Nitrogen and phosphorus recycling mediated by copepods in Western Tropical South Pacific

Type Article
Date 2018-01-25
Language English
Author(s) Valdés Valentina1, 2, Carlotti François3, Escribano Ruben4, 5, Donoso Katty3, Pagano Marc3, Molina Veronica6, Fernandez Camila2, 7, 8
Affiliation(s) 1 : Programa de Doctorado en Oceanografía, Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Concepción, Chile
2 : UPMC Univ Paris 06, UMR 7621, Laboratoire d'Océanographie Microbienne, Observatoire Océanologique, Sorbonne Universités, Banyuls sur Mer F-66650, France
3 : Aix-Marseille Univ, Universite de Toulon, CNRS, IRD, OSU PYTHEAS, Mediterranean Institute of Oceanography MIO, UM 110, 13288, Marseille, Cedex 09, France
4 : Departamento de Oceanografía, Universidad de Concepción, Concepción, Chile
5 : Instituto Milenio de Oceanografía, Universidad de Concepción, Concepción, Chile
6 : Departamento de Biología and Programa de Biodiversidad, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha, Playa Ancha, Valparaíso, Chile
7 : FONDAP INCAR center (15110027), and PFB-31 COPAS Sur Austral program, Departamento de Oceanografía, Universidad de Concepción, Concepción, Chile
8 : Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile
Source Biogeosciences (1726-4170) (Copernicus GmbH), 2018-01-25 , Vol. 15 , N. 20 , P. 6019-6032
DOI 10.5194/bg-2017-563
Note Special issue Interactions between planktonic organisms and biogeochemical cycles across trophic and N2 fixation gradients in the western tropical South Pacific Ocean: a multidisciplinary approach (OUTPACE experiment) Editor(s): T. Moutin, S. Bonnet, K. Richards, D. G. Capone, E. Marañón, and L. Mémery

Zooplankton play a key role in the regeneration of nitrogen and phosphorus in the ocean through grazing and metabolism. This study investigates the role of the organic and inorganic nitrogen and phosphorus compounds released by copepods on biogeochemical processes and on the microbial community composition during the OUTPACE cruise (18 February–3 April 2015) at three long duration stations (LD). Two LD stations were located in the Melanesian Archipelago region (MA; LD A and LD B) and one in the South Pacific Gyre (SG; LD C), which represent oligotrophic and ultraoligotrophic regions respectively. At each station, microcosm onboard experiments were performed with locally sampled organisms, comprising a mix of epipelagic copepods fed with their natural food and then incubated along with wild microbial assemblages. In presence of copepods, ammonium and dissolved organic nitrogen showed a significant increase, compared to a control in two situations: in ammonium concentration (increasing rate: 0.29 μmol L−1 h−1 after 4 h of incubation) in LD C and in dissolved organic nitrogen concentration (rate: 2.13 μmol L−1 h−1 after 0.5 h of incubation) in LD A. In addition, during the three experiments, an enhanced remineralization (ammonification and nitrification) was observed when adding copepods compared to the controls. A shift in the composition of active bacterial community was observed for the experiments in LD A and LD B mainly characterized by an increase in Alteromonadales and SAR11, respectively and linked with changes in nutrient concentrations. In the experiment performed in LD C, both groups increased but at different periods of incubation, Alteromonadales between 1 and 2 h after the beginning of the experiment, and SAR 11 at the end of incubation. Finally, our experimental results in near in situ conditions, show that copepods can be a source of organic and inorganic compounds for bacterial communities, which respond to excretion pulses at different scales, depending on the initial environmental conditions and on their community composition. These processes can contribute significantly to nutrient recycling in the epipelagic ecosystem of ultra and oligotrophic oceanic regions.

Full Text
File Pages Size Access
Discussion paper 29 5 MB Open access
Supplement to the discussion paper 12 6 MB Open access
Final revised paper 14 5 MB Open access
Supplement to the final revised paper 13 6 MB Open access
Top of the page

How to cite 

Valdés Valentina, Carlotti François, Escribano Ruben, Donoso Katty, Pagano Marc, Molina Veronica, Fernandez Camila (2018). Nitrogen and phosphorus recycling mediated by copepods in Western Tropical South Pacific. Biogeosciences, 15(20), 6019-6032. Publisher's official version : , Open Access version :