Light dependence of phosphorus uptake by microorganisms in the subtropical North and South Pacific Ocean

Duhamel, Solange; Björkman, Karin M.; Karl, David M.

doi:10.3354/ame01593

Cited by 33 publications

(30 citation statements)

References 76 publications

(102 reference statements)

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“…4d). Ratios of L:D P i -uptake in other studies have also been found to be greater than 1, for example in the North Atlantic (Donald et al, 2001) and Pacific Ocean (Duhamel et al, 2012), although ratios closer to 1 have been reported from the North Pacific subtropical gyre (Björkman et al 2000). Variability in L:D uptake ratios likely reflects seasonal variability in substrate (P i ) availability and energetic (light, C) constraints on P i -uptake and cellular P-demands (Sterner and Elser, 2002;Björkman et al, 2000).…”

Section: The Dynamics Of Phosphate Uptakementioning

confidence: 91%

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

Poulton

Davis

Daniels

et al. 2019

Progress in Oceanography

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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.

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Section: The Dynamics Of Phosphate Uptakementioning

confidence: 91%

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

Poulton

Davis

Daniels

et al. 2019

Progress in Oceanography

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“…Higher light intensity in winter usually means more energy input. Light may enhance microbial activity by increasing the nutrient uptake (such as phosphorus) (Duhamel et al, 2012) and thus facilitate invertebrate growth.…”

Section: Temperaturementioning

confidence: 99%

Context dependency of the density–body mass relationship in litter invertebrates along an elevational gradient

Zhang

Lin

et al. 2015

Soil Biology and Biochemistry

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a b s t r a c tHow community structure responds to environmental changes in space and time is a key concern in ecology. As a synthesized indicator of community structure, the densityebody mass (DBM) relationship reflecting body size distributions can serve as a linkage between community response and ecological processes and function. However, the drivers of the spatial and temporal shifts in the DBM relationship for brown food webs remain largely unknown. This study aimed to find the elevational pattern of body size distributions of litter invertebrate communities and understand the causes of climate and resource factors shaping this pattern in different spatio-temporal contexts. We identified the elevational pattern of body size distributions of litter invertebrates in a temperate montane forest and, for the first time, examined this pattern by taking account of the temporal contexts integrating the growing and dormant seasons. Furthermore, we assessed the relative roles of climate factors (i.e., temperature, light, and moisture) and resource factors (i.e., litter quality and quantity) in body size distribution patterns. In general, we demonstrated litter invertebrate communities were size-structured at all elevations and in different seasons, which underpins the DBM. However, the elevational patterns of the DBM slopes varied between seasons: In the growing season the DBM slopes were shallower with increasing elevation. Contrasting, the DBM slopes were steeper with increasing elevation in the dormant season. This is indicating that along the elevation, the larger litter invertebrates benefited more in the growing season compared with the smaller invertebrates, which benefited more in the dormant season. The drivers of the DBM relationship were context dependent: (1) temperature was a fundamental driver for the DBM relationship across space and time, with increasing temperature benefiting smaller invertebrates; (2) crown density only matters in the dormant season, with increasing light intensity benefiting larger invertebrates. No impact of soil moisture on the body size distributions was detected; and (3) litter availability impact varied with season in quality (i.e., litter C:N and C:S ratios) and quantity (i.e., litter amount), mainly functioning in the growing and the dormant season, respectively. This finding would enhance a more predictive understanding of how environmental change may restructure ecosystems and soil functioning from an allometric scaling perspective in the context of global warming.

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“…Pi and ATP-derived P uptake rates were determined using ) as tracers, respectively, as described in Duhamel et al (2012). Samples were incubated in 75 ml PC bottles in the on-deck incubators and were typically labeled to give an initial activity of 1.2 to 3.…”

Section: P Uptakementioning

confidence: 99%

“…To determine group-specific uptake rates, subsamples from the incubations used to determine total and size-fractionated uptake rates were kept in the dark until sorting (< 8 h) on an Influx Mariner flow cytometer as described in Duhamel et al (2012). Microbial groups were sorted using the same discrimination parameters as for cell counts.…”

Section: P Uptakementioning

confidence: 99%

Microbial response to enhanced phosphorus cycling in the North Pacific Subtropical Gyre

Duhamel¹,

Björkman²,

Doggett³

et al. 2014

Mar. Ecol. Prog. Ser.

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Microbial community response to nitrogen (N) amendments and induced phosphorus (P) stress was investigated in the North Pacific Subtropical Gyre (NPSG). Samples amended with reduced sources of N, in the form of nitrate plus ammonium, showed significant increases in microbial cell abundance and biomass and decreases in dissolved inorganic phosphate (Pi) and silicate concentrations during an incubation period of 6 d. Primary productivity, P uptake rates (as both Pi and adenosine-5'-triphosphate [ATP]) and alkaline phosphatase activity (APA) all increased following N amendment. Dissolved organic P (DOP) concentrations did not change, but the large increase in APA and ATP uptake rates suggests that DOP was a dynamic pool and an important source for microbial P nutrition in P-stressed samples. Significant changes were also observed in the structure of the microbial community, with Synecho coccus and picoalgae abundances increasing substantially in the N-amended treatments, while non-pigmented picoplankton abundances were unchanged. Data on P resource partitioning among groups of picoplankton separated by size using membrane filters of different porosities, or by scattering and fluorescence properties using flow cytometry sorting, indicate that Synechococcus could have a greater role in the NPSG P cycling following episodic N inputs. This experimental manipulation of nutrient loading combined with observations at the total population to the microbial group levels constitutes a unique approach to improve our understanding of microbial community structure and function in response to environmental forcing.

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Light dependence of phosphorus uptake by microorganisms in the subtropical North and South Pacific Ocean

Cited by 33 publications

References 76 publications

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

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

Context dependency of the density–body mass relationship in litter invertebrates along an elevational gradient

Microbial response to enhanced phosphorus cycling in the North Pacific Subtropical Gyre

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