Title: Coral Carbonate Mounds as archives in Submarine Canyon Exchange
Researchers: Dr Aaron Lim, Prof. Andy Wheeler
Irish continental margin settings are areas of potential economic activity and development. We have a limited understanding of the environments and environmental drivers in many of the settings where industrial activity may take place. Many of the processes that operate in these settings are dynamic on timescales beyond the reach monitoring and requiring the study of conventional geological archives. This project explores the use of cold-water coral reefs and mounds as novel palaeo-environmental archives constraining seabed environmental development histories. In the case of Irish banks and margins, there is often a lack of sediment accumulations to be accessed as archives to understand the nature of environmental change as sediment supply can be limited and existing sediments are often mobile, reworked and/or swept away.
In Irish waters, offshore development is proposed in several deep-water settings from quiescent to contourite dominated margins, to deep basin settings to canyon dominated margins. Submarine canyons are identified as sensitive habitats on margins and therefore, of all the margin settings, worthy of focussed study. Submarine canyons are identified as sites of rapid connectivity between shelf waters and the deep sea. They are dynamic environments and biologically sensitive. The ability for shelf waters and particles to cascade and transfer down canyons identifies them as a key conduit between surface waters (susceptible to anthropogenic impact and atmosphere/climate interaction) with the much larger oceanic deep water reservoirs. Seabed pollution in canyon head settings has the potential to mobilise rapidly to deeper waters. The ability and rapidity at which anthropogenic inputs can enter the deep ocean through canyon systems is a recent revelation. As such, understanding the role and impact of canyon processes has taken renewed focus.
The Porcupine Bank offers a natural laboratory to study the potential of cold-water coral environmental archives in a low net sedimentation setting, subjected as it is to a strong current regime, in close association with submarine canyons. In effect, the Porcupine Bank Canyon and associated coral carbonate offer the potential to document changes occurring in margin settings which are not available elsewhere in Irish waters. The Porcupine Bank Canyon is also an SAC, knowledge of which is important to managing its protected resource.
This project has inter-linked objectives:
- to study the Porcupine Bank Canyon head environment and sediment/particulate exchanges,
- to study canyon head coral reefs as palaeo-environmental archives,
- to assess the fidelity of the archives with respect to processes observed in the canyon heads.