Title :

The effects of nutrient additions on particulate and dissolved primary production and metabolic state in surface waters of three Mediterranean eddies

Author(s) :

Lagaria, A. [Auteur]
Psarra, S. [Auteur]
Lefèvre, Dominique [Auteur]
Institut méditerranéen d'océanologie [MIO]
van Wambeke, France [Auteur]
Institut méditerranéen d'océanologie [MIO]
Courties, C. [Auteur]
Observatoire océanologique de Banyuls [OOB]
Pujo-Pay, Mireille [Auteur]
Laboratoire d'Océanographie Microbienne [LOMIC]
Oriol, L. [Auteur]
Laboratoire d'Océanographie Microbienne [LOMIC]
Tanaka, T. [Auteur]
Laboratoire d'Océanographie Physique et Biogéochimique [LOPB]
Christaki, Urania [Auteur]
Université du Littoral Côte d'Opale [ULCO]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]

Journal title :

Biogeosciences
Special issue : Interactions between planktonic organisms and the biogeochemical cycles of biogenic elements in the Mediterranean Sea during intense summer stratification: the BOUM experiment

Pages :

2595-2607

Publisher :

European Geosciences Union

Publication date :

2011-09-14

ISSN :

1726-4170

English keyword(s) :

CARBON FLUX
PLANKTON METABOLISM
MICROCOSM EXPERIMENT
PHOSPHORUS LIMITATION
P-LIMITATION
HETEROTROPHIC BACTERIA
ORGANIC-MATTER
MICROBIAL FOOD WEBS
NET COMMUNITY PRODUCTION
ALMERIA-ORAN FRONT

HAL domain(s) :

Planète et Univers [physics]/Océan, Atmosphère

English abstract : [en]

We examined the effects of nutrient additions on rates of C-14-based particulate and dissolved primary production as well as O-2-based metabolic rates in surface waters (8 m) of three anticyclonic eddies, located in the ...
Show more >We examined the effects of nutrient additions on rates of C-14-based particulate and dissolved primary production as well as O-2-based metabolic rates in surface waters (8 m) of three anticyclonic eddies, located in the Western, Central and Eastern Mediterranean. Ship-board microcosm experiments employing additions of inorganic nitrogen (+N) and phosphorus (+P), alone and in combination (+NP), were conducted in June/July 2008 during the BOUM (Biogeochemistry from the Oligotrophic to the Ultra-oligotrophic Mediterranean) cruise. In all three experiments, particulate primary production was significantly stimulated by the additions of nitrogen (+N, +NP) while no effect was observed with the addition of phosphorus alone (+P). Percent extracellular release of photosynthate (PER) displayed the lowest values (4-8%) in the +NP treatment. Among the three treatments (+N, +P, +NP), the +NP had the strongest effect on oxygen metabolic rates, leading to positive values of net community production (NCP>0). These changes of NCP were mainly due to enhanced gross primary production (GPP) rather than reduced dark community respiration rates (DCR). In all three sites, in +NP treatment autotrophic production (whether expressed as GPP or PPtotal) was sufficient to fulfil the estimated carbon requirements of heterotrophic prokaryotes, while addition of nitrogen alone (+N) had a weaker effect on GPP, resulting in metabolically balanced systems. At the three sites, in treatments with N (+N, +NP), phytoplankton and heterotrophic prokaryote production were positively correlated. Heterotrophic conditions were observed in the Control and +P treatment at the central and eastern sites, and autotrophic production was not sufficient to supply estimated bacterial carbon demand, evidence of a decoupling of phytoplankton production and consumption by heterotrophic prokaryotes.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Non spécifiée

Popular science :

Non

Collections :

• Laboratoire d'Océanologie et de Géosciences (LOG) - UMR 8187

Source :

Harvested from HAL