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Nutrient enrichment of the subarctic Pacific Ocean pycnocline
Author(s) -
Whitney Frank A.,
Bograd Steven J.,
Ono Tsuneo
Publication year - 2013
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 - 10.1002/grl.50439
Subject(s) - pycnocline , subarctic climate , oceanography , nutrient , environmental science , thermohaline circulation , stratification (seeds) , new production , nitrate , geology , ecology , biology , phytoplankton , seed dormancy , botany , germination , dormancy
Abstract At the end of the global thermohaline circulation, the subarctic Pacific is the richest nutrient repository in the world oceans. Trends towards lower oxygen and higher nutrients in waters below the surface layer (the pycnocline) have been observed in recent decades. We assess these trends using data from four programs and suggest the enrichment of pycnocline nitrate (200 Gmol y −1 ) is essential in keeping supply to the surface ocean constant, despite increasing upper ocean stratification. A nitrate budget helps identify possible vertical processes that could account for nutrient redistribution. We hypothesize that warming and oxygen loss in the deeper pycnocline, arising from ice loss in the Okhotsk Sea, have initiated a largely vertical redistribution of nutrients due to compression of vertical migrator habitat and/or changes in dissolution of sinking particulates. Coupled climate‐ecosystem models will need to incorporate these processes to more fully understand projected changes in the subarctic Pacific.