Fish living in deep waters on the continental slope around the UK play an important role carrying carbon from the surface to the seafloor.
It has been assumed that deep water fishes all depend on particles that fall from the surface for their energy. These bottom-living deep water fishes never come to the surface and the carbon in their bodies stays at the seafloor. However, at mid-slope depths there is an abundant and diverse ecosystem where a huge volume of animals make daily vertical migrations to feed at the surface during the night. The animals conducting this migration then transport nutrients from the surface back to the deep.
Researchers from the University of Southampton and Marine Institute, Ireland used novel biochemical tracers to piece together the diets of deep-water fish revealing their role in transferring carbon to the ocean depths.
They found that more than half of all the fishes living on the seafloor get their energy from animals that otherwise go back to the surface, and not from settling particles. These bottom-living fishes therefore become a carbon capture and storage facility. Global peaks in abundance and biomass of animals at mid slope depths (between 500 and 1800 m) occur because this is the depth range where the vertically migrating animals are most easily captured by fishes that live at or near the seafloor.
Lead author, Dr Clive Trueman from the University of Southampton, says: “As fishing, energy extraction and mining extend into deeper waters, these unfamiliar and seldom seen fishes in fact provide a valuable service to all of us. Recognising and valuing these ecosystem services is important when we make decisions about how to exploit deep water habitats for food, energy or mineral resources.”
The study is published in the journal Proceedings of the Royal Society B.
Proc. R. Soc. B 22 July 2014 vol. 281 no. 1787 20140669
Photo credit: Citron, CC BY-SA 3.0
The Marine Conservation Society wants to know if you’ve seen any basking sharks, turtles or jellyfish – in UK and Irish waters.
Jellyfish? Yes, because jellyfish are the favourite food of Leatherback Turtles. And they don’t just want to know about live jellyfish but about strandings on beaches as well. Identification of live jellyfish is usually easy but once they’ve washed up on the beach it can become more difficult. They want you to therefore send photos if possible, and offer a jellyfish identification guide.
Leatherback turtles (Dermochelys coriacea) are the largest species of turtle, and occasional visitors to the North and Irish seas. By comparing the distribution of jellyfish with environmental factors such as sea temperature, plankton production and current flow, the Marine Conservation Society (MCS) hope to understand what influences the seasonal distribution of jellyfish and leatherbacks in UK waters.
The basking shark (Cetorhinus maximus) is Britain’s largest fish. They can grow up to 11 metres long and weigh up to 7 tonnes – about the size and weight of a double-decker bus. Once numerous in the UK basking sharks were hunted for their liver oil and their populations declined to such an extent that now they are considered to be endangered in UK waters. The MCS Basking Shark Watch programme has generated the largest basking shark sightings database in the world and is instrumental in identifying surface feeding hotspots.
So if you dive around UK or Ireland, get over to the MCS site and report your sitings at http://www.mcsuk.org/what_we_do/Wildlife protection/Report wildlife sightings/Report wildlife sightings
Europe boasts some world class dive sites, with great visibility and masses of underwater life. In a recent poll of SCUBA Travel readers, these were voted the ten best dive sites in Europe. Disagree? Then cast your vote.
- The Zenobia, Cyprus
The pristine wreck of a huge ferry. Lying on its port side, the wreck starts at about 15 m and descends to 42 m. Fabulous dive. Possibly the best shipwreck dive in the world in recreational depths. 20 m plus visibility and some great swim-throughs. Needs several dives to see anything like all of it.
- Blue Hole, Gozo
A beautiful sharp drop off into the blue hole with what seems like limitless visibility and literally feels like you are on the very edge of the world. A most extraordinary dive.
- Cirkewwa, Malta
Features the wreck of the Rozi MV as well as stunning underwater topography. Visibility is very good and there iss ea life in abundance: barracuda, morays, octopus, cuttlefish and even dolphins.
- Booroo, Isle of Man
The Burroo, with its extremely diverse and plentiful marine life offers a truly magnificent dive. In fact, in areas exposed to the fast flowing current, it is something of a challenge to find a single square centimetre of bare bedrock, so abundant is the life here.
- Blockship Tabarka, Scapa Flow, Scotland
This shallow 18 m dive is a real beauty. One of the block ships scuttled to prevent submarine attack during WW2. Covered in life, a beautiful place. Worth the trip and the one of surprises of Scapa.
- Diamond Rocks, Kilkee, Ireland
Claimed to by on a par with the famous Yongala. It is a cold water dive off Ireland’s west coast. The bay is fairly sheltered and is teaming with life. The terrain is full of rocks and gullies and the water is really clear.
- Eddystone Reef, England
12 miles off Plymouth, England. The reef is from 8 to 60 m. Encrusted with jewel anemones and with the remains of ancient wrecks, including a large 17th century anchor. Stunning.
- Secca della Columbara, Italy
One of the best dives in the Mediterranean. It features a steep, beautifully-decorated, wall; large shoal of barracuda; grouper; giant amberjacks and a wreck. The wreck is a 74 m ship which was carrying slabs of marble. It sank in 2005 and rests at 20 m in two parts.
- Fanore, Ireland
Shore dive in crystal clear Atlantic water with abundant fish.
- Chios island, Greece
Small undersea caves and paths between impressive rocks, colourful reefs and vertical walls.
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