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Balakrishnan Nair TM, Sarma VVSS, Lotliker AA, Muraleedharan KR, Samanta A, Baliarsingh SK, Shivaprasad S, Gireeshkumar TR, Raulo S, Vighneshwar SP, Shesu RV, Krishna M, Kumar NK, Naik RC, Joseph S, Annapurnaiah K, Rao EPR, Srinivasa Kumar T. An integrated buoy-satellite based coastal water quality nowcasting system: India's pioneering efforts towards addressing UN ocean decade challenges. J Environ Manage 2024; 354:120477. [PMID: 38417362 DOI: 10.1016/j.jenvman.2024.120477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 02/15/2024] [Accepted: 02/20/2024] [Indexed: 03/01/2024]
Abstract
The Indian coastal waters are stressed due to a multitude of factors, such as the discharge of industrial effluents, urbanization (municipal sewage), agricultural runoff, and river discharge. The coastal waters along the eastern and western seaboard of India exhibit contrasting characteristics in terms of seasonality, the magnitude of river influx, circulation pattern, and degree of anthropogenic activity. Therefore, understanding these processes and forecasting their occurrence is highly necessary to secure the health of coastal waters, habitats, marine resources, and the safety of tourists. This article introduces an integrated buoy-satellite based Water Quality Nowcasting System (WQNS) to address the unique challenges of water quality monitoring in Indian coastal waters and to boost the regional blue economy. The Indian National Centre for Ocean Information Services (INCOIS) has launched a first-of-its-kind WQNS, and positioned the buoys at two important locations along the east (Visakhapatnam) and west (Kochi) coast of India, covering a range of environmental conditions and tourist-intensive zones. These buoys are equipped with different physical-biogeochemical sensors, data telemetry systems, and integration with satellite-based observations for real-time data transmission to land. The sensors onboard these buoys continuously measure 22 water quality parameters, including surface current (speed and direction), salinity, temperature, pH, dissolved oxygen, phycocyanin, phycoerythrin, Coloured Dissolved Organic Matter, chlorophyll-a, turbidity, dissolved methane, hydrocarbon (crude and refined), scattering, pCO2 (water and air), and inorganic macronutrients (nitrite, nitrate, ammonium, phosphate, silicate). This real-time data is transmitted to a central processing facility at INCOIS, and after necessary quality control, the data is disseminated through the INCOIS website. Preliminary results from the WQNS show promising outcomes, including the short-term changes in the water column oxic and hypoxic regimes within a day in coastal waters off Kochi during the monsoon period, whereas effluxing of high levels of CO2 into the atmosphere associated with the mixing of water, driven by local depression in the coastal waters off Visakhapatnam. The system has demonstrated its ability to detect changes in the water column properties due to episodic events and mesoscale processes. Additionally, it offers valuable data for research, management, and policy development related to coastal water quality.
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Affiliation(s)
- T M Balakrishnan Nair
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
| | - V V S S Sarma
- CSIR-National Institute of Oceanography, Regional Centre, Visakhapatnam, 530017, India
| | - Aneesh A Lotliker
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
| | - K R Muraleedharan
- CSIR-National Institute of Oceanography, Regional Centre, Kochi, 682018, India
| | - Alakes Samanta
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
| | - Sanjiba Kumar Baliarsingh
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India.
| | - S Shivaprasad
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
| | - T R Gireeshkumar
- CSIR-National Institute of Oceanography, Regional Centre, Kochi, 682018, India
| | - Susmita Raulo
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
| | - S P Vighneshwar
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
| | - R Venkat Shesu
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
| | - Murali Krishna
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
| | - N Kiran Kumar
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
| | - R Chandrasekhar Naik
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
| | - Sudheer Joseph
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
| | - K Annapurnaiah
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
| | - E Pattabhi Rama Rao
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
| | - T Srinivasa Kumar
- Indian National Centre for Ocean Information Services, Ministry of Earth Sciences, Govt. of India, Hyderabad, 500090, India
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Abdul Azeez S, Gireeshkumar TR, Muraleedharan KR, Vignesh ER, Jaleel AKU, Arya KS, Ravikumar Nair C, Ratheesh R. Factors influencing nearshore hypoxia in the southeastern Arabian Sea: A sensor-based study. Mar Pollut Bull 2023; 197:115696. [PMID: 37897966 DOI: 10.1016/j.marpolbul.2023.115696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 10/30/2023]
Abstract
Seasonal upwelling and the associated incursion of hypoxic waters into the coastal zone is a widely studied topic over different upwelling zones. However, its persistence or variations over short time scales are poorly addressed. The present study, therefore, brings out a first report on hourly variations in the temperature, salinity and dissolved oxygen recorded by an environmental data buoy equipped with sensors, deployed in the nearshore waters of Alappuzha (southeastern Arabian Sea) from April to August 2022. The characteristic feature of the Alappuzha coast is the development of mud banks during the southwest monsoon, providing a tranquil environment suitable for continuous sensor-based measurements when the sea remains turbulent elsewhere. The results showed that despite an advance in the upwelling intensity, there is a significant variation in the oxygen concentration in the study domain on a diurnal scale. In general, the nearshore region was under hypoxia during the first half of the day (00:00 to 12:00 h), which increased steadily to reach normoxic and supersaturated levels during the rest of the day (12:00 to 24:00 h). Statistical analysis showed that winds significantly correlate to the coastal environment's subsurface oxygen concentration. During the morning hours, the wind was weak, and the water column remained stratified over the subsurface hypoxic water layer. The situation changed in the afternoon (12:00 h onwards), as there was a steady increase in the local wind speed (>5 m/s), which was sustained during the rest of the day. A local wind speed >5 m/s can disturb the stratification and enhance the mixing process from 12:00 to 24:00 h. The total kinetic energy of 11.5 J/m3 is the threshold for this oxygen supersaturation. These findings emphasize the role of wind-induced mixing in alleviating coastal hypoxia, highlighting the need for further biogeochemical and ecological investigations into the impacts of alternating oxic-hypoxic conditions in nearshore waters.
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Affiliation(s)
- S Abdul Azeez
- CSIR - National Institute of Oceanography, Regional Centre, 31261, Kochi 682 018, India
| | - T R Gireeshkumar
- CSIR - National Institute of Oceanography, Regional Centre, 31261, Kochi 682 018, India.
| | - K R Muraleedharan
- CSIR - National Institute of Oceanography, Regional Centre, 31261, Kochi 682 018, India
| | - E R Vignesh
- CSIR - National Institute of Oceanography, Regional Centre, 31261, Kochi 682 018, India; Cochin University of Science and Technology, India
| | - A K U Jaleel
- CSIR - National Institute of Oceanography, Regional Centre, 31261, Kochi 682 018, India
| | - K S Arya
- CSIR - National Institute of Oceanography, Regional Centre, 31261, Kochi 682 018, India; Cochin University of Science and Technology, India
| | - C Ravikumar Nair
- CSIR - National Institute of Oceanography, Regional Centre, 31261, Kochi 682 018, India
| | - R Ratheesh
- Geo Sciences Division, Space Applications Centre, ISRO, Ahmedabad, India
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