Mesozooplankton Biomass Measured during the JGOFS Equatorial Pacific Process Study

The Equatorial Pacific Process Study (EQPAC) was conducted along 140 deg W
longitude during 1992.

Four cruises took place: February 3 - March 9, March 19 - April 15,
August 5 - September 18, and September 24 - October 21. A fifth benthic
cruise and sediment trap legs were added. During the first cruise
(TT007), 15 stations were occupied along 140 deg W longitude from
12 deg N latitude to 12 deg S latitude. During the second cruise
(TT008), data were collected at 8 stations along 140 deg W longitude
from 9 deg S latitude to 9 deg N latitude. During the third cruise
(TT011), data were collected at 15 stations along 140 deg W from 12 deg N
latitude to 12 deg S latitude. During the fourth cruise (TT012), data were
collected at 5 stations along 140 deg W longitude from 17 deg S
latitude to the equator.

Mesozooplankton greater than 64 microns were collected from
day/night pairs of tows with a 0.25 square meter mouth area MOCNESS
equipped with 9 nets with 7:1 mouth:length ratio. Sensors on the
MOCNESS measured fluorescence, temperature, conductivity, depth, frame
angle, volume filtered, and net closing response at 1-s intervals.
Oblique tows were taken from 1000m (deep tows) or 200m (shallow tows)
to the surface at an angle of 45 degrees. Eight depth strata were
sampled per tow.

The contents of each net was wet-sieved to yield four different
size classes of mesozooplankton: 2.0-1.0 mm, 1.0-0.5 mm, 0.5-0.2 mm,
and 0.2-0.064 mm. The size classes were filtered and dried, and
organic carbon and nitrogen were measured on a CHN analyzer. Biomass
for each size class and total biomass for all fractions are reported
in mgC/m^3.

The data is public domain and can be retrieved on-line at
"http://usjgofs.whoi.edu/jg/dir/jgofs/"

[The information in this summary was taken from the JGOFS
World Wide Web pages.]