@article{WackerPiephoSpijkerman2015,
  author    = {Wacker, Alexander and Piepho, Maike and Spijkerman, Elly},
  title     = {Photosynthetic and fatty acid acclimation of four phytoplankton species in response to light intensity and phosphorus availability},
  series = {European journal of phycology},
  volume    = {50},
  journal   = {European journal of phycology},
  number    = {3},
  publisher = {Routledge, Taylor \& Francis Group},
  address   = {Abingdon},
  issn      = {0967-0262},
  doi       = {10.1080/09670262.2015.1050068},
  pages     = {288 -- 300},
  year      = {2015},
  abstract  = {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.},
  language  = {en}
}
@article{EngelPiontekGrossartetal.2014,
  author    = {Engel, Anja and Piontek, Judith and Grossart, Hans-Peter and Riebesell, Ulf and Schulz, Kai Georg and Sperling, Martin},
  title     = {Impact of CO2 enrichment on organic matter dynamics during nutrient induced coastal phytoplankton blooms},
  series = {Journal of plankton research},
  volume    = {36},
  journal   = {Journal of plankton research},
  number    = {3},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0142-7873},
  doi       = {10.1093/plankt/fbt125},
  pages     = {641 -- 657},
  year      = {2014},
  abstract  = {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.},
  language  = {en}
}
@article{RochaGaedkeVasseur2011,
  author    = {Rocha, Marcia R. and Gaedke, Ursula and Vasseur, David A.},
  title     = {Functionally similar species have similar dynamics},
  series = {The journal of ecology},
  volume    = {99},
  journal   = {The journal of ecology},
  number    = {6},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0022-0477},
  doi       = {10.1111/j.1365-2745.2011.01893.x},
  pages     = {1453 -- 1459},
  year      = {2011},
  abstract  = {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.},
  language  = {en}
}
@article{WackerMartinCreuzburg2012,
  author    = {Wacker, Alexander and Martin-Creuzburg, Dominik},
  title     = {Biochemical nutrient requirements of the rotifer Brachionus calyciflorus co-limitation by sterols and amino acids},
  series = {Functional ecology : an official journal of the British Ecological Society},
  volume    = {26},
  journal   = {Functional ecology : an official journal of the British Ecological Society},
  number    = {5},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0269-8463},
  doi       = {10.1111/j.1365-2435.2012.02047.x},
  pages     = {1135 -- 1143},
  year      = {2012},
  abstract  = {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.},
  language  = {en}
}