Understanding the effect of environmental and climate change on coastal lagoon management

Coastal lagoons are water bodies found along the coastline and are separated from the open sea by spits and sediment barriers with limited points of water exchange. “According to a classification by Kjerfve (1986), there are three types of coastal lagoons based on the number of entrance channels (inlets) and, thus, the degree of water exchange with the ocean: (a) choked, (b) restricted, and (c) leaky. Choked lagoons have only one inlet, which restricts the influence of tidal currents and water level fluctuations in the lagoon. They can be either parallel to the shore or, when associated with river deltas, at a right angle to the shore. Restricted lagoons have two or more inlets and a well-defined tidal circulation, whilst leaky lagoons exhibit numerous inlets and are the most influenced by tidal currents in all three lagoon types. Both restricted and leaky are most usually oriented parallel to the shore.” (Source: Politi et al., 2016)

Coastal lagoons provide a plethora of ecosystem services, such as fisheries, aquaculture, storm protection and tourism (e.g. Newton et al., 2014Rova et al., 2015, Sousa et al., 2016), and as a result they are hotspots of human settlement and activities. Lying at the intersection between land and the ocean, coastal lagoons are influenced by both land input (e.g. nutrients, runoff, river management activities) and interaction with the sea (e.g. tides, sea pollution, erosion, storm surges and sea level change). Such dynamic systems are highly sensitive to environmental and climate change, but our understanding of how lagoons respond to change globally is limited. Sea level rise already threatens shallow coastal lagoons such as the Venice Lagoon (UNESCO, 2011) and a plethora of pressures and drivers of change in lagoons, often with direct implications for societal well-being, have been identified (Newton et al., 2014).

Improving our understanding of how lagoons respond to change at local, regional and global scales is necessary to sustainably manage these ecosystems, and the ecosystem services they provide, and assess the socio-environmental implications of future development (Abigail et al., 2009). Having recognised a data and knowledge gap in the systematic study of coastal lagoons, we propose to establish a Lagoons Forum that will study those vulnerable ecosystems holistically, by integrating environmental, social and economic datasets from multiple sources. Through linking with international experts, stakeholders, researchers and scientists, we aim to co-design lagoon management strategies that address current and future issues in coastal lagoon ecosystems and their ecosystem services.