Oxygen, carbon, and nutrients in the oligotrophic eastern subtropical North Atlantic
The Beta Triangle, a region of the oligotrophic subtropical eastern North Atlantic Ocean, is notorious for its enigmatic oxygen, carbon, and nitrogen balances, in which nutrient supply is said to explain only a fraction of production necessary for estimated carbon export. Rates of dissolved organic...
Published in: | Biogeosciences |
---|---|
Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications (EGU)
2010
|
Subjects: | |
Online Access: | https://oceanrep.geomar.de/id/eprint/8477/ https://oceanrep.geomar.de/id/eprint/8477/2/k%C3%A4hler.pdf https://doi.org/10.5194/bg-7-1143-2010 |
id |
ftoceanrep:oai:oceanrep.geomar.de:8477 |
---|---|
record_format |
openpolar |
spelling |
ftoceanrep:oai:oceanrep.geomar.de:8477 2023-05-15T17:32:06+02:00 Oxygen, carbon, and nutrients in the oligotrophic eastern subtropical North Atlantic Kähler, Paul Oschlies, Andreas Dietze, Heiner Koeve, Wolfgang 2010-03-26 text https://oceanrep.geomar.de/id/eprint/8477/ https://oceanrep.geomar.de/id/eprint/8477/2/k%C3%A4hler.pdf https://doi.org/10.5194/bg-7-1143-2010 en eng Copernicus Publications (EGU) https://oceanrep.geomar.de/id/eprint/8477/2/k%C3%A4hler.pdf Kähler, P., Oschlies, A. , Dietze, H. and Koeve, W. (2010) Oxygen, carbon, and nutrients in the oligotrophic eastern subtropical North Atlantic. Open Access Biogeosciences (BG), 7 (3). pp. 1143-1156. DOI 10.5194/bg-7-1143-2010 <https://doi.org/10.5194/bg-7-1143-2010>. doi:10.5194/bg-7-1143-2010 info:eu-repo/semantics/openAccess Article PeerReviewed 2010 ftoceanrep https://doi.org/10.5194/bg-7-1143-2010 2023-04-07T14:56:49Z The Beta Triangle, a region of the oligotrophic subtropical eastern North Atlantic Ocean, is notorious for its enigmatic oxygen, carbon, and nitrogen balances, in which nutrient supply is said to explain only a fraction of production necessary for estimated carbon export. Rates of dissolved organic carbon accumulation and dissolved organic nitrogen utilization in surface water and an assessment of oxygen utilized, organic matter consumed, and nitrate and phosphate regenerated in subsurface water, show that conventional production estimates miss substantial shares of biotic production. The shallow export of total organic carbon, predominantly dissolved (DOC), by subduction is responsible for about 50–70% of apparent oxygen utilization in subsurface water between the base of the surface layer at ca. 140 m and ca. 195 m depth, but it is insignificant below. Additionally, there is an estimated accumulation of 1.0 to 1.75 mol DOC m−2 a−1 in surface water. Including DOC dynamics in its carbon balance reveals the surface of this ultra-oligotrophic part of the ocean to be net autotrophic. Increasing subsurface values of excess nitrogen (DINxs) imply the export of nitrogen from surface water stemming from production not exclusively fuelled by new nitrate supplied from below. Total organic nitrogen (almost exclusively dissolved, DON) is consumed in the surface layer at a rate estimated at 0.13 to 0.23 mol m−2 a−1. There is no variation in dissolved organic phosphorus (DOP) in the same direction. DON utilization thus contributes to the pronounced subsurface DINxs signature. DOC export and accumulation are important in the carbon balance in surface and near-surface water. DON utilization and, probably, N2 fixation contribute significant amounts to the nitrogen supply of surface water. These processes can close part of the enigmatic carbon and nitrogen balances in the Beta Triangle. There are, however, no comparable processes which can explain the equally enigmatic situation concerning phosphorus supply in this area. Article in Journal/Newspaper North Atlantic OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Biogeosciences 7 3 1143 1156 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
The Beta Triangle, a region of the oligotrophic subtropical eastern North Atlantic Ocean, is notorious for its enigmatic oxygen, carbon, and nitrogen balances, in which nutrient supply is said to explain only a fraction of production necessary for estimated carbon export. Rates of dissolved organic carbon accumulation and dissolved organic nitrogen utilization in surface water and an assessment of oxygen utilized, organic matter consumed, and nitrate and phosphate regenerated in subsurface water, show that conventional production estimates miss substantial shares of biotic production. The shallow export of total organic carbon, predominantly dissolved (DOC), by subduction is responsible for about 50–70% of apparent oxygen utilization in subsurface water between the base of the surface layer at ca. 140 m and ca. 195 m depth, but it is insignificant below. Additionally, there is an estimated accumulation of 1.0 to 1.75 mol DOC m−2 a−1 in surface water. Including DOC dynamics in its carbon balance reveals the surface of this ultra-oligotrophic part of the ocean to be net autotrophic. Increasing subsurface values of excess nitrogen (DINxs) imply the export of nitrogen from surface water stemming from production not exclusively fuelled by new nitrate supplied from below. Total organic nitrogen (almost exclusively dissolved, DON) is consumed in the surface layer at a rate estimated at 0.13 to 0.23 mol m−2 a−1. There is no variation in dissolved organic phosphorus (DOP) in the same direction. DON utilization thus contributes to the pronounced subsurface DINxs signature. DOC export and accumulation are important in the carbon balance in surface and near-surface water. DON utilization and, probably, N2 fixation contribute significant amounts to the nitrogen supply of surface water. These processes can close part of the enigmatic carbon and nitrogen balances in the Beta Triangle. There are, however, no comparable processes which can explain the equally enigmatic situation concerning phosphorus supply in this area. |
format |
Article in Journal/Newspaper |
author |
Kähler, Paul Oschlies, Andreas Dietze, Heiner Koeve, Wolfgang |
spellingShingle |
Kähler, Paul Oschlies, Andreas Dietze, Heiner Koeve, Wolfgang Oxygen, carbon, and nutrients in the oligotrophic eastern subtropical North Atlantic |
author_facet |
Kähler, Paul Oschlies, Andreas Dietze, Heiner Koeve, Wolfgang |
author_sort |
Kähler, Paul |
title |
Oxygen, carbon, and nutrients in the oligotrophic eastern subtropical North Atlantic |
title_short |
Oxygen, carbon, and nutrients in the oligotrophic eastern subtropical North Atlantic |
title_full |
Oxygen, carbon, and nutrients in the oligotrophic eastern subtropical North Atlantic |
title_fullStr |
Oxygen, carbon, and nutrients in the oligotrophic eastern subtropical North Atlantic |
title_full_unstemmed |
Oxygen, carbon, and nutrients in the oligotrophic eastern subtropical North Atlantic |
title_sort |
oxygen, carbon, and nutrients in the oligotrophic eastern subtropical north atlantic |
publisher |
Copernicus Publications (EGU) |
publishDate |
2010 |
url |
https://oceanrep.geomar.de/id/eprint/8477/ https://oceanrep.geomar.de/id/eprint/8477/2/k%C3%A4hler.pdf https://doi.org/10.5194/bg-7-1143-2010 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://oceanrep.geomar.de/id/eprint/8477/2/k%C3%A4hler.pdf Kähler, P., Oschlies, A. , Dietze, H. and Koeve, W. (2010) Oxygen, carbon, and nutrients in the oligotrophic eastern subtropical North Atlantic. Open Access Biogeosciences (BG), 7 (3). pp. 1143-1156. DOI 10.5194/bg-7-1143-2010 <https://doi.org/10.5194/bg-7-1143-2010>. doi:10.5194/bg-7-1143-2010 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/bg-7-1143-2010 |
container_title |
Biogeosciences |
container_volume |
7 |
container_issue |
3 |
container_start_page |
1143 |
op_container_end_page |
1156 |
_version_ |
1766130048747700224 |