New and regenerated sources of nitrogen: from the ice edge to the equator in the South Pacific Ocean

Fuente: PANGAEA
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Autori principali: Raes, Eric J, Van De Kamp, Jodie, Bodrossy, Levente, Fong, Allison A, Riekenberg, Jessica, Eyre, Bradley D, Waite, Anya M
Natura: Dataset Open Access
Lingua:en
Pubblicazione: PANGAEA 2018
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author Raes, Eric J
Van De Kamp, Jodie
Bodrossy, Levente
Fong, Allison A
Riekenberg, Jessica
Eyre, Bradley D
Waite, Anya M
author_facet Raes, Eric J
Van De Kamp, Jodie
Bodrossy, Levente
Fong, Allison A
Riekenberg, Jessica
Eyre, Bradley D
Waite, Anya M
collection Datos científicos de ciencias marinas y ambientales
contents The distribution of diazotrophs and the magnitude of N2 fixation along with the input of new N through this process remains poorly constrained globally, but particularly in the Southern Pacific Ocean. Here we present a high-resolution dataset (every 0.5° latitude) describing the different N-cycling pathways which control the fixation and sequestration of carbon in the surface waters along a 7000 km transect in the South Pacific Ocean. Key oceanographic features along the P15S GO-SHIP transect from the Antarctic ice edge to the equator, included crossing of the subtropical front (STF), from the sub-Antarctic waters towards the oligotrophic tropics, and the equatorial upwelling region. We show how the natural isotopic abundance of particulate organic matter relate to different biogeochemical transformations in the N-cycle across four oceanic provinces. At all stations we measured N2 fixation rates. In the cold and nutrient rich waters of the Southern Ocean we found measurable N2 fixation rates (>0.2 nmol L-1.d-1), which increased after the subtropical front, and remained at about 15 nmol L-1.d-1 until the equator. In the subtropical and tropical waters, the input of new nitrogen through N2 fixation could fuel on average 13±19% of the net primary productivity. Our data analysis showed that nitrifying organisms, from bacterial and archaeal genera such as Nitrospina, Nitrospinaceae, Nitrosopumilus, Nitrosopelagicus and Nitrosoarchaeum, prevailed in the Southern Ocean and within the STF. Nitrification rates ranged up to 60 nmol L-1.d-1 within the mixed layer depth in the Southern Ocean. Our results suggest that nitrification above the pycnoclines is an important component of the N cycle in the Southern Ocean. Our data has given us a better understanding of how the different N-cycling pathways relate to primary productivity in the South Pacific Ocean, as well as insights into the potential geographical N pathway shifts in light of the rapidly changing climate.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_885170
institution PANGAEA
language en
publishDate 2018
publisher PANGAEA
record_format pangaea
spellingShingle New and regenerated sources of nitrogen: from the ice edge to the equator in the South Pacific Ocean
Raes, Eric J
Van De Kamp, Jodie
Bodrossy, Levente
Fong, Allison A
Riekenberg, Jessica
Eyre, Bradley D
Waite, Anya M
AWI_BioOce; Biological Oceanography @ AWI
The distribution of diazotrophs and the magnitude of N2 fixation along with the input of new N through this process remains poorly constrained globally, but particularly in the Southern Pacific Ocean. Here we present a high-resolution dataset (every 0.5° latitude) describing the different N-cycling pathways which control the fixation and sequestration of carbon in the surface waters along a 7000 km transect in the South Pacific Ocean. Key oceanographic features along the P15S GO-SHIP transect from the Antarctic ice edge to the equator, included crossing of the subtropical front (STF), from the sub-Antarctic waters towards the oligotrophic tropics, and the equatorial upwelling region. We show how the natural isotopic abundance of particulate organic matter relate to different biogeochemical transformations in the N-cycle across four oceanic provinces. At all stations we measured N2 fixation rates. In the cold and nutrient rich waters of the Southern Ocean we found measurable N2 fixation rates (>0.2 nmol L-1.d-1), which increased after the subtropical front, and remained at about 15 nmol L-1.d-1 until the equator. In the subtropical and tropical waters, the input of new nitrogen through N2 fixation could fuel on average 13±19% of the net primary productivity. Our data analysis showed that nitrifying organisms, from bacterial and archaeal genera such as Nitrospina, Nitrospinaceae, Nitrosopumilus, Nitrosopelagicus and Nitrosoarchaeum, prevailed in the Southern Ocean and within the STF. Nitrification rates ranged up to 60 nmol L-1.d-1 within the mixed layer depth in the Southern Ocean. Our results suggest that nitrification above the pycnoclines is an important component of the N cycle in the Southern Ocean. Our data has given us a better understanding of how the different N-cycling pathways relate to primary productivity in the South Pacific Ocean, as well as insights into the potential geographical N pathway shifts in light of the rapidly changing climate.
title New and regenerated sources of nitrogen: from the ice edge to the equator in the South Pacific Ocean
topic AWI_BioOce; Biological Oceanography @ AWI
url https://doi.org/10.1594/PANGAEA.885170