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.