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Bacterial response to dust pulses in the western Mediterranean: Implications for carbon cycling in the oligotrophic ocean
Author(s) -
PulidoVillena Elvira,
Wagener Thibaut,
Guieu Cécile
Publication year - 2008
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2007gb003091
Subject(s) - mediterranean climate , mineral dust , bacterioplankton , environmental science , carbon cycle , mediterranean sea , environmental chemistry , mixed layer , bloom , nutrient , oceanography , heterotroph , cycling , atmospheric sciences , chemistry , ecology , bacteria , aerosol , biology , phytoplankton , ecosystem , geology , geography , genetics , organic chemistry , archaeology
The bacterial response to dust pulses was investigated in the Mediterranean Sea through a combined field and experimental study. During the stratification period, characterized by a nutrient‐starved mixed layer isolated from the depth, a Saharan dust event (2.6 g m −2 ) induced a 1.5‐fold increase in bacterial abundance (BA) and a 2‐fold increase in bacterial respiration (BR). Experimental dust additions (equivalent to fluxes of 5 and 20 g m −2 ) to bacteria natural assemblages also stimulated BA (between 2‐ and 4‐fold increases) and BR (between 1.5‐ and 3‐fold increases). Pooling the in situ and experimental data, linear relationships were obtained between dust concentration and BA (r 2 = 0.86; p < 0.01) and BR (r 2 = 0.89; p < 0.001). The dust‐induced bacterial bloom resulted in a C mineralization of 0.5 g m −2 , which may represent up to 70% of bioavailable DOC annually exported to the depth in the Mediterranean. These results demonstrate that heterotrophic bacteria may play a much larger role in the connections between dust and the ocean carbon cycle than previously recognized and highlight the need for a more accurate understanding of how dust pulses may affect C export in the oligotrophic ocean.