Benthic Lander Deployment

A benthic lander is a large three-legged frame with oceanographic instruments and sensors attached to it. These measure a range of parameters in-situ at the seabed; such as in this case, the current speed, temperature, salinity and turbulence. They are designed to operate in some cases 1000s of meters below the sea surface. Weights or ballasts are used to make the otherwise positively buoyant lander land down on the seafloor.

Here it was deployed from the Irish research vessel the Celtic Voyager in Galway Bay, West of Ireland, during a cruise by the National University of Ireland, Galway. The lander remains monitoring the conditions at the seabed for one month, in this case at depth of ~25m. Whilst out at sea during this period, it observes the impact of storm waves on the sediment transport. By making measurements at various heights above the seabed, it can obtain a profile of the benthic boundary layer and allow us to study how this changes during a storm.

By adding different sensors, you can also measure the chemical and biophysical properties of the water at the sediment-water interface. In-situ measurements allow us to study in the natural laboratory of the sea, without the need to remove anything. The measurements obtained by benthic landers are often used to verify as well as compliment laboratory results made under controlled situations.

It also has an acoustic positioning transponder which responds to the ship’s positioning call, to locate it for collection after its deployment. The weights or ballasts are released, with the buoyancy from the yellow floats allowing the lander to float back up to the surface.

What's New

International Rhodolith Workshop

The IV International Rhodolith Workshop took place in Granada, Spain in September. Meeting every three years, delegates were from Brazil, Spain, United Kingdom, USA, Ireland, Mexico, New Zealand and Australia, as well as other countries. Rhodolith is a term largely used interchangeably to “maerl,” as free living non-geniculate coralline algae. Researchers came to share the latest research about one of the big four macrophyte dominated benthic communities (others being kelp beds, seagrass meadows and biogenic reefs) (Foster, 2001). Topics included taxonomy, ecology, management and conservation biology, genetics, geochemistry, evolution, palaeoecology, climate change studies and sediment dynamics.

Two excursion took place; the Granada coast to look at living rhodoliths and a two-day excursion to Almería-Cabo de Gata to observe both fossil and living rhodolith beds. The first excursion involved diving off the Granada coast or shorkelling to explore the small sea-caves along the coast. The second excursion involved exploring the processes responsible for deposition of rhodolith debris as cliff-deposits and how they have been preserved across geological time.

Further information can be found on the conference website. My poster presented to the conference can be found on the Griffith NUIG Biogeosciences website

References

Foster M, 2001, Rhodoliths: Between rocks and soft places, Journal of Phycology, Vol 37 Issue 5, 659-667

Science

Cruise aboard RV Thalassa: France – Iceland – Azores

The ICE-CTD research cruise investigated cold water coral reefs and seawater properties around coral and non-coral areas. The objective was to characterise the present and past coral environmental conditions. Coral were sampled for dating, geochemical and genetic studies. The GIS Technician’s job mainly involved using ArcGIS to prepare the ROV dive routes and produce maps. They were also in charge of transferring the real-time data and comparing the real-time routes with the planned dive.

The ship left Brest on the 11th of June and headed straight to the Icelandic waters. It was initially planned to investigate the Logachev mound province but this was cancelled due to bad weather conditions. The ROV was deployed in three locations off southern Iceland and coral reefs were found in each area. Included are pictures from some of the spectacular locations discovered. The ship docked in Reykjavík for one night, allowing everyone to scramble off and explore Iceland’s beautiful scenery (geysers, icesheets, the mid-atlantic ridge, waterfalls!). The ROV team left the ship at Iceland and the rest of the team continued down the middle of the Atlantic to the Azores. CTD measurements were taken along the way and ARGOS floats were deployed, but it was a much quieter cruise on the way back.

Here is the link to the cruise blog:

Image Credits

All the pictures are taken by the GENAVIR ROV team and are credited to the following source: ICE-CTD cruise on N/O Thalassa, conducted by the LSCE and IFREMER under the lead of Dr. Norbert Frank, Laboratory for Climate and Environmental Research LSCE. (links: http://www.lsce.ipsl.fr and http://www.ifremer.fr and contact email Norbert.Frank@lsce.ipsl.fr and Sophie.Arnaud@ifremer.fr) and to Fiona Stapleton, National University of Ireland, Galway.

Science

Interview with British Researcher Chris Yesson

The second in our series of interviews, Dr. Chris Yesson, Institute of Zoology, Zoological Society of London speaks about habitat suitability modelling of cold water corals and his team’s work as part of the CoralFISH FP7 project. He discusses his work the to identify suitable habitats for octocorals and stony corals from the North Atlantic and globally. Interview carried out at the Zoology and Marine Biology Museum, National University of Ireland, Galway. For more information please see the Institute of Zoology, Zoological Society of London website.

Acknowledgements

Special thanks go to Dr. Chris Yesson for permission for inclusion of this interview in this blog.

Science

Interview with Icelandic Ecologist Julian Burgos

Benthic ecologist Julian Burgos, Marine Research Institute, Iceland, gives us a rare perspective about cold water corals living in Icelandic deep waters and his team’s work as part of the CoralFISH FP7 project. CoralFISH is assessing the interaction between cold water corals, fish and fisheries, in order to develop monitoring and predictive modelling tools for ecosystem based management in the deep waters of Europe and beyond. More information about the findings of the study can be found on the CoralFISH website.

Acknowledgements

Special thanks go to Dr. Julian Burgos for permission for inclusion of this interview in this blog.

Science

Cold water corals, carbonate mounds and ocean currents

Coral reefs are usually associated with warm, tropical waters and exotic fish, but not with the cold, deep and dark waters of the North Atlantic where corals were regarded as oddities on the seafloor. It is now known that cold-water coral species also produce reefs, which may rival their tropical cousins in terms of the species richness of associated marine life. Increasing commercial operations in deep waters, and the use of advanced offshore technology have slowly revealed the true extent of Europe’s hidden coral ecosystems. The discovery of extraordinary, 10 km-long chains of the reef-building corals Lophelia pertusa and Madrepora oculata in several hundred metres of water on the Norwegian and Irish Shelves have deeply challenged conventional views. The same coral assemblages are also found associated with large seabed structures in the Porcupine Seabight (offshore Ireland), where they are so abundant that their skeletal remains have, over the millennia, contributed to carbonate mound structures up to 300m high in 700-1200m water depths. The potential of cold-water corals to contribute to the formation of these large seafloor features and their high biological diversity have attracted considerable public attention through reports in numerous national TV and newspaper features.

via University of Liverpool

Coinciding with World Oceans Day, Prof. David van Rooij, Renard Centre of Marine Geology (RCMG), Dept. of Geology and Soil Science, Ghent University, Belgium gave a seminar today in Galway, entitled “Go with the flow: Impact of the Mediterranean Outflow Water (MOW) on NE Atlantic sedimentary processes and ecosystems.” The talk particularly focused on the colonisation of Atlantic margins by cold-water corals since the end of the last Ice Age and how variation in the MOW explains the current distribution pattern of carbonate mounds found, for example, in Irish waters. See also the Lophelia.org website for some more background on cold water corals and carbonate mound provinces.