonal aquatic habitats settled by organisms, which demonstrate an ecomorphological range from planktonic organisms to crawling ‘scrapers’.
... The environmental changes discussed above will be beneficial to some species and harmful for others. It is likely that species interactions will change, and a system primarily built on abiotic drivers of distributions may start to shift towards a more biotically driven system (Convey, 2010;Nielsen & Wall, 2013). Increased competition for space and resources may lead to a loss of local endemism and the emergence of more similar communities across regions (as is being observed in urban areas globally; Concepción et al., 2015;Clergeau et al., 2006). ...
Antarctic biodiversity faces an unknown future with a changing climate. Most terrestrial biota is restricted to limited patches of ice‐free land in a sea of ice, where they are adapted to the continent’s extreme cold and wind and exploit microhabitats of suitable conditions. As temperatures rise, ice‐free areas are predicted to expand, more rapidly in some areas than others. There is high uncertainty as to how species’ distributions, physiology, abundance and survivorship will be affected as their habitats transform. Here we use current knowledge to propose hypotheses that ice‐free area expansion i) will increase habitat availability, though the quality of habitat will vary; ii) will increase structural connectivity, although not necessarily increase opportunities for species establishment; iii) combined with milder climates will increase likelihood of non‐native species establishment, but may also lengthen activity windows for all species; and iv) will benefit some species and not others, possibly resulting in increased homogeneity of biodiversity. We anticipate considerable spatial, temporal, and taxonomic variation in species responses, and a heightened need for interdisciplinary research to understand the factors associated with ecosystem resilience under future scenarios. Such research will help identify at‐risk species or vulnerable localities and is crucial for informing environmental management and policymaking into the future.
... The windiest, coldest and driest continent, the Antarctica, has only 0.32% of its land ice-free (Chown and Convey 2007). The three biogeographic zones of Antarctica i.e., Sub-Antarctic zone, Maritime Antarctica and Continental Antarctica have different climatic conditions and terrestrial ecosystems (Peter 2010). Studies are been conducted to review the Antarctic climate variability in past years and have reported the warming and climate change on the western side of the Antarctic Peninsula (Bajerski and Wagner 2013). ...
Antarctica is the coldest and driest continent globally and has always been an exciting habitat to study extremophiles. The study reveals a monostromatic nitrophilic green alga Prasiola crispa (Trebouxiophyceae) growing on Adelie penguin guano at a penguin rockery, Larsemann Hills, Eastern Antarctica. This study is the first report of the barcode of this algal genus from Eastern Antarctica in general and the Larsemann Hills in particular. There are 35 species currently accepted in this genus, while four were reported from Antarctica. The present study relied on morphological diagnoses as well as the phylogenetic inference based on nuclear-encoded ITS gene and plastid-encoded tufA gene for species identification. The study generated phylogenetic reconstruction at the two selected loci for the first time for this species from Antarctica.
... Perhaps, the most comprehensive dataset was used in the article of Fontaneto et al. cited above (2015b) which is devoted to analysis of rotifer biogeography patterns in Antarctica. But the survey area is still small in comparison to habitats available on the continent (Convey 2010;Convey et al. 2014), thus we may assume that the rotifer species list in Antarctica will be much bigger. In accordance with the most recent data related to significant rotifers endemism in Antarctica (Velasco-Castrillon et al. 2014b;Iakovenko et al. 2015) we believe that the researching of these invertebrates at the icebound continent could lead to results of large importance in understanding of distribution, biogeography and evolution of the phylum Rotifera. ...
The paper presents the results of rotiferological studies carried out during the set of the Belarusian Antarctic Expeditions (2007–2017) in East Antarctica (Enderby Land and Prydz Bay). The plankton samples were collected from 52 water bodies (lakes and meltwater ponds), and from terrestrial habitats (lichen fouling, algal mats) from several sites. A total of 20 species were found, 12 of them belonging to Monogononta, 8 – to Bdelloidea. Despite the presence of some cosmopolitan species and Antarctic endemics, the set of species and forms seems to be the firstly noted taxa in East Antarctica.
... The vegetation in the Antarctic environment is restricted to ice-free areas, mainly in the Antarctic islands and in the coastal areas of the continent regions (Alberdi et al., 2002;Convey, 2006;Fretwell et al., 2011). These plant communities are predominantly cryptogamic, also known as lower plants or biological soil crusts (BSC) (Convey, 2010), and their growth season length depends on the climatic conditions, latitude, and relief (Selkirk & Skotnicki, 2007). The availability of liquid water is the most critical factor for the development of vegetation communities in Antarctica, which is available during few months when snow melts and summers rain occurs, or when the humidity can be absorbed directly from the air (Elster, 2002;Bölter et al., 2002;Choi et al., 2015). ...
The Antarctic vegetation maps are usually made using very high-resolution images collected by orbital sensors or unmanned aerial vehicles, generating isolated maps with information valid only for the time of image acquisition. In the context of global environmental change, mapping the current Antarctic vegetation distribution on a regular basis is necessary for a better understanding of the changes in this fragile environment. This work aimed to generate validated vegetation maps for the North Antarctic Peninsula and South Shetlands Islands based on Sentinel-2 images using cloud processing. Sentinel-2 imagery level 1C, acquired between 2016 and 2021 (January-April), were used. Land pixels were masked with the minimum value composite image for the "water vapor" band. The NDVI maximum value composite image was sliced, and its classes were associated with the occurrence of algae (0.15 - 0.20), lichens (0.20 - 0.50), and mosses (0.50 - 0.80). The vegetation map was validated by comparing it with those from the literature. The present study showed that Sentinel-2 images allow building a validated vegetation type distribution map for Antarctica Peninsula and South Shetlands Islands.
... The Antarctic convergence zone is classified into three biogeographical regions: Continental Antarctica, Maritime Antarctica, and Sub-Antarctica (Convey, 2010). These three regions are differentiated mainly by their average annual temperatures, rainfall, and winds, and are also associated with characteristic biota. ...
The objective of this study is to identify and analyze integrons and antibiotic resistance genes (ARGs) in samples collected from diverse sites in terrestrial Antarctica. The metagenomic analysis allowed us to identify novel predicted intI integrases and gene cassettes (GCs), which mostly encode unknown functions.
Abstract
The objective of this study is to identify and analyze integrons and antibiotic resistance genes (ARGs) in samples collected from diverse sites in terrestrial Antarctica. Integrons were studied using two independent methods. One involved the construction and analysis of intI gene amplicon libraries. In addition, we sequenced 17 metagenomes of microbial mats and soil by high-throughput sequencing and analyzed these data using the IntegronFinder program. As expected, the metagenomic analysis allowed for the identification of novel predicted intI integrases and gene cassettes (GCs), which mostly encode unknown functions. However, some intI genes are similar to sequences previously identified by amplicon library analysis in soil samples collected from non-Antarctic sites. ARGs were analyzed in the metagenomes using ABRIcate with CARD database and verified if these genes could be classified as GCs by IntegronFinder. We identified 53 ARGs in 15 metagenomes, but only four were classified as GCs, one in MTG12 metagenome (Continental Antarctica), encoding an aminoglycoside-modifying enzyme (AAC(6´)acetyltransferase) and the other three in CS1 metagenome (Maritime Antarctica). One of these genes encodes a class D β-lactamase (blaOXA-205) and the other two are located in the same contig. One is part of a gene encoding the first 76 amino acids of aminoglycoside adenyltransferase (aadA6), and the other is a qacG2 gene.
... It is comprised of three distinct biogeographi-cal sub-regions that can be defined both geographically and climatically: sub-Antarctic Region, the Maritime Antarctic Region and the Continental Antarctic Region. The Maritime Antarctic Region consists of the regions west of the Antarctic Peninsula extending south to Marguerite Bay, including the South Shetland Islands, S. Orkney, and S. Sandwich and Bouvet Islands (Convey 2010). ...
The Antarctic diatom flora has been at the centre of interest of many studies in past decades. The present paper brings new information on the species richness, biogeography and community composition of diatoms on the Ardley Island, South Shetland Islands. One fresh-water and ten soil samples had been collected from the Antarctic Special protected area (ASPA) in the spring of 2019. The following analysis revealed eighty-six diatom taxa in well-developed communities, dominated by Luticola muticopsis, L. truncata, Pinnularia australoschoenfelderi, P. austroshetlandica and P. borealis. According to the current biogeographical knowledge, the majority of species have restricted distribution among the Antarctic Realm; 46.5% of them are reported from various islands of the Maritime Antarctic Region. Based on the dominance of species as Luticola muticopsis and L. truncata and their ecological preferences, we concluded that the species composition of the diatom communities is driven by high nutrient input from breeding seabirds and the moisture availability during the austral summer.
... The Antarctic is a continent isolated by the Antarctic Circumpolar Current, where weather conditions are very harsh and thus, the diversity of the fauna and flora occurring there is low (Dodds, 2012;Convey, 2010;Olech, 2004). For example, the terrestrial flora consists of only mosses, lichens, and two species of vascular plants (Olech, 2004). ...
The present article introduces data on natural radioactivity (⁴⁰K, 230,232Th, 234,238U) in the Antarctic marine and terrestrial environment. Various biota samples were analysed due to internal exposure to ⁴⁰K, 230,232Th, 234,238U. Activity concentration of ⁴⁰K was the highest in both marine and terrestrial samples. Mean values of ⁴⁰K activity concentration are 1340 Bq/kg and 370 Bq/kg for the marine and terrestrial samples respectively. ²³⁴U/²³⁸U ratios analysis revealed that sea waters and sea spray are the main source of the uranium in the terrestrial samples. Average 230,232Th, 234,238U activity concentrations in the Antarctic biota do not exceed 6 Bq/kg. Weighted internal dose rates are relatively low; they range from approximately 0.1 to 0.6 μGy/h. Statistically significant differences in radionuclide accumulation were discovered between the mosses and lichens. It may point to various mechanisms of the nutrient absorption from the environment by these organisms.
... Recent interest in climate change and global warming has affected the distribution and function of vegetation by changing the environmental conditions of ecosystems [1]. Since the Antarctic ecosystem is particularly sensitive to environmental change, studying its responses can enhance our understanding of such changes [2][3][4][5][6]. The monitoring of terrestrial biodiversity in the Antarctic Peninsula and the South Shetland Islands, which are some of the most rapidly warming areas in the world [6,7], is vital as a proxy for climate change. ...
Spectral information is a proxy for understanding the characteristics of ground targets without a potentially disruptive contact. A spectral library is a collection of this information and serves as reference data in remote sensing analyses. Although widely used, data of this type for most ground objects in polar regions are notably absent. Remote sensing data are widely used in polar research because they can provide helpful information for difficult-to-access or extensive areas. However, a lack of ground truth hinders remote sensing efforts. Accordingly, a spectral library was developed for 16 common vegetation species and decayed moss in the ice-free areas of Antarctica using a field spectrometer. In particular, the relative importance of shortwave infrared wavelengths in identifying Antarctic vegetation using spectral similarity comparisons was demonstrated. Due to the lack of available remote sensing images of the study area, simulated images were generated using the developed spectral library. Then, these images were used to evaluate the potential performance of the classification and spectral unmixing according to spectral resolution. We believe that the developed library will enhance our understanding of Antarctic vegetation and will assist in the analysis of various remote sensing data.
... The fact that the Antarctic continent is heavily glaciated with only 0.34% of ice-free surface (Convey, 2010;British Antarctic Survey, 2004) limits the availability of terrestrial paleoenvironmental records, such as lacustrine sediments, marine terraces and very few glacially-polished bedrocks, moraines and erratic boulders, that can be used to trace the deglaciation processes (Seong et al., 2009;Palacios et al., 2020 and references therein). ...
The small ice caps distributed across the Antarctic Peninsula region have undergone large ice volume changes since the Last Glacial Cycle, in line with most of the Antarctic continent. While the surface extent of glacial shrinking is relatively well known, the timing of glacial oscillations and the magnitude of ice thinning remain little investigated. Cosmic-Ray Exposure (CRE) dating applied on ice-free vertical sequences can provide insights about the temporal framework of glacial oscillations. However, the potential occurrence of nuclide inheritance may overestimate the real timing of the last glacial retreat. This problem has been observed in many areas in Continental Antarctica, but similar studies have not yet been conducted in environments of the Maritime Antarctica, such as the South Shetland Islands (SSI). This research focuses on the Hurd Peninsula ice cap (HPIC, ca. 60°22′ W, 62°40’ S), located in the SW of Livingston Island, SSI. Past climate oscillations since the Last Glacial Cycle have determined the amount of ice stored in the ice cap. Today, this polythermal ice cap is surrounded by several nunataks standing out above the ice. Three of them have been selected to explore their deglaciation history and to test the potential occurrence of nuclide inheritance in deglaciated bedrocks associated with polythermal glaciers. We present a new dataset with 10 10Be exposure dates. Some of them were found to be anomalously old, evidencing that nuclide inheritance is present in bedrocks associated with polythermal ice caps and suggesting complex glacial exposure histories. We attribute this to limited erosion, given the gentle slope of the nunatak margins and the cold-based character of the surrounding ice. The remaining samples allowed to approach local surface-elevation changes of the HPIC. Our results suggest that ice thinning started during the Last Glacial Maximum (LGM) at ∼22 ka but intense glacial shrinking occurred from ∼18 to ∼13 ka, when the nunataks became exposed, being particularly intense at the end of this period (∼14–13 ka) coinciding with the time of the meltwater pulse 1a (MWP-1a) and the end of the Antarctic Cold Reversal (ACR).
... The Antarctic Peninsula (AP) is known for its climate variability and the recent changes observed in the components of the cryosphere [1][2][3], as well as in terrestrial, marine, and other aquatic ecosystems along the western and eastern coasts [4,5]. At the end of the 20th century, the warming was very intense [6], but a cooling trend was identified at the beginning of the 21st century [7]. ...
The Antarctic Peninsula belongs to the regions of the Earth that have seen the highest increase in air temperature in the past few decades. The warming is reflected in degradation of the cryospheric system. The impact of climate variability and interactions between the atmosphere and the cryosphere can be studied using numerical atmospheric models. In this study, the standard version of the Weather Research and Forecasting (WRF) model was validated on James Ross Island in the northern part of the Antarctic Peninsula. The aim of this study was to verify the WRF model output at 700 m horizontal resolution using air temperature, wind speed and wind direction observations from automatic weather stations on the Ulu Peninsula, the northernmost part of James Ross Island. Validation was carried out for two contrasting periods (summer and winter) in 2019/2020 to assess possible seasonal effects on model accuracy. Simulated air temperatures were in very good agreement with measurements (mean bias −1.7 °C to 1.4 °C). The exception was a strong air temperature inversion during two of the winter days when a significant positive bias occurred at the coastal and lower-altitude locations on the Ulu Peninsula. Further analysis of the WRF estimates showed a good skill in simulating near-surface wind speed with higher correlation coefficients in winter (0.81–0.93) than in summer (0.41–0.59). However, bias and RMSE for wind speed tended to be better in summer. The performance of three WRF boundary layer schemes (MYJ, MYNN, QNSE) was further evaluated. The QNSE scheme was generally more accurate than MYNN and MYJ, but the differences were quite small and varied with time and place. The MYNN and QNSE schemes tended to achieve better wind speed simulation quality than the MYJ scheme. The model successfully captured wind direction, showing only slight differences to the observed values. It was shown that at lower altitudes the performance of the model can vary greatly with time. The model results were more accurate during high wind speed southwestern flow, while the accuracy decreased under weak synoptic-scale forcing, accompanied by an occurrence of mesoscale atmospheric processes.
... Moreover, manure from abandoned cow sheds provided specific ameliorated environmental conditions enabling the survival of terrestrial invertebrate species not yet recorded elsewhere in Svalbard [18][19][20]. Introduction of new species to islands can be deleterious since the island communities may be disrupted, often resulting in the extinction of their endemic species [176][177][178]. ...
Svalbard is a singular region to study biodiversity. Located at a high latitude and geographically isolated, the archipelago possesses widely varying environmental conditions and unique flora and fauna communities. It is also here where particularly rapid environmental changes are occurring, having amongst the fastest increases in mean air temperature in the Arctic. One of the most common and species-rich invertebrate groups in Svalbard is the mites (Acari). We here describe the characteristics of the Svalbard acarofauna, and, as a baseline, an updated inventory of 178 species (one Ixodida, 36 Mesostigmata, 43 Trombidiformes, and 98 Sarcoptiformes) along with their occurrences. In contrast to the Trombidiformes and Sarcoptiformes, which are dominated in Svalbard by species with wide geographical distributions, the Mesostigmata include many Arctic species (39%); it would thus be an interesting future study to determine if mesostigmatid communities are more affected by global warming then other mite groups. A large number of new species (42 spp.) have been described from Svalbard, including 15 that have so far been found exclusively there. It is yet uncertain if any of these latter species are endemic: six are recent findings, the others are old records and, in most cases, impossible to verify. That the Arctic is still insufficiently sampled also limits conclusions concerning endemicity.
... Freezing and desiccation are key challenges for the survival of invertebrates in the Antarctic region (Wharton, 2003;Teets and Denlinger, 2014). Most free-living Antarctic arthropods are endemic and are believed to have established prior to the last glacial maximum, displaying a variety of physiological adaptations to these extreme environmental conditions (Convey, 2010;Mortimer et al., 2011;Teets and Denlinger, 2014). For parasitic arthropods, survival in the Antarctic environment may be achieved by remaining closely associated with the host throughout the entire life cycle, including when the host forages at sea, or to develop physiological adaptations to survive in the terrestrial habitat while the host is away (e.g. ...
Due to its cold and dry climate and scarcity of ice-free land, Antarctica has one of the most extreme environments on our planet. To survive in the Antarctic region, parasitic arthropods must either remain closely associated with their hosts throughout the entire life cycle or develop physiological adaptations to survive in the terrestrial habitat while their hosts are away foraging at sea or overwintering at lower latitudes. Forty-eight species of birds and seven species of pinnipeds breed in the Antarctic region, with 158 species/subspecies of parasitic arthropods recorded thus far, comprising: sucking lice (Echinophthiriidae), chewing lice (Menoponidae, Philopteridae), fleas (Ceratophyllidae, Pygiopsyllidae, Rhopalopsyllidae), pentastomes (Reighardiidae), hard ticks (Ixodidae), nest-associated haematophagous mites (Laelapidae), nasal mites (Halarachnidae, Rhinonyssidae) and feather mites (Alloptidae, Avenzoariidae, Xolalgidae, Freyanidae). In this review, we provide an updated compilation of the available information on the host-parasite associations of arthropods infesting birds and pinnipeds in the Antarctic region, and discuss some over-arching ecological patterns and gaps of knowledge.
... Yet, even under such extreme conditions, microscopic animals can survive (Zeppilli et al. 2018). Among the most successful microscopic animals living in Antarctica are the nematodes, rotifers, and tardigrades (Convey 2010). Such microscopic animals were already known at the time of the first expeditions: ''The microscope showed that rotifers, water-bears, and other forms of minute animal-life existed'' (Shackleton 1909b). ...
We present a data set on Antarctic biodiversity for the phylum Rotifera, making it publicly available through the Antarctic Biodiversity Information facility. We provide taxonomic information, geographic distribution, location, and habitat for each record. The data set gathers all the published literature about rotifers found and identified across the Continental, Maritime, and Subantarctic biogeographic regions of Antarctica. A total of 1455 records of rotifers in Antarctica found from 1907 to 2018 is reported, with information on taxonomic hierarchies, updated nomenclature, geographic information, geographic coordinates, and type of habitat. The aim is to provide a georeferenced data set on Antarctic rotifers as a baseline for further studies, to improve our knowledge on what has been considered one of the most diverse and successful groups of animals living in Antarctica.
... Near-surface air temperature in Antarctica is an important driver of terrestrial biodiversity (Convey, 2010) and is decisive for hydrological (Herbei et al., 2016) and glaciological processes (Cook et al., 2005). Under a warming global climate Antarctica has been the focus of climate scientists for its impacted melting ice shelves, surface mass balance, sea ice changes (Siegert, 15 2016;Favier et al., 2017;Steig et al., 2013Steig et al., , 2009, and changes in atmospheric circulation patterns promoting higher meridional transport of atmospheric moisture and heat towards the Antarctic coastline (Turner et al., 2013;Raphael et al., 2016;Marshall et al., 2017). ...
Abstract. Air temperature is an important baseline parameter for terrestrial Antarctica in the context of patterns and processes in climatology, hydrology or ecology. There are still large uncertainties on how the Antarctic system responds to spatio-temporal variability of temperature. This can partly be attributed to the lack of high resolution datasets. In this paper, we present AntAir, a new dataset of gridded air temperatures in 1 km spatial and daily temporal resolution that is available since 2003. AntAir was created by modelling daily air temperature from MODIS land surface temperature using machine learning algorithms. Data from 70 weather stations was used as a reference. Daily temperatures could be estimated with a R 2 of 0.91 and a RMSE of 5.07 °C validated on independent years. The performance to estimate the time series of a new spatial location was R 2 = 0.78 and RMSE = 5.83 °C. Hence the high spatial and temporal resolution of the dataset as well as the high accuracy make AntAir an important baseline dataset for a wide range of applications in environmental science of Antarctica. The dataset is available at https://doi.pangaea.de/10.1594/PANGAEA.902166 (daily, Meyer et al., 2019a) and https://doi.pangaea.de/10.1594/PANGAEA.902193 (monthly, Meyer et al., 2019b).
... This biotic focus is consistent with the increased biological activity that occurs there, supported by the wetter moisture regime, more mature soils and warmer temperatures. The emphasis on tracks within ice-free areas may be attributed to the Maritime Antarctic representing the most diverse terrestrial Antarctic ecosystems (Convey 2010, Tejedo et al. 2016), more walking-based scientific activity (Pertierra et al. 2017) and relatively frequent pedestrian activity introduced by ship-based tourism. By extrapolating these results to station environments within the region, heavily disturbed sites with intense human activity are expected to have similar or more pronounced impacts compared with those found from walking tracks. ...
The small ice-free areas of Antarctica provide an essential habitat for most evident terrestrial biodiversity, as well as being disproportionately targeted by human activity. Visual detection of disturbance within these environments has become a useful tool for measuring areas affected by human impact, but questions remain as to what environmental consequences such disturbance actually has. To answer such questions, several factors must be considered, including the climate and biotic and abiotic characteristics. Although a body of research has established the consequences of disturbance at given locations, this paper was conceived in order to assess whether their findings could be generalized as a statement across the Antarctic continent. From a review of 31 studies within the Maritime Antarctic, Continental Antarctic and McMurdo Dry Valleys regions, we found that 83% confirmed impacts in areas of visible disturbance. Disturbance was found to modify the physical environment, consequently reducing habitat suitability as well as directly damaging biota. Visible disturbance was also associated with hydrocarbon and heavy metal contamination and non-native species establishment, reflecting the pressures from human activity in these sites. The results add significance to existing footprint measurements based on visual analysis, should aid on-the-ground appreciation of probable impacts in sites of disturbance and benefit environmental assessment processes.
... Antarctic soil is distinct from other biomes as consequence of its long-term persistence under harsh environmental conditions, in addition to its long history of isolation, resulting in a high degree of endemism (Convey 2010). Today, anthropic influences increasingly threaten the unique Antarctic soil communities through human-mediated climate change, increasing pollution, and the introduction of exogenous organisms by exploration activities, which may outcompete the endemic diversity in some environmental sites. ...
Fungi can colonize a wide variety of substrates in the Antarctic environment and have been found in diverse habitats on this continent. These fungi are often described by traditional microbiological methods. However, it is thought that a small fraction of the total fungal diversity can be recovered by isolation and cultivation techniques, and most species have been hitherto unculturable. Cultivation-independent methods have been proposed to be more accurate in describing fungal diversity and include a variety of techniques, such as scanning electron microscopy, fluorescence microscopy, microarray, and quantification analysis of ergosterol. In recent decades, molecular techniques, such as PCR amplification of the 18S and/or 28S rRNA gene region combined with fingerprint methods, clone libraries, and quantitative PCR, have mainly been developed in clinical microbiology. These approaches have been shown to be more informative, precise, reproducible, and faster compared with previous methods and, consequently, have been widely employed for describing fungal communities. More recently, next-generation sequencing has been widely used to study Antarctic fungal communities in diverse sample types, including arid and maritime soil, wood structures and soils at historic sites, rocks and stones, lichens, permafrost and active layer in permafrost, accretion ice from lakes, water from ice-covered lakes, hypersaline brines, and snow. In this chapter, we mainly focus on the fungal diversity characterized to date in Antarctic samples using cultivation-independent methods. An understanding of uncultured fungi can contribute to the elucidation of microbial functions and interactions that are responsible for maintaining life in extreme conditions.
Antarctica is populated by a diverse array of terrestrial fauna that have successfully adapted to its extreme environmental conditions. The origins and diversity of the taxa have been of continuous interest to ecologists since their discovery. Early theory considered contemporary populations as descendants of recent arrivals; however, mounting molecular evidence points to firmly established indigenous taxa far earlier than the Last Glacial Maximum, thus indicating more ancient origins. Here we present insights into Antarctica's terrestrial invertebrates by synthesizing available phylogeographic studies. Molecular dating supports ancient origins for most indigenous taxa, including Acari (up to 100 million years ago; Ma), Collembola (21–11 Ma), Nematoda (~30 Ma), Tardigrada (> 1 Ma) and Chironomidae (> 49 Ma), while Rotifera appear to be more recent colonizers (~130 Ka). Subsequent population bottlenecks and rapid speciation have occurred with limited gene transfer between Continental and Maritime Antarctica, while repeated wind- or water-borne dispersal and colonization of contiguous regions during interglacial periods shaped current distributions. Greater knowledge of Antarctica's fauna will focus conservation efforts to ensure their persistence.
Mosses play a key role in Antarctic ecosystems. Understanding of moss diversity and its likely drivers across Antarctica is, however, limited, as is the extent to which Antarctic Specially Protected Areas (ASPAs) represent this diversity. Both are important given changing climates and direct human impacts in the region. Here we investigate variation in moss diversity, the frequency distribution of their range sizes, and their continent‐wide conservation. Richness is positively related to temperature, but negatively related to latitude, distance from bird colonies and geothermal sites; terrain roughness showed weak, yet positive, effects. Beta‐diversity is similar to that found for assemblages separated by long distances, dominated by species turnover. Multi‐site turnover (zeta diversity) suggests that niche‐related mechanisms are likely more responsible for diversity patterns than neutral mechanisms, despite the significant role wind‐driven dispersal is thought to play in structuring Antarctic biodiversity patterns. The frequency distribution of range sizes of mosses was right skewed, indicating that several moss species have very small range sizes, while a few species have larger ranges. Where ASPAs include mosses, richness varies between 1 and 41 species, with 65.1% (71 species) of the 109 species known from the continent included in the ASPA network. Twenty‐four species lie within 25 km² radius of an ASPA, and 14 species beyond this distance could be considered relatively more difficult to protect. These findings lend support to the proposal that changing temperatures and expanding ice‐free areas will substantially increase Antarctica's diversity. Nonetheless, the mosses are reasonably well represented by the ASPA network, contrasting with other Antarctic taxa.
Soil bacterial communities are a crucial biological indicator of soil health and crop performance; however, their response to climate change remains poorly understood. In Maine, wild blueberry farms are experiencing unprecedented temperature changes, which may exacerbate microbial responses and potentially harm the crop. To elucidate the response of bacterial communities to warming during the growing season, we employed passive and active open-top chambers to simulate climate warming scenarios in wild blueberry fields. Warming treatments elevated atmospheric temperatures by 1.2 and 3.3 oC (passive and active warming), respectively, but did not affect soil temperatures. Nevertheless, soils in the active warming treatment exhibited significantly lower water content than ambient conditions. Overall, soil bacterial diversity and richness (June, July, and August data combined) under the warming (passive and active) treatments and ambient controls did not demonstrate significant differences after two years of experimental warming. However, significantly higher bacterial evenness and diversity under warming treatments were observed in the early growing season (June). Our study also reveals pronounced seasonal shifts in the evenness and diversity of bacteria in wild blueberry soil, suggesting that the variation in bacterial community structure may be more influenced by seasonal changes in temperature and plant activity during the growing season than by warming treatments. The increased bacterial evenness and diversity under warming treatments in June may be attributed to advanced plant phenology, indicating a potential future shift in seasonal dynamics of bacterial activity under global warming.
Alongside terrestrial habitats, aquatic habitats are of great importance in various parts of the Earth.
Studying and monitoring animals in terrestrial environments is easier and more accessible for
researchers than aquatic environments. The Antarctic is a geographical area where studies on the effects
of sound pollution on animal species are limited due to isolated areas, distance of habitat range and
climatic conditions. Here, I aim to provide an overview of the importance of biological studies,
behavioral aspects related to bioacoustics, and the potential impact of sound pollution resulting from
human activities, also known as “anthropogenic sound”, on the species diversity in the southern region
of Antarctica. Considering the importance of the biodiversity of animal species, conducting behavioral
studies for unique species in this geographical area is recommended. Passive acoustic monitoring can
be used to conduct behavioral biology studies and identify unique species in Antarctic ecosystems.
Furthermore, I suggest that it is essential to establish, develop and equip research stations for
bioacoustics and behavioral studies of aquatic organisms in the Antarctic region to develop scientific
collaborations with scientists from various international institutes.
Carrion decomposition contributes to the soil microbial community structure. This research aimed to identify the soil arthropod, nematode, bacterial, and fungal communities associated with penguin carrion on King George Island, Antarctica. Soil samples were collected around and beneath fresh (freshly killed penguins by the predators) and dried (decomposed more than a year) penguin carrion. Soil bacterial and fungal communities associated with the penguin carrion were analyzed using the 16S rRNA Illumina MiSeq sequencing. Arthropod identification was using Sanger sequencing and nematodes were determined using morphological identification. This study demonstrated that there are no significant differences in arthropod and nematode (p = 0.415), bacteria (p = 0.386), and fungi (p = 0.635) communities between decomposition stages, soil location, and species of penguin carrion. This is the first study to identify soil arthropods, nematodes, bacterial, and fungal communities associated with penguin carrion, offering important insights into the initial documentation of the necrobiome communities in the polar region.
Hydrocarbons may have a natural or anthropogenic origin and serve as a source of carbon and energy for microorganisms in Antarctic soils. Herein, 16S rRNA gene and shotgun sequencing were employed to characterize taxonomic diversity and genetic potential for hydrocarbon degradation of the microbiome from sediments of sites located in two Antarctic islands subjected to different temperatures, geochemical compositions, and levels of presumed anthropogenic impact, named: Crater Lake / Deception Island (pristine area), Whalers Bay and Fumarole Bay / Deception Island (anthropogenic-impacted area), and Hannah Point / Livingston Island (anthropogenic-impacted area). Hydrocarbon concentrations were measured for further correlation analyses with biological data. The majority of the hydrocarbon-degrading genes were affiliated to the most abundant bacterial groups of the microbiome: Proteobacteria and Actinobacteria. KEGG annotation revealed 125 catabolic genes related to aromatic hydrocarbon (styrene, toluene, ethylbenzene, xylene, naphthalene, polycyclic hydrocarbons) and aliphatic (alkanes and cycloalkanes) pathways. Only aliphatic hydrocarbons, in low concentrations, were detected in all areas, thus not characterizing the areas under study as anthropogenically impacted or non-impacted. The high richness and abundance of hydrocarbon-degrading genes suggest that the genetic potential of the microbiome from Antarctic sediments for hydrocarbon degradation is driven by natural hydrocarbon occurrence.
Parochlus steinenii is the only flying insect native to Antarctica. To elucidate the molecular mechanisms underlying its adaptation to cold environments, we conducted comparative genomic analyses of P. steinenii and closely related lineages. In an analysis of gene family evolution, 68 rapidly evolving gene families, involved in the innate immune system, unfolded protein response, DNA packaging, protein folding, and unsaturated fatty acid biosynthesis were detected. Some gene families were P. steinenii-specific and showed phylogenetic instability. Acyl-CoA delta desaturase and heat shock cognate protein 70 (Hsc70) were representative gene families, showing signatures of positive selection with multiple gene duplication events. Acyl-CoA delta desaturases may play pivotal roles in membrane fluidity, and expanded Hsc70 genes may function as chaperones or thermal sensors in cold environments. These findings suggest that multiple gene family expansions contributed to the adaptation of P. steinenii to cold environments.
Polar deserts contain unique and sensitive communities responsive to climate-associated habitat changes. However, unlike temperate desert ecosystems, characterizing and predicting the responses of polar ecosystems to environmental change remains a significant challenge due to logistical constraints. Here we aim to demonstrate the use of a custom-designed Polar Desert Environmental Chamber (PDEC) to perform off-continent experimental ecological research. We did so by characterizing the structure and composition of arid edaphic bacterial communities collected from the McMurdo Dry Valleys during a simulated wetting event. The results were discussed in light of previous field observations. Rapid structural and compositional changes were observed during wetting and re-drying treatments. Those were driven by changes in the relative abundance of co-existing taxa, which fluctuated asynchronously over time in response to the treatments. While selection was the main ecological factor attributed to the changes observed during the initial wetting, over time, neutral processes began to drive community assembly in communities that remained wet. Ultimately, this observation reflects the presence of microbial taxa with divergent adaptations to water stress, which can be argued as beneficial to increasing resilience in polar deserts. Our findings demonstrate that experiments conducted in PDEC provide valuable contextual data on community response to environmental change and can accelerate our ability to assess biological thresholds to change within polar desert ecosystems. We advocate that, with careful consideration of key emulated environmental attributes, laboratory-based Antarctic research can complement fieldwork to achieve a nuanced and evidence-based understanding of the ecology of Antarctica's ice-free regions.
Anthropogenic pressure and climate change have generated important changes in the environmental conditions of Antarctic ecosystems (e.g., arrival of non-native species, increase in temperature, precipitation, and ice-free areas), which can generate negative impacts on the native flora. Thus, we evaluated how the presence of the non-native plants Poa annua and Juncus bufonius could impact the native species Colobanthus quitensis and Deschampsia antarctica under climate change scenarios. Individuals of C quitensis / D. antarctica and J. bufonius / P. annua were subjected to four growth conditions: 6°C/low water availability (LW); 8°C/LW and 6°C/high water availability (HW) and 8°C/HW. We hypothesize that competition will be more intense at 8°C/HW, while at 6°C/LW the predominant interaction will be facilitation. Under 8°C/HW conditions all species significantly increase biomass production, but mortality of native species tends to increase. The relative interaction index (RII) showed a competitive effect of both non-native species on D. antarctica , independent of temperature and water availability, while for C. quitensis competition is more intense at LW. These results show that the effect of climate change could enhance the impact of non-native species on native species in Antarctic ecosystems, including non-native species that have been reported but do not have stable populations in the Antarctic Peninsula.
Climate change is affecting Antarctica and the Southern Ocean and effects have been already reported for the abiotic compartments of the ecosystems, e.g. ice loss and iceberg calving. Global warming can alter also the distribution of persistent organic pollutant (POPs) both at a global scale and in the Antarctic Region, due to their physical-chemical characteristics. Effects of climate changes have been already reported on feeding behaviour and reproductive process of organisms. Another consequence for organisms includes the POP bioaccumulation. Here we review the literature reporting the linkage between recorded effects of climate changes and POP bioaccumulation in resident marine Antarctic species (fish and penguins). Notwithstanding Antarctica is a final sink for persistent contaminants due to the extreme cold climate, a general decreasing POP trend has been observed for some POPs. Their concentrations in biota are reported to be linked to ice melting and large iceberg calving; the peculiar marine Antarctic ecosystems and the pelagic-benthic coupling may also contribute to alterations in the bioaccumulation processes. These effects are similar in polar regions, although the comparison with the Arctic biota is not possible due to the lack of data in the Antarctic Region. It remains an open question if the POP amount accumulated in the Antarctic ecosystems is decreasing or not.
In the ongoing climate crisis, more and more states of the world undertake initiatives that would reduce negative impact of dangerous growth of global average temperature, including droughts, drowning of coastal cities and water shortage. Recently, an ambitious idea to provide huge supplies of water for the population of the United Arab Emirates was initiated by one of Emirati businessmen – Mr Abdulla Alsheni, who plans to tow a huge Antarctic iceberg to the coast of Emirates. The plan itself is a logistic challenge, but at the same time may raise certain concerns on its compliance with international law. Hereby article has as an aim response to a question whether an act of towing an Antarctic iceberg would breach international law provisions, particularly those related to Antarctic Treaty System and law of the seas.
Notwithstanding its largely lifeless appearance, Antarctica hosts considerable biodiversity and ecosystem (trophic‐level) complexity. Antarctic soils, ice‐covered areas, coastal regions, and the surrounding Southern Ocean contributes to this biodiversity. However, studies related to the number of species present, how and where they are located and their influence on the ecosystem processes are still scarce. Biodiversity and biogeochemical cycles often coincide with climate change studies. Photosynthetic carbon fixation by phytoplanktons in the Antarctic coasts influences the atmospheric CO 2 levels. On a geological timescale, such processes determine the climate. In this chapter, studies on Essential Ocean Variables and elemental cycles in Antarctica are reviewed to understand the biogeochemistry of the coast of Antarctica, and how these parameters and cycles influence the different coastal features of Antarctica. In the recent past, Antarctica has experienced a rapid rate of warming that in turn has threatened its biodiversity. The effects of climate change on biogeochemical parameters and their further consequences are therefore discussed here. The second half of this chapter deals with the prokaryotic as well as eukaryotic microbial diversities of Antarctica, and the implications they hold for climate change.
Knowledge of the biodiversity of the Thala Hills oasis (Enderby Land, East Antarctica) is very limited. Here, we integrate all information available since 1962, when the Russian ‘Molodyozhnaya’ station was established in the western part of the oasis. The published data on local eukaryote diversity (lichens, embryophytes, metazoans) include records of 90 species. Since 2008, Belarusian Antarctic Expedition researchers have worked in the eastern part of the oasis, accessible from the Belarusian station ‘Vechernyaya Mount'. This research revealed 95 species, including 44 species not recorded in the earlier published literature. The level of available information is uneven across major taxa. Lichens are the better-known group, with 51 species recorded in total, including 13 species recently recorded for the first time in the oasis. New records were also obtained for rotifers. Thala Hills biodiversity is consistent with wider patterns of Antarctic biogeography, with a high proportion of regionally endemic species (especially metazoans), the occurrence of both endemic and bipolar species of lichens and generally low numbers of cosmopolitan species (largely limited to aquatic rotifers, with the caveat that up-to-date taxonomic studies are required). The lack of data on marine macrobenthos, soil nematodes and terrestrial rotifers emphasizes the need for studies focusing on these groups.
his study investigates, through computational modeling, the climatic effects of a possible scenario of prolonged solar minimum of activity, such as the Maunder Minimum, and the increase of CO2 in the terrestrial climate system. This research is conducted using the Community Earth System Model (CESM), which is the state-of-the-art in climate modeling, and is also one of the CMIP/IPCC models. The results reinforce that a future scenario of a prolonged solar minimum of activity has greater regional climate impacts than global ones. The effects of a future prolonged minimum of solar activity indicate that this scenario is only capable of slowing down the temperature increase caused by the increased concentration of CO2 in the earth's atmosphere. The climate change caused by these scenarios suggests that the most affected regions in South America, even with the deceleration of temperature increase, are northern and northeastern Brazil.
Antarctic seaweeds are highly shade-adapted organisms, which can photosynthesize under very dim light. This remarkable characteristic allows them colonizing over 30 m depths and surviving extended dark periods during the polar winter. On the other hand, they are well equipped to cope with high light stress, which points to a trade-off between shade adaptation and efficient UV stress tolerance. Optical properties of water determine both the underwater light climate for photosynthesis and the risk of seaweeds for UV exposure in their habitats. Thus, understanding the natural (spatial, temporal) and anthropogenic-driven changes in spectral transparency of water and factors governing it is fundamental in evaluating the state of seaweeds under current and future environmental scenarios. In the present chapter the aspects related to the optical properties determining the underwater habitat of Antarctic seaweeds are summarized, along with the potential changes in water optics as a result of climate change, ozone depletion and other environmental and emerging threats, and their interactions.
Meteorological connectivity between biological hot spots of the McMurdo Dry Valleys (MDVs) of Antarctica is thought to play a role in species distribution and abundance through the aeolian transport of bioaerosols. Understanding the potential role of such meteorological connectivity requires an understanding of near-surface wind flow within and between valley airsheds. To address this, we applied Lagrangian wind trajectory modeling to mesoscale (spatial resolution of ~1 km) weather model output to predict connectivity pathways, focusing on regions of high biodiversity. Our models produce maps of a likelihood metric of wind connectivity that demonstrate the synoptic and mesoscale dependence of connections between local, near-local, and nonlocal areas on wind transport, modulated by synoptic weather and topographic forcing. These connectivity areas can have spatial trends modulated by the synoptic weather patterns and locally induced topographically forced winds. This method is transferrable to other regions of Antarctica for broader terrestrial, coastal, and offshore ecological connectivity research. Also, our analysis and methods can inform better placement of aeolian dust and bioaerosol samplers in the McMurdo Dry Valleys, provide preliminary guidelines behind the meteorological controls of sediment transport and smaller particle distribution, and present quantifiable knowledge informing new hypotheses around the potential of wind acting as a physical driver for biological connectivity in the MDVs.
Diatoms are important ecological indicators in Antarctica, and paleolimnologists routinely apply transfer functions to fossil diatoms recovered from lake sediments to reconstruct past environments. However, living diatom communities may differ among the possible habitat types represented in sediment cores (both within lakes and their immediate proximity), hindering the full and accurate interpretation of fossil records. Therefore, an improved understanding of Antarctic diatom habitat preferences would substantially aid in interpreting regional paleo-material. To gain insights into habitat differences, we sampled epipelon, epilithon, Nostoc mats, lake-adjacent moss, and wet soil from > 30 lakes and ponds from Clearwater Mesa, James Ross Island, spanning a broad gradient in conductivity (a common basis for transfer functions). We found that diatom communities significantly differed between habitat types (although abundances were too low in Nostoc mats to characterize communities), with the clearest distinctions being between submerged (epipelon and epilithon) and exposed (moss and wet soil) groups. Submerged habitat types had greater abundances of attached aquatic taxa (i.e. Gomphonema spp.), while exposed habitats harboured more abundant aerophilic genera (e.g. Hantzschia, Luticola, and Pinnularia). Furthermore, only epilithon communities were significantly related to conductivity, and both epipelon and epilithon habitats showed conspicuous increases in Denticula jamesrossensis at greater conductivity values. Collectively, these results improve our knowledge of limno-terrestrial diatoms from the Maritime Antarctic Region, and further highlight the utility of incorporating knowledge of habitat preferences into (paleo)ecological research.
This study aimed to use nutrients in lake inflows as proxies for assessing human impact and separating this from natural transformations of material in the soil active layer. Nutrients, conductivity and gN lg N lgP lgP l-1 in human impacted catchments. The maximum levels of both DIN and DRP in surface inflows were much higher in human impacted than in natural catchments. Conductivity and δ18O data showed general enrichment of snowbank meltwater presumably through evaporation from the active layer. This combined with fluctuating nutrient levels in catchment waters indicated that soil brines and decaying organic matter of natural and human origin were possible sources for nutrients and other salts. Marked salinization and substantially increased DIN levels near the research stations indicated that lake waters were receiving nutrients generated by humans.
The chironomid midges Belgica antarctica, Eretmoptera murphyi (subfamily Orthocladiinae) and Parochlus steinenii (subfamily Podonominae), are the only Diptera species currently found in Antarctica. The relationships between these species
and a range of further taxa of Chironomidae were examined by sequencing domains 1 and 3–5 of 28S ribosomal RNA. The resulting
molecular relationships between B. antarctica and E. murphyi, within Orthocladiinae, were highly supported by validation analyses, confirming their position within Chironomidae, as generated
by classical taxonomy. Within Podonominae, P. steinenii from the Maritime Antarctic was more closely related to material from sub-Antarctic South Georgia than to material from Patagonia.
Taking advantage of the availability of a molecular substitution rate calculated for this gene in Diptera, a dating of divergence
between our study taxa was tentatively established. The divergence dates obtained were 49 million years (Myr), between B. antarctica and E. murphyi, and 68.5Myr between these species and the closest Orthocladiinae taxon tested from Patagonia, suggesting that B. antarctica and E. murphyi were representatives of an ancient lineage. As both are endemic to their respective tectonic microplates, their contemporary
distribution is, therefore, likely to have been shaped by vicariance rather than dispersal.
Based on a new analysis of passive microwave satellite data, we demonstrate that the annual mean extent of Antarctic sea ice has increased at a statistically significant rate of 0.97% dec-1 since the late 1970s. The largest increase has been in autumn when there has been a dipole of significant positive and negative trends in the Ross and Amundsen-Bellingshausen Seas respectively. The autumn increase in the Ross Sea sector is primarily a result of stronger cyclonic atmospheric flow over the Amundsen Sea. Model experiments suggest that the trend towards stronger cyclonic circulation is mainly a result of stratospheric ozone depletion, which has strengthened autumn wind speeds around the continent, deepening the Amundsen Sea Low through flow separation around the high coastal orography. However, statistics derived from a climate model control run suggest that the observed sea ice increase might still be within the range of natural climate variability.
Drake Passage opening has often been viewed as a single, discrete event,
possibly associated with abrupt changes in global circulation and
climate at or near the Eocene-Oligocene boundary. A new plate tectonic
model, based on recent reinterpretations of the opening history of
basins in the Scotia Sea, suggests that an effective ocean gateway may
have developed even earlier, during the middle Eocene. This is
consistent with a growing body of evidence from sediment core proxy data
for Eocene changes in Southern Ocean circulation and biological
productivity. The period between earliest opening after ˜50 Ma and
the latest Eocene was characterized by the evolution of various current
pathways across the subsiding continental shelves and intervening deep
basins. This shallow opening may have caused important changes in
Southern Ocean circulation, contributing to Eocene cooling and the
growth of Antarctic ice sheets.
Sub-Antarctic islands share many similarities in their history of human interaction and impacts before the mid-twentieth century. Large impacts on land were associated with the marine exploitation industries of sealing and whaling. Their onshore activities involved consider - able construction and pollution in many accessible landing bays, inevitably destroying large areas of coastal terrestrial habitat. Consider- able transfer of nutrients to terrestrial environments will have been associated with scavengers utilising large carrion supplies. Attempted establishment of agricultural industries, particularly the introduction of grazing mammals, took place on several islands and, although rarely proving economically viable, often resulted in the long-term creation of feral populations. These were accompanied by introductions of other alien vertebrates, plants and invertebrates to most sub-Antarctic islands, although precise records of introduction events, or subsequent biological studies in this period, largely do not exist. Thus, exploitation industries in this region inevitably led to considerable alterations and impacts to terrestrial ecosystems almost from the outset of human contact with the islands. In the absence of baseline ecological and biodiversity studies, the true magnitude of many of these impacts is difficult to assess, although their legacy continues to the present day. Indeed, the almost complete removal of fur seals may have allowed coastal vegetation to become more extensive and lush than hitherto, paradoxically now regarded as "typical" and threatened by recovery of seal populations.
Challenges to the traditional circumscription of Apiaceae and Araliaceae are emerging as a result of phylogenetic analysis of DNA sequences. Traditionally classified as Araliaceae, Stilbocarpa emerges with Schizeilema and Azorella, both members of the Apiaceae. In our analyses of nuclear ITS sequences, these three genera comprise a distinct Southern Hemisphere lineage. The humid climate, cool equable temperatures, locally abundant nutrients, and absence of herbivores are ecological features of the sub-antarctic islands that may have contributed to the evolution of the unusual megaherb, Stilbocarpa, from these diminutive apiaceous ancestors.
Research in Antarctica in the past two decades has fundamentally changed our perceptions of the southern continent. This volume describes typical terrestrial environments of the maritime and continental Antarctic. Life and chemical processes are restricted to small ranges of ambient temperature, availability of water and nutrients. This is reflected not only in life processes, but also in those of weathering and pedogenesis. The volume focuses on interactions between plants, animals and soils. It includes aspects of climate change, soil development and biology, as well as above- and below-ground results of interdisciplinary research projects combining data from botany, zoology, microbiology, pedology, and soil ecology.
Bryophyte colonists develop from sexual and asexual propagules deposited over a long period from both local and distant provenances. Some may rapidly establish new plants; others remain dormant indefinitely on or beneath the surface of the substratum. The viable component of these diaspores, the soil propagule bank, constitutes a reservoir of potential colonists. An environmental stimulus or suite of stimuli may activate the dormant viable propagules into developing as new plants. Before this, microbial modification of the soil surface is usually required to bind and stabilize soil particles and provide a nutrient base. Laboratory and field experiments on maritime Antarctic soils are used to illustrate aspects of the bryophyte propagule bank. The importance of ice fields as a sink for spores and vegetative propagules is stressed. Their release in meltwater onto terrestrial habitats near the ice margins is of particular importance in colonziation of newly exposed substrata. Possible efects of global warming, especially in polar regions, on these propagule banks, on the rate of colonization and on the species composition of the developing communities is considered. -from Author
The sub-Antarctic islands have been subjected to man's influence for about 200yr, yet in that time many have been greatly affected by introduced species. The key factor influencing the success of a region for the establishment of introduced species is whether it affords a year-round supply of food. For herbivores this implies the existence of plants, and such animals are therefore indirectly as well as directly affected by temperature and other climatic features. The distributions, histories of introduction, ecology and environmental impacts are described for: rats Rattus norvegicus and R. rattus, house mouse Mus musculus, rabbit Oryctolagus cuniculus, reindeer Rangifer tarandus and car Felis catus. Implications for conservation are noted.-P.J.Jarvis
Environmental monitoring by means of soil algae and microorganisms has been studied around Syowa Station in order to assess human impact on terrestrial habitat. As many buildings in Syowa Station were reconstructed or newly built in recent years, most monitoring sites became unsuitable for the study because of changing situation such as a change of snow-drift by reconstruction of building, etc. around the station. Then, new eight monitoring sites for soil algae and for cellulolytic activity by microorganisms were established at the beginning of February 2000 in JARE-41. We describe a summary of environmental monitoring by soil algae and microorganisms, and propose new monitoring sites and methods in this report.
The terrestrial microbial and invertebrate fauna of the Antarctic inhabits a series of environments ranging from cold desert through progressively warmer conditions in the continental coastal fringe and the maritime zone to the sub-Antarctic. An outline is given of microbial and invertebrate biology and ecology arranged by taxonomic group. Environmental adaptations are examined, in particular the mechanisms which produce invertebrate cold hardiness, and a review is made of ecosystem structure and function.-P.J.Jarvis
Parts of Antarctica, particularly the Antarctic Peninsula region and sub-Antarctic Islands, are experiencing rapid changes in climate, particularly temperature, precipitation/hydration and irradiation, although it is becoming clear that many of these are driven by regional rather than global processes. Terrestrial ecosystems of this remote region provide a “natural experiment” in which to identify biological responses (at scales between cell biochemistry and whole ecosystem) to changing climate variables, both in isolation and combination. The conclusions drawn may be applied to more complex lower latitude ecosystems, where change is perceived to have more direct relevance to Mankind. This paper gives an overview of recent and continuing studies of Antarctic terrestrial biology, assessing these in the context of existing predictive literature. The importance of flexibility (physiological and ecological) and resilience of existing taxa in the face of change are highlighted. In the longterm, large-scale changes in ecosystem structure, complexity and diversity are likely as a consequence of long-distance colonisation by exotic species. However, in the shorter term, geographical isolation will limit responses to those of existing terrestrial biota. In contrast with some earlier predictions of wide-ranging deleterious effects, these now appear likely to be subtle and multifactorial in origin.
The simplicity of maritime Antarctic terrestrial ecosystems, combined with rapid changes in several environmental variables, creates a natural laboratory probably unparalleled worldwide in which to study biological consequences of climate change. The Antarctic Peninsula and Scotia Arc provide a gradient from oceanic cool temperate to frigid continental desert conditions, giving a natural model of climate change predictions. Biota are limited by the twin environmental factors of low temperature and lack of water, while also facing changes in the timing of UV-B maxima, associated with the spring ozone hole. Biological changes consistent with predictions from climate amelioration are visible in the form of expansions in range and local population numbers amongst elements of the flora. Field manipulations demonstrate (i) potential for massive species and community responses to climate amelioration, (ii) the importance of existing soil propagule banks, and (iii) biochemical responses to changing radiation environments. Antarctic species possess considerable resistance/resilience and response flexibility to a range of environmental stresses. Wide environmental variability in Antarctic terrestrial habitats also means that predicted levels of change often fall well within the range already experienced. Thus, climate amelioration may generate positive responses from resident biota, at least while they remain protected through isolation from colonization by more effective competitors. Responses are likely to be subtle and multifactorial in origin, arising from changes in resource allocation and energy economics. The integration of subtle responses may lead to greater consequential impacts in communities and ecosystems.
Anarctic terrestrial communities are characterised by their geographical isolation and the survival of extreme enviromental stresses. Of particular significance to life history strategies of organisms in continental and maritime Antarctic zones is the pronounced seasonality, with short (1-4month) cold summers and long (8-11 month) winters. Activity and growth are largely limited to the summer period, although maintenance coats, undetectable in the short-term, may become significant over winter. Sub-Antarctic invertebrate communities experience a less rigorous, as climatic extremes are ameliorated by their oceanic environment, with positive mean temperatures occuring over 6-12 months. Here, year-round activity and growth of invertebrates are common. This paper considers our limited knowledge of the life histoties of sub-Anatartic terresttrial invertebrates, to identified features correlated with seasonal and/or climatic cues. There is little evidence for diapause, although seasonal patterns of variation in cold tolerance and cryoprotectant production in direct response to desiccation and decreasing temperature have been reported. A rapid response to feeding and growth opportunity is shown by maritime Antarctic species, irrespective of season, although moulting does not occuring over winter. Associated reduction of feeding, along with arrested growth and reproductive activity due to the low thermal energy buget over winter are probably sufficient to explain the peaks of moulting and reproduction often observed at the end of winter. Generally there is a high level of flexibility in the observed species life hostories, with varying development duration and much overlap of generation being the norm, particulaly in maritime and continental Antarctica. A formal diapause may be a disadvantage in maritime and continetal Antarctic zones, as it would reduce the oppertunity of capaitalizing on short period of optimal enviromental conditions, and could be erroneously triggered by severe condition during summer. In contrast, the development of specific overwintering strategies including diapuese may be unnecessary or even irrelevant in much of the sub-Antarctic where seasonality is greatly reduced and the risk of severe or stressful environmental conditions during winter is negligible.
This paper draws to a large extent on the recent benchmark review by Frenot et al. (2005) of the presence and status of non-indigenous (alien) species, carried out under the auspices of the RiSCC (Regional Sensitivity to Climate Change in Antarctica) programme of the Scientific Commitee on Antarctic Research (SCAR). The aim of the review was to document the current state of knowledge on alien species in terrestrial, marine and freshwater ecosystems of continental Antarctica, and the subantarctic in terms of extent, impact and implications, and taking into account contemporary changes in climate and patterns of human activities in these regions.
Outlines the characteristics of the Antarctic terrestrial biological regions, the origins of the past and present flora, and the history of the present vegetation. Species diversity and taxonomic status of the vascular and cryptogamic flora are reviewed, noting the significance to dispersal of the geographical isolation of the Antarctic, and the cool or cold - though not necessarily short - austral summers, which reduce the potential for survival. Phytogeography and distribution patterns of the vascular and cryptogamic flora are reported, including notes on the alien flora. There are descriptions of the vegetation of 1) the sub-Antarctic islands; tall and short tussock grasslands, meadow, mire, bog, flush, swamp, herbfield, fern-brake and fellfield; 2) maritime and continental Antarctic: crustaceous and foliaceous lichens, fruticose and foliose lichens, short moss cushion and turf, tall moss turf, tall moss cushion, bryophyte carpet, alga-sheet, and grass and cushion chamaephytes. Comments are made on plant community dynamics, especially colonisation and succession, and environmental and morphological pattern and zonation. Phenology, diaspore production, germination, growth, standing crop, production, gas exchange, photosynthate translocation, water relations, decomposition, plant chemistry and survival strategies are all considered at length. -P.J.Jarvis
Reviews the nature of the origin of the Antarctic, and indicates the significance of snow-free ground and volcanic activity. Macroclimate is described. Plant and invertebrate microclimates are reported with particular attention paid to radiation, temperature and water and wind relations. Vertebrate microclimates are considered in relation to bird habitat and behaviour, and wind chill and cooling power. Soils are discussed with emphasis on periglacial processes, soil type, age and genesis. -P.J.Jarvis
The physical environment of high latitude lakes exerts a wide-ranging influence on their aquatic ecology. Certain features of Arctic and Antarctic lakes - such as prolonged ice cover and stratification, persistent low temperatures, and low concentrations of optically active materials - make them highly sensitive to climate change and to other environmental perturbations. This chapter describes the snow and ice dynamics of high latitude lakes, and the factors that control their dates of freeze-up and breakup. The effects of ice cover and optical variables on the penetration of solar radiation that, in turn, influences heating and stratification, convective mixing, photochemical reactions, and photobiological processes including primary production are examined. This is followed by a description of stratification and mixing regimes including meromixis in stratified saline lakes, and a summary of water budgets, currents, flux pathways, and mixing processes that operate in ice-covered waters.
Polar lakes act as key early detectors of global change effects. Duration and thickness of snow and ice cover determines albedo, underwater light availability, thermal and chemical regimes and mixing properties. However, quantitative data on responses by aquatic systems to regional-scale change remain scant. Here, by utilizing 48 year (1947-1995) air temperature and 33 year (1963-1996) lake environmental datasets obtained at Signy Island, South Orkney Islands, we report one of the fastest responses to regional climate change so far documented in the southern hemisphere. Between 1980-1995 lake water temperatures increased by 2-3 times the local air temperature rise. Autumn freeze and spring break up dates of lake ice have changed, extending the open water period by up to 4 weeks. Winter total extractable phytopigments, alkalinity and orthophosphate show 2- to 10-fold increases, all linked with an areal reduction of the island's ice cover of similar to 45% in total in the last 50 years. These results indicate that its geographical position allows Signy Island to be a sensitive indicator of rapid ecological change in Antarctic freshwater environments. Such rapid change will be widespread in polar regions if current global change predictions are correct.
A reference checklist has been compiled giving the names of all species of non-lichenized fungi described by collection, observation or culture from the general Antarctic region since records were first published in 1847. The list gives the current names and taxonomic dispositions of over 1000 reported fungi (c. 750 species), together with links to bibliographic references for each report. Additional data include some details on the collection or isolation, and some limited information on associated organisms and substrates. The list is maintained online via the Antarctic F Environmental Data Centre at: www.antarctica.ac.uk/bas research/data/access/fungi/. The list is updated on a regular basis.
The number of individual plants and colonies of the two native Antarctic vascular plants, Colobanthus quitensis and Deschampsia antarctica, have been monitored between 1964 and 1990 on three islands in the Argentine Islands archipelago, western Antarctic Peninsula. The Deschampsia population increased by nearly 25-fold and Colobanthus by over 5-fold. Furthermore there was a considerable increase in the number of Deschampsia colonies, although no additional colonies of Colobanthus were recorded. An analysis of Colobanthus plant size in 1974 and 1990 indicated that recruitment was probably irregular although the population structure remained essentially the same. The reasons for this and the increases in population size of both species are discussed. The relatively rapid increase in the abundance and distribution of these species is considered to be a response to the increasing summer air temperatures being experienced in the region of the maritime Antarctic. In particular, there is probably improved success in reproductive behavior resulting from warmer and/or longer growing seasons.
Passive cloches were deployed for 27 months (three austral summers) at Cape Bird, Ross Island, Antarctica (77°13′S, 166°26′E) to investigate the response of soil invertebrates to increased temperatures. Soil surface temperatures in cloches were significantly higher than in lidless control plots or unmanipulated sites. Soil surfaces in cloche plots exceeded 0 °C and 8 °C (the approximate threshold for growth and development in several invertebrate species) for longer than in control plots. No consistent changes in populations of Gomphiocephalus hodgsoni (Collembola), Stereotydeus mollis (Acari) Nanorchestes antarcticus (Acari) or observed in the cloche plots after 3 growing seasons at higher temperatures. Abundance of S. mollis was strongly related to algal biomass, but abundances of other species were not clearly related to the environmental characteristics of manipulation plots. Although low temperatures may have a role as a limiting factor on a geographical scale, local populations of invertebrates are probably influenced more by the availability of liquid water; and invertebrate responses could be very slow owing to short growing seasons and long life cycles in continental Antarctica.
There is increasing evidence of climate change in Antarctica, especially elevated temperature and ultraviolet B (UVB) flux within the ozone "hole." Its origins are debatable, but the effects on ice recession, water availability, and summer growth conditions are demonstrable. Light-dependent, temperature-sensitive, fast-growing organisms respond to these physical and biogeographical changes. Microalgae (cyanobacteria and eukaryotic algae), which are pioneer colonists of Antarctic mineral fellfield soils, are therefore highly suitable biological indicators of such changes. In frost-heaved soil polygons containing naturally sorted fine mineral particles, microalgal growth is restricted to a shallow zone of light penetration. By virtue of this light requirement, microalgae are exposed to extreme seasonal fluctuations in temperature (air and black-body radiation), photosynthetically active radiation, UV radiation, and desiccation. Dominance of conspicuous autofluorescent indicator species with distinctive morphology allowed quantification of responses using epifluorescence microscopy, and image analysis of undisturbed, unstained communities. However, the physical changes in climate, although significant in the long term, are gradual. The changes were therefore amplified experimentally by enclosing the communities at a fellfield site on Signy Island, maritime Antarctica, in cloches (small greenhouses). These were made of polystyrene of either UV transparent or UV opaque acrylic plastic, with or without walls. During a 6-year period, statistically significant changes were observed in microalgal colonization of the soil surface and in the morphology of filamentous populations. Evidence of community succession correlated with measured changes in local environment was found. Results from Signy Island and at continental sites on Alexander Island suggested that rates of microalgal colonization and community development might change significantly during current climate changes in Antarctica.
This book reviews the biology of bryophytes and lichens in the polar tundra, where these plants may form a dominant component of the vegetation. It considers adaptation to severe environments in terms of growth form, physiology and reproduction. The role of bryophytes and lichens is discussed in vegetation processes such as colonisation and succession, and in energy flow, nutrient cycling and other functional aspects of polar ecosystems, both natural and as modified by man, The range of microclimates experience by polar cryptograms is described using an energy budget approach, and the environmental relationships of CO2 exchange, stress resistance, growth and other physiological responses are discussed against this background. Reproductive biology is also reviewed as an introduction to a consideration of population ecology, distribution patterns, dispersal potential and the origin and adaptation of polar cryptogamic floras. This book integrates the results of work in the Arctic and the Antarctic, and includes a classification of vegetation zones applicable to both polar regions. The study of plant ecology in these areas has advanced dramatically and the results synthesised here contribute to a general understanding both of polar ecosystems and of the environmental relationships of bryophytes and lichens.
The development of and compliance with the code of conduct embodied in the Antarctic Treaty to prevent or minimize the introduction of plants into the Antarctic is outlined. A chronological account of all known experimental and accidental introductions of higher plants in the field and their success and fate, if known, is given. The potential danger to the natural Antarctic ecosystem of importing plants rooted in their original soil is discussed with particular regard to the introduction of microorganisms, invertebrates and viable plant propagules. Unintentional dispersal of non-indigenous biota by human activities, and dispersal by natural agents (wind, birds) into and within the Antarctic, is assessed and numerous examples which contravened the measures of the Antarctic Treaty for the control of introduced biota are noted. The need for strict observance of the new Protocol on Environmental Protection to the Antarctic Treaty is emphasized.
We describe a terrestrial faunal community including only Tardigrada and Rotifera, present on inland nunataks of Ellsworth Land, Antarctica (∼75°-77° S, 70°-73° W). The fauna is exceptional in its simplicity, including five tardigrade species (three new to science) and at least two rotifer species, which comprise two consumer trophic levels. Nematode worms, the most important element of the simplest faunal communities previously reported worldwide (from the Ross Sea Dry Valley region of continental Antarctica), and microarthropods, otherwise represented in all known Antarctic terrestrial communities, are absent. The tardigrade community composition shows affinity with the continental Antarctic fauna, with which it shares three species. The remaining two species are unique to Ellsworth Land and may suggest a prolonged existence as a distinct biogeographical unit.
We are studying the distribution, biodiversity, and abundance of nematodes in the most extreme terrestrial environment on earth, the Dry Valley region of Antarctica. Here we report that the nematode community structure of 1-3 species in two functional groups may be the simplest soil food web of any terrestrial ecosystem. Nematodes were widespread and not correlated with moisture, C, or N, factors that define soil biotic complexity elsewhere. In a field experiment, treatments increasing soil water, carbon, and temperature, alone or in combination, generally decreased the abundance of the single omnivore-predator species and increased the abundance of its microbivorous prey species. These low-diversity nematode communities, limited to ≤3 species, apparently lack species redundancy and appear sensitive to environmental change. Our findings suggest that Antarctic soil ecosystems are sensitive to anthropogenic disturbance.