| |
| |
|
|
|
|
| |
 |
Biogeochemistry in oligotrophic ocean gyres
|
| |
|
|
The compensation depth in the open ocean
P-M2-04
John F Marra* , Brooklyn College of the City University of New York, Brooklyn, NY. USA
Presenter Email: jfm7780@brooklyn.cuny.edu |
| The depth of the ocean's productive zone is unknown, except by mutual agreement. To address this unknown, I consider optical data from four, north-south, transects from the WOCE Hydrographic Program, two in the Atlantic (A15, A20), and two in the Pacific (P16, P19). The data were collected using a profiling package consisting of a MER2040 (including PAR), a beam transimissometer, and a fluorometer. An attached sampler and bucket sampling allowed two water samples to be collected with each cast. The overall distributions reflect the basin-scale oceanography. For example, in the Pacific, the deep chlorophyll maximum (DCM) (estimated from in vivo fluorescence) rises to shallower depths across the equator, and deepens in the north and south subtropical gyres. The base of the DCM ranges from 120-170 m. If it is assumed that the productive zone includes all autotrophic biomass (see Marra et al., 2014, Deep-Sea Research, 83:45-50), then the euphotic zone in these data extends much deeper than how it is usually specified, that is, the depth of 1% of surface PAR. The bottom of the deep chlorophyll maximum coincides with the depth of 1% of Ed(488). |
|
|
|
|
|
|
|
|