01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-08-0197 |
| Title of Abstract | Three Decades of Ecosystem Change and Plankton Community Dynamics in Kuwaiti Waters: Time-Series Insights from the Northwestern Arabian/Persian Gulf, a Marginal Sea of the Indian Ocean |
| Authors | Rakhesh Madhusoodhanan*, Turki Al-Said, Loreta Fernandes, Takahiro Yamamoto, Ayaz Ahmed, Jessy Sebastian, Waleed Al-Zekri, Maryam Al-Enezi, Faiza Al-Yamani |
| Organisation | Kuwait Institute for Scientific Research |
| Address | Salmiya Block 2 Salmiya, Hawally, Kuwait Pincode: 20002 E-mail: rmdhanan@kisr.edu.kw |
| Country | Kuwait |
| Presentation | Oral |
| Abstract | Kuwaiti waters in the north-western Arabian/Persian Gulf (NWAG) are among the most environmentally stressed marine systems, shaped by extreme hydrographic variability and chronic human pressures. For more than three decades, the Kuwait Institute for Scientific Research (KISR) has conducted extensive time-series oceanographic monitoring across Kuwait Bay and adjacent coastal and offshore waters, creating the first long-term dataset from the Gulf for evaluating decadal changes in water quality and ecosystem productivity. This study examines salinity, silicate, and total chlorophyll a (Chl a) from 1995 to 2022, alongside the size structure of phytoplankton (2007⿿2017) and microzooplankton (tintinnid ciliates; 2003⿿2015), to assess how hydrographic and nutrient dynamics affect productivity and plankton community structure. Over this period, progressive salinity increase, driven by reduced freshwater inflow and upstream damming, coincided with marked declines in silicate and other nutrient inputs from the Shatt Al-Arab River (SAR), disrupting the Si:N:P balance and reducing large microphytoplankton production. Total Chl a trends varied spatially: consistent decline near the SAR mouth (St. A), modest increases within Kuwait Bay (St. 4) and outside the Bay (St. 6), and stability offshore (St. 18). Size-fractionated Chl a indicated a shift toward smaller phytoplankton (0.4⿿5 µm) and reduced microphytoplankton (>50 µm). Tintinnid data similarly showed smaller ciliates, consistent with salinity rise and nutrient limitation. Episodic rainfall in 2019⿿2021 temporarily lowered salinity, increased nutrient availability, and partially reversed phytoplankton size shifts at coastal and mid-shelf sites. Findings demonstrate that reduced SAR inflow has fundamentally altered NWAG hydrography and nutrient regimes, with elevated salinity and nutrient decline driving long-term shifts toward smaller plankton cells, weakening diatom-based production, altering trophic pathways, and increasing ecosystem vulnerability. These changes have implications for food-web efficiency, fisheries productivity, and marine food security. Sustained time-series monitoring and adaptive management are vital to protect ecosystem resilience under intensifying pressures. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Hypersaline system, Salinity rise, Nutrient limitation, Plankton size-structure, Damming effect, Marine food security |
| For Awards | no |