Publication Date:
2022-05-26
Description:
Cruise IV of the ANTON BRUUN was planned as a three-month multi-disciplinary
exploration of the Arabian Sea during the fall of 1963.
The interests of applicants for the cruise ranged from chemistry and
microbiology to the taxonomy, distribution, and biochemistry of the
large invertebrates and fishes. In addition, Cruise IV was scheduled
as one of the cooperative cruises with the Bureau of Commercial
Fisheries, U. S. Fish and Wildlife Service, whose personnel had planned
an intensive bottom-trawling program to determine the distribution and
abundance of commercially valuable species of benthic fishes and
invertebrates on the continental shelf around the periphery of the
Arabian Sea.
Because of the broad scope of the program, the large number of
qualified applicants who wished to take part, and the fact that some
of the planned activities were mutually exclusive in terms of
geographical area, shipboard space, etc., it was decided to split
Cruise 4 into two sections, both to work in the Arabian Sea but each
with different objectives, scientific programs, and personnel.
Cruise IV-A included the basic program of hydrography, chemistry,
and plankton biology, with extra sampling time provided for additional
work in chemistry and microbiology. The basic program included 40
hydrographic casts, usually to the bottom, for determination of
temperature, salinity, dissolved oxygen, phosphate, nitrite, nitrate,
silicate, primary productivity, and chlorophyll. Three types of plankton
samples were taken: (1) vertical tows from 200 meters with an Indian
Ocean Standard Net, (2) vertical tows from 200 meters with a
micro-plankton net, and (3) an oblique series from depth intervals of
2000-1000, 1000-500, 500-250, 250-125, and 125-0 meters with the Bé
multiple plankton sampler.
Special studies on Cruise 4A included sampling for dissolved and
particulate organic carbon, dissolved and particulate organic nitrogen,
particulate phosphorus, and particulate iron, dissolved molybdinum,
culture and isolation of nitrifying bacteria, uptake of N15-tagged
atmospheric nitrogen, nitrate, and ammonia, enrichment cultures of
phytoplankton to study limiting factors to their growth, and sampling
for larval and adult scombroid fishes.
Cruise IV-A consisted for the most part of sections from the
central part of the Arabian Sea into and normal to the coast. Because
of time limitations, the work was concentrated in the Western Arabian
Sea.
Cruise IV-B consisted almost exclusively of shallow-water bottom
trawling with a Gulf-of-Mexico shrimp trawl on the continental shelf
from Bombay to Aden. In addition, some dredging, set-lining, handlining,
and dip-netting were carried out. Basic hydrographic stations
were not made on Cruise IV-B but surface and bottom measurements of
temperature, salinity, dissolved oxygen, and phosphate were made
routinely at each trawling station.
Reference is made to U. S. Program in Biology, I.I.O.E., News
Bulletins 5 and 6 (Narrative reports of Cruises IV-A and IV-B) for a
more detailed description of the work accomplished on these two
cruises.
Keywords:
International Indian Ocean Expedition (1960-1965)
Repository Name:
Woods Hole Open Access Server
Type:
Working Paper
Format:
application/pdf
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