A subsurface particle maximum layer and enhanced microbial activity in the secondary nitrite maximum of the northeastern tropical Pacific Ocean

Abstract

Profiles of light transmission, disolved oxygen, disolved nutrients,electron transport system (ETS) activity, temperatura and salinity were made in the north Eastern tropical Pacific Ocean. A particle máximum at 150-300 m within the oxygen mínimum and secondary nitrite máximum was associated with the salinity máximum of Subtropical Subsurface Water. A subsurface máximum in ETS activity was als ofound to be associated with the secondary nitrite máximum and the particle maximum. Persistence of these features at a constant depth and their location within a minimum in vertical static stability suggest an advective and/or in situ origin for the particles and an in situ development of the associated chemical and biochemical extremes.