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Temperature and annual cycle of nitrification in waters of Narragansett Bay.
Author(s) -
Berounsky Veronica M.,
Nixon Scott W.
Publication year - 1990
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1990.35.7.1610
Subject(s) - nitrification , phytoplankton , bay , estuary , nutrient , environmental science , pelagic zone , oceanography , nitrogen , ecology , chemistry , biology , geology , organic chemistry
Pelagic nitrification, measured over an annual cycle at two sites in Narragansett Bay, Rhode Island, was strongly correlated with temperature. At a nutrient‐poor site, rates ranged from near zero in winter to almost 1 µ mol N liter −1 d −1 in summer, with an apparent Q 10 of 6.8. Rates were always higher at a nutrient‐rich Providence River estuary site, with a summer maximum >11 µ mol N liter −1 d −1 and an apparent Q 10 of 17.6. Laboratory experiments that examined the response of nitrification to temperature alone resulted in a Q 10 of 7.5. The high summer rate of nitrification was balanced by NO 3 − uptake by phytoplankton. Elevated levels of NO 3 − in fall resulted from a marked decline in phytoplankton uptake and a continuing slow rate of nitrification and were not dependent on river inputs. Other N transformations do not respond to temperature as strongly as nitrification did, thus temperature increases may effect the distribution of N.