Enhanced nutrient fluxes at the shelf sea seasonal thermocline caused by stratified flow over a bank

Jacqueline F. Tweddle, Jonathan Sharples, Matthew R. Palmer, Keith Davidson, Sharon McNeill

Research output: Contribution to journalArticle

22 Citations (Scopus)
4 Downloads (Pure)

Abstract

Patches of enhanced chlorophyll a (Chl) concentrations within the thermocline were observed over the slopes of several banks in the Celtic Sea. The turbulent mixing of nutrients from the bottom water into the thermocline was found to be greatly enhanced over the slope of a bank (up to 52 mmol nitrate m−2 day−1), compared to over nearby flat seafloor (∼2 mmol nitrate m−2 day−1). This increased nutrient supply, forced by locally generated lee waves and internal mixing, is greater than nitrate supplies to the productive tidal mixing fronts or to the shelf edge. We hypothesize this nutrient flux promotes an increase in phytoplankton growth in the thermocline over and downstream of shelf sea banks, contributing to the horizontal patchiness in the thermocline Chl signal. The persistence of the strong biological response to mixing at the bank, combined with the ubiquity of shelf sea banks, suggests these bathymetric features have wide importance for “new” primary production in shelf seas.
Original languageEnglish
Pages (from-to)37-47
Number of pages11
JournalProgress in Oceanography
Volume117
Early online date27 Jun 2013
DOIs
Publication statusPublished - Oct 2013

Fingerprint

stratified flow
shelf sea
thermocline
nutrient
nitrates
nutrients
nitrate
chlorophyll a
lee wave
chlorophyll
turbulent mixing
patchiness
shelf break
bottom water
primary production
seafloor
persistence
phytoplankton
water

Cite this

Enhanced nutrient fluxes at the shelf sea seasonal thermocline caused by stratified flow over a bank. / Tweddle, Jacqueline F. ; Sharples, Jonathan; Palmer, Matthew R. ; Davidson, Keith; McNeill, Sharon.

In: Progress in Oceanography, Vol. 117, 10.2013, p. 37-47.

Research output: Contribution to journalArticle

Tweddle, Jacqueline F. ; Sharples, Jonathan ; Palmer, Matthew R. ; Davidson, Keith ; McNeill, Sharon. / Enhanced nutrient fluxes at the shelf sea seasonal thermocline caused by stratified flow over a bank. In: Progress in Oceanography. 2013 ; Vol. 117. pp. 37-47.
@article{c6021b806e124d4a875c3371a01243d5,
title = "Enhanced nutrient fluxes at the shelf sea seasonal thermocline caused by stratified flow over a bank",
abstract = "Patches of enhanced chlorophyll a (Chl) concentrations within the thermocline were observed over the slopes of several banks in the Celtic Sea. The turbulent mixing of nutrients from the bottom water into the thermocline was found to be greatly enhanced over the slope of a bank (up to 52 mmol nitrate m−2 day−1), compared to over nearby flat seafloor (∼2 mmol nitrate m−2 day−1). This increased nutrient supply, forced by locally generated lee waves and internal mixing, is greater than nitrate supplies to the productive tidal mixing fronts or to the shelf edge. We hypothesize this nutrient flux promotes an increase in phytoplankton growth in the thermocline over and downstream of shelf sea banks, contributing to the horizontal patchiness in the thermocline Chl signal. The persistence of the strong biological response to mixing at the bank, combined with the ubiquity of shelf sea banks, suggests these bathymetric features have wide importance for “new” primary production in shelf seas.",
author = "Tweddle, {Jacqueline F.} and Jonathan Sharples and Palmer, {Matthew R.} and Keith Davidson and Sharon McNeill",
year = "2013",
month = "10",
doi = "10.1016/j.pocean.2013.06.018",
language = "English",
volume = "117",
pages = "37--47",
journal = "Progress in Oceanography",
issn = "0079-6611",
publisher = "Elsevier Limited",

}

TY - JOUR

T1 - Enhanced nutrient fluxes at the shelf sea seasonal thermocline caused by stratified flow over a bank

AU - Tweddle, Jacqueline F.

AU - Sharples, Jonathan

AU - Palmer, Matthew R.

AU - Davidson, Keith

AU - McNeill, Sharon

PY - 2013/10

Y1 - 2013/10

N2 - Patches of enhanced chlorophyll a (Chl) concentrations within the thermocline were observed over the slopes of several banks in the Celtic Sea. The turbulent mixing of nutrients from the bottom water into the thermocline was found to be greatly enhanced over the slope of a bank (up to 52 mmol nitrate m−2 day−1), compared to over nearby flat seafloor (∼2 mmol nitrate m−2 day−1). This increased nutrient supply, forced by locally generated lee waves and internal mixing, is greater than nitrate supplies to the productive tidal mixing fronts or to the shelf edge. We hypothesize this nutrient flux promotes an increase in phytoplankton growth in the thermocline over and downstream of shelf sea banks, contributing to the horizontal patchiness in the thermocline Chl signal. The persistence of the strong biological response to mixing at the bank, combined with the ubiquity of shelf sea banks, suggests these bathymetric features have wide importance for “new” primary production in shelf seas.

AB - Patches of enhanced chlorophyll a (Chl) concentrations within the thermocline were observed over the slopes of several banks in the Celtic Sea. The turbulent mixing of nutrients from the bottom water into the thermocline was found to be greatly enhanced over the slope of a bank (up to 52 mmol nitrate m−2 day−1), compared to over nearby flat seafloor (∼2 mmol nitrate m−2 day−1). This increased nutrient supply, forced by locally generated lee waves and internal mixing, is greater than nitrate supplies to the productive tidal mixing fronts or to the shelf edge. We hypothesize this nutrient flux promotes an increase in phytoplankton growth in the thermocline over and downstream of shelf sea banks, contributing to the horizontal patchiness in the thermocline Chl signal. The persistence of the strong biological response to mixing at the bank, combined with the ubiquity of shelf sea banks, suggests these bathymetric features have wide importance for “new” primary production in shelf seas.

U2 - 10.1016/j.pocean.2013.06.018

DO - 10.1016/j.pocean.2013.06.018

M3 - Article

VL - 117

SP - 37

EP - 47

JO - Progress in Oceanography

JF - Progress in Oceanography

SN - 0079-6611

ER -