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Project "Bathypelagic" is a join effort from the "Institute of Oceanography and Global Change (IOCAG)", the "Institute of Intelligent Systems and Numeric Applications in Engineering (SIANI), both at the University of Las Palmas de Gran Canaria (Canary Islands), the "Institute of Marine Sciences (ICM-CSIC)" of Barcelona, the "Spanish Institute of Oceanography (IEO)" at Baleares and A Coruña, and the University of Cádiz (UCA). Below is the project abstract.
Sequestration, in contrast to export, is a mechanism of the
biological pump in the ocean occurring when carbon cannot return to the
atmosphere in at least 100 years, normally the carbon transported below 1000 m
depth. Particulate organic carbon is remineralized on its way through the water
column by prokaryotes and pelagic fauna. A fraction of these animals are
vertical migrants feeding at shallow ocean layers and releasing carbon at depth
through respiration, defecation, excretion, molting, lipid consumption and
mortality, also supporting deep-sea food webs. Knowledge about this transport
in the mesopelagic layer is growing. However, the role of the pelagic fauna to
fuel the bathypelagic zone, the layer where effective carbon sequestration
occurs, is largely unknown. Here we propose to study this flux based on a
review of zooplankton biomass in the epi-, meso- and bathypelagic zones, as
obtained by net samples, showing a relationship with primary production, and
denoting carbon transport to deeper layers. Carbon sequestration assessed only
from conservative estimates of zooplankton mortality in the 1000-2000 m layer
was in the order of recent estimates of passive carbon sequestration. These
estimates were also correlated with large-scale estimates of primary
production, implying the transference of a significant fraction of primary
production from the epipelagic to the deep ocean. These results point at a
pivotal role of the pelagic fauna in carbon sequestration as other mechanisms
of active flux (respiration, defecation, lipid consumption and excretion) by
zooplankton and micronekton, including deeper layers (>2000 m depth), should
also be considered. The objective of this project is to assess gut,
respiratory, lipid and excretory fluxes below the permanent thermocline.
Preliminary results raises the question of whether an enrichment in the upper
layers is transported downward, and whether we are heavily underestimating
carbon sequestration in the ocean. The assessment of active flux through the
bathypelagic jointly with passive flux will produce for the first time complete
values of carbon sequestration in the ocean.
