Influence of a tropical cyclone on Chlorophyll-a Concentration in the Arabian Sea

Inter-annual and seasonal variability in the nutritional parameters of the edible portion of skipjack tuna (Katsuwonus pelamis) collected from the Arabian Sea were determined for a period of 4 years. Greater levels of long chain n-3 fatty acids (35% during pre-monsoon), critical in the human diet for their anti-inflammatory properties with greater n-3:n-6 fatty acid ratio (8:12) demonstrated that this species may serve as an alternative to balance the greater amount of n-6 fatty acids. The present study demonstrated skipjack tuna as a significant source of protein, amino acids, minerals and vitamins. A balanced essential to non-essential amino acid ratio (1.2:1.4) in the fillets indicated that this species could provide well-balanced protein depositions. Vitamins A and K1 demonstrated post-monsoon maxima, whilst vitamins D3 and E showed pre-monsoon maxima. Greater calcium (172 mg 100 g−1) and phosphorus contents (923 mg 100 g−1) were recorded in the fillets of skipjack tuna during the pre-monsoon season. The chlorophyll-a concentration and sea surface temperature of its habitat were considered to understand their effect on the nutritional composition of skipjack tuna all through the study period. Significant correlation between long chain n-3 polyunsaturated fatty acids such as eicosapentaenoic acid and docosahexaenoic acid (r2 ~ 0.99) of skipjack tuna alongside chlorophyll-a concentration was observed, particularly during the monsoon. The lesser atherogenic/thrombogenicity indices (<1), greater hypocholesterolaemic/hypercholesterolaemic ratio (>1.0), and lesser cholesterol contents (<50 mg 100 g−1) of the fillets in skipjack tuna contributed towards its parameters to be qualified as a high value, balanced nutritional source.

Download Full-text

Projected climate change in the South Asia and northern Indian Ocean by the end of the 21st century as obtained from a Regional Earth System Model

10.5194/egusphere-egu21-11989 ◽

2021 ◽

Author(s):

Anton Yu. Dvornikov ◽

Dmitry V. Sein ◽

Stanislav D. Martyanov ◽

Vladimir A. Ryabchenko ◽

Pankaj Kumar

Keyword(s):

Chlorophyll A ◽

Bay Of Bengal ◽

Arabian Sea ◽

Future Climate ◽

System Model ◽

Earth System ◽

Chlorophyll A Concentration ◽

The Future ◽

Continental Runoff ◽

The Ganges

Detailed atmospheric, ocean physical and biogeochemical characteristics for the period 2015-2100 within the South Asia CORDEX domain have been obtained from simulations of the Regional Earth System Model ROM.Comparative analysis of average climatic characteristics for the past (1975-2004) and future (2070-2099) climates has been carried out. It shows significant future SST increase, reaching 3&#186;C on average, over the considered area. The salinity of the ocean's upper layer will decrease by 1 &#8240; on average, which indicates a change in the precipitation-evaporation balance in the future climate. The simulated annual MLD will decrease by 5 m in the future. However, this MLD change will be strongly irregular, both in time and space. Simulations also show a widespread decrease of the chlorophyll-a concentration in the surface layer (up to 2 mg Chl m-3) in the future, especially pronounced in the northern and western parts of the Arabian Sea. It is a significant change, given that absolute chlorophyll-a concentration in these areas is typically 3-4 mg Chl m-3 in spring and 5-8 mg Chl m-3 in summer, as obtained for the 1975-2004 model run. The model also shows that the chlorophyll-a concentration at the surface will decrease by 1&#8211;2 mg Chl m-3 along the western coast of the Bay of Bengal in the future. The relative decrease in the surface chlorophyll-a concentration will be about 40% in the future climate in the Arabian Sea and the Bay of Bengal.The model solution according to the SSP5-8.5 scenario shows a decrease in the amount of precipitation in the future climate (up to 3-4 mm/day) over the northeastern part of India and over Nepal in summer. But over the central part of India, in the Andaman Sea, over Thailand and Myanmar, there will be an increase in the amount of precipitation. The total continental runoff into the Bay of Bengal will increase, but the runoff in the Ganges delta will be greatly weakened. Thus, despite the decrease in the runoff of the Ganges and Brahmaputra rivers, the total continental runoff into the Bay of Bengal turns out to be higher in the future climate (2070-2099) relative to retrospective calculations (1975-2004) due to the runoff of smaller rivers.&#160;Acknowledgements: This work is funded by Russian Science Foundation (RSF, Project 19-47-02015) and Department of Science and Technology (DST, Govt. of India, grant DST/INT/RUS/RSF/P-33/G). The research was performed in the framework of the state assignment of the Ministry of Science and Higher Education of Russia (theme No. 0128-2021-0014). This work used resources of the Deutsches Klimarechenzentrum (DKRZ) granted by its Scientific Steering Committee (WLA) under project ID ba1144.

Download Full-text