ABSTRACT: Coastal lagoons are natural features of the coasts of all continents consisting in shallow water bodies that are continuously or intermittently connected to the sea. They are typically characterized by significant inputs of nutrients and particulate organic matter of continental origin that can sustain high rates of primary production and intense biogeochemical fluxes. Several kinds of lagoons can be distinguished depending on the extent of their water exchange with the nearby sea. The most confined ones show low hydrodynamism and proper chemical-physical properties, and they may experience peaks of primary production that, especially if co-occurring with poor mixing regimes, lead to oxygen depletion in sediments and bottom waters, occasionally extending to the entire water column. Relatively deep coastal lagoons can also undergo chemical and physical water column stratification, with a normally oxygenated upper layer that is separated from bottom anoxic (and sulfidic) waters by a ‘chemocline,’ which harbors distinctive microbial communities featuring a variety of energy metabolism pathways.
Due to their good accessibility, favorable morphology and high trophic state, confined coastal lagoons are perfect locations for economic activities such as finfish and shellfish farming and provide valuable ecosystem services. On the other hand, these lagoons are often heavily subjected to anthropic impacts and stressors that may cause persistent pollution and eutrophication. Furthermore, similarly to other transition zones, coastal lagoons are widely recognized as being particularly susceptible to the effects of climate change. For this reason, and due to the human-mediated introduction of alien species, some of them can turn into enclaves for species from distant biogeographical areas.
Coastal lagoons are thus extraordinary habitats where fluxes of energy and materials occur at high rates, and are often characterized by peculiar biological communities, besides being unique points of contact between hydrosphere, lithosphere and anthroposphere. Nevertheless, they are also sensitive and vulnerable ecosystems, highly impacted by human activities and lacking the considerable buffering potential of pelagic regions, with a consequential high risk of environmental collapse.
Saccà A. (2016). In book: Coastal Lagoons - Geology, Characteristics and Diversity, Chapter: 1, Publisher: Nova Science Publishers, Inc., New York, USA, Editors: Carole Snyder, pp.1-23
Due to their good accessibility, favorable morphology and high trophic state, confined coastal lagoons are perfect locations for economic activities such as finfish and shellfish farming and provide valuable ecosystem services. On the other hand, these lagoons are often heavily subjected to anthropic impacts and stressors that may cause persistent pollution and eutrophication. Furthermore, similarly to other transition zones, coastal lagoons are widely recognized as being particularly susceptible to the effects of climate change. For this reason, and due to the human-mediated introduction of alien species, some of them can turn into enclaves for species from distant biogeographical areas.
Coastal lagoons are thus extraordinary habitats where fluxes of energy and materials occur at high rates, and are often characterized by peculiar biological communities, besides being unique points of contact between hydrosphere, lithosphere and anthroposphere. Nevertheless, they are also sensitive and vulnerable ecosystems, highly impacted by human activities and lacking the considerable buffering potential of pelagic regions, with a consequential high risk of environmental collapse.
Saccà A. (2016). In book: Coastal Lagoons - Geology, Characteristics and Diversity, Chapter: 1, Publisher: Nova Science Publishers, Inc., New York, USA, Editors: Carole Snyder, pp.1-23
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