Linking the Land-based Activities with Ecosystem Dynamics of Pulicat Lagoon in India

The Project

The Global Partnership for Nutrient Management (GPNM), within the framework of the within the framework of the Global Programme of Action for the Protection of the Marine Environment from Land based Activities (GPA), serves as the focal point for United Nations Environment Assembly (UNEA) Resolution on “Sustainable Nitrogen Management” (UNEP/EA.4./ Res.14).

The study “Linking the land based activities with theecosystem dynamics of Pulicat Lagoon in India”aims at identifying potential options for agricultural management surrounding Pulicat Lagoon in India to reduce greenhouse gas emission, nutrient loads and lessen future algal bloom events in the Lagoon.  This SSFA is being implemented as part of the UNEP Programme of Work Project No 522.4 “Protecting the Marine Environment from Land-Based Pollution through Strengthened Coordination of Global Action” under Output C:  Tools, approaches, frameworks, and demonstration projects for enhanced sustainable nutrient managementNCSCM is well placed to undertake this demonstration project, given its prominent role in the development of the UNEA4 resolution on Sustainable Nitrogen Management, which was adopted under the leadership of the Government of India.

Pulicat lagoon is the second largest brackish water lagoon in India after Chilika. It is shared between two states i.e. 1/3rdin Tamil Nadu and 2/3rd in Andhra Pradesh.  Existing environmental issues on the Pulicat lagoon are largely related to changing land use, coastal erosion and siltation, overfishing, bar mouth dynamics related to tidal exchange of seawater and declining biodiversity. Resource extraction has increased in the past few years, resulting in habitat loss and degradation.  The lagoon is further affected by the alteration of flow and water quality through upstream check dams, modification of flow dynamics, and climate-related changes in precipitation patterns resulting in a drastic reduction in freshwater flow to the lagoon. There are several industries located around Pulicat lagoon (including thermal power station), discharging their effluents indirectly into the lagoon. At present, the Buckingham canal also carries domestic sewage and storm water runoff throughout its length. In addition, Agricultural and aquaculture activities in and around the catchment areasactivities contribute significant nutrient and pollutant load to the lagoon and its environment.Under the present scenario, Conservation, management, and restoration of the Lagoon and surrounding areas have become priorityfor its ecological, socio-economic, cultural importance to region. This calls for an immediate assessment of the status of Pulicat lagoon in terms of Small-Scale Funding Agreement (SSFA)

Multifunctional land use is an operational concept to simultaneously plan for and generate ecological, social, and economic benefits. It requires the coordination of land uses and management over a larger area, usually with a range of partners, land owners, and stakeholders.  These kinds of quantitative analyses are important in identifying synergies and trade-offs among alternative land use planning environmental management policies and restoration scenarios. Any alteration in land use (such as conversion of agriculture to aquaculture, forest to barren land, agriculture land to settlement, etc.) may influence the ecosystem synergy and functioning. These changes in ecosystem dynamics can be a result of or can lead to differential nitrogen retention and release, changed water budget and changes in biodiversity.

The overall goal of this study will be to identify potential options for agricultural management surrounding Pulicat Lagoon to reduce greenhouse gas emission, nutrient loads and lessen future bloom events in the Lagoon. Considering the existing land use practices, multiple watershed models will be applied to examine the ability of a series of land management scenarios, developed in consultation with agricultural and environmental stakeholders, to reach the proposed targets. Additionally, existing agricultural practices (selective classes), soil mineralization and net N loss around the Lagoon will be assessed for prioritizing Crop Management to increase Nitrogen Use Efficiency (NUE) and restrict Cultural Eutrophication in Pulicat Lagoon. The study has been conceptualized in following objectives:

  • Identification of key geomorphological features and areas with anthropogenic activities, which may act/ influence nitrogen behavior in Pulicat
  • Assessment of decadal land use changes for assessing areas conversion which may have influenced nitrogen retention, release and losses
  • Quantification of land-based sources and sea-based sources of nitrogen
  • Assessment of nitrogen use efficiency for Pulicat lagoon.
  • Preparation of report card for Pulicat Lagoon

Land use around the Pulicat Lagoon (Source: NCSCM, 2011)



Quantify the biogeochemical controls of Greenhouse gas emissions in pristine and impacted mangrove ecosystems and determine emission inventories.


  • Greenhouse gas emissions from Pristine and Impacted Blue carbon ecosystems

    • Identification of the processes governing emissions in coastal ecosystems through various field-based and laboratory-based measurements
  • Real time exchange of greenhouse gases and energy in mangrove ecosystems

    • Comprehensive understanding of the source-sink characteristics and the degree of biosphere-atmosphere coupling of mangrove ecosystems