The University of Southampton
University of Southampton Institutional Repository

Micro- and macronutrients in the southeastern Bering Sea: Insight into iron-replete and iron-depleted regimes

Micro- and macronutrients in the southeastern Bering Sea: Insight into iron-replete and iron-depleted regimes
Micro- and macronutrients in the southeastern Bering Sea: Insight into iron-replete and iron-depleted regimes

Surface transects and vertical profiles of macronutrients, dissolved iron (D-Fe), and dissolved manganese (D-Mn) were investigated during August 2003 in the southeastern Bering Sea. We observed iron-limited, HNLC surface waters in the deep basin of the Bering Sea (15-20 μmol/kg nitrate, ∼0.07 nmol/kg D-Fe, and ≤1.0 nmol/kg D-Mn); nitrate-limited, iron-replete surface waters over the shelf (<0.1 μmol/kg nitrate, 0.5-4 nmol/kg D-Fe, and 2-33 nmol/kg D-Mn); and high biomass at the shelf break ("Green Belt"), where diatoms appeared to have been stressed by low D-Fe concentrations (<0.3 nmol/kg). Sources of nitrate and iron to the Green Belt were investigated. A mixture of Aleutian North Slope Current water (with elevated, but non-sufficient iron concentrations relative to its high nitrate concentrations) and surface waters from the vicinity of the Bering Canyon (with lower nitrate concentrations, but similar dissolved iron concentrations) was carried along the shelf break by the Bering Slope Current. This water mixture provided macro- and micronutrients at the southern end of the shelf break. The oceanic domain supplied additional macronutrients to Green Belt waters, while the bottom layer of the outer shelf domain supplied additional macro- and micronutrients through enhanced vertical mixing at the shelf break. Surface waters near the Pribilof Islands, where the highest surface D-Fe concentrations were observed (∼5-6 nmol/kg), represent a potential source of additional iron to Green Belt waters. During summer, the subsurface water of the middle shelf domain is a potential source of nitrate to the nitrate depleted waters of the shelf. In this subsurface cool pool, we observed evidence of substantial denitrification with lower than expected nitrate concentrations.

Dissolved iron, Dissolved manganese, HNLC region, Nutrients, Regional index: USA, Alaska, southeastern Bering Sea, Trace metals
0079-6611
99-126
Aguilar-Islas, Ana M.
95163f7a-93d5-4d52-8da0-c793d05bc8d7
Hurst, Matthew P.
8b9da87c-f82e-4ea6-b857-78db6881061d
Buck, Kristen N.
a6cfcd5a-0aac-4e8d-8225-59e7faa00f53
Sohst, Bettina
99417f40-f100-4abd-baf2-59f386a9c56e
Smith, Geoffrey J.
4d47f3c8-1158-4df9-9750-3ca2955661cb
Lohan, Maeve C.
6ca10597-2d0f-40e8-8e4f-7619dfac5088
Bruland, Kenneth W.
f3e947c6-f9b7-435c-ac84-b3476306a368
Aguilar-Islas, Ana M.
95163f7a-93d5-4d52-8da0-c793d05bc8d7
Hurst, Matthew P.
8b9da87c-f82e-4ea6-b857-78db6881061d
Buck, Kristen N.
a6cfcd5a-0aac-4e8d-8225-59e7faa00f53
Sohst, Bettina
99417f40-f100-4abd-baf2-59f386a9c56e
Smith, Geoffrey J.
4d47f3c8-1158-4df9-9750-3ca2955661cb
Lohan, Maeve C.
6ca10597-2d0f-40e8-8e4f-7619dfac5088
Bruland, Kenneth W.
f3e947c6-f9b7-435c-ac84-b3476306a368

Aguilar-Islas, Ana M., Hurst, Matthew P., Buck, Kristen N., Sohst, Bettina, Smith, Geoffrey J., Lohan, Maeve C. and Bruland, Kenneth W. (2007) Micro- and macronutrients in the southeastern Bering Sea: Insight into iron-replete and iron-depleted regimes. Progress in Oceanography, 73 (2), 99-126. (doi:10.1016/j.pocean.2006.12.002).

Record type: Article

Abstract

Surface transects and vertical profiles of macronutrients, dissolved iron (D-Fe), and dissolved manganese (D-Mn) were investigated during August 2003 in the southeastern Bering Sea. We observed iron-limited, HNLC surface waters in the deep basin of the Bering Sea (15-20 μmol/kg nitrate, ∼0.07 nmol/kg D-Fe, and ≤1.0 nmol/kg D-Mn); nitrate-limited, iron-replete surface waters over the shelf (<0.1 μmol/kg nitrate, 0.5-4 nmol/kg D-Fe, and 2-33 nmol/kg D-Mn); and high biomass at the shelf break ("Green Belt"), where diatoms appeared to have been stressed by low D-Fe concentrations (<0.3 nmol/kg). Sources of nitrate and iron to the Green Belt were investigated. A mixture of Aleutian North Slope Current water (with elevated, but non-sufficient iron concentrations relative to its high nitrate concentrations) and surface waters from the vicinity of the Bering Canyon (with lower nitrate concentrations, but similar dissolved iron concentrations) was carried along the shelf break by the Bering Slope Current. This water mixture provided macro- and micronutrients at the southern end of the shelf break. The oceanic domain supplied additional macronutrients to Green Belt waters, while the bottom layer of the outer shelf domain supplied additional macro- and micronutrients through enhanced vertical mixing at the shelf break. Surface waters near the Pribilof Islands, where the highest surface D-Fe concentrations were observed (∼5-6 nmol/kg), represent a potential source of additional iron to Green Belt waters. During summer, the subsurface water of the middle shelf domain is a potential source of nitrate to the nitrate depleted waters of the shelf. In this subsurface cool pool, we observed evidence of substantial denitrification with lower than expected nitrate concentrations.

Full text not available from this repository.

More information

Accepted/In Press date: 27 December 2006
e-pub ahead of print date: 1 March 2007
Published date: May 2007
Keywords: Dissolved iron, Dissolved manganese, HNLC region, Nutrients, Regional index: USA, Alaska, southeastern Bering Sea, Trace metals

Identifiers

Local EPrints ID: 413898
URI: https://eprints.soton.ac.uk/id/eprint/413898
ISSN: 0079-6611
PURE UUID: 94124fbb-d344-47f8-96a4-3138927bd4d8

Catalogue record

Date deposited: 08 Sep 2017 16:31
Last modified: 13 Mar 2019 20:11

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×