David B. Ryves

David B. Ryves
Loughborough University | Lough · Geography and Environment

PhD

About

89
Publications
22,046
Reads
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3,676
Citations
Additional affiliations
April 2004 - August 2019
Loughborough University
Position
  • Lecturer
April 2004 - present
Loughborough University
Position
  • Reader in Environmental Change
April 2004 - present
Loughborough University
Position
  • Reader in Environmental Change

Publications

Publications (89)
Preprint
Full-text available
Fungal endophytes are ubiquitous plant symbionts existing asymptomatically inside plant tissues but playing a crucial role in plant health and function. Endophytes have been extensively studied in many plants, such as agricultural systems, but in carnivorous plants which may engage microbes to aid in digestion, they are poorly understood. To addres...
Article
Full-text available
With ambitious targets to drastically increase economic activity over the next decade, Kenya’s future is undoubtedly energy-intensive. Current power capacity expansion plans will see Kenya considerably ramp up fossil fuel generation, significantly increasing emissions. Therefore, Kenya is at a crucial stage of its national development, with critica...
Article
Full-text available
Many northwest European lake systems are suffering from the effects of eutrophication due to continued loading and/or poor, ineffective management strategies. Coastal brackish lakes are particularly difficult to manage due to complex nitrogen, phosphorus, and salinity dynamics that may exert varying influence on lake biological communities, but lon...
Preprint
Full-text available
With ambitious targets to drastically increase economic activity over the next decade in order to propel itself to become a middle-income country, Kenya’s future is undoubtedly energy intensive. Through the achievement of its bold and aspiring goals, Kenya is poised to become a regional economic giant with the capacity to strengthen its position as...
Preprint
Full-text available
With ambitious targets to drastically increase economic activity over the next decade in order to propel itself to become a middle-income country, Kenya’s future is undoubtedly energy intensive. Through the achievement of its bold and aspiring goals, Kenya is poised to become a regional economic giant with the capacity to strengthen its position as...
Article
Full-text available
We explored the roles of phytoplankton production, carbon source, and human activity on carbon accumulation in a eutrophic lake (Rostherne Mere, UK) to understand how changes in nutrient loading, algal community structure and catchment management can influence carbon sequestration in lake sediments. Water samples (dissolved inorganic, organic and p...
Article
Full-text available
The nature of human dispersals out of Africa has remained elusive because of the poor resolution of paleoecological data in direct association with remains of the earliest non-African people. Here, we report hominin and non-hominin mammalian tracks from an ancient lake deposit in the Arabian Peninsula, dated within the last interglacial. The findin...
Article
Full-text available
Sediment trapping is a widely accepted technique in lake studies for analyzing seasonal limnological events and can provide insight into ecological succession as well as the seasonal dynamics of organic and inorganic fluxes. More recently, organic flux measurement from traps has been especially important in estimating whole‐lake C sequestration as...
Article
Full-text available
Nutrient reduction in impacted lowland freshwater systems is ecologically and culturally important. Gaining a greater insight into how lakes respond to lowering nutrient loads and how climate-driven physical limnology affects present and future cycling of available nutrients is important for ecosystem resource management. This study examines the nu...
Article
Full-text available
Although the oxygen isotope composition (δ¹⁸O) of calcite (δ¹⁸Ocalcite) and, to a lesser extent, diatom silica (δ¹⁸Odiatom) are widely used tracers of past hydroclimates (especially temperature and surface water hydrology), the degree to which these two hosts simultaneously acquire their isotope signals in modern lacustrine environments, or how the...
Article
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How climate and ecology affect key cultural transformations remains debated in the context of long-term socio-cultural development because of spatially and temporally disjunct climate and archaeological records. The introduction of agriculture triggered a major population increase across Europe. However, in Southern Scandinavia it was preceded by ~...
Article
Full-text available
River impoundment constitutes one of the most important anthropogenic impacts on the World’s rivers. An increasing number of studies have tried to quantify the effects of river impoundment on riverine ecosystems over the past two decades, often focusing on the effects of individual large reservoirs. This study is one of the first to use a large-sca...
Article
Background: Carnivorous plants are an ideal model system for evaluating the role of secondary metabolites in plant ecology and evolution. Carnivory is a striking example of convergent evolution to attract, capture and digest prey for nutrients to enhance growth and reproduction and has evolved independently at least ten times. Though the role of m...
Article
Norsminde Fjord has received extensive geoarchaeological investigation, hosting one of the classic Stone Age shell midden sites in Denmark, and one of the best examples of the widespread oyster decline at the Mesolithic–Neolithic transition. Here, intra-shell δ ¹⁸ O (and δ ¹³ C) analyses from the common periwinkle Littorina littorea (L.) are used t...
Article
Full-text available
The large‐scale shifts in the salinity of the Baltic Sea over the Holocene are well understood and have been comprehensively documented using sedimentary proxy records. More recent work has focused on understanding how past salinity fluctuations have affected other ecological parameters (e.g. primary productivity, nutrient content) of the Baltic ba...
Article
Understanding the spatial patterns and environmental drivers of freshwater diversity and community structure isa key challenge in biogeography and conservation biology. However, previous studies have focussed primarilyon taxonomic diversity and have largely ignored the phylogenetic and functional facets resulting in an in-complete understanding of...
Article
Full-text available
• Nutrient availability and climate have substantial effects on the structure and function of lakes. Predicted changes to climate (particularly temperature) over the 21st century are expected to adjust physical lake functions, changing thermal and nutrient use processes. Both increasing anthropogenic nutrient inputs and net reductions following rem...
Poster
The Somerset Levels (‘The Levels’ hereafter) are a low-lying and flood-prone agricultural landscape in South West England, UK. The Levels drainage network is heavily managed for navigation and flood relief purposes and there is a legacy of dredging, to help mitigate flood risk. Despite widespread application of the technique internationally, knowle...
Article
The exploitation of lakes has led to large-scale contemporary impacts on freshwater systems, largely in response to catchment clearance. Such clearance is causing changes to carbon dynamics in tropical lakes which may have significance for wider carbon budgets, depending on the changes in carbon sequestration and mineralisation driven by changing r...
Article
Multi-proxy analyses of an 8 m sediment core from Lake Hayk, a closed, freshwater lake in the north-central highlands of Ethiopia, provide a record of changing lake level and inferred regional climatic change for the last 15.6 cal ka years. Between ca. 15.6–15.2 cal ka BP, a lowstand was synchronous with Heinrich Event 1 and an intense drought acro...
Presentation
The Somerset Levels (‘The Levels’ hereafter) are a low-lying and flood-prone agricultural landscape in South West England. The rivers, rhynes and ditches of The Levels are heavily managed for navigation and flood relief purposes and there is a legacy of dredging, typically excavation (using large mechanical digging / dredging apparatus), to help mi...
Article
Coastal flooding catastrophes have affected human societies on coastal plains around the world on several occasions in the past, and are threatening 21st century societies under global warming and sea-level rise. However, the role of coastal flooding in the interruption of the Neolithic Liangzhu culture in the lower Yangtze valley, East China coast...
Article
Full-text available
This study investigates recent changes in the geochemistry of organic material from a hypereutrophic lake (Rostherne Mere, United Kingdom) using the geochemical and molecular composition of radiometrically dated sediment cores. Modern samples suggest that recent sedimentation is dominated by algal production; however, a minor component of allochtho...
Article
The Taihu Plain of the Lower Yangtze valley, China was a centre of rice agriculture during the Neolithic period. Reasons for the rapid development of rice cultivation during this period, however, have not been fully understood for this coastal lowland, which is highly sensitive to sea-level change. To improve understanding of the geomorphological a...
Article
Full-text available
Ponds are common and abundant landscape features in temperate environments, particularly on floodplains where lateral connectivity with riverine systems persists. Despite their widespread occurrence and importance to regional diversity, research on the ecology and hydrology of temperate ephemeral and perennial floodplain ponds lags behind that of o...
Article
Full-text available
Advances in metacommunity theory have made a significant contribution to understanding the drivers of variation in biological communities. However, there has been limited empirical research exploring the expression of metacommunity theory for two fundamental components of beta diversity: nestedness and species turnover. In this paper, we examine th...
Article
Full-text available
Many studies have viewed lakes as quasi-static systems with regard to the rate of organic carbon (OC) burial, assuming that the dominant control on BE is sediment mineralization. However, in systems undergoing eutrophication or oligotrophication (i.e., altered nutrient loading), or climatic forcing, the changes in primary production will vary on bo...
Article
Full-text available
Global aquatic ecosystems are under increasing threat from anthropogenic activity, as well as being exposed to past (and projected) climate change, however, the nature of how climate and human impacts are recorded in lake sediments is often ambiguous. Natural and anthropogenic drivers can force a similar response in lake systems, yet the ability to...
Article
The well-known and widespread replacement of oysters (abundant during the Mesolithic period) by cockles and mussels in many Danish Stone Age shell middens ca. 5900 cal yrs BP coincides with the transition to agriculture in southern Scandinavia. This human resource shift is commonly believed to reflect changing resource availability, driven by envir...
Article
Ponds are among the most biodiverse freshwater ecosystems, yet face significant threats from removal, habitat degradation and a lack of legislative protection globally. Information regarding the habitat quality and biodiversity of ponds across a range of land uses is vital for the long term conservation and management of ecological resources. In th...
Article
Full-text available
Ecological and biogeochemical processes in lakes are strongly dependent upon water temperature. Long-term surface warming of many lakes is unequivocal, but little is known about the comparative magnitude of temperature variation at diel timescales, due to a lack of appropriately resolved data. Here we quantify the pattern and magnitude of diel temp...
Article
Full-text available
RATIONALE: Current studies which use the oxygen isotope composition from diatom silica (δ18Odiatom) as a palaeoclimate proxy assume that the δ18Odiatom value reflects the isotopic composition of the water in which the diatom formed. However, diatoms dissolve post mortem, preferentially losing less silicified structures in the water column and durin...
Article
Full-text available
Equatorial East Africa has a complex regional patchwork of climate regimes, sensitive to climate fluctuations over a variety of temporal and spatial scales during the late Holocene. Understanding how these changes are recorded in and interpreted from biological and geochemical proxies in lake sedimentary records remains a key challenge to answering...
Article
Full-text available
The Limfjord region of northern Jutland, Denmark, supports a rich archaeological record dating back to the Mesolithic, which documents long-term change in human practices and utilisation of marine resources since approximately 7500 BP. The presence and availability of marine resources in the Limfjord is sensitively regulated by environmental parame...
Article
Full-text available
Equatorial East Africa has a complex, regional patchwork of climate regimes, with multiple interacting drivers. Recent studies have focussed on large lakes and reveal signals that are smoothed in both space and time, and, whilst useful at a continental scale, are of less relevance when understanding short-term, abrupt or immediate impacts of climat...
Article
Full-text available
Palaeoenvironmental and 14C reservoir age variability in the Limfjord, a sound through northern Jutland, Denmark, was investigated for the period 7300 to 1300 cal yr BP. Shells and bulk sediment samples from a core from a former inlet, Kilen, were analysed by radiocarbon dating and stable isotope (C/N) measurements. A strong correlation between the...
Article
The late Holocene history of the South African summer rainfall zone offers insights into the effects of climate on ecosystems and human societies, as well as into the accuracy of model projections of the future. However, some important aspects of this region’s climatic history remain unresolved. Here we present new high-resolution diatom records re...
Article
Diatom preservation can be a major taphonomic issue in many lakes but is often unrecognised and its impacts on qualitative and quantitative inferences (such as productivity and biodiversity estimates) from sedimentary archives are seldom explored. Here two palaeolimnological case studies of 20th-century anthropogenic eutrophication of freshwater la...
Article
Diatom surface sediment samples and corresponding water chemistry were collected from 56 lakes across a natural conductivity gradient in western Uganda (reflecting a regional climatic gradient of effective moisture) to explore factors controlling diatom distribution. Here we develop a regional training set from these crater lakes to test the hypoth...
Article
The last millennium is a key period for understanding environmental change in eastern Africa, as there is clear evidence of marked fluctuations in climate (effective moisture) that place modern concern with future climate change in a proper context, both in terms of environmental and societal impacts and responses. Here, we compare sediment records...
Article
Full-text available
Quantitative climate reconstructions are fundamental to understand long-term trends in natural climate variability and to test climate models used to predict future climate change. Recent advances in molecular geochemistry have led to calibrations using glycerol dialkyl glycerol tetraethers (GDGTs), a group of temperature-sensitive membrane lipids...
Article
Between 15,000 and 18,000 years ago, large amounts of ice and meltwater entered the North Atlantic during Heinrich stadial 1. This caused substantial regional cooling, but major climatic impacts also occurred in the tropics. Here, we demonstrate that the height of this stadial, about 16,000 to 17,000 years ago (Heinrich event 1), coincided with one...
Article
Full-text available
This study interprets the recent history of Lake Kivu, a tropical lake in the East African Rift Valley. The current gross sedimentation was characterized from a moored sediment trap array deployed over 2years. The past net sedimentation was investigated with three short cores from two different basins. Diatom assemblages from cores were interpreted...
Article
Full-text available
The integrity of all sedimentary diatom assemblages is influenced to some degree by taphonomic processes. Recognising these processes with regard to preservation pathways for diatom assemblages and for individual species can be instructive for interpreting sediment core diatom records. Diatoms deposited in saline lakes are usually particularly expo...
Conference Paper
The integrity of all sedimentary diatom assemblages is influenced to sonic degree by taphonomic processes. Recognising these processes with regard to preservation pathways for diatom assemblages and for individual species can be instructive for interpreting sediment core diatom records. Diatoms deposited in saline lakes are usually particularly exp...
Article
Identifying the nature of the association between climate, environmental, socio-economic and political context and disease remains a major challenge, yet a better comprehension of the linkages is imperative if predictive models to guide public health responses are to be devised. Our understanding of the relationships could be improved through inves...
Article
Taphonomic issues pose fundamental challenges for Quaternary scientists to recover environmental signals from biological proxies and make accurate inferences of past environments. The problem of microfossil preservation, specifically diatom dissolution, remains an important, but often overlooked, source of error in both qualitative and quantitative...
Article
The dominant processes determining biological structure in lakes at millennial timescales are complex. In this study, we used a multi-proxy approach to determine the relative importance of in-lake versus indirect processes on the Holocene development of an oligotrophic lake in SW Greenland (66.99°N, 50.97°W). A 14C and 210Pb-dated sediment core cov...
Data
The dominant processes determining biological structure in lakes at millennial timescales are complex. In this study, we used a multi-proxy approach to determine the relative importance of in-lake versus indirect processes on the Holocene development of an oligotrophic lake in SW Greenland (66.99°N, 50.97°W). A 14C and 210Pb-dated sediment core cov...
Article
Full-text available
Modern geological research into the late and postglacial history of the inner Danish waters (i.e. Kattegat, Bælthavet and Øresund, plus the adjoining fjords and estuaries) began at the turn of the last century. Since then most investigations have focused on the timing of the initial marine inundation of the area, the early to mid-Holocene changes i...
Article
Diatoms in Lake Baikal exhibit significant spatial variation, related to prevailing climate, lake morphology and fluvial input into the lake. Here we have assessed the threats to endemic planktonic diatom species (through the development of empirical models), which form a major component of primary production within the lake. Multivariate technique...
Article
Diatom dissolution in surface sediment samples from two regional lake datasets in the Northern Great Plains (NGP; n 5 64) and West Greenland (n 5 40) is assessed using a morphological approach categorizing valves during routine diatom analysis. Two dissolution indices are derived to parameterize diatom dissolution, and, when compared between two an...
Article
The mainly endemic phytoplankton record of Lake Baikal has been used in this study to help interpret climate variability during the last 1000 years in central Asia. The diatom record was derived from a short core taken from the south basin and has been shown to be free from any sedimentary heterogeneities. We employ here a diatom-based inference mo...
Article
In order to assess how faithfully the composition of diatom assemblages in the recent sediments of Lake Baikal represents the composition of the planktonic diatom populations in the lake, we have compared the flux of diatoms from the water column (i.e., “expected” in the sediment) with the accumulation rates of the same diatom taxa (i.e., “observed...
Article
Full-text available
A new diatom series with 1–6year resolution from Lake Victoria, East Africa, shows that lake level minima occurred ca. 820–760, 680–660, 640–620, 370–340, and 220–150 calendar years BP. Inferred lake levels were exceptionally high during most of the Little Ice Age (ca. 600–200 calendar years BP). Synchrony between East African high lake levels and...
Article
Pollen, plant macrofossil and charcoal records from two neighbouring crater lakes (Lake Wandakara and Lake Kasenda) in lower montane (altitude-1200m) western Uganda (0.5DN, 30) reveal major changes in local and regional vegetation over the last 1200 years, which can be related to regional variations in climate (especially effective precipitation) a...
Article
This article was published in the Canadian Journal of Fisheries and Aquatic Sciences [© NRC Canada] and can also be found at: http://cjfas.nrc.ca Diatoms in surface sediments from a data set of 27 brackish lakes and nine fjords in Jutland, Denmark (range 0.2 – 31 g·L–1 total dissolved solids (TDS)), were analysed using multivariate methods to deter...
Article
Full-text available
Endemic planktonic diatoms are a major component of Lake Baikal sediments during interglacial periods. To investigate how these diatom assemblages are altered during sediment formation, quantitative plankton monitoring (1995–1998) was integrated with sediment trapping over 2 yr (1996–1997) in Baikal's southern basin (depth 1,400 m). The traps consi...
Article
Sub-fossils of Cladocera and Foraminifera were used to reconstruct changes since 1870 in the trophic dynamics of two brackish lakes, Glombak and Han Vejle, located in the Vejlerne nature reserve, Denmark, a site of international conservation importance. After creation of the lakes in the mid-1870s following land reclamation, the two lakes have deve...
Article
We explore possible quantitative relationships between diatom species and environmental data for Lake Baikal using multivariate techniques. Our approach differs from published studies in other regions (on training sets and transfer functions) because (1) although only one lake is examined, we use the internal lake gradients rather than gradients am...
Article
Holocene changes in effective precipitation (precipitation-evaporation; P-E) were reconstructed for the Søndre Strømfjord region of southwest Greenland using the sediment records of two neighbouring closed-basin ‘saline’ lakes. Past lakewater conductivities (a proxy for P-E balance) were estimated using a diatom-inferred conductivity model. Broadly...
Article
Full-text available
High-resolution TECHNICAP sediment traps have been deployed in Lake Baikal since 1996. Results of these experiments show distinct seasonal differences in particle flux, ranging from a few mg m-2d-1 to several g m-2d-1. Analyses of trap material show that removal of particles is very fast and efficient. Downward transport through the 1400 m deep wat...
Article
1. The area around Kangerlussuaq (Søndre Strømfjord; West Greenland, 67°N 51°W) contains thousands of lakes ranging from coastal, dilute (conductivity < 30 μS cm –1 ) oligotrophic systems to subsaline (∼4000 μS cm –1 ), closed basin lakes close to the ice sheet margin. In closed basins, salinity (or conductivity) is often a proxy for effective mois...
Article
Over 80 lakes were sampled between the ice margin and the coast in West Greenland between 66 and 67 degreesN and analyzed for their pH, alkalinity, conductivity, and tivity values < 150 muS cm(-1). There are, however, also saline lakes (2000-4000 muS cm(-1) NaHCO(3)/CO(3), and Mg HCO(3)/CO(3)-doniinated), mainly around the head of the fjord. The ma...
Article
Over 80 lakes were sampled between the ice margin and the coast in West Greenland between 66 and 67°N and analyzed for their pH, alkalinity, conductivity, and major ions. Most of the lakes (67%) are dilute, circumneutral, and have conductivity values <150 μS cm⁻¹. There are, however, also saline lakes (2000–4000 μS cm⁻¹; NaHCO3/CO3, and Mg HCO3/CO3...
Article
Four laboratory experiments on fresh, modern diatoms collected from lakes in the Northern Great Plains of North America were carried out to assess the effects of dissolution on diatom abundance and composition. Marked differences in mean dissolution susceptibility exist between species, despite sometimes significant intra-specific variation between...