Particulate organic matter : Vector for carbon export, indicator for aquaculture impact and microbial hotspot

Abstract

Marine particulate organic matter (POM) can serve as vector for carbon (C) export, indicator for aquaculture impact and microbial hotspot: Off NW Africa, upwelling stimulates primary production. Despite the importance of bacteria for the biological C pump (BCP), little is known about bacterial communities (BCC) off NW Africa. Hence, the first objective is the description of the free-living (FL) and particle-attached (PA) BCC off NW Africa and potential key players in C degradation. Results reveal high relative abundances of C degrading bacteria, suggesting their key role in POM turnover. Aquacultures in the tropics are often accompanied by eutrophication and high POM loads. In Bolinao, Philippines, recurring hypoxia leads to major fish kills. So far POM characteristics have not been quantified. Results indicate the aquaculture activities in POM characteristics, rendering them ideal indicators for aquaculture impact. Overall, the results advance our understanding of the BCP and biogeochemical processes on aquaculture-derived POM. Furthermore, they indicate how processes occurring on the microscale are relevant for current global challenges