Open AccessAerosol inputs enhance new production in the subtropical northeast Atlantic
Author(s) -
Duarte Carlos M.,
Dachs Jordi,
Llabrés Moira,
AlonsoLaita Patricia,
Gasol Josep M.,
TovarSánchez Antonio,
SañudoWilhemy Sergio,
Agustí Susana
Publication year - 2006
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2005jg000140
Subject(s) - aerosol , phytoplankton , autotroph , environmental science , plankton , subtropics , deposition (geology) , oceanography , nutrient , biomass (ecology) , new production , primary production , dominance (genetics) , environmental chemistry , heterotroph , atmospheric sciences , chemistry , ecology , ecosystem , biology , geology , bacteria , paleontology , biochemistry , genetics , organic chemistry , sediment , gene
Atmospheric deposition is an important source of limiting nutrients to the ocean, potentially stimulating oceanic biota. Atmospheric inputs can also deliver important amounts of organic matter, which may fuel heterotrophic activity in the ocean. The effect of atmospheric dry aerosol deposition on the metabolic balance and net production of planktonic communities remains unresolved. Here we report high inputs of aerosol‐bound N, Si, P, Fe and organic C to the subtropical NE Atlantic and experimentally demonstrate these inputs to stimulate autotrophic abundance and metabolism far beyond the modest stimulation of heterotrophic processes, thereby enhancing new production. Aerosol dry deposition was threefold to tenfold higher in the coastal ocean than in the open ocean, and supplied high average (±SE) inputs of organic C (980 ± 220 μ mol C m −2 d −1 ), total N (280 ± 70 μ mol N m −2 d −1 ), Si (211 ± 39 μ mol Si m −2 d −1 ), and labile Fe (1.01 ± 0.19 μ mol Fe m −2 d −1 ), but low amounts of total P (8 ± 1.6 μ mol P m −2 d −1 ) to the region during the study. Experimental aerosol inputs to oceanic planktonic communities from the studied area resulted, at the highest doses applied, in a sharp increase in phytoplankton biomass (sevenfold) and production (tenfold) within 4 days, with the community shifting from a dominance of picocyanobacteria to one of diatoms. In contrast, bacterial abundance and production showed little response. Primary production showed a much greater increase in response to aerosol inputs than community respiration did, so that the P/R ratio increased from around 0.95 in the ambient waters, where communities were close to metabolic balance, to 3.3 at the highest nutrient inputs, indicative of a high excess production and a potential for substantial net CO 2 removal by the community in response to aerosol inputs. These results showed that aerosol inputs are major vectors of nutrient and carbon inputs, which can, during high depositional events, enhance new production in the NE subtropical Atlantic Ocean.