- Researchers have discovered way to measure the quantity of chlorophyll-a in the Bay of Bengal — a dominant pigment found in phytoplankton cell and present in a few areas of the ocean — in real-time.
- The research was carried out by a team of scientists from the Indian National Centre for Ocean Information Services (INCOIS).
- Phytoplanktons are tiny microscopic plants found in the ocean.
- They are important ecological indicators that regulate life in ocean.
- They have chlorophyll to capture sunlight, and use photosynthesis to turn it into chemical energy.
- They consume carbon dioxide and release oxygen.
- All phytoplankton photosynthesise, but some get additional energy by consuming other organisms.
- Phytoplanktons contribute to more than half of the oxygen that we breathe.
- That apart, they influence our climate by absorbing human-induced carbon dioxide, a heat-trapping greenhouse gas.
- They also serve as the foundation of the aquatic food web.
- The study was based on in-situ and satellite data spanning over the last 16 years.
- They observed significant increase of chlorophyll-a concentration during pre-southwest monsoon seasons.
- The other parameters studied were total suspended matter (TSM) and coloured dissolved organic matter (CDOM), which are optically active substances in water.
- There were two peaks of chlorophyll-a —
- the primary peak occurred during the pre-southwest monsoon due to the recurrent phytoplankton bloom in the coastal water;
- the secondary peak occurred during the end of the southwest monsoon, spreading to far offshore areas.
- Apart from phytoplankton bloom contributing to this increase of chlorophyll-a in nearshore waters, the study found physical forces such as
- upwelling, wind-induced vertical mixing,
- convective overturn and
- Local circulation pattern influenced the peaks by supplying dissolved chemical input from various sources including river / terrigenous runoff.
- Though such trends could tell an overall improved health status of the ecosystems as a whole, they could be detrimental to ocean health because of eutrophication.
- Land run-off that deposits an excess of nutrients from agricultural land to the coastal waters facilitates growth of harmful algal blooms at a large scale.
- These algal blooms deplete the oxygen level in water, disrupting the ocean ecosystem. As a result, oceanic fauna such as fish assemblages are badly affected.
- This leads to decline in fish catch.
- Like terrestrial plants, the eco-friendly phytoplankton is largely dependent on light, temperature and nutrients.
