TY  - JOUR
A1  - Ehrlich, Elias
A1  - Thygesen, Uffe Høgsbro
A1  - Kiørboe, Thomas
T1  - Evolution of toxins as a public good in phytoplankton
JF  - Proceedings of the Royal Society of London : B, Biological sciences
N2  - Toxic phytoplankton blooms have increased in many waterbodies worldwide with well-known negative impacts on human health, fisheries and ecosystems. However, why and how phytoplankton evolved toxin production is still a puzzling question, given that the producer that pays the costs often shares the benefit with other competing algae and thus provides toxins as a 'public good' (e.g. damaging a common competitor or predator). Furthermore, blooming phytoplankton species often show a high intraspecific variation in toxicity and we lack an understanding of what drives the dynamics of coexisting toxic and non-toxic genotypes. Here, by using an individual-based two-dimensional model, we show that small-scale patchiness of phytoplankton strains caused by demography can explain toxin evolution in phytoplankton with low motility and the maintenance of genetic diversity within their blooms. This patchiness vanishes for phytoplankton with high diffusive motility, suggesting different evolutionary pathways for different phytoplankton groups. In conclusion, our study reveals that small-scale spatial heterogeneity, generated by cell division and counteracted by diffusive cell motility and turbulence, can crucially affect toxin evolution and eco-evolutionary dynamics in toxic phytoplankton species. This contributes to a better understanding of conditions favouring toxin production and the evolution of public goods in asexually reproducing organisms in general.
KW  - toxic algal blooms
KW  - evolution of cooperation
KW  - coexistence
KW  - patchiness in
KW  - phytoplankton
KW  - eco-evolutionary feedback
KW  - spatial pattern formation
Y1  - 2022
U6  - https://doi.org/10.1098/rspb.2022.0393
SN  - 0962-8452
SN  - 1471-2954
VL  - 289
IS  - 1977
PB  - Royal Society
CY  - London
ER  - 
TY  - JOUR
A1  - Chorus, Ingrid
A1  - Spijkerman, Elly
T1  - What Colin Reynolds could tell us about nutrient limitation, N:P ratios and eutrophication control
JF  - Hydrobiologia : acta hydrobiologica, hydrographica, limnologica et protistologica
N2  - Colin Reynolds exquisitely consolidated our understanding of driving forces shaping phytoplankton communities and those setting the upper limit to biomass yield, with limitation typically shifting from light in winter to phosphorus in spring. Nonetheless, co-limitation is frequently postulated from enhanced growth responses to enrichments with both N and P or from N:P ranging around the Redfield ratio, concluding a need to reduce both N and P in order to mitigate eutrophication. Here, we review the current understanding of limitation through N and P and of co-limitation. We conclude that Reynolds is still correct: (i) Liebig's law of the minimum holds and reducing P is sufficient, provided concentrations achieved are low enough; (ii) analyses of nutrient limitation need to exclude evidently non-limiting situations, i.e. where soluble P exceeds 3-10 mu g/l, dissolved N exceeds 100-130 mu g/l and total P and N support high biomass levels with self-shading causing light limitation; (iii) additionally decreasing N to limiting concentrations may be useful in specific situations (e.g. shallow waterbodies with high internal P and pronounced denitrification); (iv) management decisions require local, situation-specific assessments. The value of research on stoichiometry and co-limitation lies in promoting our understanding of phytoplankton ecophysiology and community ecology.
KW  - phytoplankton
KW  - nitrogen limitation
KW  - redfield ratio
KW  - co-limitation
KW  - enrichment experiments
Y1  - 2020
U6  - https://doi.org/10.1007/s10750-020-04377-w
SN  - 0018-8158
SN  - 1573-5117
VL  - 848
IS  - 1
SP  - 95
EP  - 111
PB  - Springer Nature
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Ehrlich, Elias
A1  - Gaedke, Ursula
T1  - Coupled changes in traits and biomasses cascading through a tritrophic plankton food web
JF  - Limnology and oceanography
N2  - Trait-based approaches have broadened our understanding of how the composition of ecological communities responds to environmental drivers. This research has mainly focussed on abiotic factors and competition determining the community trait distribution, while effects of trophic interactions on trait dynamics, if considered at all, have been studied for two trophic levels at maximum. However, natural food webs are typically at least tritrophic. This enables indirect interactions of traits and biomasses among multiple trophic levels leading to underexplored effects on food web dynamics. Here, we demonstrate the occurrence of mutual trait adjustment among three trophic levels in a natural plankton food web (Lake Constance) and in a corresponding mathematical model. We found highly recurrent seasonal biomass and trait dynamics, where herbivorous zooplankton increased its size, and thus its ability to counter phytoplankton defense, before phytoplankton defense actually increased. This is contrary to predictions from bitrophic systems where counter-defense of the consumer is a reaction to prey defense. In contrast, counter-defense of carnivores by size adjustment followed the defense of herbivores as expected. By combining observations and model simulations, we show how the reversed trait dynamics at the two lower trophic levels result from a "trophic biomass-trait cascade" driven by the carnivores. Trait adjustment between two trophic levels can therefore be altered by biomass or trait changes of adjacent trophic levels. Hence, analyses of only pairwise trait adjustment can be misleading in natural food webs, while multitrophic trait-based approaches capture indirect biomass-trait interactions among multiple trophic levels.
KW  - community ecology
KW  - cyclops vicinus
KW  - dynamics
KW  - functional traits
KW  - lake
KW  - life-cycle
KW  - natural rotifer
KW  - phytoplankton
KW  - trophic cascades
KW  - zooplankton
Y1  - 2020
U6  - https://doi.org/10.1002/lno.11466
SN  - 0024-3590
SN  - 1939-5590
VL  - 65
IS  - 10
SP  - 2502
EP  - 2514
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Van den Wyngaert, Silke
A1  - Seto, Kensuke
A1  - Rojas-Jimenez, Keilor
A1  - Kagami, Maiko
A1  - Grossart, Hans-Peter
T1  - A New Parasitic Chytrid, Staurastromyces oculus (Rhizophydiales, Staurastromy-cetaceae fam. nov.), Infecting the Freshwater Desmid Staurastrum sp.
JF  - Protist
N2  - Chytrids are a diverse group of ubiquitous true zoosporic fungi. The recent molecular discovery of a large diversity of undescribed chytrids has raised awareness on their important, but so far understudied ecological role in aquatic ecosystems. In the pelagic zone, of both freshwater and marine ecosystems, many chytrid species have been morphologically described as parasites on almost all major groups of phytoplankton. However, the majority of these parasitic chytrids has rarely been isolated and lack DNA sequence data, resulting in a large proportion of "dark taxa" in databases. Here, we report on the isolation and in-depth morphological, molecular and host range characterization of a chytrid infecting the common freshwater desmid Staurastrum sp. We provide first insights on the metabolic activity of the different chytrid development stages by using the vital dye FUN (R)-1 (2-chloro-4-[2,3-dihydro-3-methyl-[benzo-1,3-thiazol-2-yl]-methylidene]-1-phenylquinolinium iodide). Cross infection experiments suggest that this chytrid is an obligate parasite and specific for the genus Staurastrum sp. Phylogenetic analysis, based on ITS1-5.8S-ITS2 and 28S rDNA sequences, placed it in the order Rhizophydiales. Based on the unique zoospore ultrastructure, combined with thallus morphology, and molecular phylogenetic placement, we describe this parasitic chytrid as a new genus and species Staurastromyces oculus, within a new family Staurastromycetaceae. (C) 2017 Elsevier GmbH. All rights reserved.
KW  - Chytrids
KW  - parasite
KW  - phytoplankton
KW  - Staurastromyces oculus
KW  - Staurastrum sp.
Y1  - 2017
U6  - https://doi.org/10.1016/j.protis.2017.05.001
SN  - 1434-4610
VL  - 168
SP  - 392
EP  - 407
PB  - Elsevier
CY  - Jena
ER  - 
TY  - JOUR
A1  - Van den Wyngaert, Silke
A1  - Rojas-Jimenez, Keilor
A1  - Seto, Kensuke
A1  - Kagami, Maiko
A1  - Grossart, Hans-Peter
T1  - Diversity and Hidden Host Specificity of Chytrids Infecting Colonial Volvocacean Algae
JF  - Journal of Eukaryotic Microbiology
N2  - Chytrids are zoosporic fungi that play an important, but yet understudied, ecological role in aquatic ecosystems. Many chytrid species have been morphologically described as parasites on phytoplankton. However, the majority of them have rarely been isolated and lack DNA sequence data. In this study we isolated and cultivated three parasitic chytrids, infecting a common volvocacean host species, Yamagishiella unicocca. To identify the chytrids, we characterized morphology and life cycle, and analyzed phylogenetic relationships based on 18S and 28S rDNA genes. Host range and specificity of the chytrids was determined by cross-infection assays with host strains, characterized by rbcL and ITS markers. We were able to confirm the identity of two chytrid strains as Endocoenobium eudorinae Ingold and Dangeardia mamillata Schroder and described the third chytrid strain as Algomyces stechlinensis gen. et sp. nov. The three chytrids were assigned to novel and phylogenetically distant clades within the phylum Chytridiomycota, each exhibiting different host specificities. By integrating morphological and molecular data of both the parasitic chytrids and their respective host species, we unveiled cryptic host-parasite associations. This study highlights that a high prevalence of (pseudo)cryptic diversity requires molecular characterization of both phytoplankton host and parasitic chytrid to accurately identify and compare host range and specificity, and to study phytoplankton-chytrid interactions in general.
KW  - Chytridiomycota
KW  - Dangeardia mamillata
KW  - Endocoenobium eudorinae
KW  - fungal parasites
KW  - life cycle
KW  - phytoplankton
Y1  - 2018
U6  - https://doi.org/10.1111/jeu.12632
SN  - 1066-5234
SN  - 1550-7408
VL  - 65
IS  - 6
SP  - 870
EP  - 881
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Bolius, Sarah
A1  - Karoline Morling, 
A1  - Wiedner, Claudia
A1  - Weithoff, Guntram
T1  - Genetic Identity and Herbivory Drive the Invasion of a Common Aquatic Microbial Invader
JF  - Frontiers in Microbiology
N2  - Despite the increasing number of species invasions, the factors driving invasiveness are still under debate. This is particularly the case for “invisible” invasions by aquatic microbial species. Since in many cases only a few individuals or propagules enter a new habitat, their genetic variation is low and might limit their invasion success, known as the genetic bottleneck. Thus, a key question is, how genetic identity and diversity of invading species influences their invasion success and, subsequently, affect the resident community. We conducted invader-addition experiments using genetically different strains of the globally invasive, aquatic cyanobacterium Raphidiopsis raciborskii (formerly: Cylindrospermopsis raciborskii) to determine the role of invader identity and genetic diversity (strain richness) at four levels of herbivory. We tested the invasion success of solitary single strain invasions against the invader genetic diversity, which was experimentally increased up to ten strains (multi-strain populations). By using amplicon sequencing we determined the strain-specific invasion success in the multi-strain treatments and compared those with the success of these strains in the single-strain treatments. Furthermore, we tested for the invasion success under different herbivore pressures. We showed that high grazing pressure by a generalist herbivore prevented invasion, whereas a specialist herbivore enabled coexistence of consumer and invader. We found a weak effect of diversity on invasion success only under highly competitive conditions. When invasions were successful, the magnitude of this success was strain-specific and consistent among invasions performed with single-strain or multi-strain populations. A strain-specific effect was also observed on the resident phytoplankton community composition, highlighting the strong role of invader genetic identity. Our results point to a strong effect of the genetic identity on the invasion success under low predation pressure. The genetic diversity of the invader population, however, had little effect on invasion success in our study, in contrast to most previous findings. Instead, it is the interaction between the consumer abundance and type together with the strain identity of the invader that defined invasion success. This study underlines the importance of strain choice in invasion research and in ecological studies in general.
KW  - alien species
KW  - genotype
KW  - invasibility
KW  - cyanobacteria
KW  - consumptive resistance
KW  - phytoplankton
KW  - Raphidiopsis
KW  - genetic diversity
Y1  - 2019
U6  - https://doi.org/10.3389/fmicb.2020.01598
SN  - 1664-302X
VL  - 11
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Weithoff, Guntram
A1  - Gaedke, Ursula
T1  - Mean functional traits of lake phytoplankton reflect seasonal and inter-annual changes in nutrients, climate and herbivory
JF  - Journal of plankton research
N2  - Trait-based approaches have become increasingly successful in community ecology. They assume that the distribution of functional traits within communities responds in a predictable way to alterations in environmental forcing and that strong forcing may accelerate such trait changes. We used high frequency measurements of phytoplankton to test these assumptions. We analyzed the seasonal and long-term dynamics of the community trait mean within a multi-dimensional trait space under alternating multifactorial environmental conditions. The community trait mean exhibited a distinct recurrent annual pattern that reflected minor changes in climate, herbivory and nutrients. Independent of early spring conditions, the community trait mean was repeatedly driven into a narrow confined area in the trait space under pronounced herbivory during the clear water phase. The speed of movement was highest at the onset and the relaxation of such strong unidirectional forcing. Thus, our data support the conceptual framework of trait-based ecology that alterations in environmental conditions are systematically tracked by adjustments in the dominant functional trait values and that the speed of trait changes depends on the kind and intensity of the selection pressure. Our approach provides a sensitive tool to detect small functional differences in the community related to subtle differences in forcing.
KW  - phytoplankton
KW  - temporal dynamics
KW  - climate
KW  - trait distribution
KW  - Lake Constance
KW  - functional traits
Y1  - 2017
U6  - https://doi.org/10.1093/plankt/fbw072
SN  - 0142-7873
SN  - 1464-3774
VL  - 39
SP  - 509
EP  - 517
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Lischke, Betty
A1  - Weithoff, Guntram
A1  - Wickham, Stephen A.
A1  - Attermeyer, Katrin
A1  - Großart, Hans-Peter
A1  - Scharnweber, Inga Kristin
A1  - Hilt, Sabine
A1  - Gaedke, Ursula
T1  - Large biomass of small feeders: ciliates may dominate herbivory in eutrophic lakes
JF  - Journal of plankton research
N2  - The importance of ciliates as herbivores and in biogeochemical cycles is increasingly recognized. An opportunity to observe the potential consequences of zooplankton dominated by ciliates arose when winter fish kills resulted in strong suppression of crustaceans by young planktivorous fish in two shallow lakes. On an annual average, ciliates made up 38-76% of the total zooplankton biomass in both lakes during two subsequent years. Consequently, ciliate biomass and their estimated grazing potential were extremely high compared with other lakes of various trophic states and depths. Grazing estimates based on abundance and size suggest that ciliates should have cleared the water column of small (<5 mu m) and intermediate (5-50 mu m) sized phytoplankton more than once a day. Especially, small feeders within the ciliates were important, likely exerting a strong top-down control on small phytoplankton. Particle-attached bacteria were presumably strongly suppressed by intermediate-sized ciliate feeders. In contrast to other lakes, large phytoplankton was proportionately very abundant. The phytoplankton community had a high evenness, which may be attributed to the feeding by numerous fast growing and selective ciliate species. Our study highlights ciliates as an important trophic link and adds to the growing awareness of the role of winter processes for plankton dynamics.
KW  - phytoplankton
KW  - crustaceans
KW  - rotifers
KW  - filtration rate
KW  - winter fish kill
Y1  - 2016
U6  - https://doi.org/10.1093/plankt/fbv102
SN  - 0142-7873
SN  - 1464-3774
VL  - 38
SP  - 2
EP  - 15
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Brentrup, Jennifer A.
A1  - Williamson, Craig E.
A1  - Colom-Montero, William
A1  - Eckert, Werner
A1  - de Eyto, Elvira
A1  - Großart, Hans-Peter
A1  - Huot, Yannick
A1  - Isles, Peter D. F.
A1  - Knoll, Lesley B.
A1  - Leach, Taylor H.
A1  - McBride, Chris G.
A1  - Pierson, Don
A1  - Pomati, Francesco
A1  - Read, Jordan S.
A1  - Rose, Kevin C.
A1  - Samal, Nihar R.
A1  - Staehr, Peter A.
A1  - Winslow, Luke A.
T1  - The potential of high-frequency profiling to assess vertical and seasonal patterns of phytoplankton dynamics in lakes: an extension of the Plankton Ecology Group (PEG) model
JF  - Inland waters : journal of the International Society of Limnology
N2  - The use of high-frequency sensors on profiling buoys to investigate physical, chemical, and biological processes in lakes is 
increasing rapidly. Profiling buoys with automated winches and sensors that collect high-frequency chlorophyll fluorescence 
(ChlF) profiles in 11 lakes in the Global Lake Ecological Observatory Network (GLEON) allowed the study of the vertical 
and temporal distribution of ChlF, including the formation of subsurface chlorophyll maxima (SSCM). The effectiveness of 3 
methods for sampling phytoplankton distributions in lakes, including (1) manual profiles, (2) single-depth buoys, and (3) 
profiling buoys were assessed. High-frequency ChlF surface data and profiles were compared to predictions from the 
Plankton Ecology Group (PEG) model. The depth-integrated ChlF dynamics measured by the profiling buoy data revealed a 
greater complexity that neither conventional sampling nor the generalized PEG model captured. Conventional sampling 
techniques would have missed SSCM in 7 of 11 study lakes. Although surface-only ChlF data underestimated average water 
column ChlF, at times by nearly 2-fold in 4 of the lakes, overall there was a remarkable similarity between surface and mean 
water column data. Contrary to the PEG model’s proposed negligible role for physical control of phytoplankton during the 
growing season, thermal structure and light availability were closely associated with ChlF seasonal depth distribution. Thus, 
an extension of the PEG model is proposed, with a new conceptual framework that explicitly includes physical metrics to 
better predict SSCM formation in lakes and highlight when profiling buoys are especially informative.
KW  - chlorophyll fluorescence
KW  - Global Lake Ecological Observatory Network (GLEON)
KW  - high-frequency sensors
KW  - PEG model
KW  - phytoplankton
KW  - profiling buoys
KW  - subsurface chlorophyll maximum
Y1  - 2016
U6  - https://doi.org/10.5268/IW-6.4.890
SN  - 2044-2041
SN  - 2044-205X
VL  - 6
SP  - 565
EP  - 580
PB  - Freshwater Biological Association
CY  - Ambleside
ER  - 
TY  - JOUR
A1  - Spijkerman, Elly
A1  - Stojkovic, Slobodanka
A1  - Holland, Daryl
A1  - Lachmann, Sabrina C.
A1  - Beardall, John
T1  - Nutrient induced fluorescence transients (NIFTs) provide a rapid measure of P and C (co-)limitation in a green alga
JF  - European journal of phycology
N2  - Nutrient Induced Fluorescence Transients (NIFTs) have been shown to be a possible way of testing for the limiting nutrient in algal populations. In this study we tested the hypothesis that NIFTs can be used to detect a (co-)limitation for inorganic phosphorus (Pi) and CO2 in the green alga Chlamydomonas acidophila and that the magnitude of the NIFTs can be related to cellular P:C ratios. We show a co-limitation response for Pi and CO2 via traditional nutrient enrichment experiments in natural phytoplankton populations dominated by C. acidophila. We measured NIFT responses after a Pi- or a CO2-spike in C. acidophila batch cultures at various stages of Pi and inorganic C limitation. Significant NIFTs were observed in response to spikes in both nutrients. The NIFT response to a Pi-spike showed a strong negative correlation with cellular P:C ratio that was pronounced below 3 mmol P: mol C (equivalent to 0.2 pg P cell(-1)). Both cellular P and C content influenced the extent of the Pi-NIFT response. The NIFT response to a CO2-spike correlated to low CO2 culturing conditions and also had a negative correlation with cellular P content. A secondary response within the Pi-NIFT response was related to the CO2 concentration and potentially reflected co-limitation. In conclusion, NIFTs provided a quick and reliable method to detect the growth-limiting nutrient in an extremophile green alga, under Pi-, CO2- and Pi/CO2 (co-)limited growth conditions.
KW  - acidophile
KW  - Chlamydomonas
KW  - CO2 concentrating mechanism
KW  - CO2 limitation
KW  - extremophile
KW  - nutrient limitation
KW  - photosynthesis response
KW  - phytoplankton
KW  - stoichiometry
Y1  - 2016
U6  - https://doi.org/10.1080/09670262.2015.1095355
SN  - 0967-0262
SN  - 1469-4433
VL  - 51
SP  - 47
EP  - 58
PB  - Hindawi
CY  - Abingdon
ER  - 
TY  - JOUR
A1  - Wacker, Alexander
A1  - Piepho, Maike
A1  - Spijkerman, Elly
T1  - Photosynthetic and fatty acid acclimation of four phytoplankton species in response to light intensity and phosphorus availability
JF  - European journal of phycology
N2  - Photosynthetic acclimation of phytoplankton to lower irradiation can be met by several strategies such as increasing the affinity for light or increasing antenna size and stacking of the thylakoids. The latter is reflected by a higher proportion of polyunsaturated fatty acids (PUFAs). Additionally, photosynthetic capacity (P-max), respiratory losses, and proton leakage can be reduced under low light. Here we consider the effect of light intensity and phosphorus availability simultaneously on the photosynthetic acclimation and fatty acid composition of four phytoplankters. We studied representatives of the Chlorophyceae, Cryptophyceae and Mediophyceae, all of which are important components of plankton communities in temperate lakes. In our analysis, excluding fatty acid composition, we found different acclimation strategies in the chlorophytes Scenedesmus quadricauda, Chlamydomonas globosa, cryptophyte Cryptomonas ovata and ochrophyte Cyclotella meneghiniana. We observed interactive effects of light and phosphorus conditions on photosynthetic capacity in S. quadricauda and Cry. ovata. Cry. ovata can be characterized as a low light-acclimated species, whereas S. quadricauda and Cyc. meneghiniana can cope best with a combination of high light intensities and low phosphorus supply. Principal component analyses (PCA), including fatty acid composition, showed further species-specific patterns in their regulation of P-max with PUFAs and light. In S. quadricauda and Cyc. meneghiniana, PUFAs negatively affected the relationship between P-max and light. In Chl. globosa, lower light coincided with higher PUFAs and lower P-max, but PCA also indicated that PUFAs had no direct influence on P-max. PUFAs and P-max were unaffected by light in Cry. ovata. We did not observe a general trend in the four species tested and concluded that, in particular, the interactive effects highlight the importance of taking into account more than one environmental factor when assessing photosynthetic acclimation to lower irradiation.
KW  - chlorophyll content
KW  - dark respiration
KW  - FAME
KW  - light acclimation
KW  - oxygen evolution
KW  - photosynthesis
KW  - phytoplankton
KW  - polyunsaturated fatty acids
Y1  - 2015
U6  - https://doi.org/10.1080/09670262.2015.1050068
SN  - 0967-0262
SN  - 1469-4433
VL  - 50
IS  - 3
SP  - 288
EP  - 300
PB  - Routledge, Taylor & Francis Group
CY  - Abingdon
ER  - 
TY  - JOUR
A1  - Engel, Anja
A1  - Piontek, Judith
A1  - Grossart, Hans-Peter
A1  - Riebesell, Ulf
A1  - Schulz, Kai Georg
A1  - Sperling, Martin
T1  - Impact of CO2 enrichment on organic matter dynamics during nutrient induced coastal phytoplankton blooms
JF  - Journal of plankton research
N2  - A mesocosm experiment was conducted to investigate the impact of rising fCO(2) on the build-up and decline of organic matter during coastal phytoplankton blooms. Five mesocosms (similar to 38 mA(3) each) were deployed in the Baltic Sea during spring (2009) and enriched with CO2 to yield a gradient of 355-862 A mu atm. Mesocosms were nutrient fertilized initially to induce phytoplankton bloom development. Changes in particulate and dissolved organic matter concentrations, including dissolved high-molecular weight (> 1 kDa) combined carbohydrates, dissolved free and combined amino acids as well as transparent exopolymer particles (TEP), were monitored over 21 days together with bacterial abundance, and hydrolytic extracellular enzyme activities. Overall, organic matter followed well-known bloom dynamics in all CO2 treatments alike. At high fCO(2,) higher Delta POC:Delta PON during bloom rise, and higher TEP concentrations during bloom peak, suggested preferential accumulation of carbon-rich components. TEP concentration at bloom peak was significantly related to subsequent sedimentation of particulate organic matter. Bacterial abundance increased during the bloom and was highest at high fCO(2). We conclude that increasing fCO(2) supports production and exudation of carbon-rich components, enhancing particle aggregation and settling, but also providing substrate and attachment sites for bacteria. More labile organic carbon and higher bacterial abundance can increase rates of oxygen consumption and may intensify the already high risk of oxygen depletion in coastal seas in the future.
KW  - mesocosm
KW  - ocean acidification
KW  - phytoplankton
KW  - organic matter
KW  - TEP
Y1  - 2014
U6  - https://doi.org/10.1093/plankt/fbt125
SN  - 0142-7873
SN  - 1464-3774
VL  - 36
IS  - 3
SP  - 641
EP  - 657
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Rocha, Marcia R.
A1  - Gaedke, Ursula
A1  - Vasseur, David A.
T1  - Functionally similar species have similar dynamics
JF  - The journal of ecology
N2  - 1. Improving the mechanistic basis of biodiversity-ecosystem function relationships requires a better understanding of how functional traits drive the dynamics of populations. For example, environmental disturbances or grazing may increase synchronization of functionally similar species, whereas functionally different species may show independent dynamics, because of different responses to the environment. Competition for resources, on the other hand, may yield a wide range of dynamic patterns among competitors and lead functionally similar and different species to display synchronized to compensatory dynamics. The mixed effect of these forces will influence the temporal fluctuations of populations and, thus, the variability of aggregate community properties.
 2. To search for a relationship between functional and dynamics similarity, we studied the relationship between functional trait similarity and temporal dynamics similarity for 36 morphotypes of phytoplankton using long-term high-frequency measurements.
 3. Our results show that functionally similar morphotypes exhibit dynamics that are more synchronized than those of functionally dissimilar ones. Functionally dissimilar morphotypes predominantly display independent temporal dynamics. This pattern is especially strong when short time-scales are considered.
 4. Negative correlations are present among both functionally similar and dissimilar phytoplankton morphotypes, but are rarer and weaker than positive ones over all temporal scales.
 5. Synthesis. We demonstrate that diversity in functional traits decreases community variability and ecosystem-level properties by decoupling the dynamics of individual morphotypes.
KW  - compensatory dynamics
KW  - competition
KW  - environmental forcing
KW  - functional diversity
KW  - functional traits
KW  - grazing
KW  - phytoplankton
KW  - plant population and community dynamics
KW  - synchrony
KW  - temporal dynamics
Y1  - 2011
U6  - https://doi.org/10.1111/j.1365-2745.2011.01893.x
SN  - 0022-0477
VL  - 99
IS  - 6
SP  - 1453
EP  - 1459
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Wacker, Alexander
A1  - Martin-Creuzburg, Dominik
T1  - Biochemical nutrient requirements of the rotifer Brachionus calyciflorus co-limitation by sterols and amino acids
JF  - Functional ecology : an official journal of the British Ecological Society
N2  - It has been proposed that growth and reproduction of animals is frequently limited by multiple nutrients simultaneously. To improve our understanding of the consequences of multiple nutrient limitations (i.e. co-limitation) for the performance of animals, we conducted standardized population growth experiments using an important aquatic consumer, the rotifer Brachionus calyciflorus. We compared nutrient profiles (sterols, fatty acids and amino acids) of rotifers and their diets to reveal consumerdiet imbalances and thus potentially limiting nutrients. In concomitant growth experiments, we directly supplemented potentially limiting substances (sterols, fatty acids, amino acids) to a nutrient-deficient diet, the cyanobacterium Synechococcus elongatus, and recorded population growth rates. The results from the supplementation experiments corroborated the nutrient limitations predicted by assessing consumerdiet imbalances, but provided more detailed information on co-limiting nutrients. While the fatty acid deficiency of the cyanobacterium appeared to be of minor importance, the addition of both cholesterol and certain amino acids (leucine and isoleucine) improved population growth rates of rotifers, indicating a simultaneous limitation by sterols and amino acids. Our results add to growing evidence that consumers frequently face multiple nutrient limitations and suggest that the concept of co-limitation has to be considered in studies assessing nutrient-limited growth responses of consumers.
KW  - consumer
KW  - consumer-diet imbalance
KW  - dietary mismatch
KW  - fatty acid
KW  - global change
KW  - lipid
KW  - nutrition
KW  - phytoplankton
KW  - tetrahymanol
KW  - zooplankton
Y1  - 2012
U6  - https://doi.org/10.1111/j.1365-2435.2012.02047.x
SN  - 0269-8463
VL  - 26
IS  - 5
SP  - 1135
EP  - 1143
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -