CRUISE IN THE COASTAL LACCADIVE SEA.
My boss during 1980-82, Prof. C. Karunakaran (founderDirector, CESS, Trivandrum), quite often made it a point, if and when I was
readying my team in MSD (Marine Sciences Div.) to go for sea-work. My boss,
Prof. CK had a knack of making this poser to me in the Head of Divisions
meeting held once a month in his office.
Well, luck played a very surprising role in this
respect, when the Harbour Engineering Department of the GoK came to CESS to
explore for the type of scientific help with regard to the severe siltation in the boat basin of the Vizhinjam harbor near Trivandrum, I had the first
opportunity to go for seawork.. The siltation in the harbor was triggered right
after the completion of the main breakwater – one covered with tetrapods on the
sea facing side. In order to contain the siltation and erosion of the backshore
coastal hills to the south, and after some model studies, a second EW oriented
breakwater was designed and put in place.
In fact, the Harbours Chief Engineer retained the
CESS (i.e., the MSD) as a consultant on a fee to study the siltation issue,
based on a research proposal developed by us in the MSD. In fact, this study
was very significant locally as this happened to be the first of its type as
far as the organization was concerned.
With me as the leader, I had put together a team
consisting of M/s Suchindan, Terry Machado, Vasudevan et al to be in direct
charge of the project. We had two surveyors on loan from the Harbours department.
The workhorse was S/V. Rocket owned by the ISRO, Trivandrum. This small 18 ft.
single engine boat had no navigation system and usually relied on dead
reckoning. Our own boat driver was asked
to join the cruise as he would be of help chiefly in the deck work, like
casting and retrieving the samples and sampling process. We had a van Veen grab
for collecting bottom sediment. We also retrofitted the boat with a fish finder
category of echo sounder. In fact we were all set to go off land on the cruise.
Then, we based on an approved project, went into the
coastal sea to collect bottom profile data as well as seabed samples at certain
fixed intervals. It was in fact early January, and the sea was calm – ideally
suited for working out of a small boat. It was so clam that water surface
appeared like a sheet of glass to me, with the exception of the evenings when
the sea became kind of choppy – anyway only on our way back to the harbor.
The cruise had covered water depths of 60 to 70 m and
six profiles of 12-16 km each in length and spaced between Poovar in the south
and Varkala in the north. The entire trip was very enjoyable; no one got
seasick; boat worked very well not defying our expectations. The sea exposure
primed the team for more work in the study relating to the siltation of the
Vizinjam harbor as well as in backwaters of Kerala.
One of the important outcomes of the study was
reported in the Indian Journal of Marine Sciences, on the find of “Glauconite ”in the relict sediment at the seabed off Trivandrum. The identification was
purely based on the morphology of the particles of grass grains in the medium
sand fraction of the sediment. Some of the organismic casts were re-designated
as pterapods by Singh. Further P. Rao, basing the results of his mineralogical
investigations re-identified the glauconite grains as a different authigenic mineral.
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