Friday, 21 March 2014

INFOMAR supports academic research in Irish water.

INFOMAR supports academic research in Irish water.

Over the last 2 weeks, INFOMAR provided support for the WICPro survey project on board the R.V. Celtic Explorer. The survey, led by Prof. Andy Wheeler, represents a coming together of several Irish university research groups and international collaborators. Dr. Fabio Sacchetti from the INFOMAR team was on board as co-investigator and to support geophysical and sediment sampling activities.
The survey focused on the collection of sediment core material and geophysical data from several survey areas in support of different research objectives.

Objective 1: Study of environmental records from cold-water coral reefs on the Moira Mounds. The aim is to test hypotheses relating to cold-water coral reef initiation and development and sedimentological dynamics in a zone of active coral growth in the eastern Porcupine Seabight.
Objective 2: Study the history of glaciomarine deposition from the Porcupine Bank flank. The study will focus on the effect of glaciation on the development of the outer western Porcupine Bank, to explore evidence for sea ice extent, pro-glacial sediment supply and ocean circulation changes.
Objective 3: Study the ice limits and glacial processes on the western shelf. The primary aim is to use seismic data to define ideal sites for coring during the BRITICE-CHRONO programme on the RSS James Cook later on in 2014. Additionally, Irish sediment cores/sparker data will help to determine the nature of glaciation on the shelf edge and will be used to date some of the glacial moraines present on the continental shelf.

The survey was also a good opportunity to test the sediment sampling capabilities of the R.V. Celtic Explorer and in particular the performance of the recently acquired 6 m gravity corer.

Fig. 1 shows the new 6 m gravity corer being prepared for deployment. The red cylinder connected to the top of the corer is the USBL acoustic beacon used to monitor the position and depth of the corer during its descent.

Preliminary results
On-mound and off-mound cores were retrieved from the Moira Mounds in the eastern Porcupine Seabight. Cores were retrieved from the Porcupine Bank margin targeting glacial sequences down to 3000m water depth. Also on the Porcupine Bank, a small number of box cores and a gravity core were taken from the canyons mounds (both on- and off-mound).

Fig. 2 shows the box-corer been deployed and some of the seabed fauna found inside the sediment sample.

Considerable effort was made to collect geophysical (sparker) data and retrieve vibrocores from the western shelf to date the end of the last glaciation. These proved hard to get as they targeted reworked gravels and diamictons which consist of very stiff mud, super compressed by the weight of the former ice sheet that once covered the continental shelf. However, successful cores up to 3 m long were collected on various sites.
Fig. 3 shows the preparation phase of the vibrocorer before its deployment. The yellow and orange unit at the top is the vibrating electric engine that allows the corer to penetrate in relatively hard and coarse sediment. The last image shows the “core catcher”, a set of metal blades designed to allow the sediment to go inside the core but avoid it to escape during the recovery phase.

The scientific team and the crew of the R.V. Celtic Explorer worked around the clock to get the best out of the good weather. Not even S.Patrick day could stop them as can be seen on figure below.

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