Irish seagrass ecology and habitat mapping in the context of climate change

• Main Author: Beca-Carretero, Pedro
• Other Authors: Stengel, Dagmar, College of Science, National University of Ireland, Galway
• Format: Thesis
• Language: unknown
• Published: NUI Galway 2019
• Subjects: Science; Botany and plant science; Botany; Plant Science; Seagrass; Zostera marina; vegetative development; climate change; biochemical composition; fatty acids; habitat mapping; species distribution models; nutritional value; Mediterranean Sea; Red Sea; Greenland
• Online Access: http://hdl.handle.net/10379/14997

Seagrasses play an important ecological role worldwide, providing numerous ecosystems services. Zostera marina is a dominant meadow-forming seagrass in temperate regions in the northern hemisphere, including Irish coasts. This study primarily aimed at providing new ecological and spatial information on this species in Ireland and evaluated the potential of fatty acids as a physiological indicator of different environmental scenarios. Firstly, we assessed growth and population responses alongside with the fatty acid and photosynthesis pigment production in Irish Z. marina populations across seasonal and depth gradients. Our results revealed that Irish eelgrass populations displayed shoot and population dynamics similar to other shallow and deep-adapted perennial populations inhabiting similar latitudes and exposed to comparable climate regimes. Plants under colder and darker environmental conditions accumulated more total fatty acids (TFA) and also exhibited larger concentration of polyunsaturated fatty acids (PUFA) relative to saturated fatty acids (SFA). Additionally, the comparison of FA composition of Z. marina across its latitudinal distribution range (from southern Spain to Greenland) showed that southern populations adapted to warm in-situ seawater temperatures had significantly lower PUFA/SFA ratios than northern, cold-adapted populations. Furthermore, we studied both morphological and biochemical responses of Halophila stipulacea populations from Gulf of Aqava (Red Sea) across an irradiance gradient. Also, we performed two warming experiments; one with Irish Z. marina populations and a second with the Mediterranean seagrass species Posidonia oceanica and Cymodocea nodosa. Moreover, experimental and in-situ analysis of FA suggested that future warming may negatively affect the lipid nutritional value of Z. marina and the Mediterranean seagrass species; this may have implications for higher trophic levels. In combination, these results highlight the capacity of seagrasses to adjust their lipid composition ...