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Kathrin Lengfellner

Bio: Kathrin Lengfellner is an academic researcher from Umeå University. The author has contributed to research in topics: Spring bloom & Phytoplankton. The author has an hindex of 10, co-authored 14 publications receiving 1783 citations. Previous affiliations of Kathrin Lengfellner include Leibniz Institute of Marine Sciences & Leibniz Association.
Topics: Spring bloom, Phytoplankton, Mesocosm, Plankton, Bloom

Papers
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Journal ArticleDOI
TL;DR: This study provides evidence that reduced body size is the third universal ecological response to global warming in aquatic systems besides the shift of species ranges toward higher altitudes and latitudes and the seasonal shifts in life cycle events.
Abstract: Understanding the ecological impacts of climate change is a crucial challenge of the twenty-first century. There is a clear lack of general rules regarding the impacts of global warming on biota. Here, we present a metaanalysis of the effect of climate change on body size of ectothermic aquatic organisms (bacteria, phyto- and zooplankton, and fish) from the community to the individual level. Using long-term surveys, experimental data and published results, we show a significant increase in the proportion of small-sized species and young age classes and a decrease in size-at-age. These results are in accordance with the ecological rules dealing with the temperature–size relationships (i.e., Bergmann's rule, James' rule and Temperature–Size Rule). Our study provides evidence that reduced body size is the third universal ecological response to global warming in aquatic systems besides the shift of species ranges toward higher altitudes and latitudes and the seasonal shifts in life cycle events.

1,292 citations

Journal ArticleDOI
TL;DR: In this article, the authors show that winter and spring warming will lead to substantial changes in the spring bloom of phytoplankton, while light appears to play a more important role in its initiation.
Abstract: In this article, we show by mesocosm experiments that winter and spring warming will lead to substantial changes in the spring bloom of phytoplankton. The timing of the spring bloom shows only little response to warming as such, while light appears. to play a more important role in its initiation. The daily light dose needed for the start of the phytoplankton spring bloom in our experiments agrees well with. a recently published critical light intensity found in a field survey of the North'Atlantic -(around 1.3 mol photons m -2 day -1 ). Experimental temperature elevation had a strong effect on phytoplankton peak biomass (decreasing with-temperature),'mean cell size (decreasing" with temperature) and on the share of microplankton diatoms (decreasing with temperature). All these changes will lead to poorer feeding conditions for copepod-zooplankton and, thus, to a less efficient energy transfer from primary to fish production under a warmer climate.

256 citations

Journal ArticleDOI
TL;DR: The strong difference between the Acceleration of the phytoplankton peak and the acceleration of the nauplii could be one of the “Achilles heels” of pelagic systems subject to climate change.
Abstract: An indoor mesocosm system was set up to study the response of phytoplankton and zooplankton spring succession to winter and spring warming of sea surface temperatures. The experimental temperature regimes consisted of the decadal average of the Kiel Bight, Baltic Sea, and three elevated regimes with 2°C, 4°C, and 6°C temperature difference from that at baseline. While the peak of the phytoplankton spring bloom was accelerated only weakly by increasing temperatures (1.4 days per degree Celsius), the subsequent biomass minimum of phytoplankton was accelerated more strongly (4.25 days per degree Celsius). Phytoplankton size structure showed a pronounced response to warming, with large phytoplankton being more dominant in the cooler mesocosms. The first seasonal ciliate peak was accelerated by 2.1 days per degree Celsius and the second one by 2.0 days per degree Celsius. The over-wintering copepod populations declined faster in the warmer mesocosm, and the appearance of nauplii was strongly accelerated by temperature (9.2 days per degree Celsius). The strong difference between the acceleration of the phytoplankton peak and the acceleration of the nauplii could be one of the “Achilles heels” of pelagic systems subject to climate change, because nauplii are the most starvation-sensitive life cycle stage of copepods and the most important food item of first-feeding fish larvae.

137 citations

Journal ArticleDOI
TL;DR: This study aimed at simulating different degrees of winter warming and at assessing its potential effects on ciliate succession and grazing-related patterns by using indoor mesocosms filled with unfiltered water from Kiel Bight, natural light and four different temperature regimes, phytoplankton spring blooms were induced and the thermal responses of ciliates were quantified.
Abstract: This study aimed at simulating different degrees of winter warming and at assessing its potential effects on ciliate succession and grazing-related patterns. By using indoor mesocosms filled with unfiltered water from Kiel Bight, natural light and four different temperature regimes, phytoplankton spring blooms were induced and the thermal responses of ciliates were quantified. Two distinct ciliate assemblages, a pre-spring and a spring bloom assemblage, could be detected, while their formation was strongly temperature-dependent. Both assemblages were dominated by Strobilidiids; the pre-spring bloom phase was dominated by the small Strobilidiids Lohmaniella oviformis, and the spring bloom was mainly dominated by large Strobilidiids of the genus Strobilidium. The numerical response of ciliates to increasing food concentrations showed a strong acceleration by temperature. Grazing rates of ciliates and copepods were low during the pre-spring bloom period and high during the bloom ranging from 0.06 (Δ0°C) to 0.23 day−1 (Δ4°C) for ciliates and 0.09 (Δ0°C) to 1.62 day−1 (Δ4°C) for copepods. During the spring bloom ciliates and copepods showed a strong dietary overlap characterized by a wide food spectrum consisting mainly of Chrysochromulina sp., diatom chains and large, single-celled diatoms.

118 citations

Journal ArticleDOI
TL;DR: Meta-analysis confirms the general shift toward earlier blooms at increased temperature in both marine and freshwater systems and supports predictions that effects of climate change on plankton production will vary among sites, depending on resource limitation and species composition.
Abstract: Shifts in the timing and magnitude of the spring plankton bloom in response to climate change have been observed across a wide range of aquatic systems. We used meta-analysis to investigate phenological responses of marine and freshwater plankton communities in mesocosms subjected to experimental manipulations of temperature and light intensity. Systems differed with respect to the dominant mesozooplankton (copepods in seawater and daphnids in freshwater). Higher water temperatures advanced the bloom timing of most functional plankton groups in both marine and freshwater systems. In contrast to timing, responses of bloom magnitudes were more variable among taxa and systems and were influenced by light intensity and trophic interactions. Increased light levels increased the magnitude of the spring peaks of most phytoplankton taxa and of total phytoplankton biomass. Intensified size-selective grazing of copepods in warming scenarios affected phytoplankton size structure and lowered intermediate (20–200 μm)-sized phytoplankton in marine systems. In contrast, plankton peak magnitudes in freshwater systems were unaffected by temperature, but decreased at lower light intensities, suggesting that filter feeding daphnids are sensitive to changes in algal carrying capacity as mediated by light supply. Our analysis confirms the general shift toward earlier blooms at increased temperature in both marine and freshwater systems and supports predictions that effects of climate change on plankton production will vary among sites, depending on resource limitation and species composition.

75 citations


Cited by
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Journal ArticleDOI
TL;DR: This study provides evidence that reduced body size is the third universal ecological response to global warming in aquatic systems besides the shift of species ranges toward higher altitudes and latitudes and the seasonal shifts in life cycle events.
Abstract: Understanding the ecological impacts of climate change is a crucial challenge of the twenty-first century. There is a clear lack of general rules regarding the impacts of global warming on biota. Here, we present a metaanalysis of the effect of climate change on body size of ectothermic aquatic organisms (bacteria, phyto- and zooplankton, and fish) from the community to the individual level. Using long-term surveys, experimental data and published results, we show a significant increase in the proportion of small-sized species and young age classes and a decrease in size-at-age. These results are in accordance with the ecological rules dealing with the temperature–size relationships (i.e., Bergmann's rule, James' rule and Temperature–Size Rule). Our study provides evidence that reduced body size is the third universal ecological response to global warming in aquatic systems besides the shift of species ranges toward higher altitudes and latitudes and the seasonal shifts in life cycle events.

1,292 citations

Journal ArticleDOI
TL;DR: A review of recent studies shows heterogeneity in the magnitude and direction of size responses, exposing a need for large-scale phylogenetically controlled comparative analyses of temporal size change as mentioned in this paper, which will increase both understanding of the underlying mechanisms and physiological consequences of size shifts and therefore, the ability to predict the sensitivities of species to climate change.
Abstract: A recently documented correlate of anthropogenic climate change involves reductions in body size, the nature and scale of the pattern leading to suggestions of a third universal response to climate warming. Because body size affects thermoregulation and energetics, changing body size has implications for resilience in the face of climate change. A review of recent studies shows heterogeneity in the magnitude and direction of size responses, exposing a need for large-scale phylogenetically controlled comparative analyses of temporal size change. Integrative analyses of museum data combined with new theoretical models of size-dependent thermoregulatory and metabolic responses will increase both understanding of the underlying mechanisms and physiological consequences of size shifts and, therefore, the ability to predict the sensitivities of species to climate change.

830 citations

Journal ArticleDOI
11 Nov 2016-Science
TL;DR: The full range and scale of climate change effects on global biodiversity that have been observed in natural systems are described, and a set of core ecological processes that underpin ecosystem functioning and support services to people are identified.
Abstract: Most ecological processes now show responses to anthropogenic climate change. In terrestrial, freshwater, and marine ecosystems, species are changing genetically, physiologically, morphologically, and phenologically and are shifting their distributions, which affects food webs and results in new interactions. Disruptions scale from the gene to the ecosystem and have documented consequences for people, including unpredictable fisheries and crop yields, loss of genetic diversity in wild crop varieties, and increasing impacts of pests and diseases. In addition to the more easily observed changes, such as shifts in flowering phenology, we argue that many hidden dynamics, such as genetic changes, are also taking place. Understanding shifts in ecological processes can guide human adaptation strategies. In addition to reducing greenhouse gases, climate action and policy must therefore focus equally on strategies that safeguard biodiversity and ecosystems.

815 citations

Journal ArticleDOI
TL;DR: This Perspective looks at the evidence for shrinking body size across endothermic and ectothermic organisms and proposes future research directions.
Abstract: It is well recognized that species are shifting their distributions and the timing of key life events in response to climate change. What is less appreciated is that many species are also experiencing reductions in body size, with implications for food availability and the balance of ecosystems. This Perspective looks at the evidence for shrinking body size across endothermic and ectothermic organisms and proposes future research directions.

730 citations

Journal ArticleDOI
23 Oct 2009-Science
TL;DR: In the Arctic Ocean, phytoplankton cell sizes have decreased with warming temperatures and fresher surface waters, and since 2004, there has been an increase in the smallest algae and bacteria along with a concomitant decrease in somewhat larger algae.
Abstract: As climate changes and the upper Arctic Ocean receives more heat and fresh water, it becomes more difficult for mixing processes to deliver nutrients from depth to the surface for phytoplankton growth. Competitive advantage will presumably accrue to small cells because they are more effective in acquiring nutrients and less susceptible to gravitational settling than large cells. Since 2004, we have discerned an increase in the smallest algae and bacteria along with a concomitant decrease in somewhat larger algae. If this trend toward a community of smaller cells is sustained, it may lead to reduced biological production at higher trophic levels.

628 citations