Study of life in the Mid-Atlantic yields trove of species and new insights
A scientist and a student from the University of Aberdeen are amongst a team of international researchers whose work has marked the start of a new era in our understanding of life in the deepest oceans.
Exploring life in the Mid-Atlantic at various depths down to 4km (2.5 miles), 60 scientists from 13 countries were part of an expedition which has surfaced a wealth of new information and insights, stunning images and marine life specimens, several thought to be species never before known to science.
The international team will be arriving in the city today (Tuesday, 3 August) following a two-month expedition along the Mid-Atlantic Ridge (MAR) between Iceland and the Azores.
Professor Monty Priede, Director of the University's highly-acclaimed Oceanlab, and Nicola King joined other scientists on board one of the world's most advanced research vessels, the Norwegian RV, G.O. Sars, and the vessel will be docking at Aberdeen Harbour today.
The two became part of the international research project, MAR-ECO, and used the latest technology to learn more about what is living in this remote and relatively unexplored deep-sea environment.
Using remotely operated deep-sea vehicles, and other technologies for sampling and observation, the Norwegian-led MAR-ECO expedition has captured or recorded rare and potentially new species of squid and fish, measured the abundance of life, and advanced knowledge of many other aspects of the Mid-Atlantic ecosystem.
Nicola King, a PhD student from the University's Oceanlab has undertaken the most extensive photographic survey of scavenging deep-sea fishes on the MAR. The RObust BIOdiversity (ROBIO) lander vehicle, equipped with a state-of-the-art digital stills camera, completed 19 dives to the sea floor. Thousands of images were captured of fish attracted to bait and the deepest dive exceeded 3,500m. The ROBIO images are an informative insight into the lives of these deep-sea fish, never seen before by human eyes.
Landers are a highly efficient method of studying inhabitants of the deep-sea floor, working autonomously and using minimal ship time. The landers sink to the seafloor where they conduct a series of pre-programmed tasks. Once complete, a sound signal is sent to a receiver on the lander, causing it to release its ballast and the lander then returns to the surface by virtue of the floats attached to a mooring line above.
The MAR rises to an altitude of 3,000-4,000m above the abyssal plains between Europe and America dividing the floor of the ocean into eastern and western basins. Due to the very rough terrain, this area has never been properly explored, but using the advanced technology available on the brand new research ship, the MAR-ECO expedition has made significant progress. About the same height as the Alps, the ridge is criss-crossed by large valleys and canyons, with steep sides over a mile high.
The Aberdeen team discovered that the MAR is a barrier to movement of deep-sea fish between the east and west Atlantic Ocean. Abyssal grenadier fish were confined to the valleys, apparently never taking short-cuts over the peaks. Genetic studies on samples will show whether eastern and western fish meet and interbreed. Photos of juveniles suggest that the area is a nursery ground for grenadiers that as adults live throughout the floor of the world's oceans. A lander known as DOBO (Deep Ocean Bottom Observatory) was retrieved after a month on the floor of the giant canyon of Charlie Gibbs Fracture Zone. It was strategically placed to intercept movements of grenadiers along this potential major deep-sea highway. Film from DOBO was retrieved and will be studied by another Oceanlab PhD student, Kirsty Kemp.
The Aberdeen team filmed pairs of wolf fish living on the ridge tops, deep-sea sharks on the slopes and the valleys were occupied by hordes of hungry grenadier fish that voraciously consumed the bait provided. As many as 20 fish over a metre long squabbled over a single mackerel in full view of the camera.
The wolf fish were a remarkable find. They are amongst the ugliest fish on the planet and yet males and females pair up in elaborate courtship behaviour and guard their eggs. Professor Priede, said: "We had no idea these fish would be found living in the mid-ocean like this and it was quite poignant to see the devoted 'ugly couple' in their deep sea Eden on the mid-ocean ridge."
Almost all life in the deep depends on what falls out from above and to study the life in the water column the Oceanlab team deployed a new ISIT bioluminescence profiler. This was lowered through the water and recorded bursts of light produced by animals impacting on a sensor grid. The videos resemble a firework display as jellyfish, sea gooseberries, fish and shrimps release explosions of light betraying their presence. Analysis of these videos will enable the researchers to find out information on the vertical and horizontal distribution of living material in the water.
Pupils from Ellon Academy, Aberdeenshire, located near Oceanlab, are following the work of the MAR-ECO project. Pupils from the school will be visiting the ship to meet the scientists on board and get a first hand view of research at sea. Dr Brian Wilkins, Rector of Ellon Academy, said: "We are delighted to be part of the world-wide network of schools associated with MAR-ECO and the G.O. Sars coming to Aberdeen is a real bonus for our pupils."
The Sars will return to Bergen with thousands of samples of rare animals and a vast archive of pictures and videos, which mark the start of a new era in our understanding of the life in the oceans.