Ecological constraints on planktonic nitrogen fixation in saline estuaries. II. Grazing controls on cyanobacterial population dynamics. Chan, F., Marino, R., Howarth, R., & Pace, M. Marine Ecology Progress Series, 309:41--53, 2006.
Ecological constraints on planktonic nitrogen fixation in saline estuaries. II. Grazing controls on cyanobacterial population dynamics [link]Paper  doi  abstract   bibtex   
Blooms of nitrogen (N)-fixing cyanobacteria are common in freshwater lakes of moderateto high productivity. In contrast, blooms of N-fixing cyanobacteria are largely absent from thewater columns of N-limited estuaries. In a companion study, we reported that the abundance andN-fixation rates of planktonic filamentous heterocystous cyanobacteria are strongly suppressed bythe presence of zooplankton consumers in saline estuarine mesocosms. Here, we show that bloomformation in these estuarine cyanobacterial N-fixers (Anabaena sp.) is strongly dependent on theirability to grow into sufficiently large filamentous colonies that are capable of developing heterocystsand thereby fixing N. This basic physiological constraint on N fixation results in a sensitivity ofN-fixer bloom initiation to suppression by herbivorous zooplankton. In the presence of zooplanktonconsumers, small populations of heterocystous cyanobacteria exhibited reduced colonial filamentsize, decreased heterocyst frequencies, and suppressed growth rates. In short-term grazing assays,estuarine zooplankton (Acartia tonsa) directly consumed heterocystous cyanobacteria. This consumptionoccurred at high rates and resulted, at times, in marked reductions in colonial filament size.These results provide a mechanistic understanding of how trophic interactions can mediate the functionalcomposition of phytoplankton communities and thereby constrain the biogeochemicalresponse of estuaries to N limitation.
@article{ Chan2006,
  abstract = {Blooms of nitrogen (N)-fixing cyanobacteria are common in freshwater lakes of moderateto high productivity. In contrast, blooms of N-fixing cyanobacteria are largely absent from thewater columns of N-limited estuaries. In a companion study, we reported that the abundance andN-fixation rates of planktonic filamentous heterocystous cyanobacteria are strongly suppressed bythe presence of zooplankton consumers in saline estuarine mesocosms. Here, we show that bloomformation in these estuarine cyanobacterial N-fixers (Anabaena sp.) is strongly dependent on theirability to grow into sufficiently large filamentous colonies that are capable of developing heterocystsand thereby fixing N. This basic physiological constraint on N fixation results in a sensitivity ofN-fixer bloom initiation to suppression by herbivorous zooplankton. In the presence of zooplanktonconsumers, small populations of heterocystous cyanobacteria exhibited reduced colonial filamentsize, decreased heterocyst frequencies, and suppressed growth rates. In short-term grazing assays,estuarine zooplankton (Acartia tonsa) directly consumed heterocystous cyanobacteria. This consumptionoccurred at high rates and resulted, at times, in marked reductions in colonial filament size.These results provide a mechanistic understanding of how trophic interactions can mediate the functionalcomposition of phytoplankton communities and thereby constrain the biogeochemicalresponse of estuaries to N limitation.},
  author = {Chan, F and Marino, Rl and Howarth, Rw and Pace, Ml},
  doi = {10.3354/meps309041},
  file = {:E$\backslash$:/Users/Melanie/AA-PROJECTS/All_Journal_Articles/MendeleyAuto/Chan et al._2006_Marine Ecology Progress Series.pdf:pdf},
  issn = {01718630},
  journal = {Marine Ecology Progress Series},
  keywords = {estuaries,heterocystous cyanobacteria,nitrogen fixation,permitted without written consent,publisher,resale republication not,zooplankton grazing},
  pages = {41--53},
  title = {{Ecological constraints on planktonic nitrogen fixation in saline estuaries. II. Grazing controls on cyanobacterial population dynamics}},
  url = {http://www.int-res.com/abstracts/meps/v309/p41-53/},
  volume = {309},
  year = {2006}
}
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