scholarly journals Composition, age, and provenance of organic matter in NW African dust over the Atlantic Ocean

2002 ◽  
Vol 3 (8) ◽  
pp. 1-27 ◽  
Author(s):  
T. I. Eglinton ◽  
G. Eglinton ◽  
L. Dupont ◽  
E. R. Sholkovitz ◽  
D. Montluçon ◽  
...  
Keyword(s):  
Organic Matter ◽  
Atlantic Ocean ◽  
African Dust

scholarly journals Response of heterotrophic and autotrophic microbial plankton to inorganic and organic inputs along a latitudinal transect in the Atlantic Ocean

2010 ◽  
Vol 7 (5) ◽  
pp. 1701-1713 ◽  
Author(s):  
S. Martínez-García ◽  
E. Fernández ◽  
A. Calvo-Díaz ◽  
E. Marañón ◽  
X. A. G. Morán ◽  
...  
Keyword(s):  
Organic Matter ◽  
Atlantic Ocean ◽  
Bacterial Growth ◽  
Heterotrophic Bacteria ◽  
Growth Efficiency ◽  
Bacterial Growth Efficiency ◽  
Organic Nutrient ◽  
Plankton Biomass ◽  
Latitudinal Transect ◽  
Microbial Plankton

Abstract. The effects of inorganic and/or organic nutrient inputs on phytoplankton and heterotrophic bacteria have never been concurrently assessed in open ocean oligotrophic communities over a wide spatial gradient. We studied the effects of potentially limiting inorganic (nitrate, ammonium, phosphate, silica) and organic nutrient (glucose, aminoacids) inputs added separately as well as jointly, on microbial plankton biomass, community structure and metabolism in five microcosm experiments conducted along a latitudinal transect in the Atlantic Ocean (from 26° N to 29° S). Primary production rates increased up to 1.8-fold. Bacterial respiration and microbial community respiration increased up to 14.3 and 12.7-fold respectively. Bacterial production and bacterial growth efficiency increased up to 58.8-fold and 2.5-fold respectively. The largest increases were measured after mixed inorganic-organic nutrients additions. Changes in microbial plankton biomass were small as compared with those in metabolic rates. A north to south increase in the response of heterotrophic bacteria was observed, which could be related to a latitudinal gradient in phosphorus availability. Our results suggest that organic matter inputs will result in a predominantly heterotrophic versus autotrophic response and in increases in bacterial growth efficiency, particularly in the southern hemisphere. Subtle differences in the initial environmental and biological conditions are likely to result in differential microbial responses to inorganic and organic matter inputs.

Seasonal radiogenic isotopic variability of the African dust outflow to the tropical Atlantic Ocean and across to the Caribbean

2018 ◽  
Vol 487 ◽  
pp. 94-105 ◽  
Author(s):  
Ashwini Kumar ◽  
W. Abouchami ◽  
S.J.G. Galer ◽  
Satinder Pal Singh ◽  
K.W. Fomba ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Tropical Atlantic ◽  
Tropical Atlantic Ocean ◽  
African Dust ◽  
The Caribbean

scholarly journals Methylphosphonate Oxidation inProchlorococcusStrain MIT9301 Supports Phosphate Acquisition, Formate Excretion, and Carbon Assimilation into Purines

2019 ◽  
Vol 85 (13) ◽  
Author(s):  
Oscar A. Sosa ◽  
John R. Casey ◽  
David M. Karl
Keyword(s):  
Organic Matter ◽  
Atlantic Ocean ◽  
Dissolved Organic Matter ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Carbon Assimilation ◽  
Unicellular Cyanobacterium ◽  
Content Type ◽  
The North ◽  
Oxidative Pathway

ABSTRACTThe marine unicellular cyanobacteriumProchlorococcusis an abundant primary producer and widespread inhabitant of the photic layer in tropical and subtropical marine ecosystems, where the inorganic nutrients required for growth are limiting. In this study, we demonstrate thatProchlorococcushigh-light strain MIT9301, an isolate from the phosphate-depleted subtropical North Atlantic Ocean, can oxidize methylphosphonate (MPn) and hydroxymethylphosphonate (HMPn), two phosphonate compounds present in marine dissolved organic matter, to obtain phosphorus. The oxidation of these phosphonates releases the methyl group as formate, which is both excreted and assimilated into purines in RNA and DNA. Genes encoding the predicted phosphonate oxidative pathway of MIT9301 were predominantly present inProchlorococcusgenomes from parts of the North Atlantic Ocean where phosphate availability is typically low, suggesting that phosphonate oxidation is an ecosystem-specific adaptation of someProchlorococcuspopulations to cope with phosphate scarcity.IMPORTANCEUntil recently, MPn was only known to be degraded in the environment by the bacterial carbon-phosphorus (CP) lyase pathway, a reaction that releases the greenhouse gas methane. The identification of a formate-yielding MPn oxidative pathway in the marine planctomyceteGimesia maris(S. R. Gama, M. Vogt, T. Kalina, K. Hupp, et al., ACS Chem Biol 14:735–741, 2019,https://doi.org/10.1021/acschembio.9b00024) and the presence of this pathway inProchlorococcusindicate that this compound can follow an alternative fate in the environment while providing a valuable source of P to organisms. In the ocean, where MPn is a major component of dissolved organic matter, the oxidation of MPn to formate byProchlorococcusmay direct the flow of this one-carbon compound to carbon dioxide or assimilation into biomass, thus limiting the production of methane.

Metabolic poise in the North Atlantic Ocean diagnosed from organic matter transports

2004 ◽  
Vol 49 (4) ◽  
pp. 1084-1094 ◽  
Author(s):  
Dennis A. Hansell ◽  
Hugh W. Ducklow ◽  
Alison M. Macdonald ◽  
Molly O-Neil Baringer
Keyword(s):  
Organic Matter ◽  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
The North ◽  
The North Atlantic

scholarly journals African biomass burning is a substantial source of phosphorus deposition to the Amazon, Tropical Atlantic Ocean, and Southern Ocean

2019 ◽  
Vol 116 (33) ◽  
pp. 16216-16221 ◽  
Author(s):  
Anne E. Barkley ◽  
Joseph M. Prospero ◽  
Natalie Mahowald ◽  
Douglas S. Hamilton ◽  
Kimberly J. Popendorf ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Biomass Burning ◽  
Amazon Basin ◽  
Transport Model ◽  
Boreal Summer ◽  
Tropical Atlantic ◽  
Dust Transport ◽  
Tropical Atlantic Ocean ◽  
African Dust ◽  
Soluble P

The deposition of phosphorus (P) from African dust is believed to play an important role in bolstering primary productivity in the Amazon Basin and Tropical Atlantic Ocean (TAO), leading to sequestration of carbon dioxide. However, there are few measurements of African dust in South America that can robustly test this hypothesis and even fewer measurements of soluble P, which is readily available for stimulating primary production in the ocean. To test this hypothesis, we measured total and soluble P in long-range transported aerosols collected in Cayenne, French Guiana, a TAO coastal site located at the northeastern edge of the Amazon. Our measurements confirm that in boreal spring when African dust transport is greatest, dust supplies the majority of P, of which 5% is soluble. In boreal fall, when dust transport is at an annual minimum, we measured unexpectedly high concentrations of soluble P, which we show is associated with the transport of biomass burning (BB) from southern Africa. Integrating our results into a chemical transport model, we show that African BB supplies up to half of the P deposited annually to the Amazon from transported African aerosol. This observational study links P-rich BB aerosols from Africa to enhanced P deposition in the Amazon. Contrary to current thought, we also show that African BB is a more important source of soluble P than dust to the TAO and oceans in the Southern Hemisphere and may be more important for marine productivity, particularly in boreal summer and fall.

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