Climate Change and Marine Science - Batch 1

Assessing the Role of Seagrasses as a Socio-Ecological System: A Case Study from Cape Verde (Gamboa Bay)

2024-04-24T12:42:09Z

Assessing the Role of Seagrasses as a Socio-Ecological System: A Case Study from Cape Verde (Gamboa Bay) Soumah, Seydouba The marine ecosystems are extremely productive and highly valuable, with importance for the overall health of both marine and terrestrial environments. However, climate change and intensive exploitation of natural resources have significant impacts on ocean ecosystems, including seagrasses. Seagrasses provide essential habitat and food sources for many aquatic species. Although they cover a small portion of the ocean’s surface, they have a great ability to sequester and store blue carbon. Globally, important areas of seagrass ecosystems have been lost, with no certainty for future recovery. In West Africa, the knowledge of seagrasses is still rudimentary, and their presence has been confirmed in only seven countries. Climate change, combined with direct anthropogenic pressures, may decrease the resilience of seagrasses to adapt to changing conditions leading to their degradation and subsequent loss of ecosystem services. The first record of seagrass in Cape Verde was reported in 2016 at Gamboa bay, Praia, Santiago Island; the only documented site of a seagrass meadow and known as habitat and food source for marine species. However, the site is exposed to human activity such as coastal development, with no study exploring the impacts on seagrass health and status. This study aims to assess and compare the present to previous state of the seagrass meadows in Gamboa and then evaluate fishers’ perception of seagrass. Field assessments were used to collect and compare ecological parameters, and a questionnaire was used to assess stakeholders' perceptions. The study results show that parameters such as total cover, biomass, rhizome, and canopy height of Halodule wrightii species of seagrass identified have increased, while the shoot density has decreased between 2016 and 2021. The actual shoot density is 5-fold less than that reported in 2016, and the total biomass is 1-fold more than that reported in 2016. The ten (10) patches of 20 m2 recorded then have extended to 6243 m2. Fishers understand the importance of the sea and are conscious about its cleanliness but not fully aware of seagrasses, their ecosystem services and not sure about how to protect them. If further conservation and management of seagrasses are intended, socio-economic adjustment is required to provide guidance and information that can positively impact conservation and management activities. A Thesis submitted to the West African Science Service Center on Climate Change and Adapted Land Use and Universidade Técnica do Atlântico, Cabo Verde in partial fulfillment of the requirements for the Master of Science Degree in Climate Change and Marine Science

Investigating Coastal Sea Level Variability of the Cape Verde Archipelago in the Face of Climate Change

2024-04-24T12:42:48Z

Investigating Coastal Sea Level Variability of the Cape Verde Archipelago in the Face of Climate Change Mintah Ayim, Samuel The coast which serves as an intermediary between land and the ocean is subject to variable sea level from a scale of seconds to centuries. This study quantifies the drivers for coastal sea level variability of Cape Verde. By making use of the only public available tide gauge at Palmeira, Sal (spanning March 2000 to December 2019), the relative contribution of tides, surges, surface waves and sea level changes driven by ocean currents (dynamic topography) are estimated. A spectra analysis revealed that the tides (M2, S2, etc.) contribute up to 815mm of the 1300 mm range in observed sea level variability. Further analyzing the sea level at Palmeira with the tidal signal removed (SLA_residual) reveals multiannual variability with a magnitude of about 212mm. Furthermore, identified event-like, short term surges and lows may add another 155mm, lasting a few hours. Operational wave and sea level products revealed that Cape Verde’s highest sea level variability is due to waves (averagely 1700mm and 4400mm in some instances) in temporal scale <12 seconds and were primarily wind driven. The long term trends for the study period were 2.238mm/year, 3.024mm/year and -0.156mm/year for the CMEMS reanalysis, satellite and tide gauge, respectively. The satellite based dynamical heights sea level anomaly had a range of 182 and 208mm when using the satellite and reanalysis datasets with strong connections to the region’s SST and wind stress curl. An extension of the tide gauge observational network for the Cape Verde region would help verify the operational products used here and thus help to create a spatial monitoring of the sea level in the Cape Verde region. Services such as the desalination-plants, local harbors, coastal businesses, etc. would benefit from such a network, for planning and operations. A Thesis submitted to the West African Science Service Center on Climate Change and Adapted Land Use and Universidade Técnica do Atlântico, Cabo Verde in partial fulfillment of the requirements for the Master of Science Degree in Climate Change and Marine Science

Assessment of the impacts of climate change on the Grand Saloum transboundary Wetland Complex (Senegal-Gambia)

2024-04-24T12:43:41Z

Assessment of the impacts of climate change on the Grand Saloum transboundary Wetland Complex (Senegal-Gambia) Badji, Ousmane The Grand Saloum (Saloum Delta Reserve in Senegal and Niumi Park in The Gambia) is the first African Transboundary Ramsar Site Complex. Ecosystems in this complex were disrupted by a major extreme event (Storm) in 1987. This wetland complex is now subjected to significant dynamics characterised by shoreline mobility. The goal of this study is to assess the effects of climate phenomenon in the coastal Wetland Complex using multi-temporal (1990–2020) GIS analysis and a socio-economic survey. The rate of change of the coastline is obtained through the End Point Rate (EPR) index using DSAS. The vegetation dynamic was done by a supervised classification in Google Earth Engine (GEE). The socio-ecological survey data were analysed using SPSS software. The results revealed an annual average erosion rate of 2.44 m/year and an average accretion rate of 1.84 m/year. The coastal vegetation close to the shoreline showed a decrease of the mangrove area from 16.43% in 2000 to 15.17% in 2005 (1.26% of total mangrove cover). The mangrove area increased very slightly from 16.37% to 16.81% for the year 2010 to 2020 respectively (0.5% of total mangrove cover). The survey moreover revealed that loss of habitat and coastal vegetation removal was the main impacts of erosion. Limited access to the ecosystem resources and an increase in work difficulties were the main impacts due to the accretion. The main impacts caused by floods were land degradation and habitat loss. Hypersalinity led mainly to land degradation and loss of ecosystem resources. The local community adaptation measures were based on the type of shore and the distance of build-up from the coast. Mangrove reforestation, tree planting, dike rehabilitation, and capacity building were dominant strategies in sandy-muddy shores. These findings reveal the need for strengthening mitigation and adaptation strategies in order to address the impacts of the climate phenomenon in the ecosystem and local livelihood. A Thesis submitted to the West African Science Service Center on Climate Change and Adapted Land Use and Universidade Técnica do Atlântico, Cabo Verde in partial fulfillment of the requirements for the Master of Science Degree in Climate Change and Marine Science

Comparative Analysis of Population Structure of Gymnothorax Vicinus (Muraenidae) in the Northern Islands of Cabo Verde through Morphological Features and Genetic Markers

2024-04-24T12:45:16Z

Comparative Analysis of Population Structure of Gymnothorax Vicinus (Muraenidae) in the Northern Islands of Cabo Verde through Morphological Features and Genetic Markers Konate, Moussa Dothian Data from 10039 specimens of Gymnothorax vicinus (Castelnau 1855), commonly known as black moray eels, were sampled on the islands of São Vicente, Santa Luzia, and Santo Antão, between 2002 and 2020. The series of morphometric data were provided by the Institute of Marine Research in Cabo Verde - IMAR, as a result of 18 years of biological sampling of the species. Likewise, a total of 26 specimens were collected in the present study, analysed for genetic purposes, and sequenced the Cytochrome Oxidase I for genetic characterisation. The analysis of the length-weight relationships showed a significant difference between the islands, and the respective parameters of the correlation straight line (a and b) were 0.0019 and 2.95 for Santa Luzia, 0.0017 and 2.97 for São Vicente, and 0.0026 and 2.88 for Santo Antão, respectively. The trend for the Fulton K condition factor revealed that relatively high values were found between 2006 - 2007 and 2013 - 2014. For length-frequency distributions, significant differences were identified for smaller sample sizes as well as not significant between islands. With increasing sample size, the differences between islands disappeared. The differences in length-weight relationships between Santo Antão on one side and São Vicente and Santa Luzia on the other did not have repercussions on the analyses of genetic data. Of the 26 specimens aligned with data from Genbank, 18 haplotypes unique to Cabo Verde were found. Haplotype diversity was high, and nucleotide diversity was low. The haplotype network revealed the non-existence of a population genetic pattern in G. vicinus between these three islands, the haplotypes in Cabo Verde is very similar to each other. The only significant difference that was observed in the length-weight relationships could be related to the environmental influences of the habitats of these specimens. A Thesis submitted to the West African Science Service Center on Climate Change and Adapted Land Use and Universidade Técnica do Atlântico, Cabo Verde in partial fulfillment of the requirements for the Master of Science Degree in Climate Change and Marine Science