Assessment of eutrophication status of two Northern Irish Loughs

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia do Ambiente, perfil Engenharia Sanitária

Coastal eutrophication is a global problem which affects many natural systems and human activities throughout the world. The phenomenon of eutrophication has increased substantially due to human activities. It is caused by excess nutrients and is identified by the emergence of some symptoms. The proposed assessment will address this problem in a more specific way. The Assessment of Estuarine Trophic Status (ASSETS)methodology is going to be performed to two Northern Irish Loughs in order to rank their eutrophication status and allow a comparison with other existing methods. The data available for these systems allowed the implementation of this innovative methodology, which can provide a classification based on pressure, state and response. Thus, by considering the influences of anthropogenic activities over the coastal areas, examination of specific symptoms of the water systems and analyzing the indicators for future response, it is possible to achieve consistent results regarding the quality of the water in the “loughs” and, consequently, identify the most adequate tools to enable their proper management. By controlling the nutrient enrichment of coastal areas it is possible to avoid problems, such as, fish kills, interdiction of shellfish aquaculture, loss or degradation of sea grass beds and smothering of bivalves and other benthic organisms. As a result, many social and economical costs can be reduced. ASSETS was successfully applied to both Strangford Lough and Belfast Lough, classifying them as “Moderate”. This classification will not change their water quality status under the Water Framework Directive, Urban Wastewater Treatment Directive or Nitrates Directive, however, it is a tool to guide policy makers into better decisions in terms of future management.