Many (most) fish in the sea - Publico.es

One study, in which the Superior Council for Scientific Research (CSIC) participates publishes new information on mesopelagic lantern-like fish (Myctophidae) and cyclothonids (Gonostomatidae) living below the photic zone, between 200 and 1000 m depth-from acoustic observations conducted during the circumnavigation of the Malaspina expedition. These fish are the most numerous vertebrates of the biosphere, but also the great unknowns of the open ocean, and that there are gaps in the knowledge of their biology, ecology, adaptation and overall biomass.

During that traveled 32,000 nautical miles during the circumnavigation, scientists Malaspina, a project led by CSIC researcher Carlos Duarte, took steps between 40 ° N and 40 ° S, from 200 to 1,000 meters depth during the day.

These fish are the most numerous vertebrates of the biosphere, but also the great unknowns of the open ocean

“Malaspina has offered us a unique opportunity to evaluate the stock of mesopelagic fish in the ocean. So far our disposal only the data provided by trawling. has recently been discovered that these fish are able to detect network and run, which makes trawling in a biased tool when accounting for biomass, “says Duarte.

Transport of organic carbon

“That the biomass of mesopelagic and therefore also the total biomass of fish is at least 10 times higher than previously thought has important implications in the understanding of carbon fluxes in the ocean and operation so far what we considered ocean deserts “says Xabier Irigoien researcher Azti-Tecnalia and KAUST (Saudi Arabia) and leader of this research.

mesopelagic fish come out at night to the upper layers of the ocean to feed, while day back down to avoid detection by predators. This behavior speeds up the transport of organic matter into the ocean, the engine of the biological pump that removes CO ₂ of the atmosphere, because instead of slowly sinking from the surface, is transported rapidly to 500 and 700 meters deep and is released as feces.

His role in the biogeochemical cycles of ocean ecosystems and global ocean has to be reconsidered

“The mesopelagic fish accelerate the flow to actively transport organic matter from the upper layers of the water column, where most of the organic carbon flux from the sediment particles is lost. Their role in the biogeochemical cycles of ecosystems oceanic and global ocean has to be reconsidered, as it is likely to be breathing between 1% and 10% of primary production in deep water, “says Irigoien.

excretion of material from the surface could partly explain, according to scientists, the unexpected microbial respiration recorded in these deep ocean. Mesopelagic fish act therefore link between plankton and top predators, and have a key role in reducing the oxygen from the depths of the open ocean.

Malaspina expedition is a Consolider-Ingenio 2010 project managed by the CSIC and funded by the Ministry of Economy and Competitiveness. Malaspina comprises about 50 research groups, including 27 research groups, the CSIC, the Spanish Institute of Oceanography, 16 Spanish universities, a museum, research foundation AZTI-Tecnalia, the Spanish Armada, and several Spanish universities. The total funding, which also helped the CSIC, IEO, the BBVA Foundation, AZTI-Tecnalia, several Spanish universities and public research organizations, is about 6 million euros.