Lower prokaryotic leucine incorporation rates under in situ pressure than under decompressed conditions in the deep north Atlantic

LOWER PROKARYOTIC LEUCINE INCORPORATION RATES UNDER IN SITU PRESSURE THAN UNDER DECOMPRESSED CONDITIONS IN THE DEEP NORTH ATLANTIC P oka yo ic ac i i y and communi y composi ion is highly dep h-s a i ied in he oceanic wa e column e lec ing he inc easing ecalci ance o dissol ed o ganic ma e and dec easing empe a u e wi h dep h. The ole o inc easing hyd os a ic p essu e in con olling deep ocean mic obial ac i i y is less well-s udied. To de e mine he in luence in hyd os a ic p essu e on he e o ophic mic obial ac i i y, an in si u incuba o was deployed in he No h A lan ic Ocean a a dep h be ween 500 o 2000 m. The in si u incuba o was p og ammed o collec and incuba e p oka yo es unde he wa e a e adding 3H-leucine and o ix a ce ain olume o he incuba ed samples a speci ic ime in e als (3 o 10 h depending on he dep h). P oka yo ic leucine inco po a ion ob ained unde in si u p essu e condi ions was gene ally lowe han ha on decomp essed samples incuba ed on boa d. Ra ios o in si u p oka yo ic leucine inco po a ion o decomp essed condi ions dec eased wi h inc easing dep h. Ou esul s sugges ha bulk he e o ophic p oka yo ic p oduc ion in he deep sea migh be lowe han expec ed.