Assessing the P fractionation in a tropical river-estuarine system of South India

• Published in: Chemistry and ecology Vol. 26; no. 6; pp. 453 - 466
• Main Authors: Padma, P., Nair, S. M.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 01-12-2010; Taylor & Francis Ltd
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Brackish; Ca-bound P; Ecotoxicology, biological effects of pollution; Fe/Al-bound P; Fractionation; Fresh water ecosystems; Freshwater; Fundamental and applied biological sciences. Psychology; General aspects; Marine; nutrient; phosphorus; riparian vegetation; Synecology; Asia; India; India, Kerala, Chalakudy R; ISW, India, Kerala; Brackish water environment; fractionation; Tropical zone; Estuaries; Phosphorus; Rivers; Climatic zone; Fe/Al-bound P; Freshwater environment; Aquatic environment; Ca-bound P; riparian vegetation; Riparian; Vegetation; Nutrient; Stream
• ISSN: 0275-7540; 1029-0370
• DOI: 10.1080/02757540.2010.512009

Seasonal variations in dissolved and particulate P forms were assessed in the estuarine system of Chalakudy River, Kerala, South India - a tropical river having substantial relics of riparian vegetation. The contribution of the reactive P form extended to 84-96% compared with the residual fraction. Geographical and human activities have had effects on the phosphorus-loading capacity at various locations, which reveal pronounced variability in P distribution. Not all forms of phosphate in suspended particulate matter are likely to be released, and thus the nature of the P forms within the stock is a sensitive factor that can be utilised. Ca-bound P in suspensates increases to a highly significant level in the estuarine area, whereas Fe/Al-bound P predominates at the riverine and catchment areas during both the monsoon and non-monsoon seasons. Thus, calcium compounds determine the availability of P in the alkaline estuarine environment, whereas in the riverine environment, Al and Fe control P solubility. The comparatively low P load in upstream waters indicates that, under ambient situations, vegetative riparian zones can be very important P filters.