- Dona Paula, Goa, India.
- +91-0832- 2450327
- iiosc2020[at]nio[dot]org
| Abstract Submission No. | ABS-2022-05-0174 |
| Title of Abstract | Distribution of dissolved zinc in the Indian Ocean: Implications to their sources, sinks and internal cycling |
| Authors | Venkatesh Chinni*, Sunil Kumar Singh, Naman Deep Singh |
| Organisation | CSIR-National Institute of Oceanography |
| Address | NIO Colony Dona Paula, Goa, India Pincode: 403004 Mobile: 9173272696 E-mail: venkateshchinni19@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | Zinc (Zn) is an essential micronutrient influencing marine phytoplankton growth and hence plays a significant role in controlling the primary production and hence the carbon cycle. The bioavailability and internal cycling of dissolved zinc (dZn) and its dissemination in the oceans is regulated by the numerous physico-bio-geo-chemical processes. In this study, the biogeochemical cycling of dZn has been investigated in the Indian Ocean with an unprecedented data set from several GEOTRACES-India section cruises. The dZn vertical profiles in the study region display a typical nutrient type behavior and showed a good linear relationship with silicic acid (hereafter Si) consistent with the other oceanic basins. Interestingly, the dZn/Si is significantly different between the productive (i.e., northern Indian Ocean) and oligotrophic regions of the Indian Ocean, with significantly lower value in the northern Indian Ocean controlled mostly by the dZn distribution in the oxygen minimum zone. Dissolved Zn could be lost via sulfide precipitation or its biological uptake and subsequent release in the oxygen deficient waters of the northern Indian Ocean might be having a profound impact on Zn biogeochemical cycle in this region. Resuspension of sediments could be an important source of Zn along the Indian continental margins. Hydrothermal activity does not seem to play an important role in dZn budget of the Indian Ocean. The estimated Zn:C remineralization ratios from our data set is comparable with the published Zn:C uptake ratios of the phytoplankton community in the Indian Ocean. The preliminary estimates suggest upwelling and horizontal advection/diffusion processes exert dominant control on dZn budget in the Arabian Sea compared to atmospheric input which are balanced by the biotic and abiotic removal processes. The first geochemical budget estimate for dZn in this region provides residence time for Zn in photic waters of the Arabian Sea in the range of 0.3-0.9 years. |