Premium
Evidence for a heterotrophic subtropical northeast Atlantic
Author(s) -
Duarte Carlos M.,
Agustí Susana,
Arístegui Javier,
González Natalia,
Anadón Ricardo
Publication year - 2001
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.2001.46.2.0425
Subject(s) - heterotroph , photic zone , subtropics , plankton , primary production , environmental science , oceanography , ecosystem , zoology , ecology , biology , phytoplankton , geology , nutrient , bacteria , genetics
The mean (±SE) depth‐integrated gross production (P) of 2,600 ± 271 mg O 2 m −2 d −1 derived from a compilation of data from nine cruises conducted between 1991–2000 in the subtropical NE Atlantic was found to be significantly lower (t‐test, P = 0.005, N = 33) than the mean (±SE) community respiration (R) of 3,821 ± 276 mg O 2 m −2 d −1 . Two‐thirds of the stations investigated were heterotrophic, and the P/R ratio of the communities tended to increase as P increased, such that communities where P < 3,000 mg O 2 m −2 d −1 tended to be heterotrophic. The tendency for R to exceed P (P/R , 1.0) was statistically significant (Wilcoxon ranked sign test, P < 0.05) in the upper and deep layers of the photic zone, with an overall balance between P and R at intermediate depths. These results provide evidence that the subtropical NE Atlantic is a heterotrophic ecosystem, where planktonic communities respire more organic carbon than they produce, thereby acting as net sources of CO 2 .