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Internal tidal mixing as a control on continental margin ecosystems
Author(s) -
Sharples Jonathan,
Moore C. Mark,
Hickman Anna E.,
Holligan Patrick M.,
Tweddle Jacqueline F.,
Palmer Matthew R.,
Simpson John H.
Publication year - 2009
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl040683
Subject(s) - continental shelf , oceanography , phytoplankton , environmental science , marine ecosystem , ecosystem , bathymetry , geology , water column , fishery , ecology , nutrient , biology
We show that a breaking internal tide at a shelf edge is a fundamental control on the structural and functional properties of ecosystems. Contrasts in vertical mixing of nitrate between the shelf and the open ocean correspond with horizontal and vertical changes in phytoplankton communities, with largest cells found in surface waters at the shelf edge. Intense fishing activity is commonly seen at continental shelf edges, targeting spawning fish stocks. We suggest that the internal tide, a globally ubiquitous physical process at steep shelf edge bathymetry, supports shelf edge fisheries by providing large‐celled phytoplankton for first‐feeding fish larvae. The repeatability of the internal tide removes fish from the need to time spawning with a spring bloom. Also, with large phytoplankton cells dominating particulate organic carbon export, the internal tides could be an important influence on spatial and temporal variability in patterns of global carbon sequestration in deep water and sediments.