Rate of release of extracellular amino acids and carbohydrates from the marine diatom <i>Chaetoceros affinis</i>

Myklestad, Sverre; Holm‐Hansen, Osmund; Vårum, Kjell M.; Volcani, Benjamin E.

doi:10.1093/plankt/11.4.763

Cited by 206 publications

(155 citation statements)

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“…Myklestad (1995) concluded that phytoplankton release carbohydrates into the surrounding medium under conditions of severe N or P limitation, as carbohydrates do not contain these potentially limiting nutrients. Myklestad et al (1989) found that the rates of release of carbohydrates and amino acids by Chaetoceros affinis were highest in the growth phase compared with stationary phase batch cultures. However, the photosynthesis rate of nutrient-limited cells was lower and therefore DOM release accounted for 58% of productivity in stationary phase cells, compared with 10% during exponential growth.…”

Section: Overflow Hypothesismentioning

confidence: 94%

“…(Poulet & Martin-Jézéquel, 1983;Myklestad et al, 1989) and Skeletonema costatum (Mague et al, 1980;Granum et al, 2002) release amino acids into the growth medium. Myklestad (2000) concluded, based on the literature, that the following amino acids are commonly released by diatoms: serine, glycine, lysine, alanine, glutamic acid, aspartic acid, ornithine and histidine.…”

Section: Amino Acids and Proteinsmentioning

confidence: 99%

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Dissolved organic matter (DOM) release by phytoplankton in the contemporary and future ocean

Thornton

2014

European Journal of Phycology

365

311

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The partitioning of organic matter (OM) between dissolved and particulate phases is an important factor in determining the fate of organic carbon in the ocean. Dissolved organic matter (DOM) release by phytoplankton is a ubiquitous process, resulting in 2-50% of the carbon fixed by photosynthesis leaving the cell. This loss can be divided into two components: passive leakage by diffusion across the cell membrane and the active exudation of DOM into the surrounding environment. At present there is no method to distinguish whether DOM is released via leakage or exudation. Most explanations for exudation remain hypothetical; as while DOM release has been measured extensively, there has been relatively little work to determine why DOM is released. Further research is needed to determine the composition of the DOM released by phytoplankton and to link composition to phytoplankton physiological status and environmental conditions. For example, the causes and physiology of phytoplankton cell death are poorly understood, though cell death increases membrane permeability and presumably DOM release. Recent work has shown that phytoplankton interactions with bacteria are important in determining both the amount and composition of the DOM released. In response to increasing CO 2 in the atmosphere, climate change is creating increasingly stressful conditions for phytoplankton in the surface ocean, including relatively warm water, low pH, low nutrient supply and high light. As ocean physics and chemistry change, it is hypothesized that a greater proportion of primary production will be released directly by phytoplankton into the water as DOM. Changes in the partitioning of primary production between the dissolved and particulate phases will have bottom-up effects on ecosystem structure and function. There is a need for research to determine how these changes affect the fate of organic matter in the ocean, particularly the efficiency of the biological carbon pump.

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Section: Overflow Hypothesismentioning

confidence: 94%

Section: Amino Acids and Proteinsmentioning

confidence: 99%

Dissolved organic matter (DOM) release by phytoplankton in the contemporary and future ocean

Thornton

2014

European Journal of Phycology

365

311

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“…Другие данные указывают на то, что пул внеклеточного углерода был заметно выше в течение всего экспоненциального периода роста культур и в 8 раз превышал аналогичный показатель стационарного этапа развития культур . Приведенные результаты согласуются с аналогичными исследованиями морской диатомовой водоросли Chaetoceros affinis Lauder (Myklestad et al, 1989). Кроме того, увеличение экскрекции углерода с 2-4% до 14-65% экспоненциально растущими клетками культуры S. costatum на экспоненциальной фазе роста установлено при дефиците питательных веществ (Ignatiades, Fogg, 1973).…”

Section: продуцирование экзополисахаридов Bacillariophytа в зависимосunclassified

Ecological role of exopolysaccharides of Bacillariophyta: A review

Shnyukova¹,

Zolotareva²

2017

Algologia

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“…For example, the DOM composition released by a phytoplankton species may vary with cells age (Myklestad et al, 1989), the degradation rate can be affected by the local climate conditions (Ho et al, 2012;Oberhaus et al, 2007) and by the bacterial community composition (Jones et al, 2009). Thus, in vitro tests, under controlled conditions, are starting points for understanding the interactions between different factors.…”

Section: Introductionmentioning

confidence: 99%

Bacterial degradation of dissolved organic matter released by Planktothrix agardhii (Cyanobacteria)

et al. 2017

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Although Planktothrix agardhii often produces toxic blooms in eutrophic water bodies around the world, little is known about the fate of the organic matter released by these abundant Cyanobacteria. Thus, this study focused in estimating the bacterial consumption of the DOC and DON (dissolved organic carbon and dissolved organic nitrogen, respectively) produced by axenic P. agardhii cultures and identifying some of the bacterial OTUs (operational taxonomic units) involved in the process. Both P. agardhii and bacterial inocula were sampled from the eutrophic Barra Bonita Reservoir (SP, Brazil). Two distinct carbon degradation phases were observed: during the first three days, higher degradation coefficients were calculated, which were followed by a slower degradation phase. The maximum value observed for particulate bacterial carbon (POC) was 11.9 mg L -1 , which consisted of 62.5% of the total available DOC, and its mineralization coefficient was 0.477 day -1 (t½ = 1.45 days). A similar pattern of degradation was observed for DON, although the coefficients were slightly different. Changes in the OTUs patterns were observed during the different steps of the degradation. The main OTUs were related to the classes Alphaproteobacteria (8 OTUs), Betaproteobacteria (2 OTUs) and Gammaproteobacteria (3 OTUs). The genus Acinetobacter was the only identified organism that occurred during the whole process. Bacterial richness was higher at the slower degradation phase, which could be related to the small amounts of DOM (dissolved organic matter) available, particularly carbon. The kinetics of the bacterial degradation of P. agardhii-originated DOM suggests minimal loss of DOM from the Barra Bonita reservoir.Keywords: dissolved organic matter, bacterial community, DGGE, degradation. Degradação bacteriana da matéria orgânica dissolvida liberada porPlanktothrix agardhii (Cyanobacteria) ResumoEmbora Planktothrix agardhii frequentemente forme florações tóxicas em corpos d'água pelo mundo, pouco ainda se sabe sobre o destino da matéria orgânica liberada por essa abundante Cyanobacteria. Assim, este estudo foi focado na estimativa do consumo bacteriano do carbono orgânico dissolvido (DOC) e nitrogênio orgânico dissolvido (DON) produzido por culturas axênicas de P. agardhii e identificação de algumas das unidades taxonômicas operacionais (OTUs) bacterianas envolvidas no processo. Ambos a linhagem de P. agardhii e o inóculo bacteriano foram amostrados do reservatório eutrófico de Barra Bonita (SP, Brasil). Foram observadas duas fases distintas da degradação do DOC: durante os três primeiros dias, coeficientes mais altos de degradação foram calculados, que foram então seguidos por uma fase mais lenta da degradação do carbono. O valor máximo calculado para o carbono bacteriano particulado (POC) foi de 11,9 mgL -1 , o que equivale a aproximadamente 62,5% do DOC disponível para consumo, e o seu coeficiente de mineralização foi de 0,477 dia -1 (t 1/2 = 1,45 dias). Um padrão similar de degradação foi observado para DON, embora os c...

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Rate of release of extracellular amino acids and carbohydrates from the marine diatom Chaetoceros affinis

Cited by 206 publications

References 0 publications

Dissolved organic matter (DOM) release by phytoplankton in the contemporary and future ocean

Dissolved organic matter (DOM) release by phytoplankton in the contemporary and future ocean

Ecological role of exopolysaccharides of Bacillariophyta: A review

Bacterial degradation of dissolved organic matter released by Planktothrix agardhii (Cyanobacteria)

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