Marine Observation System Along Indian Coast (MOSAIC): a new initiative | POGO

Marine Observation System Along Indian Coast (MOSAIC): a new initiative

The increasing population density and rapid economic growth of the countries surrounding the Arabian Sea and Bay of Bengal make these semi-enclosed seas particularly vulnerable to warming and other anthropogenic influences. A large population in the Indian sub-continent resides in coastal areas and depends on coastal ocean for their food and economy. The human impacts on the coastal ocean in terms of pollution and waste disposals have greatly modified the fluxes of material to the coastal waters. It has already been noticed that nutrients load to the coastal ocean is increasing since past three decades in the South East Asia. Natural processes such as monsoonal winds, fresh water fluxes from rivers and seasonally reversing currents, though have significant intra, inter-annual and decadal variations add to these anthropogenic perturbations and often magnify them. Despite this the Indian coastal region remains largely unexplored and our understanding on this aspect is still primitive. According to an estimate over 400 coastal sites spread, all over the world is experiencing eutrophication and associated coastal hypoxia. The coastal hypoxia along eastern Bay of Bengal has also reportedly intensified in the past few decades. It is, therefore, imperative to monitor various biogeochemical properties over a longer period of time to assess the change and understand the processes responsible for the observed change. At present the Indian Coastal waters do not have reliable time series data to interpret and quantify the changes that might occur due to the anthropogenic activities. To overcome this shortcoming, a comprehensive coastal observation plan has been chalked out which aims to establish Marine Observation System Along Indian Coast (MOSAIC). MOSAIC programme aims to establish six sustained coastal buoy-based automated observatories to monitor water quality parameters, develop understanding of coastal processes, assess the health of the coastal and estuarine waters, use the data for now-casting of water quality all around the coast. The collected data will also be used for model validation, assimilation and forecasting of water quality parameters. The proposed coastal observatory will be in the form of moored buoys housing multiple sensors for meteorological, physical and water quality parameters with real-time data transmission facility. Monthly in-situ sampling will also be carried out at the buoy location to ensure the quality of the sensor data.

 

 

Fig 1: Schematic diagram on objectives and deliverables of MOSAIC programme

 

In order to kick-start the MOSAIC programme and to conduct the preliminary assessment of coastal waters to select appropriate sites for establishing coastal observatories, five expeditions (Table 1) were conducted over the past one and half years in the coastal waters of Bay of Bengal. The sampling was done onboard CRV Sagar Manjusha.

S. No

Cruise No.

Period

1.

SM 13/2017

03 May - 13 May 2017

2.

SM 21/2017

19 October – 02 November 2017

3.

SM 01/2018

20 January – 03 February 2018

4.

SM 09/2018

27 June – 12 July 2018

5.

SM 18/2018

04 November-16 November 2018

 

Table 1. List of cruises conducted under MOSAIC programme

 

 

The scientific objectives of these expeditions were to collect in situ optical and biogeochemical data to conduct survey of the coastal waters in the Bay of Bengal, to understand physical-biological variability and interactions in the coastal waters, to assess the impact of river water discharge on coastal ecosystem and to develop algorithm to derive geophysical parameters for coastal waters. During all the five cruises samples were collected on various physical, chemical and biological parameters at ten transects (Fig 2). Since the proposed coastal observatories will be established close to the coast at 30m water depth, the sampling was done at 30-100 m water depth. The samples are being analysed in the laboratory at INCOIS. The scientific team expect to get some new and exciting insights on the coastal dynamics, optics and biogeochemical interactions.  

Fig 2: Track and sampling location of cruises conducted under MOSAIC programme

 

 

Fig 3: Collage of onboard sampling activities

 

This article was provided by Satya Prakash, Aneesh Lotliker and Balakrishnan Nair T.M., Indian National Centre for Ocean Information Services (INCOIS)

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