| 1. |
- Lewandowska, A. M., et al.
(author)
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The influence of balanced and imbalanced resource supply on biodiversity-functioning relationship across ecosystems
- 2016
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In: Philosophical Transactions of the Royal Society B-Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 371:1694
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Journal article (peer-reviewed)abstract
- Numerous studies show that increasing species richness leads to higher ecosystem productivity. This effect is often attributed to more efficient portioning of multiple resources in communities with higher numbers of competing species, indicating the role of resource supply and stoichiometry for biodiversity ecosystern functioning relationships. Here, we merged theory on ecological stoichiometry with a framework of biodiversity ecosystem functioning to understand how resource use transfers into primary production. We applied a structural equation model to define patterns of diversity productivity relationships with respect to available resources. Meta-analysis was used to summarize the findings across ecosystem types ranging from aquatic ecosystems to grasslands and forests. As hypothesized, resource supply increased realized productivity and richness, but we found significant differences between ecosystems and study types. Increased richness was associated with increased productivity, although this effect was not seen in experiments. More even communities had lower productivity, indicating that biomass production is often maintained by a few dominant species, and reduced dominance generally reduced ecosystem productivity. This synthesis, which integrates observational and experimental studies in a variety of ecosystems and geographical regions, exposes common pattems and differences in biodiversity functioning relationships, and increases the mechanistic understanding of changes in ecosystems productivity.
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| 2. |
- Arnott, Shelley E., et al.
(author)
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Widespread variation in salt tolerance within freshwater zooplankton species reduces the predictability of community-level salt tolerance
- 2023
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In: Limnology and Oceanography Letters. - : John Wiley & Sons. - 2378-2242. ; 8:1, s. 8-18
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Journal article (peer-reviewed)abstract
- The salinization of freshwaters is a global threat to aquatic biodiversity. We quantified variation in chloride (Cl-) tolerance of 19 freshwater zooplankton species in four countries to answer three questions: (1) How much variation in Cl- tolerance is present among populations? (2) What factors predict intraspecific variation in Cl- tolerance? (3) Must we account for intraspecific variation to accurately predict community Cl- tolerance? We conducted field mesocosm experiments at 16 sites and compiled acute LC(50)s from published laboratory studies. We found high variation in LC(50)s for Cl- tolerance in multiple species, which, in the experiment, was only explained by zooplankton community composition. Variation in species-LC50 was high enough that at 45% of lakes, community response was not predictable based on species tolerances measured at other sites. This suggests that water quality guidelines should be based on multiple populations and communities to account for large intraspecific variation in Cl- tolerance.
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| 3. |
- Berger, S. A., et al.
(author)
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Water temperature and mixing depth affect timing and magnitude of events during spring succession of the plankton
- 2007
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In: Oecologia. ; 150:4, s. 643-654
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Journal article (peer-reviewed)abstract
- In many lakes, the most conspicuous seasonal events are the phytoplankton spring bloom and the subsequent clear-water phase, a period of low-phytoplankton biomass that is frequently caused by mesozooplankton (Daphnia) grazing. In Central European lakes, the timing of the clear-water phase is linked to large-scale climatic forcing, with warmer winters being followed by an earlier onset of the clear-water phase. Mild winters may favour an early build-up of Daphnia populations, both directly through increased surface temperatures and indirectly by reducing light limitation and enhancing algal production, all being a consequence of earlier thermal stratification. We conducted a field experiment to disentangle the separate impacts of stratification depth (affecting light supply) and temperature on the magnitude and timing of successional events in the plankton. We followed the dynamics of the phytoplankton spring bloom, the clear-water phase and the spring peak in Daphnia abundance in response to our experimental manipulations. Deeper mixing delayed the timing of all spring seasonal events and reduced the magnitudes of the phytoplankton bloom and the subsequent Daphnia peak. Colder temperatures retarded the timing of the clear-water phase and the subsequent Daphnia peak, whereas the timing of the phytoplankton peak was unrelated to temperature. Most effects of mixing depth (light) and temperature manipulations were independent, effects of mixing depth being more prevalent than effects of temperature. Because mixing depth governs both the light climate and the temperature regime in the mixed surface layer, we propose that climate-driven changes in the timing and depth of water column stratification may have far-reaching consequences for plankton dynamics and should receive increased attention.
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| 4. |
- Hebert, Marie-Pier, et al.
(author)
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Lake salinization drives consistent losses of zooplankton abundance and diversity across coordinated mesocosm experiments
- 2023
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In: Limnology and Oceanography Letters. - : John Wiley & Sons. - 2378-2242. ; 8:1, s. 19-29
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Journal article (peer-reviewed)abstract
- Human-induced salinization increasingly threatens inland waters; yet we know little about the multifaceted response of lake communities to salt contamination. By conducting a coordinated mesocosm experiment of lake salinization across 16 sites in North America and Europe, we quantified the response of zooplankton abundance and (taxonomic and functional) community structure to a broad gradient of environmentally relevant chloride concentrations, ranging from 4 to ca. 1400 mg Cl- L-1. We found that crustaceans were distinctly more sensitive to elevated chloride than rotifers; yet, rotifers did not show compensatory abundance increases in response to crustacean declines. For crustaceans, our among-site comparisons indicate: (1) highly consistent decreases in abundance and taxon richness with salinity; (2) widespread chloride sensitivity across major taxonomic groups (Cladocera, Cyclopoida, and Calanoida); and (3) weaker loss of functional than taxonomic diversity. Overall, our study demonstrates that aggregate properties of zooplankton communities can be adversely affected at chloride concentrations relevant to anthropogenic salinization in lakes.
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| 5. |
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| 6. |
- Urrutia-Cordero, P., et al.
(author)
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SITES AquaNet: An open infrastructure for mesocosm experiments with high frequency sensor monitoring across lakes
- 2021
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In: Limnology and Oceanography-Methods. - : Wiley. - 1541-5856. ; 19:6, s. 385-400
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Journal article (peer-reviewed)abstract
- For aquatic scientists mesocosm experiments are important tools for hypothesis testing as they offer a compromise between experimental control and realism. Here we present a new mesocosm infrastructure-SITES AquaNET-located in five lakes connected to field stations in Sweden that cover a similar to 760 km latitudinal gradient. SITES AquaNet overcomes major hindrances in aquatic experimental research through: (i) openness to the scientific community, (ii) the potential to implement coordinated experiments across sites and time, and (iii) high-frequency measurements (temperature, photosynthetic photon flux density, turbidity and dissolved oxygen, chlorophyll a and phycocyanin concentrations) with an autonomous sensor system. Moreover, the infrastructure provides operational guidance and sensor expertise from technical staff, and connections to a multi-layered monitoring programme ("SITES Water") for each lake. This enables ecological observations from whole lake ecosystems to be compared with experimental studies aiming at disentangling major drivers and mechanisms underlying observed changes. Here we describe the technical properties of the infrastructure along with possibilities for experimental manipulations to tackle pressing issues in aquatic ecology and global change science. As a proof of concept, we also present a first mesocosm experiment across all five field sites with a cross-factorial design to evaluate responses of the sensor measurements to press/bottom-up (constant light reduction) and pulse/top-down (temporary fish predation) disturbances. This demonstrates the suitability of the infrastructure and autonomous sensor system to host modularized experiments and exemplifies the power and advantages of the approach to integrate a network of mecsocosm facilities with manageable costs across large geographic areas.
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| 7. |
- Gerhard, Miriam, et al.
(author)
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Environmental variability in aquatic ecosystems : Avenues for future multifactorial experiments
- 2023
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In: Limnology and Oceanography Letters. - : John Wiley & Sons. - 2378-2242. ; 8:2, s. 247-266
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Journal article (peer-reviewed)abstract
- The relevance of considering environmental variability for understanding and predicting biological responses to environmental changes has resulted in a recent surge in variability-focused ecological research. However, integration of findings that emerge across studies and identification of remaining knowledge gaps in aquatic ecosystems remain critical. Here, we address these aspects by: (1) summarizing relevant terms of variability research including the components (characteristics) of variability and key interactions when considering multiple environmental factors; (2) identifying conceptual frameworks for understanding the consequences of environmental variability in single and multifactorial scenarios; (3) highlighting challenges for bridging theoretical and experimental studies involving transitioning from simple to more complex scenarios; (4) proposing improved approaches to overcome current mismatches between theoretical predictions and experimental observations; and (5) providing a guide for designing integrated experiments across multiple scales, degrees of control, and complexity in light of their specific strengths and limitations.
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| 8. |
- Hintz, William D., et al.
(author)
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Current water quality guidelines across North America and Europe do not protect lakes from salinization
- 2022
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In: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 119:9
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Journal article (peer-reviewed)abstract
- Human-induced salinization caused by the use of road deicing salts, agricultural practices, mining operations, and climate change is a major threat to the biodiversity and functioning of freshwater ecosystems. Yet, it is unclear if freshwater ecosystems are protected from salinization by current water quality guidelines. Leveraging an experimental network of land-based and in-lake mesocosms across North America and Europe, we tested how salinization—indicated as elevated chloride (Cl−) concentration—will affect lake food webs and if two of the lowest Cl− thresholds found globally are sufficient to protect these food webs. Our results indicated that salinization will cause substantial zooplankton mortality at the lowest Cl− thresholds established in Canada (120 mg Cl−/L) and the United States (230 mg Cl−/L) and throughout Europe where Cl− thresholds are generally higher. For instance, at 73% of our study sites, Cl− concentrations that caused a ≥50% reduction in cladoceran abundance were at or below Cl− thresholds in Canada, in the United States, and throughout Europe. Similar trends occurred for copepod and rotifer zooplankton. The loss of zooplankton triggered a cascading effect causing an increase in phytoplankton biomass at 47% of study sites. Such changes in lake food webs could alter nutrient cycling and water clarity and trigger declines in fish production. Current Cl− thresholds across North America and Europe clearly do not adequately protect lake food webs. Water quality guidelines should be developed where they do not exist, and there is an urgent need to reassess existing guidelines to protect lake ecosystems from human-induced salinization.
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| 9. |
- Moore, Josh, et al.
(author)
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OME-Zarr : A cloud-optimized bioimaging file format with international community support
- 2023
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In: Histochemistry and Cell Biology. - : Springer Nature. - 1432-119X .- 0948-6143. ; 160:3, s. 223-251
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Journal article (peer-reviewed)abstract
- A growing community is constructing a next-generation file format (NGFF) for bioimaging to overcome problems of scalability and heterogeneity. Organized by the Open Microscopy Environment (OME), individuals and institutes across diverse modalities facing these problems have designed a format specification process (OME-NGFF) to address these needs. This paper brings together a wide range of those community members to describe the cloud-optimized format itself-OME-Zarr-along with tools and data resources available today to increase FAIR access and remove barriers in the scientific process. The current momentum offers an opportunity to unify a key component of the bioimaging domain-the file format that underlies so many personal, institutional, and global data management and analysis tasks.
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| 10. |
- Striebel, M., et al.
(author)
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Carbon sequestration and stoichiometry of motile and nonmotile green algae
- 2009
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In: Limnology and Oceanography. ; 54:5, s. 1746-1752
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Journal article (peer-reviewed)abstract
- Actively motile, flagellated phytoplankton taxa often exploit vertical gradients in the availability of light and nutrients. The ability to move actively usually goes along with low investment in structural carbon components and should entail costs in terms of increased energy expenditure. This should be reflected in higher metabolic rates and higher light requirements for growth and, consequently, in lower light-dependent specific production rates, carrying capacities, and carbon-to-phosphorus (C : P) ratios (during phosphorus limitation) of flagellated compared to nonmotile taxa. Laboratory experiments with four flagellated and five nonmotile species of green algae, performed over a light gradient, corroborated these expectations. Parameter fits to short-term production-irradiance measurements suggest that flagellated taxa had higher respiration rates and higher light requirements for growth than nonmotile taxa. Accordingly, both short-term photosynthetic rates and longer-term (14 d) biomass accrual were lower for flagellated than for nonmotile taxa. While most of the variance in algal C : P ratios was explained by species-specific effects, there was also a tendency for algal C : P ratios to be lower in flagellated that in nonmotile taxa. Collectively, these results point at significant costs of motility, which may explain why flagellated taxa are often outcompeted by nonmotile taxa in turbulently mixed environments, where active motility is of little use.
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| 11. |
- Striebel, M., et al.
(author)
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Spectral Niche Complementarity and Carbon Dynamics in Pelagic Ecosystems
- 2009
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In: American Naturalist. ; 174:1, s. 141-147
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Journal article (peer-reviewed)abstract
- Positive effects of biodiversity on ecosystem function are described from an increasing number of systems, but the underlying mechanisms frequently remain elusive. A truly predictive understanding of biodiversity-ecosystem function relationships requires the a priori identification of traits conferring specific ( and possibly complementary) functions to individual species. Although planktonic organisms are responsible for approximately half of the world's primary production, few studies have reported on the relationship between phytoplankton biodiversity and planktonic primary production. We argue that taxon-specific differential equipment with photosynthetically active pigments provides a biochemical mechanism of resource use complementarity among phototrophic microorganisms, enabling more diverse communities to more completely harvest the light spectrum. In line with this, more diverse phytoplankton communities showed higher pigment diversity, higher biomass-specific light absorbance, and higher rates of primary production and biomass accrual.
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