Diversity and abundance of planktonic communities in the deep waters off the galician coast (NW Spain)

DIVERSITY AND ABUNDANCE OF PLANKTONIC COMMUNITIES IN THE DEEP WATERS OFF THE GALICIAN COAST (NW SPAIN). Plank onic communi ies play pi o al oles wi hin ma ine ecosys ems, a ec ing hei s uc u e, unc ioning and se ices. Al hough hey ha e been ex ensi ely s udied in he epipelagic ocean, he knowledge abou hese communi ies in he da k ocean is a he sho . In his s udy, we explo ed pa e ns o abundance and biomass o a wide a ie y o axonomic g oups om he p oka yo es o mesozooplank on in he epi-, meso- and ba hypelagic wa e s o he Galician coas . As expec ed, cilia e and zooplank on abundances a e deple ed in he ba hypelagic wa e s ela i e o abundances o p oka yo es and nano lagella es. The a e o dec ease o zooplank on biomass wi h dep h is wice as ha o p oka yo es and nano lagella es, indica ing ha ela i e con ibu ion o mesozooplanc on o he o al plank on biomass dec eases wi h dep h. O e all, he di e si y o p oka yo es in he da k ocean is almos as high as in he epipelagic laye , al hough he phylo ypes a e di e en . The majo ac ion o epipelagic cilia es belongs o allo ica e gene a, whe eas in innids domina e he deep cilia e popula ions. Small copepods we e dominan in he epi- and meso-pelagic zone. By con as , o amini e ans, big copepods and myc ophic ishes we e mo e abundan in he deep ocean.