Despite their unfortunate sounding name, hagfish ought to be regarded as heroes. For these unprepossessing, primitive fish helped the University of Otago's Dr Rebecca McLeod demonstrate an important link between forest and marine environments, opening the way for further research into energy transfer between ecosystems that will have far-reaching repercussions.

McLeod's findings, which in August earned the postdoctoral researcher the 2008 MacDiarmid Young Scientist of the Year Award, could also inform the development of coastal management policy in New Zealand. Not a bad rap for a spineless, jawless, finless, blind fish whose greatest claim to fame so far is the amount of sticky, slimy mucus it produces.

Marine scientist McLeod was first intrigued by the humble hagfish in 2003 when she was diving in Fiordland as part of a project aimed at measuring the photosynthetic activity of kelp. She remembers the odd, eel-like creatures being mysteriously attracted to an underwater gadget's electrical activity, which caused them to congregate eerily around her colleague's neck.

Hagfish are primarily scavengers, but also prey upon invertebrates. They have protudable mouthparts fringed with keratinous plates, rather than teeth, and can grow up to half a metre long. They feed on dead organisms they find in the dark using their acute sense of smell. As efficient seabed rubbish collectors they seemed ideal candidates for McLeod's research into Fiordland's marine food web.

While the principal dietary elements of Fiordland hagfish were already known, it was not clear how the organisms such as clams and worms, which hagfish eat, were obtaining their energy. In order to reveal the original source of hagfish's energy - the start of the food chain - McLeod used a series of tests based on naturallyoccurring biomarkers.

She took small samples of hagfish muscle, dried them, ground them into powder and had them analysed at the Iso-trace laboratory in the University's Centre for Innovation.

Relying on chemical biomarkers found within these tissue samples which could be traced to specific carbon sources - trees or marine plants, for example - McLeod followed the food chain back from the hagfish. She discovered that the seafloor animals her slippery subjects feed on are supported by bacteria which, through a series of chemical reactions, produce carbohydrate using the hydrogen sulphide emanating from "compost" on the seafloor.

These findings established that the animals hagfish ingest in the course of their bottom-foraging derive energy from decomposing terrestrial plant matter, linking the fish with the forests that blanket Fiordland's slopes.

Like ripples spreading outwards from a pebble hitting the water, the repercussions of McLeod's discovery are far-reaching. Her research highlights gaps in our understanding of energy transfer between terrestrial and marine communities that we are only just beginning to understand, and demonstrates a strong link between two apparently disparate ecosystems. This has major implications for the management of coastal marine and forest ecosystems, where the sustainability of one is clearly reliant on the survival of the other.

McLeod refers to energy transfer as "the fundamental ecological question".

"[Fiordland] affords us an insight into how our coastal ecosystem functioned before humans started cutting down trees," she says. "We need to think about the amount of land that has been cleared in New Zealand and the subsequent effects on the coastal marine environment."

McLeod also suggests we need to rethink the "compartmentalisation" of ecological sciences if we are to tackle such environmental management challenges.

"We're trained to think in departments," she says. "I'm a marine ecologist, there are terrestrial ecologists, and generally we don't go to each other's conferences."

All that is changing, however, as a result of the kind of research McLeod and other scientists are doing, and as we begin to understand ecological interconnectedness as a result. But McLeod warns that environmental-management decisions must continue to be informed by science. She voices concern that the Department of Conservation's and the Ministry of Fisheries' Marine Protected Areas Strategy, which will see decision-making about coastal environmental protection devolved to regional stakeholder committees, could result in the dilution of science's influence on decision-making.

"To make decisions about where to put marine reserves you need good scientific information. Yet one of the worrying things is that scientists will be just one of up to 14 stakeholding groups and our voice will have no more weight than any other."

McLeod's research takes her next to Antarctica, where she joins a team applying similar methodologies as those she adopted in Fiordland to help understand how the Antarctic marine ecosystem withstands the long, dark winters.

"To make decisions about where to put marine reserves you need good scientific information."

"Down there the sun creates a short pulse of productivity once a year when there's a burst of algal growth on the underside of sea ice. When the ice retreats, the algae fall to the seafloor, so we're looking to see how that energy is transferred and recycled through the remainder of the year, helping to sustain life."

Meanwhile, the unassuming hagfish will have to await further glory in other fields. McLeod says there is a lot of "cool" hagfish research going on internationally, including investigations into the medicinal potential of its strangely elastic and antimicrobial slime.

"Hagfish are proving to be excellent indicator species for energy studies in a range of marine environments," says McLeod. "They live all over the globe and are found in the deepest parts of the ocean. Scientists studying hydrothermal vent communities (around 'black smokers') have used hagfish to determine how much of the communities' energy is derived from sulfur bacteria and how much comes from marine algae. It turns out that I am not the only one addicted to the slime!"

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