Ecological nitrogen-to-phosphorus stoichiometry at station ALOHA

Karl, David M.; Björkman, Karin M.; Dore, John E.; Fujieki, Lance; Hebel, Dale V.; Houlihan, T.; Letelier, Ricardo M.; Tupas, Luis M.

doi:10.1016/s0967-0645(00)00152-1

Cited by 296 publications

(256 citation statements)

References 66 publications

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“…A widely distributed marine bacterial phosphatase M Sebastian and JW Ammerman assemblage was not stressed by P i availability, which is supported by a recent study showing that despite evidence the NPSG is moving toward Plimitation (Karl et al, 2001), the microbial community is currently not P i -stressed (Van Mooy and Devol, 2008). The coastal marine mesocosm transcriptome was created to study the prokaryotic assemblages in a mesocosm in which a phytoplankton bloom was induced by the addition of nutrients.…”

Section: Analysis Of Metatranscriptomic Databasesmentioning

confidence: 86%

The alkaline phosphatase PhoX is more widely distributed in marine bacteria than the classical PhoA

2009

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Phosphorus (P) is a vital nutrient for all living organisms and may control the growth of bacteria in the ocean. Bacteria induce alkaline phosphatases when inorganic phosphate (Pi) is insufficient to meet their P-requirements, and therefore bulk alkaline phosphatase activity measurements have been used to assess the P-status of microbial assemblages. In this study, the molecular basis of marine bacterial phosphatases and their potential role in the environment were investigated. We found that only a limited number of homologs to the classical Escherichia coli alkaline phosphatase (PhoA) were present in marine isolates in the Bacteroidetes and γ-proteobacteria lineages. In contrast, PhoX, a recently described phosphatase, was widely distributed among diverse bacterial taxa, including Cyanobacteria, and frequently found in the marine metagenomic Global Ocean Survey database. These taxa included ecologically important groups such as Roseobacter and Trichodesmium. PhoX was induced solely upon P-starvation and accounted for approximately 90% of the phosphatase activity in the model marine bacterium Silicibacter pomeroyi. Analysis of the available transcriptomic datasets and their corresponding metagenomes indicated that PhoX is more abundant than PhoA in oligotrophic marine environments such as the North Pacific Subtropical Gyre. Those analyses also revealed that PhoA may be important when Bacteroidetes are abundant, such as in algal bloom episodes. However, PhoX appears to be much more widespread. Its identification as a gene that mediates organic P acquisition in ecologically important groups, and as a marker of Pi-stress, constitutes an important step toward a better understanding of the marine P cycle.

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Section: Analysis Of Metatranscriptomic Databasesmentioning

confidence: 86%

The alkaline phosphatase PhoX is more widely distributed in marine bacteria than the classical PhoA

2009

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“…6 B and C). At Station ALOHA, N 2 fixation leads to seasonal change in the C/P ratio of suspended POM (38,39) and to reduced concentrations of PO 4 3− (39,40). Generally, in ecosystems where export is enhanced by N 2 fixation, the microbial populations eventually become P-stressed, leading to the production of POM with elevated PC/PP ratios, in part attributable to sulfur substitution for PO 4 3− in cellular lipids (41).…”

Section: Discussionmentioning

confidence: 99%

Predictable and efficient carbon sequestration in the North Pacific Ocean supported by symbiotic nitrogen fixation

Karl

Church

Dore

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

271

308

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The atmospheric and deep sea reservoirs of carbon dioxide are linked via physical, chemical, and biological processes. The last of these include photosynthesis, particle settling, and organic matter remineralization, and are collectively termed the "biological carbon pump." Herein, we present results from a 13-y (1992-2004) sediment trap experiment conducted in the permanently oligotrophic North Pacific Subtropical Gyre that document a large, rapid, and predictable summertime (July 15-August 15) pulse in particulate matter export to the deep sea (4,000 m). Peak daily fluxes of particulate matter during the summer export pulse (SEP) average 408, 283, 24.1, 1.1, and 67.5 μmol·m −2 ·d −1 for total carbon, organic carbon, nitrogen, phosphorus (PP), and biogenic silica, respectively. The SEP is approximately threefold greater than mean wintertime particle fluxes and fuels more efficient carbon sequestration because of low remineralization during downward transit that leads to elevated total carbon/PP and organic carbon/PP particle stoichiometry (371:1 and 250:1, respectively). Our long-term observations suggest that seasonal changes in the microbial assemblage, namely, summertime increases in the biomass and productivity of symbiotic nitrogen-fixing cyanobacteria in association with diatoms, are the main cause of the prominent SEP. The recurrent SEP is enigmatic because it is focused in time despite the absence of any obvious predictable stimulus or habitat condition. We hypothesize that changes in day length (photoperiodism) may be an important environmental cue to initiate aggregation and subsequent export of organic matter to the deep sea. Approximately half of the photosynthesis on Earth is attributable to microscopic, single-celled phytoplankton that inhabit the sea (1). Within the marine environment, most (∼90%) of the photosynthetic carbon fixation takes place in the low-biomass, low-nutrient open ocean gyres that are grossly undersampled relative to coastal habitats (2, 3). A small but variable (typically <15% for open ocean ecosystems) portion of the organic matter produced in the sunlit (euphotic) zone is exported to the deeper, dark regions of the ocean by gravitational settling of living and nonliving particulate organic matter (POM). Most of the exported POM undergoes microbial decomposition before reaching the seabed. This POM remineralization process creates a deep sea reservoir of inorganic nutrients, including dissolved inorganic carbon (DIC), nitrate (NO 3 − ), and phosphate (PO 4 3− ). The resupply of these deep sea nutrients to the euphotic zone via turbulent diffusion and upwelling sustains surface ocean productivity over long time scales.The term "carbon pump" (4) is used to describe the oceanic processes that collectively sustain the large ∼272 μmol C·kg −1 global mean surface-to-deep sea increase of DIC in the ocean. The carbon pump ultimately sets the limit for carbon dioxide (CO 2 ) exchange between the ocean and the atmosphere (4). A stated goal of the seminal paper by Volk and Hoffert (4...

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“…Dissolved organic nitrogen (DON) is the second most abundant form of fixed nitrogen in the ocean, with a pool size of 7.7 (±2.3) × 10 4 Tg N (Karl et al, 2001;Bronk, 2002;Aluwihare and Meador, 2009). The total DON pool consists of numerous low and high molecular weight (LMW, HMW) compounds and compound classes of varying concentration and bioavailability including amino acids, N-acetyl amino polysaccharides (for example, chitin and peptidoglycan), dissolved proteins and uncharacterizable proteinaceous matter (Tanoue et al, 1995;McCarthy et al, 1997McCarthy et al, , 1998Aluwihare et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Diverse, uncultivated bacteria and archaea underlying the cycling of dissolved protein in the ocean

et al. 2016

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Dissolved organic nitrogen (DON) supports a significant amount of heterotrophic production in the ocean. Yet, to date, the identity and diversity of microbial groups that transform DON are not well understood. To better understand the organisms responsible for transforming high molecular weight (HMW)-DON in the upper ocean, isotopically labeled protein extract from Micromonas pusilla, a eukaryotic member of the resident phytoplankton community, was added as substrate to euphotic zone water from the central California Current system. Carbon and nitrogen remineralization rates from the added proteins ranged from 0.002 to 0.35 μmol C l − 1 per day and 0.03 to 0.27 nmol N l − 1 per day. DNA stable-isotope probing (DNA-SIP) coupled with high-throughput sequencing of 16S rRNA genes linked the activity of 77 uncultivated freeliving and particle-associated bacterial and archaeal taxa to the utilization of Micromonas protein extract. The high-throughput DNA-SIP method was sensitive in detecting isotopic assimilation by individual operational taxonomic units (OTUs), as substrate assimilation was observed after only 24 h. Many uncultivated free-living microbial taxa are newly implicated in the cycling of dissolved proteins affiliated with the Verrucomicrobia, Planctomycetes, Actinobacteria and Marine Group II (MGII) Euryarchaeota. In addition, a particle-associated community actively cycling DON was discovered, dominated by uncultivated organisms affiliated with MGII, Flavobacteria, Planctomycetes, Verrucomicrobia and Bdellovibrionaceae. The number of taxa assimilating protein correlated with genomic representation of TonB-dependent receptor (TBDR)-encoding genes, suggesting a possible role of TBDR in utilization of dissolved proteins by marine microbes. Our results significantly expand the known microbial diversity mediating the cycling of dissolved proteins in the ocean.

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Ecological nitrogen-to-phosphorus stoichiometry at station ALOHA

Cited by 296 publications

References 66 publications

The alkaline phosphatase PhoX is more widely distributed in marine bacteria than the classical PhoA

The alkaline phosphatase PhoX is more widely distributed in marine bacteria than the classical PhoA

Predictable and efficient carbon sequestration in the North Pacific Ocean supported by symbiotic nitrogen fixation

Diverse, uncultivated bacteria and archaea underlying the cycling of dissolved protein in the ocean

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