Shifting phytoplankton diversity at Sunderbans is an early sign of climate change

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Researchers in India has found a low abundance of a temperature sensitive phytoplankton Ceratium symmetricum at the estuaries and offshore of Sunderbans Biosphere Reserve. The change, which is triggered by the rise in the temperature of the surface water can be an early sign of climate change affecting the mangrove ecosystem of Sunderbans, says the study.

Ceratium symmetricum
Photo Courtsey: JOTT

Phytoplankton are minute photosynthetic aquatic organism floating on the water surface as a green discoloration of the water surface. Being primary producers, they are the foundation of a marine food web by offering food to fishes and other aquatic organisms.

The study which is the first one to examine the phytoplankton diversity in the Indian side of the Sunderbans, has assessed the presence of genus Ceratium Schrank in connection with physicochemical parameters such as Sea Surface Temperature (SST) in the estuaries of the Hooghly and Ichamati-Raymongal Rivers on the western parts of the Sunderbans.

Phytoplankton as bio-indicators

Phytoplanktons are known for their bio-indicator capabilities since any slight change in water temperature or the environment make big difference in their abundance. Members of Ceratium genus are especially known for their sensitivity towards temperature.

The research team has identified 5 species of phytoplankton from the genus - Ceratium trichoceros, Ceratium symmetricum, Ceratium fusus, Ceratium tripos and Ceratium furca- from the water samples. Among them, Ceratium symmetricum was not reported from the area earlier and was found in low abundance. According to earlier studies, low abundance of certain Ceratium species in the surface water during warm period is a sign of change.

To find out a possible cause for it, the researchers have studied the fluctuation pattern of the Sea Surface Temperature with the help of satellite imagery form 2003 to 2009. The data showed that the winter SST has been showing a rising trend in the area, possibly due to climate change.

  

Future Impact

 The lower abundance of Ceratium symmetricum and the rising trend in the winter SST are indicators of climate change affecting Sunderbans, says the study which is published in the latest issue of Journal of Threatened Taxa. It also points out that a further rise in the SST in the area may wipe the Ceratium symmetricum away from the Indian part of the Sunderbans, making it the first organism to take the toll of the climate change and the resulting temperature rise.

Anirban Akhand, Anirban Mukhopadhyay, Pranabes Sanyal and Sugata Hazra from the School of Oceanographic Studies, Jadavpur University, Sourav Maity, Indian National Centre for Ocean Information Services (INCOIS), Indrani Das, Department of Botany, Midnapore College took part in the study.

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Lake Tsomoriri, a crucial Ramsar site under threat from tourism, shows WWF case study

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Drawing stark contrast to the official response at 11th Conference of the Contracting Parties (CoP) to Ramsar Convention taking place in Romania, a WWF case study published by the convention shows that Lake Tsomoriri which is crucial for the breeding of highly threatened Black-necked Crane, Grus nigricollis is under threat from unrestricted tourism activities. 

Lake Tsomoriri
©Pankaj Chandan / WWF-India

The revelation comes at loggerheads to the official report submitted by India to the convention that the condition of Ramsar sites in the country has not changed except some improvements. According to the National Report on the Implementation of The Ramsar Convention on Wetlands submitted by India, there has been no change in the ecological condition of the wetlands in the country, especially Ramsar sites during the last three years. 

“Some of the wetlands have improved in its ecological character through management interventions like Chilka Lake in Orissa by opening up of mouth to allow flushing of saline water which not only helped in increasing fisheries potential, decreasing weeds but also enhanced tourism in the area, directly helping communities to raise their socio-economic status.”, says the National Report on the Implementation of The Ramsar Convention on Wetlands submitted at the convention.

However, according to the case study, the 120 km2 wide lake situated at an altitude of 4595 meters in a critical area in the migration routes of some 40 species of birds is plagued by tourist facilities built around the site without the necessary EIAs. 

Black-necked Crane
©Pankaj Chandan / WWF-India

Moreover, the site known to be the breeding ground of highly threatened birds like Black-necked Crane (Grus nigricollis) and Bar-headed Goose (Anser indicus) is crowded by tourists right during the breeding season. Due to the unplanned tourist activities, “tourism camps have been located in areas where there is a high risk of disturbing wildlife” and “wastes, pollution, and environmental damage are increasing around trekking routes and campsites”, says the study.  

The region which is also supporting rare mammals like Himalayan blue sheep (Pseudois nayaur), Tibetan argali (Ovis ammon hodgsoni), Kiang (Equus kiang), Tibetan Wolf (Canis lupus chanko), Lynx (Lynx isabellina), and Snow leopard (Uncia uncia) has become more accessible with the presence of a metaled road. 

Tourist operators often arrange jeep safari for the tourists which according to the case study, has caused “off-road driving of jeeps over the pastures causing soil compaction and damage to vegetation, reducing productivity, and opening the fragile soils to erosion. There are also reports of jeeps being used to chase kiangs and other species.”

According to an estimate, at least 20,000 tourists, both domestic and foreign, visit the lake in a year, but often the local community of nomadic shepherds called Changpas is not benefitted. Instead, the pastures for their cattle are grazed by horse packs accompanying the tourists, which results in social tension, says the study.

Lake Tsomoriri, 
©Pankaj Chandan / WWF-India

Read more on Ramsar CoP11 coverage by IBT