Blue Carbon and Marine Carbon Sequestration in Irish Waters and Coastal Habitats

Atmospheric CO2 is rising globally. Opportunities for reducing this trend include energy sector adjustments and management of both land and ocean resources. Improved management of coastal and oceanic ecosystems is therefore poised to contribute to, and enhance, climate mitigation and adaptation. This report outlines the emergence of blue carbon as a concept for the integration of coastal carbon dynamics into policy and management frameworks and defines blue carbon ecosystems. It also emphasises the importance of marine carbon sequestration and highlights its potential role in climate adaptation. Ireland is estimated to store at least 9.2 Mt of carbon in its saltmarsh and seagrass habitats, which cover an estimated minimum area of 162 km2. Estimates of carbon stocks in potential blue carbon ecosystems such as macroalgae beds are hampered by lack of data on extent, productivity and actual contribution. Irish coastal blue carbon ecosystems and their carbon sequestration capacity are currently threatened by anthropogenic factors such as land reclamation and poor water quality. The possibility of including saltmarsh and seagrass habitats in Ireland’s National Inventory Report on GHG emissions to the United Nations Framework Convention on Climate Change (UNFCCC) and including Ireland’s potential blue carbon ecosystems in Ireland’s Nationally Determined Contributions is highlighted. The critical knowledge gaps and future research priorities are outlined, so that Ireland can advance the pace of scientific discovery whilst harnessing the climate change potential of its coastal and marine environment.Marine Institut

The Tropical Seagrass Halophila stipulacea: Reviewing What We Know From Its Native and Invasive Habitats, Alongside Identifying Knowledge Gaps

Halophila stipulacea is a small tropical seagrass, native to the Red Sea, Persian Gulf, and the Indian Ocean. It invaded the Mediterranean Sea 150 years ago as a Lessepsian migrant, but so far has remained in insulated, small populations across this basin. Surprisingly, in 2002 it was reported in the Caribbean Sea, where within less than two decades it spread to most of the Caribbean Island nations and reaching the South American continent. Unlike its invasion of Mediterranean, in the Caribbean H. stipulacea creates large, continuous populations in many areas. Reports from the Caribbean demonstrated the invasiveness of H. stipulacea by showing that it displaces local Caribbean seagrass species. The motivation for this review comes from the necessity to unify the existing knowledge on several aspects of this species in its native and invasive habitats, identify knowledge gaps and develop a critical strategy to understand its invasive capacity and implement an effective monitoring and conservation plan to mitigate its potential spread outside its native ranges. We systematically reviewed 164 studies related to H. stipulacea to create the "Halophila stipulacea database." This allowed us to evaluate the current biological, ecological, physiological, biochemical, and molecular knowledge of H. stipulacea in its native and invasive ranges. Here we (i) discuss the possible environmental conditions and plant mechanisms involved in its invasiveness, (ii) assess the impact of H. stipulacea on native seagrasses and ecosystem functions in the invaded regions, (iii) predict the ability of this species to invade European and transoceanic coastal waters, (iv) identify knowledge gaps that should be addressed to better understand the biology and ecology of this species both in its native and non-native habitats, which would improve our ability to predict H. stipulacea's potential to expand into new areas in the future. Considering the predicted climate change scenarios and exponential human pressures on coastal areas, we stress the need for coordinated global monitoring and mapping efforts that will record changes in H. stipulacea and its associated communities over time, across its native, invasive and prospective distributional ranges. This will require the involvement of biologists, ecologists, economists, modelers, managers, and local stakeholder

Superior growth traits of invaded (Caribbean) versus native (Red sea) populations of the seagrass Halophila stipulacea

18 pages, 3 tables, 6 figuresThe seagrass Halophila stipulacea is native to the Red Sea. It invaded the Mediterranean over the past century and most of the Caribbean over the last two decades. Understanding the main drivers behind the successful invasiveness of H. stipulacea has become crucial. We performed a comprehensive study including field measurements, a mesocosm experiment, and a literature review to identify ‘superior growth traits’ that can potentially explain the success story of H. stipulacea. We assessed meadow characteristics and plant traits of three invasive H. stipulacea populations growing off the Island of Sint Eustatius (eastern Caribbean). We compared similar parameters between native (Eilat, northern Red Sea) and invasive (Caribbean) H. stipulacea plants in a common-garden mesocosm. Lastly, we compared our field measurements with published data. The newly arrived H. stipulacea plants from St. Eustatius were characterized by higher percent cover, higher below- and above-ground biomasses, more apical shoots, and faster leaf turnover rates than those measured in both native and older invaded habitats. These results were further confirmed by the mesocosm experiment where the invasive H. stipulacea plants grew faster and developed more apical shoots than the native plants. Results suggest that increased growth vigour is one of the main invasive traits that characterize successful invasive H. stipulacea populations in the Caribbean and potentially in other invaded areas. We encourage long-term monitoring of H. stipulacea in both native and invaded habitats to better understand the future spread of this species and its impacts on communities and their ecosystem functions and servicesG.W. and C.C. were supported by AssemblePlus Grants No. 311.2. G.R. and M.M. were supported by AssemblePlus Grants No. 8519. T.G.-H. and D.G. were supported by AssemblePlus Grant No 8413. We thank the continuing support of G.W. by the Israeli Ministry of Science and Technology (MOST)Peer reviewe

Effects of high temperature and marine heat waves on seagrasses: Is warming affecting the nutritional value of Posidonia oceanica?

9 pages, 5 figures, 4 tables.-- Under a Creative Commons licensePrimary producers nutritional content affects the entire food web. Here, changes in nutritional value associated with temperature rise and the occurrence of marine heat waves (MHWs) were explored in the endemic Mediterranean seagrass Posidonia oceanica. The variability of fatty acids (FAs) composition and carbon (C) and nitrogen (N) content were examined during summer 2021 from five Mediterranean sites located at the same latitude but under different thermal environments. The results highlighted a decrease in unsaturated FAs and C/N ratio and an increase of monounsaturated FA (MUFA) and N content when a MHW occurred. By contrast, the leaf biochemical composition seems to be adapted to local water temperature since only few significant changes in MUFA were found and N and C/N had an opposite pattern compared to when a MHW occurs. The projected increase in temperature and frequency of MHW suggest future changes in the nutritional value and palatability of leavesThis research was financially supported by Botany and Plant Science at University of Galway, by the project Marine Habitats Restoration in a Climate Change-impaired Mediterranean Sea [MAHRES] funded by the Italian Ministry of Research under the PRIN 2017 Program (Project N. 2017MHHWBN; CUP: 74I19001320001), by “Fondo di Ateneo per la Ricerca 2019” by the University of Sassari, by PON - National Operational Programme - Research and Innovation 2014–2020, PhDs and research contracts on innovation-related topics and by the project DRESSAGE (MIS5045792) (through the Operational Program ‘Competitiveness, Entrepreneurship and Innovation’ (EPAnEK 2014–2020)Peer reviewe

Tracking the effect of temperature in marine demersal fish communities

Under current levels of global warming most demersal species in the Northeast Atlantic are experiencing tropicalization, meridionalization or borealization of their distributions, leading to profound changes in demersal communities. We explore these changes using the Community Weighted Mean Temperature (CWMT), an index to link the thermal preference of demersal fish communities and temperature. The CWMT is calculated as the summation of the mean temperature of each fish species distribution weighted by its relative abundance in the community. The relative abundance is based on the community composition data obtained by the International Bottom Trawl Surveys (IBTS) in the Southern Bay of Biscay between 1983 and 2015. Our analyses show that the CWMT responds to the actual temperature of the water column reproducing its space–time trends in the study area: (i) an increase from SW to NE, towards the inner Bay of Biscay, (ii) a decrease with depth, except in the SW area characterized by an intense upwelling, (iii) a general increase along the time series. Applying a k-means classification to the CWMT data we identified warm-, temperate- and cold-communities over the shelf and slope and their spatial changes in the last decades. The area occupied by warm communities has expanded 268.4 km2/ yr since the 80 s, while the cold communities have retracted at a speed of − 155.4 km2/yr. The CWMT was able to capture the community dynamics in relation to environmental temperature at different temporal and spatial scales, highlighting the potential of this index to explore and anticipate the effects of climate change in demersal communities under different scenarios of global warming.En prensa2,69

Characterizing phytoplankton biomass seasonal cycles in two NE Atlantic coastal bays

The seasonal and interannual variability of chlorophyll a was studied between 2008 and 2016 in two coastal bays located in the northeastern limit of the Iberia/Canary upwelling ecosystem. The work aims (i) to understand if small latitudinal distances and/or coastline orientation can promote different chlorophyll a seasonal cycles; and (ii) to investigate if different meteorological and oceanographic variables can explain the differences observed on seasonal cycles. Results indicate three main biological seasons with different patterns in the two studied bays. A uni-modal pattern with a short early summer maximum and relatively low chlorophyll a concentration characterized the westernmost sector of the South coast, while a uni-modal pattern characterized by high biomass over a long period, slightly higher in spring than in summer, and high chlorophyll a concentration characterized the central West coast. Comparisons made between satellite estimates of chlorophyll a and in situ data in one of the bays revealed some important differences, namely the overestimation of concentrations and the anticipation of the beginning and end time of the productive period by satellite. Cross-correlation analyses were performed for phytoplankton biomass and different meteorological and oceanographic variables (SST, PAR, UI, MLD and precipitation) using different time lags to identify the drivers that promote the growth and the high levels of phytoplankton biomass. PAR contributed to the increase of phytoplankton biomass observed during winter/midspring, while upwelling and SST were the main explanatory drivers to the high Chl-a concentrations observed in late-spring/summer. Zonal transport was the variable that contributed most to the phytoplankton biomass during late-spring/summer in Lisbon Bay, while the meridional transport combined with SST was more important in Lagos Bay.FCT: SFRH/BD/52560/2014/ IPMA-BCC-2016-35/ UIDB/04292/2020/ UID/Multi/04326/2020/ UID/MAT/04561/2020 LISBOA-01-0145FEDER-031265 IPMA: MAR2020PO2M01-1490 Pinfo:eu-repo/semantics/publishedVersio

One hundred priority questions for advancing seagrass conservation in Europe

17 pages, 2 figures.-- Open AccessSeagrass meadows provide numerous ecosystem services including biodiversity, coastal protection, and carbon sequestration. In Europe, seagrasses can be found in shallow sheltered waters along coastlines, in estuaries & lagoons, and around islands, but their distribution has declined. Factors such as poor water quality, coastal modification, mechanical damage, overfishing, land-sea interactions, climate change and disease have reduced the coverage of Europe’s seagrasses necessitating their recovery. Research, monitoring and conservation efforts on seagrass ecosystems in Europe are mostly uncoordinated and biased towards certain species and regions, resulting in inadequate delivery of critical information for their management. Here, we aim to identify the 100 priority questions, that if addressed would strongly advance seagrass monitoring, research and conservation in Europe. Using a Delphi method, researchers, practitioners, and policymakers with seagrass experience from across Europe and with diverse seagrass expertise participated in the process that involved the formulation of research questions, a voting process and an online workshop to identify the final list of the 100 questions. The final list of questions covers areas across nine themes: Biodiversity & Ecology; Ecosystem services; Blue carbon; Fishery support; Drivers, Threats, Resilience & Response; Monitoring & Assessment; Conservation & Restoration; Governance, Policy & Management; and Communication. Answering these questions will fill current knowledge gaps and place European seagrass onto a positive trajectory of recoveryThis project was initiated and carried out under the EuroSea project using funding from the United Nations Educational, Scientific and Cultural Oragnisation. Additional support was from the UK Natural Environment Research Council RESOW grant to Swansea University (NE/V016385/1). The EuroSea project is funded by the European Union's Horizon 2020 research and innovation programme under grant agreement No 862626. Thanks to Toste Tanhua and Emma Heslop for their supporting this process. Thanks are due to FCT/MCTES for the financial support to CESAM (UIDB/50017/2020 + UIDP/50017/2020 + LA/P/0094/2020), through PT national funds. Financial support from Fundacao para a Ciencia e a Technologia was also provided through the research contract to A.I. Sousa (CEECIND/00962/2017)Peer reviewe

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

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 to achieve optimal membrane fluidity under variable environmental conditions. Finally, we mapped large areas of previously undocumented seagrass meadows in the Irish coast by developing a new mapping approach, integrating species distribution models (SDM), satellite-derived images and field surveys. This project is particularly relevant due to (i) the previous scarcity of knowledge available on seagrass ecology and spatial information in Ireland, (ii) the undisturbed status of the eelgrass meadows described, and (iii) the potential application of these baseline data in assessing impacts of anthropogenic disturbances or future climate change effects on these valuables ecosystems.2022-02-2

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

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 to achieve optimal membrane fluidity under variable environmental conditions. Finally, we mapped large areas of previously undocumented seagrass meadows in the Irish coast by developing a new mapping approach, integrating species distribution models (SDM), satellite-derived images and field surveys. This project is particularly relevant due to (i) the previous scarcity of knowledge available on seagrass ecology and spatial information in Ireland, (ii) the undisturbed status of the eelgrass meadows described, and (iii) the potential application of these baseline data in assessing impacts of anthropogenic disturbances or future climate change effects on these valuables ecosystems.2022-02-2