Environmental and biological characteristics of lagoons on the southwest coast of Ireland

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dc.contributor.advisor Jansen, Marcel A.K. en
dc.contributor.advisor Chapman, Deborah en
dc.contributor.author Lettice, Susan Noreen
dc.date.accessioned 2015-08-17T12:26:23Z
dc.date.issued 2014
dc.date.submitted 2014
dc.identifier.citation Lettice, Susan N. 2014. Environmental and biological characteristics of lagoons on the southwest coast of Ireland. PhD Thesis, University College Cork. en
dc.identifier.uri http://hdl.handle.net/10468/1915
dc.description.abstract Coastal lagoons are defined as shallow coastal water bodies partially separated from the adjacent sea by a restrictive barrier. Coastal lagoons are protected under Annex I of the European Habitats Directive (92/43/EEC). Lagoons are also considered to be “transitional water bodies” and are therefore included in the “register of protected areas” under the Water Framework Directive (2000/60/EC). Consequently, EU member states are required to establish monitoring plans and to regularly report on lagoon condition and conservation status. Irish lagoons are considered relatively rare and unusual because of their North Atlantic, macrotidal location on high energy coastlines and have received little attention. This work aimed to assess the physicochemical and ecological status of three lagoons, Cuskinny, Farranamanagh and Toormore, on the southwest coast of Ireland. Baseline salinity, nutrient and biological conditions were determined in order to provide reference conditions to detect perturbations, and to inform future maintenance of ecosystem health. Accumulation of organic matter is an increasing pressure in coastal lagoon habitats worldwide, often compounding existing eutrophication problems. This research also aimed to investigate the in situ decomposition process in a lagoon habitat together with exploring the associated invertebrate assemblages. Re-classification of the lagoons, under the guidelines of the Venice system for the classifications of marine waters according to salinity, was completed by taking spatial and temporal changes in salinity regimes into consideration. Based on the results of this study, Cuskinny, Farranamanagh and Toormore lagoons are now classified as mesohaline (5 ppt – 18 ppt), oligohaline (0.5 ppt – 5 ppt) and polyhaline (18 ppt – 30 ppt), respectively. Varying vertical, longitudinal and transverse salinity patterns were observed in the three lagoons. Strong correlations between salinity and cumulative rainfall highlighted the important role of precipitation in controlling the lagoon environment. Maximum effect of precipitation on the salinity of the lagoon was observed between four and fourteen days later depending on catchment area geology, indicating the uniqueness of each lagoon system. Seasonal nutrient patterns were evident in the lagoons. Nutrient concentrations were found to be reflective of the catchment area and the magnitude of the freshwater inflow. Assessment based on the Redfield molar ratio indicated a trend towards phosphorus, rather than nitrogen, limitation in Irish lagoons. Investigation of the decomposition process in Cuskinny Lagoon revealed that greatest biomass loss occurred in the winter season. Lowest biomass loss occurred in spring, possibly due to the high density of invertebrates feeding on the thick microbial layer rather than the decomposing litter. It has been reported that the decomposition of plant biomass is highest in the preferential distribution area of the plant species; however, no similar trend was observed in this study with the most active zones of decomposition varying spatially throughout the seasons. Macroinvertebrate analysis revealed low species diversity but high abundance, indicating the dominance of a small number of species. Invertebrate assemblages within the lagoon varied significantly from communities in the adjacent freshwater or marine environments. Although carried out in coastal lagoons on the southwest coast of Ireland, it is envisaged that the overall findings of this study have relevance throughout the entire island of Ireland and possibly to many North Atlantic coastal lagoon ecosystems elsewhere. en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2014, Susan N. Lettice. en
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/ en
dc.subject Water Framework Directive en
dc.subject Habitats Directive en
dc.subject Irish habitat en
dc.subject Coastal lagoon en
dc.subject Coastal habitat en
dc.subject Decomposition en
dc.subject Macroinvertebrate community en
dc.subject Nutrients en
dc.subject Salinity en
dc.subject Chlorophyll a en
dc.subject Water monitoring en
dc.subject Coastal management en
dc.subject Diversity en
dc.subject Tidal en
dc.subject Classification en
dc.title Environmental and biological characteristics of lagoons on the southwest coast of Ireland en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Science) en
dc.internal.availability Full text not available en
dc.check.info Indefinite en
dc.check.date 10000-01-01
dc.description.version Accepted Version
dc.contributor.funder Irish Research Council for Science Engineering and Technology en
dc.description.status Not peer reviewed en
dc.internal.school Biological, Earth & Environmental Sciences en
dc.check.reason This thesis is due for publication or the author is actively seeking to publish this material en
dc.check.opt-out Not applicable en
dc.thesis.opt-out true
dc.check.entireThesis Entire Thesis Restricted
dc.check.embargoformat E-thesis on CORA only en
dc.internal.conferring Autumn Conferring 2014

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© 2014, Susan N. Lettice. Except where otherwise noted, this item's license is described as © 2014, Susan N. Lettice.
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