Publications by authors named "Lisette N de Senerpont Domis"

19 Publications

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Corrigendum to An affordable and reliable assessment of aquatic decomposition: Tailoring the Tea Bag Index to surface waters [Water Research (2019) 31--43].

Water Res 2021 Apr;194:117008

Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708PB Wageningen, the Netherlands; Department of Aquatic Ecology and Water Quality Management, Wageningen University & Research, Droevendaalsesteeg 3, 6708PB Wageningen, the Netherlands.

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http://dx.doi.org/10.1016/j.watres.2021.117008DOI Listing
April 2021

The value of novel ecosystems: Disclosing the ecological quality of quarry lakes.

Sci Total Environ 2021 May 7;769:144294. Epub 2021 Jan 7.

Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB Wageningen, the Netherlands; Department of Aquatic Ecology and Water Quality Management, Wageningen University & Research, P.O. Box 226, 6700 AE Wageningen, the Netherlands. Electronic address:

Intense sand and gravel mining has created numerous man-made lakes around the world in the past century. These small quarry lakes (1-50 ha) are usually hydrologically isolated, often deep (6-40 m) and stratify during summer and in cold winters. Due to their small size, these deep man-made lakes are usually not included in the regular monitoring campaigns, e.g. as required for the European Water Framework Directive (WFD). Therefore, not much is known about the ecological functioning of these novel ecosystems. During two summers, we determined the macrophyte diversity and measured a range of physico-chemical and biological parameters in 51 quarry lakes in the catchment area of the rivers Meuse and Rhine. We compared the results of this campaign to the chemical and macrophyte sampling as performed for the WFD in the immediate surrounding shallow standing waters. Alpha (local) and beta diversity (regional), and local contribution to beta diversity were calculated for the whole region of which beta diversity was further partitioned into a true species replacement and richness difference component. Quarry lakes contain higher water quality reflected by lower nutrient and chlorophyll-a concentration compared with shallow water bodies. Additionally, quarry lakes contribute significantly to the regional macrophyte diversity pool by harboring distinctly different macrophyte communities (beta diversity - replacement). Specifically quarry lakes with a total phosphorus concentration in the water column below 35 μg P/l contribute most to beta diversity among quarry lakes. Novel ecosystems such as deep quarry lakes are often perceived as less valuable ecosystems, with strong implications regarding their management. Our results show that quarry lakes are in general of better chemical and biological quality compared with shallow standing waters. We therefore call for a more integrated assessment of the quality of quarry lakes and corresponding management strategy of these waters by water managers.
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http://dx.doi.org/10.1016/j.scitotenv.2020.144294DOI Listing
May 2021

Changing human-ecosystem interactions during COVID-19 pandemic: reflections from an urban aquatic ecology perspective.

Curr Opin Environ Sustain 2020 Oct 16;46:32-34. Epub 2020 Oct 16.

Netherlands Institute of Ecology, Droevendaalsesteeg 10, Wageningen, The Netherlands.

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http://dx.doi.org/10.1016/j.cosust.2020.10.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7566790PMC
October 2020

Storm impacts on phytoplankton community dynamics in lakes.

Glob Chang Biol 2020 05 5;26(5):2756-2784. Epub 2020 Mar 5.

National Institute of Water and Atmospheric Research, Hamilton, New Zealand.

In many regions across the globe, extreme weather events such as storms have increased in frequency, intensity, and duration due to climate change. Ecological theory predicts that such extreme events should have large impacts on ecosystem structure and function. High winds and precipitation associated with storms can affect lakes via short-term runoff events from watersheds and physical mixing of the water column. In addition, lakes connected to rivers and streams will also experience flushing due to high flow rates. Although we have a well-developed understanding of how wind and precipitation events can alter lake physical processes and some aspects of biogeochemical cycling, our mechanistic understanding of the emergent responses of phytoplankton communities is poor. Here we provide a comprehensive synthesis that identifies how storms interact with lake and watershed attributes and their antecedent conditions to generate changes in lake physical and chemical environments. Such changes can restructure phytoplankton communities and their dynamics, as well as result in altered ecological function (e.g., carbon, nutrient and energy cycling) in the short- and long-term. We summarize the current understanding of storm-induced phytoplankton dynamics, identify knowledge gaps with a systematic review of the literature, and suggest future research directions across a gradient of lake types and environmental conditions.
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http://dx.doi.org/10.1111/gcb.15033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7216882PMC
May 2020

Warming and CO effects under oligotrophication on temperate phytoplankton communities.

Water Res 2020 Apr 4;173:115579. Epub 2020 Feb 4.

Department of Ecology, Faculty of Sciences, University of Granada, Campus Fuentenueva, s/n, 18071, Granada, Spain. Electronic address:

Eutrophication, global warming, and rising carbon dioxide (CO) levels are the three most prevalent pressures impacting the biosphere. Despite their individual effects are well-known, it remains untested how oligotrophication (i.e. nutrients reduction) can alter the planktonic community responses to warming and elevated CO levels. Here, we performed an indoor mesocosm experiment to investigate the warming × CO interaction under a nutrient reduction scenario (40%) mediated by an in-lake management strategy (i.e. addition of a commercial solid-phase phosphorus sorbent -Phoslock®) on a natural freshwater plankton community. Biomass production increased under warming × CO relative to present-day conditions; however, a Phoslock®-mediated oligotrophication reduced such values by 30-70%. Conversely, the warming × CO × oligotrophication interaction stimulated the photosynthesis by 20% compared to ambient nutrient conditions, and matched with higher resource use efficiency (RUE) and nutrient demand. Surprisingly, at a group level, we found that the multi-stressors scenario increased the photosynthesis in eukaryotes by 25%, but greatly impaired in cyanobacteria (ca. -25%). This higher cyanobacterial sensitivity was coupled with a reduced light harvesting efficiency and compensation point. Since Phoslock®-induced oligotrophication unmasked a strong negative warming × CO effect on cyanobacteria, it becomes crucial to understand how the interplay between climate change and nutrient abatement actions may alter the, ecosystems functioning. With an integrative understanding of these processes, policy makers will design more appropriate management strategies to improve the ecological status of aquatic ecosystems without compromising their ecological attributes and functioning.
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http://dx.doi.org/10.1016/j.watres.2020.115579DOI Listing
April 2020

Saving water for the future: Public awareness of water usage and water quality.

J Environ Manage 2019 Jul 3;242:246-257. Epub 2019 May 3.

Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, Wageningen, 6700 AB, Netherlands; Department of Aquatic Ecology and Water Quality Management, Wageningen University & Research, P.O. Box 47, Wageningen, 6700 AA, Netherlands.

Fresh water is a limited resource under anthropogenic threat. Europeans are using an average of 3550 L per capita per day and this amount is increasing steadily as incomes rise. Water saving options are being actively promoted, but these intensified measures do not yet come close to saving enough water to prevent water shortages that may seriously affect our way of life in the near future. With projected increases in demands for good quality fresh water, educating the public about sustainable personal water use and water quality threats becomes an absolute necessity. One way to achieve this is through engaging citizens in water issues, e.g. through citizen science projects. Using snowball convenience sampling, we distributed a questionnaire among 498 people in 23 countries to investigate whether people were aware of how much water they used, what they perceived as threats to water quality and whether they would like to help improve water quality. Our results showed that the amount of daily water use was greatly underestimated among respondents, especially indirect use of water for the production of goods and services. Furthermore, the effects of climate change and detrimental habits such as feeding ducks were underestimated, presumably because of environmental illiteracy. However, eighty-five percent (85%) of our participants indicated an interest in directly working together with scientists to understand and improve their local water quality. Involving citizens in improving local lake quality promotes both environmental and scientific literacy, and can therefore result in a reduction in daily personal water use. The next iteration of the Water Framework Directive legislation will be launched shortly, requiring water managers to include citizens in their monitoring schemes. Engaging citizens will not only help improve surface water quality, and educate about cause and effect chains in water quality, but will also reduce the personal fresh water usage.
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http://dx.doi.org/10.1016/j.jenvman.2019.04.047DOI Listing
July 2019

An affordable and reliable assessment of aquatic decomposition: Tailoring the Tea Bag Index to surface waters.

Water Res 2019 03 10;151:31-43. Epub 2018 Dec 10.

Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, the Netherlands; Department of Aquatic Ecology and Water Quality Management, Wageningen University & Research, Wageningen, the Netherlands.

Litter decomposition is a vital part of the global carbon cycle as it determines not only the amount of carbon to be sequestered, but also how fast carbon re-enters the cycle. Freshwater systems play an active role in the carbon cycle as it receives, and decomposes, terrestrial litter material alongside decomposing aquatic plant litter. Decomposition of organic matter in the aquatic environment is directly controlled by water temperature and nutrient availability, which are continuously affected by global change. We adapted the Tea Bag Index (TBI), a highly standardized methodology for determining soil decomposition, for lakes by incorporating a leaching factor. By placing Lipton pyramid tea bags in the aquatic environment for 3 h, we quantified the period of intense leaching which usually takes place prior to litter (tea) decomposition. Standard TBI methodology was followed after this step to determine how fast decomposition takes place (decomposition rate, k) and how much of the material cannot be broken down and is thus sequestered (stabilization factor, S). A Citizen Science project was organized to test the aquatic TBI in 40 European lakes located in four climate zones, ranging from oligotrophic to hypereutrophic systems. We expected that warmer and/or eutrophic lakes would have a higher decomposition rate and a more efficient microbial community resulting in less tea material to be sequestered. The overall high decomposition rates (k) found confirm the active role lakes play in the global carbon cycle. Across climate regions the lakes in the warmer temperate zone displayed a higher decomposition rate (k) compared to the colder lakes in the continental and polar zones. Across trophic states, decomposition rates were higher in eutrophic lakes compared to oligotrophic lakes. Additionally, the eutrophic lakes showed a higher stabilization (S), thus a less efficient microbial community, compared to the oligotrophic lakes, although the variation within this group was high. Our results clearly show that the TBI can be used to adequately assess the decomposition process in aquatic systems. Using "alien standard litter" such as tea provides a powerful way to compare decomposition across climates, trophic states and ecosystems. By providing standardized protocols, a website, as well as face to face meetings, we also showed that collecting scientifically relevant data can go hand in hand with increasing scientific and environmental literacy in participants. Gathering process-based information about lake ecosystems gives managers the best tools to anticipate and react to future global change. Furthermore, combining this process-based information with citizen science, thus outreach, is in complete agreement with the Water Framework Directive goals as set in 2010.
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http://dx.doi.org/10.1016/j.watres.2018.11.081DOI Listing
March 2019

A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins.

Sci Data 2018 10 23;5:180226. Epub 2018 Oct 23.

Lammi Biological Station, University of Helsinki, 16900 Lammi, Finland.

Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The European Multi Lake Survey (EMLS) in summer 2015 was an initiative among scientists from 27 countries to collect and analyse lake physical, chemical and biological variables in a fully standardized manner. This database includes in-situ lake variables along with nutrient, pigment and cyanotoxin data of 369 lakes in Europe, which were centrally analysed in dedicated laboratories. Publishing the EMLS methods and dataset might inspire similar initiatives to study across large geographic areas that will contribute to better understanding lake responses in a changing environment.
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http://dx.doi.org/10.1038/sdata.2018.226DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6198753PMC
October 2018

Impacts of warming on top-down and bottom-up controls of periphyton production.

Sci Rep 2018 07 2;8(1):9901. Epub 2018 Jul 2.

Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Department of Ecosystem Research, Müggelseedamm 301, 12587, Berlin, Germany.

Global warming profoundly impacts the functioning of aquatic ecosystems. Nonetheless, the effect of warming on primary producers is poorly understood, especially periphyton production, which is affected both directly and indirectly by temperature-sensitive top-down and bottom-up controls. Here, we study the impact of warming on gross primary production in experimental ecosystems with near-realistic foodwebs during spring and early summer. We used indoor mesocosms following a temperate temperature regime (control) and a warmed (+4 °C) treatment to measure biomass and production of phytoplankton and periphyton. The mesocosms' primary production was dominated by periphyton (>82%) during the studied period (April-June). Until May, periphyton production and biomass were significantly higher in the warm treatment (up to 98% greater biomass compared to the control) due to direct temperature effects on growth and indirect effects resulting from higher sediment phosphorus release. Subsequently, enhanced grazer abundances seem to have counteracted the positive temperature effect causing a decline in periphyton biomass and production in June. We thus show, within our studied period, seasonally distinct effects of warming on periphyton, which can significantly affect overall ecosystem primary production and functioning.
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http://dx.doi.org/10.1038/s41598-018-26348-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6028635PMC
July 2018

Cross continental increase in methane ebullition under climate change.

Nat Commun 2017 11 22;8(1):1682. Epub 2017 Nov 22.

Department of Aquatic Ecology and Environmental Biology, Institute for Water and Wetland Research, Radboud University, P.O. Box 9010, 6500 GL, Nijmegen, The Netherlands.

Methane (CH) strongly contributes to observed global warming. As natural CH emissions mainly originate from wet ecosystems, it is important to unravel how climate change may affect these emissions. This is especially true for ebullition (bubble flux from sediments), a pathway that has long been underestimated but generally dominates emissions. Here we show a remarkably strong relationship between CH ebullition and temperature across a wide range of freshwater ecosystems on different continents using multi-seasonal CH ebullition data from the literature. As these temperature-ebullition relationships may have been affected by seasonal variation in organic matter availability, we also conducted a controlled year-round mesocosm experiment. Here 4 °C warming led to 51% higher total annual CH ebullition, while diffusion was not affected. Our combined findings suggest that global warming will strongly enhance freshwater CH emissions through a disproportional increase in ebullition (6-20% per 1 °C increase), contributing to global warming.
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http://dx.doi.org/10.1038/s41467-017-01535-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5700168PMC
November 2017

Combined physical, chemical and biological factors shape Alexandrium ostenfeldii blooms in The Netherlands.

Harmful Algae 2017 03 1;63:146-153. Epub 2017 Mar 1.

Department of Aquatic Ecology, Netherlands Institute of Ecology, Wageningen, The Netherlands.

Harmful algal blooms (HABs) are globally expanding, compromising water quality worldwide. HAB dynamics are determined by a complex interplay of abiotic and biotic factors, and their emergence has often been linked to eutrophication, and more recently to climate change. The dinoflagellate Alexandrium is one of the most widespread HAB genera and its success is based on key functional traits like allelopathy, mixotrophy, cyst formation and nutrient retrieval migrations. Since 2012, dense Alexandrium ostenfeldii blooms (up to 4500cellsmL) have recurred annually in a creek located in the southwest of the Netherlands, an area characterized by intense agriculture and aquaculture. We investigated how physical, chemical and biological factors influenced A. ostenfeldii bloom dynamics over three consecutive years (2013-2015). Overall, we found a decrease in the magnitude of the bloom over the years that could largely be linked to changing weather conditions during summer. More specifically, low salinities due to excessive rainfall and increased wind speed corresponded to a delayed A. ostenfeldii bloom with reduced population densities in 2015. Within each year, highest population densities generally corresponded to high temperatures, low DIN:DIP ratios and low grazer densities. Together, our results demonstrate an important role of nutrient availability, absence of grazing, and particularly of the physical environment on the magnitude and duration of A. ostenfeldii blooms. Our results suggest that predicted changes in the physical environment may enhance bloom development in future coastal waters and embayments.
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http://dx.doi.org/10.1016/j.hal.2017.02.004DOI Listing
March 2017

Pharmaceuticals May Disrupt Natural Chemical Information Flows and Species Interactions in Aquatic Systems: Ideas and Perspectives on a Hidden Global Change.

Rev Environ Contam Toxicol 2016;238:91-105

Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands.

Pharmaceuticals consumption by humans and animals is increasing substantially, leading to unprecedented levels of these compounds in aquatic environments worldwide. Recent findings that concentrations reach levels that can directly have negative effects on organisms are important per se, but also sound an alarm for other potentially more pervasive effects that arise from the interconnected nature of ecological communities. Aquatic organisms use chemical cues to navigate numerous challenges, including the location of mates and food, and the avoidance of natural enemies. Low concentrations of pharmaceuticals can disrupt this "smellscape" of information leading to maladaptive responses. Furthermore, direct effects of pharmaceuticals on the traits and abundance of one species can cascade through a community, indirectly affecting other species. We review mechanisms by which pharmaceuticals in surface waters can disrupt natural chemical information flows and species interactions. Pharmaceuticals form a new class of chemical threats, which could have far-reaching implications for ecosystem functioning and conservation management.
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http://dx.doi.org/10.1007/398_2015_5002DOI Listing
January 2017

Warming accelerates termination of a phytoplankton spring bloom by fungal parasites.

Glob Chang Biol 2016 Jan 21;22(1):299-309. Epub 2015 Oct 21.

Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6708 PB, Wageningen, The Netherlands.

Climate change is expected to favour infectious diseases across ecosystems worldwide. In freshwater and marine environments, parasites play a crucial role in controlling plankton population dynamics. Infection of phytoplankton populations will cause a transfer of carbon and nutrients into parasites, which may change the type of food available for higher trophic levels. Some phytoplankton species are inedible to zooplankton, and the termination of their population by parasites may liberate otherwise unavailable carbon and nutrients. Phytoplankton spring blooms often consist of large diatoms inedible for zooplankton, but the zoospores of their fungal parasites may serve as a food source for this higher trophic level. Here, we investigated the impact of warming on the fungal infection of a natural phytoplankton spring bloom and followed the response of a zooplankton community. Experiments were performed in ca. 1000 L indoor mesocosms exposed to a controlled seasonal temperature cycle and a warm (+4 °C) treatment in the period from March to June 2014. The spring bloom was dominated by the diatom Synedra. At the peak of infection over 40% of the Synedra population was infected by a fungal parasite (i.e. a chytrid) in both treatments. Warming did not affect the onset of the Synedra bloom, but accelerated its termination. Peak population density of Synedra tended to be lower in the warm treatments. Furthermore, Synedra carbon: phosphorus stoichiometry increased during the bloom, particularly in the control treatments. This indicates enhanced phosphorus limitation in the control treatments, which may have constrained chytrid development. Timing of the rotifer Keratella advanced in the warm treatments and closely followed chytrid infections. The chytrids' zoospores may thus have served as an alternative food source to Keratella. Our study thus emphasizes the importance of incorporating not only nutrient limitation and grazing, but also parasitism in understanding the response of plankton communities towards global warming.
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http://dx.doi.org/10.1111/gcb.13095DOI Listing
January 2016

Community stoichiometry in a changing world: combined effects of warming and eutrophication on phytoplankton dynamics.

Ecology 2014 Jun;95(6):1485-95

The current changes in our climate will likely have far-reaching consequences for aquatic ecosystems. These changes in the climate, however, do not act alone, and are often accompanied by additional stressors such as eutrophication. Both global warming and eutrophication have been shown to affect the timing and magnitude of phytoplankton blooms. Little is known about the combined effects of rising temperatures and eutrophication on the stoichiometry of entire phytoplankton communities. We exposed a natural phytoplankton spring community to different warming and phosphorus-loading scenarios using a full-factorial design. Our results demonstrate that rising temperatures promote the growth rate of an entire phytoplankton community. Furthermore, both rising temperatures and phosphorus loading stimulated the maximum biomass built up by the phytoplankton community. Rising temperatures led to higher carbon: nutrient stoichiometry of the phytoplankton community under phosphorus-limited conditions. Such a shift towards higher carbon: nutrient ratios, in combination with a higher biomass buildup, suggests a temperature-driven increase in nutrient use efficiency, the phytoplankton community. Importantly, with higher carbon: nutrient stoichiometry, phytoplankton is generally of poorer nutritional value for zooplankton. Thus, although warming may result in higher phytoplankton biomass, this may be accompanied by a stoichiometric mismatch between phytoplankton and their grazers, with possible consequences for the entire aquatic food web.
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http://dx.doi.org/10.1890/13-1251.1DOI Listing
June 2014

Temperature alters host genotype-specific susceptibility to chytrid infection.

PLoS One 2013 26;8(8):e71737. Epub 2013 Aug 26.

Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.

The cost of parasitism often depends on environmental conditions and host identity. Therefore, variation in the biotic and abiotic environment can have repercussions on both, species-level host-parasite interaction patterns but also on host genotype-specific susceptibility to disease. We exposed seven genetically different but concurrent strains of the diatom Asterionella formosa to one genotype of its naturally co-occurring chytrid parasite Zygorhizidium planktonicum across five environmentally relevant temperatures. We found that the thermal tolerance range of the tested parasite genotype was narrower than that of its host, providing the host with a "cold" and "hot" thermal refuge of very low or no infection. Susceptibility to disease was host genotype-specific and varied with temperature level so that no genotype was most or least resistant across all temperatures. This suggests a role of thermal variation in the maintenance of diversity in disease related traits in this phytoplankton host. The duration and intensity of chytrid parasite pressure on host populations is likely to be affected by the projected changes in temperature patterns due to climate warming both through altering temperature dependent disease susceptibility of the host and, potentially, through en- or disabling thermal host refugia. This, in turn may affect the selective strength of the parasite on the genetic architecture of the host population.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0071737PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3753301PMC
April 2014

Chytrid epidemics may increase genetic diversity of a diatom spring-bloom.

ISME J 2013 Oct 9;7(10):2057-9. Epub 2013 May 9.

Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.

Contrary to expectation, populations of clonal organisms are often genetically highly diverse. In phytoplankton, this diversity is maintained throughout periods of high population growth (that is, blooms), even though competitive exclusion among genotypes should hypothetically lead to the dominance of a few superior genotypes. Genotype-specific parasitism may be one mechanism that helps maintain such high-genotypic diversity of clonal organisms. Here, we present a comparison of population genetic similarity by estimating the beta-dispersion among genotypes of early and peak bloom populations of the diatom Asterionella formosa for three spring-blooms under high or low parasite pressure. The Asterionella population showed greater beta-dispersion at peak bloom than early bloom in the 2 years with high parasite pressure, whereas the within group dispersion did not change under low parasite pressure. Our findings support that high prevalence parasitism can promote genetic diversification of natural populations of clonal hosts.
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http://dx.doi.org/10.1038/ismej.2013.73DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3965307PMC
October 2013

The good, the bad and the plenty: interactive effects of food quality and quantity on the growth of different Daphnia species.

PLoS One 2012 25;7(9):e42966. Epub 2012 Sep 25.

Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.

Effects of food quality and quantity on consumers are neither independent nor interchangeable. Although consumer growth and reproduction show strong variation in relation to both food quality and quantity, the effects of food quality or food quantity have usually been studied in isolation. In two experiments, we studied the growth and reproduction in three filter-feeding freshwater zooplankton species, i.e. Daphnia galeata x hyalina, D. pulicaria and D. magna, on their algal food (Scenedesmus obliquus), varying in carbon to phosphorus (C∶P) ratios and quantities (concentrations). In the first experiment, we found a strong positive effect of the phosphorus content of food on growth of Daphnia, both in their early and late juvenile development. Variation in the relationship between the P-content of animals and their growth rate reflected interspecific differences in nutrient requirements. Although growth rates typically decreased as development neared maturation, this did not affect these species-specific couplings between growth rate and Daphnia P-content. In the second experiment, we examined the effects of food quality on Daphnia growth at different levels of food quantity. With the same decrease in P-content of food, species with higher estimated P-content at zero growth showed a larger increase in threshold food concentrations (i.e. food concentration sufficient to meet metabolic requirements but not growth). These results suggest that physiological processes such as maintenance and growth may in combination explain effects of food quality and quantity on consumers. Our study shows that differences in response to variation in food quality and quantity exist between species. As a consequence, species-specific effects of food quality on consumer growth will also determine how species deal with varying food levels, which has implications for resource-consumer interactions.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0042966PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3458054PMC
April 2013

GENOTYPE-BY-TEMPERATURE INTERACTIONS MAY HELP TO MAINTAIN CLONAL DIVERSITY IN ASTERIONELLA FORMOSA (BACILLARIOPHYCEAE).

J Phycol 2012 Oct 13;48(5):1197-208. Epub 2012 Sep 13.

Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB, Wageningen, The Netherlands.

Marine and freshwater phytoplankton populations often show large clonal diversity, which is in disagreement with clonal selection of the most vigorous genotype(s). Temporal fluctuation in selection pressures in variable environments is a leading explanation for maintenance of such genetic diversity. To test the influence of temperature as a selection force in continually (seasonally) changing aquatic systems we carried out reaction norms experiments on co-occurring clonal genotypes of a ubiquitous diatom species, Asterionella formosa Hassall, across an environmentally relevant range of temperatures. We report within population genetic diversity and extensive diversity in genotype-specific reaction norms in growth rates and cell size traits. Our results showed genotype by environment interactions, indicating that no genotype could outgrow all others across all temperature environments. Subsequently, we constructed a model to simulate the relative proportion of each genotype in a hypothetical population based on genotype and temperature-specific population growth rates. This model was run with different seasonal temperature patterns. Our modeling exercise showed a succession of two to several genotypes becoming numerically dominant depending on the underlying temperature pattern. The results suggest that (temperature) context dependent fitness may contribute to the maintenance of genetic diversity in isolated populations of clonally reproducing microorganisms in temporally variable environments.
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http://dx.doi.org/10.1111/j.1529-8817.2012.01205.xDOI Listing
October 2012

Can overwintering versus diapausing strategy in Daphnia determine match-mismatch events in zooplankton-algae interactions?

Oecologia 2007 Jan 22;150(4):682-98. Epub 2006 Sep 22.

NIOO-KNAW, Centre for Limnology, Rijksstraatweg 6, 3631 AC, Nieuwersluis, The Netherlands.

Mismatches between predator and prey due to climate change have now been documented for a number of systems. Ultimately, a mismatch may have far-reaching consequences for ecosystem functioning as decoupling of trophic relationships results in trophic cascades. Here, we examine the potential for climate change induced mismatches between zooplankton and algae during spring succession, with a focus on Daphnia and its algal food. Whereas the development of an overwintering population of daphnids may parallel shifts in phytoplankton phenology due to climate warming, changes in the photoperiod-temperature interaction may cause the emerging population of daphnids to hatch too late and mismatch their phytoplankton prey. A decoupling of the trophic relationship between the keystone herbivore Daphnia and its algal prey can result in the absence of a spring clear water phase. We extended an existing minimal model of seasonal dynamics of Daphnia and algae and varied the way the Daphnia population is started in spring, i.e., from free swimming individuals or from hatching resting eggs. Our model results show that temperature affects the timing of peak abundance in Daphnia and algae, and subsequently the timing of the clear water phase. When a population is started from a small inoculum of hatching resting eggs, extreme climate warming (+6 degrees C) results in a decoupling of trophic relationships and the clear water phase fails to occur. In the other scenarios, the trophic relationships between Daphnia and its algal food source remain intact. Analysis of 36 temperate lakes showed that shallow lakes have a higher potential for climate induced match-mismatches, as the probability of active overwintering daphnids decreases with lake depth. Future research should point out whether lake depth is a direct causal factor in determining the presence of active overwintering daphnids or merely indicative for underlying causal factors such as fish predation and macrophyte cover.
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http://dx.doi.org/10.1007/s00442-006-0549-2DOI Listing
January 2007
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