09 Aug CRUISE IN THE COASTAL LACCADIVE SEA: THRIVIKRAMJI
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.