Table of Contents
Journal of Ecosystems
Volume 2014, Article ID 152473, 8 pages
Research Article

A New Trophic State Index for Lagoons

1Earth Sciences and Hydrology Division, Marine and Earth Sciences Group, Remote Sensing Applications and Image Processing Area, Space Applications Centre, Indian Space Research Organization, Ahmedabad, Gujarat 380 015, India
2Centre for Earth Observation Science, Department of Environment and Geography, Clayton H. Riddell Faculty of Environment, Earth, and Resources, University of Manitoba, 463 Wallace Building, Winnipeg, MB, Canada R3T 2N2

Received 27 December 2013; Revised 27 January 2014; Accepted 28 January 2014; Published 9 March 2014

Academic Editor: Wen-Cheng Liu

Copyright © 2014 Mukesh Gupta. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This paper proposes a new nitrogen-based trophic state index (TSI) for the estimation of status of eutrophication in a lagoon system. Nitrite-nitrogen (NO2-N) is preferable because of its greater abundance in Chilika lagoon and its relation to other criteria of trophic state, for example, chlorophyll-a (Chl-a) and Secchi disk depth (SDD). Nitrite is preferable over nitrate because the former decreases the fluorescence and affects photosynthesis, thereby controlling primary production. This paper also computes TSI using Chl-a and SDD. The three parameters account for the biological, chemical, and physical characteristics of the lagoon. It will be possible to estimate the TSI of freshwater and brackish water lagoons and other water bodies using the new expressions taking into consideration the spatial and temporal variability in the dataset. Depending on the data availability, alternative TSI (Chl-a) and TSI (SDD) can account for the biological and physical contributions to eutrophication. The estimated TSI can account for Chl-a and NO2-N up to 322.18 mg m−3 and 61.99 μg L−1, respectively. The TSI based on these three parameters can serve as a complimentary and predictive tool for lagoon management and field programs to monitor the health of a lagoon.