Diel variability of glycolate in the eastern tropical Atlantic Ocean

Leboulanger, Christophe; Oriol, L.; Jupin, Henri; Desolas-gros, Chantal

doi:10.1016/s0967-0637(97)00090-3

Cited by 44 publications

(43 citation statements)

References 28 publications

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“…Diel fluctuations in labile DOC in the upper oceanic water column with higher concentrations in the afternoon have been shown repeatedly, attributed to phytoplankton activity and the release of photosynthetically fixed carbon, mainly amino acids and carbohydrates (MeyerReil et al 1979, Johnson et al 1981, Burney et al 1982, Fuhrman & Ferguson 1986, Leboulanger et al 1997. Bulk DOC measurements, however, are certainly too 20 Fig.…”

Section: Discussionmentioning

confidence: 99%

Diel periodicity of bacterioplankton in the euphotic zone of the subtropical Atlantic Ocean

Kuipers¹,

Noort²,

Vosjan³

et al. 2000

Mar. Ecol. Prog. Ser.

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We tested the hypothesis that in the euphotic zone of oligotrophic oceanic waters, the growth-limiting nutrients for bacterioplankton vary over a diel cycle due to competition with phytoplankton, leading to distinct diel patterns in bacterioplankton. During a cruise across the subtropical Atlantic Ocean, a distinct diel periodicity in bacterioplankton was detectable, with highest bacterial abundance in the early morning and declining over the day. A peak in the frequency of dividing cells (FDC, 20 to 25% of the total bacterial community) was recorded at midnight; FDC rates were consistently low during the day and cell volume increased over the day until the early night period. No diel variations in these parameters were detectable in the layers below the deep chlorophyll maximum (DCM). Bio-assay experiments with freshly collected, N+P amended water were started in the early morning. No significant bacterial growth was detectable in the early morning while, in the bio-assays that started at noon, significant bacterial growth was detectable in the N+P treatments. P amendment alone also caused an increase in bacterial abundance although to a lesser extent. Thus, we have evidence that the bacterioplankton in the euphotic layer of the subtropical Atlantic are not limited by the availability of N+P in the morning (most likely limited in C) but at noon when they are competing with phytoplankton for the inorganic N+P sources. Based on the concomitantly measured decline in inorganic N+P in the bio-assays, we estimated the C:N:P ratio of newly produced bacteria. The mean atomic C:N:P ratio for the bacteria in the N+P amended bio-assay experiments started in the early morning was C:N:P = 15:13:1 while the corresponding ratio for bacteria in the bio-assays started at noon was C:N:P = 118:11:1. This diel variation in the C:N:P ratio was caused by the 1 order of magnitude higher bacterial C production at noon as compared to the early morning. Thus, excess uptake of N+P occurs during the morning and luxury C uptake during noon. This plasticity in the C:N:P ratio of bacterioplankton might be a strategy to overcome, at least partly, periods of shortage in a specific nutrient species in the oligotrophic subtropical Atlantic. MARINE ECOLOGY PROGRESS SERIES

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Section: Discussionmentioning

confidence: 99%

Diel periodicity of bacterioplankton in the euphotic zone of the subtropical Atlantic Ocean

Kuipers¹,

Noort²,

Vosjan³

et al. 2000

Mar. Ecol. Prog. Ser.

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“…Follow-up studies during a phytoplankton spring bloom showed that mRNA transcripts of glcD varied over the diel cycle, with a consistent increase in transcripts during the day (Fig. 5) (101) when glycolate production is at a peak (104), suggesting that these bacteria have coupled their metabolism to glycolate availability. Interestingly, the diversity of glcD sequences varied as the bloom progressed, suggesting complex dynamics within the bacterial population as a result of competition for glycolate (101).…”

Section: Synergistic Interactionsmentioning

confidence: 96%

Interactions between Diatoms and Bacteria

Amin

Parker

Armbrust

2012

Microbiol Mol Biol Rev

822

741

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SUMMARY Diatoms and bacteria have cooccurred in common habitats for hundreds of millions of years, thus fostering specific associations and interactions with global biogeochemical consequences. Diatoms are responsible for one-fifth of the photosynthesis on Earth, while bacteria remineralize a large portion of this fixed carbon in the oceans. Through their coexistence, diatoms and bacteria cycle nutrients between oxidized and reduced states, impacting bioavailability and ultimately feeding higher trophic levels. Here we present an overview of how diatoms and bacteria interact and the implications of these interactions. We emphasize that heterotrophic bacteria in the oceans that are consistently associated with diatoms are confined to two phyla. These consistent bacterial associations result from encounter mechanisms that occur within a microscale environment surrounding a diatom cell. We review signaling mechanisms that occur in this microenvironment to pave the way for specific interactions. Finally, we discuss known interactions between diatoms and bacteria and exciting new directions and research opportunities in this field. Throughout the review, we emphasize new technological advances that will help in the discovery of new interactions. Deciphering the languages of diatoms and bacteria and how they interact will inform our understanding of the role these organisms have in shaping the ocean and how these interactions may change in future oceans.

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“…It is likely that there is rapid turnover of the glycolate pool in the ocean due to production associated with photosynthesis and consumption by heterotrophic prokaryotes. This is shown by the diurnal cycle in glycolate concentrations in the upper ocean, indicating net production during daylight and net consumption during the night (Leboulanger et al, 1997(Leboulanger et al, , 1998b.…”

Section: Nucleic Acidsmentioning

confidence: 97%

“…Concentrations varying between 0.20 and 0.80 µM were measured in coastal waters of the Irish Sea (Liverpool Bay) (AlHasan & Fogg, 1987). Leboulanger et al measured glycolate concentrations up to 0.97 µM in mesotrophic waters and 0.22 µM in oligotrophic waters of the tropical Atlantic Ocean (Leboulanger et al, 1997), and 0.32-1.17 µM during a phytoplankton bloom in coastal Mediterranean waters (Leboulanger et al, 1994). Relatively high glycolate concentrations (0.89-4.50 µM) have been measured in coastal waters off Belgium (Billen et al, 1980).…”

Section: Nucleic Acidsmentioning

confidence: 99%

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

Thornton

2014

European Journal of Phycology

356

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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Diel variability of glycolate in the eastern tropical Atlantic Ocean

Cited by 44 publications

References 28 publications

Diel periodicity of bacterioplankton in the euphotic zone of the subtropical Atlantic Ocean

Diel periodicity of bacterioplankton in the euphotic zone of the subtropical Atlantic Ocean

Interactions between Diatoms and Bacteria

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

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