Carbon and phosphate incorporation rates of microbial assemblages in contrasting environments in the Southeast Pacific

Duhamel, Solange; Moutin, Thierry

doi:10.3354/meps07765

Cited by 11 publications

(11 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Free phosphate is typically assimilated much more rapidly by bacteria than heterotrophic eukaryotic microbes and bacteria may be one of the more important contributors to the phosphorous cycle in marine ecosystems (Duhamel and Moutin, 2009;Popendorf and Duhamel, 2015). Moreover, among lake microplankton, bacteria may account for as much as 94% of the APA (Chróst et al, 1984).…”

Section: Relationships To Prior Researchmentioning

confidence: 99%

“…Although there is substantial published research on the role of organic C in microbial community dynamics, there is less research on the coupling of organic C with the phosphorus cycle, including production of microbial phosphatases, a potentially significant source of phosphate remineralization, especially in aquatic environments (Gibson et al, 1996;Dyhrman et al, 2007;Duhamel and Moutin, 2009;Ruttenberg and Dyhrman, 2012;Duhamel et al, 2014). Because of the potential threats from global warming, considerable research has been done on the coupling of nitrogen and carbon cycles, largely in relation to the effect of nitrogen on primary production, thus enhancing CO 2 sequestration (Esser et al, 2011;Zaehle, 2013).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Evidence for Coupling of the Carbon and Phosphorus Biogeochemical Cycles in Freshwater Microbial Communities

Anderson

2018

Front. Mar. Sci.

View full text Add to dashboard Cite

Considerable attention has been given to the roles of the carbon and phosphate cycles in aquatic environments, but less attention has been given to an experimental analysis of the coupling of the C and P cycles in freshwater and marine ecosystems. Using laboratory microcosm experiments, prepared with natural pond-water microbial communities, evidence is presented for the coupling of dissolved organic C with microbial production of alkaline phosphatase driving the phosphorus cycle in freshwater microbial communities. The effects of glucose C-supplementation in microcosm microbial communities (including bacteria and heterotrophic nanoflagellates) on gains in microbial C-content and alkaline phosphatase activity (APA) were estimated in relation to control microcosms without C-supplementation. The C-supplementation increased total microbial APA (pmol min −1 µg −1 bacterial C) in the C-supplemented treatment (6.5 ± 0.6) compared to the non-supplemented cultures (5.1 ± 1.7). Microbial-bound APA in the C-supplemented treatment was particularly enhanced (4.4 ± 0.9) compared to control cultures (1.3 ± 0.8), but the amount of free (soluble) APA in the aquatic phase was less compared to the controls (n = 5, p < 0.001). Alkaline phosphatase activity was highly correlated (r = 0.97) with bacterial densities in the C-supplemented cultures, further supporting the hypothesis that C-supplementation can increase phosphorus remineralization through elevated production of microbial alkaline phosphatase. This laboratory-based, experimental study suggests that additional research on the coupling of the C and P cycles in freshwater and marine environments may yield productive insights into the finer details of the roles of these two biogeochemical cycles in aquatic microbial community dynamics.

show abstract

Section: Relationships To Prior Researchmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evidence for Coupling of the Carbon and Phosphorus Biogeochemical Cycles in Freshwater Microbial Communities

Anderson

2018

Front. Mar. Sci.

View full text Add to dashboard Cite

show abstract

“…Previous studies of planktonic P i -uptake have differentiated bacterial and algal P-uptake using different pore-sized filters, for example considering bacterial uptake as from cells less than 0.6 µm and algal uptake from cells greater than 0.6 µm (e.g., Duhamel and Moutin, 2009). However, both bacterial and algal cell sizes are variable with taxonomy and physiological status (ref) and may overlap in sizedistribution; for example, the cyanobacteria Synechococcus, which is dominant in the Celtic Sea in summer (Hickman et al, 2012), may range in size from 0.4 to 0.8 µm (ref).…”

Section: The Dynamics Of Phosphate Uptakementioning

confidence: 99%

“…The low NPP:P i -uptake ratios (P-rich) in July are not associated with rapid phytoplankton growth (Table 3), but rather with high bacterial growth rates and a stronger bacterial influence on C:P uptake (and retention). Heterotrophic bacteria are recognised as strong competitors for P i under nutrient depleted conditions (Thingstad et al, 1993(Thingstad et al, , 1996Duhamel and Moutin, 2009). Whilst phytoplankton cellular C:P stoichiometry is near, or slightly lower, than the canconical Redfield ratio (Geider and LaRoche, 2002;Ho et al, 2003), bacterial cellular C:P ratios are significantly more P-rich (e.g., ~50; Fagerbakke et al, 1996;Sterner and Elser, 2002;Hessen et al, 2004;Duhamel and Moutin, 2009; see also Scott et al, 2012).…”

Section: Seasonality In Particulate Stoichiometry In the Celtic Seamentioning

confidence: 99%

“…Planktonic micro-organisms, such as heterotrophic bacteria and phytoplankton, have rapid growth rates and hence can exert a strong influence on the turnover of different C and P pools (Arrigo, 2005). Both phytoplankton and heterotrophic bacteria consume P, though the two have contradictory roles in the marine C-cycle as primary producers and remineralisers of organic material, respectively (Duhamel and Moutin, 2009), and compete strongly for available P (Thingstad et al, 1993(Thingstad et al, , 1996.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Seasonal phosphorus and carbon dynamics in a temperate shelf sea (Celtic Sea)

Poulton

Davis

Daniels

et al. 2019

Progress in Oceanography

View full text Add to dashboard Cite

Highlights: Seasonal phosphorus uptake and dissolved organic release examined in the Central Celtic Sea  Uptake highest in spring bloom, with biomass-normalised uptake equal in spring and summer  Release high in November and late spring, with efficient P-retention in summer  Strong phytoplankton influence on spring P-uptake, whilst bacteria influential in summer  Relatively C-rich uptake in November and late April, strongly P-rich in summer AbstractThe seasonal cycle of resource availability in shelf seas has a strong selective pressure on phytoplankton diversity and the biogeochemical cycling of key elements, such as carbon (C) and phosphorus (P). Shifts in carbon consumption relative to P availability, via changes in cellular stoichiometry for example, can lead to an apparent 'excess' of carbon production. We made measurements of inorganic P (P i ) uptake, in parallel to C-fixation, by plankton communities in the Central Celtic Sea (NW European Shelf) in spring (April 2015), summer (July 2015) and fall (November 2014). Short-term (<6 h) P i -uptake coupled with dissolved organic phosphorus (DOP) release, in parallel to net (24 h) primary production (NPP), were all measured across an irradiance gradient designed to typify vertically and seasonally varying light conditions. Rates of P i -uptake were highest during spring and lowest in light-limited fall conditions, although biomass-normalised P i -uptake was similar in spring and summer. The release of DOP was highest in November and declined to low levels in July, indicative of efficient utilization and recycling of the low levels of P i available. Examination of turnover times of the different particulate pools, including phytoplankton and bacteria, indicated a differing seasonal influence of autotrophs and heterotrophs in P-dynamics, with summer conditions associated with a strong bacterial influence and early spring with fast growing phytoplankton. These seasonal changes in plankton composition, coupled with changes in resource availability (P i , light) resulted in seasonal changes in the stoichiometry of NPP to P i -uptake (C:P ratio); from relatively C-rich uptake in November and late April, to P-rich uptake in early April and July. Overall these results highlight how the entire plankton community, both autotrophs and heterotrophs, influence the relative uptake of C and P and that any excess C-consumption relative to the P-rich uptake must be balanced by C-rich process such as the heterotrophic remineralisation and/or consumption of organic material.

show abstract

Diversity and productivity of photosynthetic picoeukaryotes in biogeochemically distinct regions of the South East Pacific Ocean

Rii

Duhamel

Bidigare

et al. 2016

Limnology & Oceanography

View full text Add to dashboard Cite

Picophytoplankton, including photosynthetic picoeukaryotes (PPE) and unicellular cyanobacteria, are important contributors to plankton biomass and primary productivity. In this study, phytoplankton composition and rates of carbon fixation were examined across a large trophic gradient in the South East Pacific Ocean (SEP) using a suite of approaches: photosynthetic pigments, rates of 14 C-primary productivity, and phylogenetic analyses of partial 18S rRNA genes PCR amplified and sequenced from flow cytometrically sorted cells. While phytoplankton >10 lm (diatoms and dinoflagellates) were prevalent in the upwelling region off the Chilean coast, picophytoplankton consistently accounted for 55-92% of the total chlorophyll a inventories and >60% of 14 C-primary productivity throughout the sampling region. Estimates of rates of 14 C-primary productivity derived from flow cytometric sorting of radiolabeled cells revealed that the contributions of PPE and Prochlorococcus to euphotic zone depth-integrated picoplankton productivity were nearly equivalent (ranging 36-57%) along the transect, with PPE comprising a larger share of picoplankton productivity than cyanobacteria in the well-lit (>15% surface irradiance) region compared with in the lower regions (1-7% surface irradiance) of the euphotic zone. 18S rRNA gene sequence analyses revealed the taxonomic identities of PPE; e.g., Mamiellophyceae (Ostreococcus) were the dominant PPE in the upwelling-influenced waters, while members of the Chrysophyceae, Prymnesiophyceae, Pelagophyceae, and Prasinophyceae Clades VII and IX flourished in the oligotrophic South Pacific Subtropical Gyre. Our results suggest that, despite low numerical abundance in comparison to cyanobacteria, diverse members of PPE are significant contributors to carbon cycling across biogeochemically distinct regions of the SEP.

show abstract

Carbon and phosphate incorporation rates of microbial assemblages in contrasting environments in the Southeast Pacific

Cited by 11 publications

References 48 publications

Evidence for Coupling of the Carbon and Phosphorus Biogeochemical Cycles in Freshwater Microbial Communities

Evidence for Coupling of the Carbon and Phosphorus Biogeochemical Cycles in Freshwater Microbial Communities

Seasonal phosphorus and carbon dynamics in a temperate shelf sea (Celtic Sea)

Diversity and productivity of photosynthetic picoeukaryotes in biogeochemically distinct regions of the South East Pacific Ocean

Contact Info

Product

Resources

About