scholarly journals Controlling factors on the global distribution of a representative marine heterotrophic diazotroph phylotype (Gamma A)

2022 ◽  
Author(s):  
Zhibo Shao ◽  
Ya-Wei Luo
Keyword(s):  
Primary Production ◽  
Carrying Capacity ◽  
N2 Fixation ◽  
Net Primary Production ◽  
Additive Model ◽  
Niche Differentiation ◽  
Global Ocean ◽  
Nutrient Inputs ◽  
High Concentration ◽  
Decomposition Of Organic Matter

Abstract. Heterotrophic diazotrophs emerge as a potentially important contributor to the global marine N2 fixation, while the factors controlling their distribution are unclear. Here, we explored what controls the distribution of the most sampled heterotrophic diazotroph phylotype, Gamma A, in the global ocean. First, we analyzed the relationship between nifH-based Gamma A abundance and climatological biological and environmental conditions. The carrying capacity of Gamma A abundance increased with net primary production (NPP) and saturated when NPP reached ~400 mg C m−2 d−1. The reduction in Gamma A abundance from its carrying capacity was mostly related to low temperature, which possibly slowed the decomposition of organic matter, and high concentration of dissolved iron, to which the explanation was elusive but could result from the competition with autotrophic diazotrophs. Using a generalized additive model, these climatological factors together explained 41 % of the variance in the Gamma A abundance. Second, in additional to the climatological background, we found that mesoscale cyclonic eddies can substantially elevate Gamma A abundance, implying that Gamma A can respond to short-term features and benefit from stimulated primary production by nutrient inputs. Overall, our results suggest that the distribution of Gamma A is most likely determined by the supply of organic matters, not by those factors controlling autotrophic diazotrophs, and therefore insight a niche differentiation between the heterotrophic and autotrophic N2 fixation. More samplings on Gamma A and other heterotrophic diazotroph phylotypes are needed to better reveal the controlling mechanisms of heterotrophic N2 fixation in the ocean.

scholarly journals Prediction of the Export and Fate of Global Ocean Net Primary Production: The EXPORTS Science Plan

2016 ◽  
Vol 3 ◽  
Author(s):  
David A. Siegel ◽  
Ken O. Buesseler ◽  
Michael J. Behrenfeld ◽  
Claudia R. Benitez-Nelson ◽  
Emmanuel Boss ◽  
...  
Keyword(s):  
Primary Production ◽  
Net Primary Production ◽  
Global Ocean

scholarly journals Reviews and syntheses: Hidden forests, the role of vegetated coastal habitats in the ocean carbon budget

2017 ◽  
Vol 14 (2) ◽  
pp. 301-310 ◽  
Author(s):  
Carlos M. Duarte
Keyword(s):  
Carbon Sequestration ◽  
Organic Carbon ◽  
Primary Production ◽  
Deep Sea ◽  
Carbon Budget ◽  
Net Primary Production ◽  
Global Ocean ◽  
Coastal Habitats ◽  
Global Carbon Budget ◽  
Global Carbon

Abstract. Vegetated coastal habitats, including seagrass and macroalgal beds, mangrove forests and salt marshes, form highly productive ecosystems, but their contribution to the global carbon budget remains overlooked, and these forests remain hidden in representations of the global carbon budget. Despite being confined to a narrow belt around the shoreline of the world's oceans, where they cover less than 7 million km2, vegetated coastal habitats support about 1 to 10 % of the global marine net primary production and generate a large organic carbon surplus of about 40 % of their net primary production (NPP), which is either buried in sediments within these habitats or exported away. Large, 10-fold uncertainties in the area covered by vegetated coastal habitats, along with variability about carbon flux estimates, result in a 10-fold bracket around the estimates of their contribution to organic carbon sequestration in sediments and the deep sea from 73 to 866 Tg C yr−1, representing between 3 % and 1∕3 of oceanic CO2 uptake. Up to 1∕2 of this carbon sequestration occurs in sink reservoirs (sediments or the deep sea) beyond these habitats. The organic carbon exported that does not reach depositional sites subsidizes the metabolism of heterotrophic organisms. In addition to a significant contribution to organic carbon production and sequestration, vegetated coastal habitats contribute as much to carbonate accumulation as coral reefs do. While globally relevant, the magnitude of global carbon fluxes supported by salt-marsh, mangrove, seagrass and macroalgal habitats is declining due to rapid habitat loss, contributing to loss of CO2 sequestration, storage capacity and carbon subsidies. Incorporating the carbon fluxes' vegetated coastal habitats' support into depictions of the carbon budget of the global ocean and its perturbations will improve current representations of the carbon budget of the global ocean.

scholarly journals Large deep-sea zooplankton biomass mirrors primary production in the global ocean

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Hernández-León ◽  
R. Koppelmann ◽  
E. Fraile-Nuez ◽  
A. Bode ◽  
C. Mompeán ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Deep Sea ◽  
Large Scale ◽  
Net Primary Production ◽  
Deep Ocean ◽  
Zooplankton Biomass ◽  
Global Ocean ◽  
Global Coupling ◽  
Do So

AbstractThe biological pump transports organic carbon produced by photosynthesis to the meso- and bathypelagic zones, the latter removing carbon from exchanging with the atmosphere over centennial time scales. Organisms living in both zones are supported by a passive flux of particles, and carbon transported to the deep-sea through vertical zooplankton migrations. Here we report globally-coherent positive relationships between zooplankton biomass in the epi-, meso-, and bathypelagic layers and average net primary production (NPP). We do so based on a global assessment of available deep-sea zooplankton biomass data and large-scale estimates of average NPP. The relationships obtained imply that increased NPP leads to enhanced transference of organic carbon to the deep ocean. Estimated remineralization from respiration rates by deep-sea zooplankton requires a minimum supply of 0.44 Pg C y−1 transported into the bathypelagic ocean, comparable to the passive carbon sequestration. We suggest that the global coupling between NPP and bathypelagic zooplankton biomass must be also supported by an active transport mechanism associated to vertical zooplankton migration.

Application of the MODIS MOD 17 Net Primary Production product in grassland carrying capacity assessment

2019 ◽  
Vol 78 ◽  
pp. 66-76 ◽  
Author(s):  
Jan de Leeuw ◽  
Afag Rizayeva ◽  
Elmaddin Namazov ◽  
Emil Bayramov ◽  
Michael T. Marshall ◽  
...  
Keyword(s):  
Primary Production ◽  
Carrying Capacity ◽  
Net Primary Production ◽  
Capacity Assessment

scholarly journals Diatoms Si Uptake Capacity Drives Carbon Export In Coastal Upwelling Systems

2016 ◽  
Author(s):  
F. Abrantes ◽  
P. Cermeño ◽  
C. Lopes ◽  
O. Romero ◽  
L. Matos ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Coastal Upwelling ◽  
Net Primary Production ◽  
Regional Scale ◽  
Global Scale ◽  
Global Ocean ◽  
Nutrient Concentrations ◽  
Organic Carbon Content ◽  
Organic Carbon Burial

Abstract. Coastal upwelling systems account for approximately half of global ocean primary production and contribute disproportionately to biologically driven carbon sequestration. Diatoms, silica–precipitating microalgae, constitute the dominant phytoplankton in these productive regions, and their abundance and assemblage composition in the sedimentary record is considered one of the best proxies for primary production. The study of the sedimentary diatom abundance (SDA) and total organic carbon content (TOC) in the five most important coastal upwelling systems of the modern ocean (Iberia-Canary, Benguela, Peru-Humboldt, California and Somalia-Oman) reveals a global-scale positive relationship between diatom production and organic carbon burial. The analysis of SDA in conjunction with environmental variables of coastal upwelling systems such as upwelling strength, satellite-derived net primary production and surface water nutrient concentrations shows different relations between SDA and primary production on the regional scale. At the global-scale, SDA appears modulated by the capacity of diatoms to take up silicic acid, which ultimately sets an upper limit to global export production in these ocean regions.

scholarly journals EFECTOS DE LA RECOMUNICACIÓN DEL RÍO MAGDALENA CON SU ANTIGUO DELTA: CAMBIOS EN LA PRODUCCIÓN PRIMARIA FITOPLANCTÓNICA Y RESPIRACIÓN EN EL COMPLEJO PAJARALES, 1989 A 2005

2016 ◽  
Vol 38 (2) ◽  
Author(s):  
Johan D. Rodríguez Chila ◽  
José E. Mancera Pineda ◽  
Héctor J. López Salgado
Keyword(s):  
Organic Matter ◽  
Experimental Design ◽  
Primary Production ◽  
Net Primary Production ◽  
Nutrient Inputs ◽  
Phytoplankton Primary Production ◽  
Physical Chemical ◽  
Magdalena River ◽  
Del Rio ◽  
Associated Variables

The phytoplankton primary production, pelagic respiration, photosynthetic pigments, and physical-chemical associated variables in the Pajarales Complex, were estimated to assess the potential effects of the Magdalena River recommunication with its former delta, The study carried out between September and December 2005, followed the same experimental design than one done before to the recommunication The results show a signicant increase of the net primary production when compared with the years 1988-89 (from 598 gC/m2/year to 982 gC/m2/year). The actual production seems to be driven mainly by ammonia, and there is no correlation neither with the water transparency nor the chlorophyll a concentration. The ecosystem is less efcient in the synthesis of organic matter after the recommunication with the Magdalena river. The respiration rate increased, showing higher and more prolonged heterotrophy, which may be associated to higher organic matter and inorganic nutrient inputs from the Magdalena River. The results conrm eutrophication increase in the CP between 1989 and 2005.

scholarly journals Oceanic CO<sub>2</sub> outgassing and biological production hotspots induced by pre-industrial river loads of nutrients and carbon in a global modeling approach

2020 ◽  
Vol 17 (1) ◽  
pp. 55-88 ◽  
Author(s):  
Fabrice Lacroix ◽  
Tatiana Ilyina ◽  
Jens Hartmann
Keyword(s):  
Carbon Source ◽  
Organic Carbon ◽  
Net Primary Production ◽  
Global Ocean ◽  
Nutrient Concentrations ◽  
Biogeochemical Model ◽  
Tropical Atlantic ◽  
Nutrient Inputs ◽  
Terrestrial Organic Matter

Abstract. Rivers are a major source of nutrients, carbon and alkalinity to the global ocean. In this study, we firstly estimate pre-industrial riverine loads of nutrients, carbon and alkalinity based on a hierarchy of weathering and terrestrial organic matter export models, while identifying regional hotspots of the riverine exports. Secondly, we implement the riverine loads into a global ocean biogeochemical model to describe their implications for oceanic nutrient concentrations, net primary production (NPP) and air–sea CO2 fluxes globally, as well as in an analysis of coastal regions. Thirdly, we quantitatively assess the terrestrial origins and the long-term fate of riverine carbon in the ocean. We quantify annual bioavailable pre-industrial riverine loads of 3.7 Tg P, 27 Tg N, 158 Tg Si and 603 Tg C delivered to the ocean globally. We thereby identify the tropical Atlantic catchments (20 % of global C), Arctic rivers (9 % of global C) and Southeast Asian rivers (15 % of global C) as dominant suppliers of carbon for the ocean. The riverine exports lead to a simulated net global oceanic CO2 source of 231 Tg C yr−1 to the atmosphere, which is mainly caused by inorganic carbon (source of 183 Tg C yr−1) and by organic carbon (source of 128 Tg C yr−1) riverine loads. Additionally, a sink of 80 Tg C yr−1 is caused by the enhancement of the biological carbon uptake from dissolved inorganic nutrient inputs from rivers and the resulting alkalinity production. While large outgassing fluxes are simulated mostly in proximity to major river mouths, substantial outgassing fluxes can be found further offshore, most prominently in the tropical Atlantic. Furthermore, we find evidence for the interhemispheric transfer of carbon in the model; we detect a larger relative outgassing flux (49 % of global riverine-induced outgassing) in the Southern Hemisphere in comparison to the hemisphere's relative riverine inputs (33 % of global C inputs), as well as an outgassing flux of 17 Tg C yr−1 in the Southern Ocean. The addition of riverine loads in the model leads to a strong NPP increase in the tropical west Atlantic, Bay of Bengal and the East China Sea (+166 %, +377 % and +71 %, respectively). On the light-limited Arctic shelves, the NPP is not strongly sensitive to riverine loads, but the CO2 flux is strongly altered regionally due to substantial dissolved inorganic and organic carbon supplies to the region. While our study confirms that the ocean circulation remains the main driver for biogeochemical distributions in the open ocean, it reveals the necessity to consider riverine inputs for the representation of heterogeneous features in the coastal ocean and to represent riverine-induced pre-industrial carbon outgassing in the ocean. It also underlines the need to consider long-term CO2 sources from volcanic and shale oxidation fluxes in order to close the framework's atmospheric carbon budget.

scholarly journals Diatoms Si uptake capacity drives carbon export in coastal upwelling systems

2016 ◽  
Vol 13 (14) ◽  
pp. 4099-4109 ◽  
Author(s):  
Fatima Abrantes ◽  
Pedro Cermeno ◽  
Cristina Lopes ◽  
Oscar Romero ◽  
Lélia Matos ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Primary Production ◽  
Coastal Upwelling ◽  
Net Primary Production ◽  
Regional Scale ◽  
Global Scale ◽  
Global Ocean ◽  
Nutrient Concentrations ◽  
Organic Carbon Content ◽  
Organic Carbon Burial

Abstract. Coastal upwelling systems account for approximately half of global ocean primary production and contribute disproportionately to biologically driven carbon sequestration. Diatoms, silica-precipitating microalgae, constitute the dominant phytoplankton in these productive regions, and their abundance and assemblage composition in the sedimentary record is considered one of the best proxies for primary production. The study of the sedimentary diatom abundance (SDA) and total organic carbon content (TOC) in the five most important coastal upwelling systems of the modern ocean (Iberia–Canary, Benguela, Peru–Humboldt, California, and Somalia–Oman) reveals a global-scale positive relationship between diatom production and organic carbon burial. The analysis of SDA in conjunction with environmental variables of coastal upwelling systems such as upwelling strength, satellite-derived net primary production, and surface water nutrient concentrations shows different relations between SDA and primary production on the regional scale. On the global scale, SDA appears modulated by the capacity of diatoms to take up silicic acid, which ultimately sets an upper limit to global export production in these ocean regions.

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