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Published: 10 June 2014

Deep sea fish in UK waters provide natural carbon capture and storage


Scientists have discovered that deep-water fish living on the continental slope around the UK play an important role carrying carbon from the surface to the seafloor.

This deep sea lizard fish was caught 2000 m down on the continental slope off the west coast of Scotland. The fish never comes near the surface but it eats fish that do, storing their carbon and leaving it on the seafloor when they die.
This deep sea lizard fish was caught 2000 m down on the continental slope off the west coast of Scotland. The fish never comes near the surface but it eats fish that do, storing their carbon and leaving it on the seafloor when they die.
Credit: C Trueman

The UK and Irish team found that the fish remove and store more than one million tonnes of CO2 from UK and Irish surface waters every year.

The research, published in Proceedings of the Royal Society B, used novel biochemical tracers to piece together the diets of deep water fish and reveal 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 therefore become a carbon capture and storage facility.

The ‘carbon chain’ begins at mid-slope depths, where a huge volume of animals make daily vertical migrations to feed at the surface during the night. These animals then transport nutrients from the surface back to the deep.

Fishes that live at or near the seafloor swim up to capture these mid-slope animals, bringing their biomass down to 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.’

As it is difficult to study animals living under a kilometre or more of water, the researchers measured forms, or isotopes, of carbon and nitrogen, in the muscles of fish caught in deepwater research surveys on the continental slope west of Ireland, at water depths ranging from 500 to 1800m.

Small differences in the mass of isotopes mean they are processed at slightly different speeds in the body, leading to patterns that show ‘who eats who’ in the slope ecosystem. By measuring the isotopes in the most common species, the researchers could estimate how much carbon is captured and stored by the deep water fish.

Source: University of Southampton







Published: 2010

Salinity changes show wetter wet regions, drier arid ones


Evidence that the world’s water cycle is changing, making arid regions drier and high rainfall regions wetter as atmospheric temperature increases, is contained in new research published online in the Journal of Climate.1

Ocean salinity changes indicate that arid regions are becoming drier.
Ocean salinity changes indicate that arid regions are becoming drier.
Credit: ScienceImage/Greg Heath

The study, co-authored by Hobart-based CSIRO scientists Paul Durack and Dr Susan Wijffels, shows the surface ocean beneath rainfall-dominated regions has freshened, whereas ocean regions dominated by evaporation are saltier.

The paper also confirms that surface warming of the world’s oceans over the past 50 years has penetrated into the oceans’ interior, changing deep-ocean salinity patterns.

The research was based on historical records and data provided by the Argo Program’s worldwide network of ocean profilers – robotic submersible buoys that record and report ocean salinity levels and temperatures to depths of two kilometres.


1 Journal of Climate, http://tiny.cc/mb35z




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