Home | Contact us | Staff | Students | MyExeter (Staff) | exehub (Students) | Site map |

      StudyingResearchBusiness and communityWorking hereAlumni and supportersOur departmentsVisiting usAbout us

      Open Research Exeter (ORE)

      View Item 
      •   ORE Home
      • University of Exeter Theses
      • Doctoral Theses
      • View Item
      •   ORE Home
      • University of Exeter Theses
      • Doctoral Theses
      • View Item
      JavaScript is disabled for your browser. Some features of this site may not work without it.

      The evolution of Maldivian coral reef rim islands

      Thumbnail
      View/Open
      EastH.pdf (20.63Mb)
      Date
      2017-04-07
      Author
      East, Holly Kate
      Date issued
      2017-04-07
      Type
      Thesis or dissertation
      Language
      en
      Publisher
      University of Exeter
      Embargo
      2019-06-19
      Reason for embargo
      Embargo period of 18 months to allow time to prepare papers for publication.
      Abstract
      The first detailed investigation of Maldivian rim island development and reef-to-island connectivity is presented. Study sites were selected on windward and leeward rim aspects of Huvadhu Atoll, and analyses were undertaken at a millennial, contemporary and near-future temporal scales. At millennial temporal scales, contrasting models of island development were presented for the windward and leeward sites. Marked between-site differences were found in the timings of island initiation (2,800-2,000 cal. yr. B.P. and 4,200-3,600 cal. yr. B.P. at the windward and leeward sites respectively). Hence, sea-level does not represent the sole control upon island formation. The period of island initiation and heightened mobility occurred during the mid-Holocene sea-level highstand. Future sea-level rise may thus reactivate the process regime responsible for reef island initiation, potentially inducing further island building and/or heightened island mobilisation. Contemporary analyses highlighted the homogeneity of the sediment reservoir across marine, beach and island sediments. Specifically, sand-grade coral was dominant across all samples within both sites (>50%). The most likely source of sand-grade coral is excavator parrotfish, which was consistent with ecological survey-based estimates of sediment production (excavator parrotfish accounted for 72.8% and 68.2% of sediment production at the windward and leeward sites). The highest sediment production rates were found within the lagoonward environments (59.4% and 75.4% at the windward and leeward sites), which is consistent with the more recent lateral lagoonward mode of island building. With regard to near-future analyses, the apparent recent areal expansion of seagrass beds demonstrated the capacity of ecological changes to cause shifts in sediment production budgets (contributing an additional ~243 tonnes yr-1 of sediment on the leeward rim platform). In addition, significant increases in benthic sediment mobility were found at both study sites under sea-level rise scenarios. Increases in mobility were markedly larger in magnitude at the leeward site than at the windward site. A challenge for the adaptive capacity of atoll nations is thus to acknowledge this atoll-scale diversity in future management strategies.
      Funders/Sponsor
      NERC
      Citation
      East, H. K., Perry, C. T., Kench, P. S., & Liang, Y. (2016). Atoll-scale comparisons of the sedimentary structure of coral reef rim islands, Huvadhu Atoll, Maldives. Journal of Coastal Research, 75(sp1), 577-581.
      Advisor
      Perry, Chris
      Kench, Paul
      Degree title
      PhD in Physical Geography
      Qualification level
      Doctoral
      Qualification name
      PhD
      URI
      http://hdl.handle.net/10871/30860
      Collections
      • Doctoral Theses

      Using our site |  Freedom of Information |  Data Protection |  Copyright & disclaimer |  Privacy & Cookies | 

       

       

      Related Links
      What is ORE Library Site Research Site
      Browse
      All of ORECommunities & CollectionsTitlesAuthorsTypeThis CollectionTitlesAuthorsType
      Statistics
      Most Popular ItemsStatistics by Country

      Using our site |  Freedom of Information |  Data Protection |  Copyright & disclaimer |  Privacy & Cookies |