Samplesofdeep-oceanwater(3170m)takenfromtheRockallTrough(North-EastAtlantic)were
incubatedforone-monthatatmosphericand in-situ pressure(31MPa),at4 1C andintheabsenceand
presence ofaddednutrients.Prokaryoticabundance(directcellcounts)increasedbyatleast28-foldin
enrichmentswithoutaddednutrients.However,themagnitudeofincreaseinabundancewaslessfor
incubationscarriedoutat in-situ pressure(131–181-fold)thanthoseincubationsatsurfacepressure
(163–1714-foldincreaseinabundance).