Open AccessMicrobial community production, respiration, and structure of the microbial food web of an ecosystem in the northeastern Atlantic Ocean
Author(s) -
Maixandeau Anne,
Lefèvre Dominique,
Karayanni Hera,
Christaki Urania,
Van Wambeke France,
Thyssen Melilotus,
Denis Michel,
Fernández Camila I.,
Uitz Julia,
Leblanc Karine,
Quéguiner Bernard
Publication year - 2005
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2004jc002694
Subject(s) - trophic level , biomass (ecology) , autotroph , environmental science , food web , microbial loop , ecosystem , primary production , microbial food web , microbial population biology , ecology , oceanography , biology , geology , bacteria , genetics
Gross community production (GCP), dark community respiration (DCR), and the biomass of the different size classes of organisms in the microbial community were measured in the northeastern Atlantic basin as part of the Programme Océan Multidisciplinaire Méso Echelle (POMME) project. The field experiment was conducted during three seasons (winter, spring, and late summer–fall) in 2001. Samples were collected from four different mesoscale structures within the upper 100 m. GCP rates increased from winter (101 ± 24 mmol O 2 m −2 d −1 ) to spring (153 ± 27 mmol O 2 m −2 d −1 ) and then decreased from spring to late summer (44 ± 18 mmol O 2 m −2 d −1 ). DCR rates increased from winter (−47 ± 18 mmol O 2 m −2 d −1 ) to spring (−97 ± 7 mmol O 2 m −2 d −1 ) and then decreased from spring to late summer (50 ± 7 mmol O 2 m −2 d −1 ). The onset of stratification depended on latitude as well as on the presence of mesoscale structures (eddies), and this largely contributed to the variability of GCP. The trophic status of the POMME area was defined as net autotrophic, with a mean annual net community production rate of +38 ± 18 mmol O 2 m −2 d −1 , exhibiting a seasonal variation from +2 ± 20 mmol O 2 m −2 d −1 to +57 ± 20 mmol O 2 m −2 d −1 . This study highlights that small organisms (picoautotrophs, nanoautotrophs, and bacteria) are the main organisms contributing to biological fluxes throughout the year and that episodic blooms of microphytoplankton are related to mesoscale structures.