Friday, December 13, 2013

Coral Reefs and Mangrove Swamps

The 2004 tsunami and an El Nino event in summer 2010 resulting in warming of the ocean temperature caused loss of coral reefs due to uprooting, bleaching from the warmer waters, and sedimentation. This included impacts to the rich coral reef ecosystems around the Andaman Islands. The entire Andaman-Nicobar Island archipelago is home to 6,540 documented species of animals and 2,500 species of plants--this provides a sense of the biological significance of the region. Although all wildlife are protected in India, natural disturbances, poaching, mining, development, irresponsible and rising tourism, and resulting sedimentation and pollution are contributing to the loss of biodiversity.
Dead coral exposed at low tide--the coral is dead,
but other sea life still lives on and in coral crevasses.
Despite human encroachment and impacts, the natural ecosystems in the Andaman Islands, are still relatively intact. DIVEIndia, where we stayed on Havelock Island, offers courses and fun dives to explore the coral reefs. My impression was that they are ecological conscience and practice techniques that protect these diverse and sensitive coral habitats. Only people there to dive can stay in one of the nine or so tent cabins.
The entrance to DIVEIndia
The scuba gear, rinsed and drying after a dive
A couple of the DIVEIndia Boats, moored off-shore from the dive shop
I had planned to snorkel instead of dive, as I experience some claustrophobia and wasn't sure how I'd handle being underwater with a mask over my eyes and nose and an oxygen regulator in my mouth. Srini's nephew Sidharth talked us through the use of the equipment and the proper techniques. We practiced in the boat on the way to the dive site, then in shallow water, then he took us under. I was amazed and surprised at how comfortable I was once under water and swimming around among the coral and colorful fishes and other sea life. When my head was above water I couldn't tolerate the mask and regulator very long. But underwater the sense of claustrophobia mostly dissipated.

The day we dived the surface was a little rough and therefore undersea was also a bit turbid. Still, we saw plenty of amazing creatures and I enjoyed my first scuba dive. I found the hardest part of diving to be equalizing my ear pressure. As you dive deeper you must relieve the pressure, closing mouth, pinching nose, and blowing nose softly. This is one of the most important steps to do every few feet on the descent. According to Sidharth, my guide, we went down 9 meters, about 25 feet--wow!

One morning on Havelock we took a two-hour kayak tour of mangrove-lined creeks not far from the main jetty. Our energetic and instructive tour guide Tanaz, seems to line up clients through word of mouth via a handful of the local resorts.

The dense stands of mangrove provide a buffer to the mainland--preventing erosion, filtering sediment, releasing nutrients, providing nursery sites for fish and crustaceans. The most common species was red mangrove (Rhizophora mangle). The seeds or propagules grow into mature plants before dropping into the water and eventually take root. The fully grown plants rise above the water on prop roots.
Once we got into the narrow mangrove-lined channels, we heard few sounds except for the slap of water as we dipped our paddles.

We had too little time to explore the rest of Havelock Island--either in the water or on land. A few interesting creatures crossed our paths on our walkabouts including a small house gecko hiding on in a lamp.
A common lizard hung out on one of the trees next to our tent.
And of course all the hermit crabs that I just could not get enough of.

No comments:

Post a Comment