This thesis demonstrates a multidisciplinary
approach to the study of deep-water coral reef ecosystems on the Atlantic
European margin. It is concerned with the assessment of remotely sensed
geophysical data, in conjunction with ground truthing ROV video surveys,
sediment core analysis and subsequent GIS data integration. These techniques
have been applied to assess the current state of deep-water coral reefs and
also provide insights into the history of their development. This work was
undertaken through detailed investigation of the Belgica Mounds (deep-water
coral carbonate mounds rising up to 200m above seabed) in the eastern Porcupine
Seabight, North East Atlantic. Additional data, from the western Porcupine Bank (Pelagia
Mounds) and the northern Rockall Trough (Darwin Mounds), are also presented in
order to provide a regional context.
The GIS integration of all the datasets showed that the Belgica mound
province is strongly affected
by the northerly bottom water current flows (with speeds up to 1.5m/sec) and
associated drift sedimentation. The province can be subdivided into two belts:
the eastern mound belt containing mainly retired forms, in terms of biological
coral growth, and the western belt containing active (coral colonised) mounds.
The assessment of sedimentary processes and water mass properties suggests that
the mound retirement resulted from changes in oceanographic characteristics of
the Mediterranean Outflow Water and the onset of contourite drift deposition
(with sedimentation rates c.6-100cm/ka) during Quaternary. Palaeoenvironmental
reconstructions show that climate
changes played an important role in the development of the Belgica Mounds, with
average mound growth rates of c.10cm/ka during interglacials and c.5.8cm/ka
during glacials. Examination of particle size data show a regional pattern of
temporal variations in the strength of bottom currents, suggesting that the
province underwent six peak current events during MIS (Marine Isotope Stage)
2-4. Evidence indicates that the mounds began development c.1.8-2 million years
This study provides a generalised model for the formation of the carbonate mounds.
It defines seven stages in mound development and discusses factors
imperative for the initiation,
development and sustainability of the mounds.