Snap­shots from the abyss

The Monthly (Australia) - - THE NATION REVIEWED - NI­COLE GILL

The smells of ethanol and fish hang in the air as Dr Dianne Bray, Mu­se­ums Vic­to­ria’s se­nior col­lec­tion man­ager for ver­te­brate zo­ol­ogy, ex­tracts a small, bull­dog-faced fish from one of an ar­mada of glass jars. In the Ichthy­ol­ogy and Her­petol­ogy Lab at Mel­bourne Mu­seum, she and Dr Martin Gomon, se­nior cu­ra­tor of ichthy­ol­ogy, are show­ing off the spoils of their abyssal sur­vey.

Both sci­en­tists spent a month from mid May to mid June aboard CSIRO’s re­search ves­sel, the In­ves­ti­ga­tor, work­ing along­side 40 other sci­en­tists and sup­port crew on a pro­ject spear­headed by Mu­se­ums Vic­to­ria. The Sam­pling the Abyss ex­pe­di­tion sur­veyed Aus­tralia’s east coast abyssal wa­ters from Tas­ma­nia to Queens­land, mostly at depths be­tween 2500 and 4000 me­tres be­yond the con­ti­nen­tal shelf. An in­ter­na­tional team of sci­en­tists is now en­gaged in the lengthy process of pre­serv­ing,

iden­ti­fy­ing, la­belling and cat­a­logu­ing the ex­pe­di­tion’s deep-sea trea­sures for re­searchers present and fu­ture.

When deep-sea crea­tures are hauled from the depths, they rarely emerge alive. On board the ship, their bright colours and bi­o­lu­mi­nes­cent fea­tures rapidly pale, and they are quickly posed for di­ag­nos­tic por­traits be­fore their life lights com­pletely fade. Work­ing swiftly, sci­en­tists “fix” the spec­i­mens’ flesh with for­ma­lin be­fore de­cant­ing them into ethanol for longer-term stor­age. But Bray and Gomon’s lab feels less like a morgue than a place of lively en­quiry.

Bray ges­tures to­wards the jars of pickled crea­tures – squat-bod­ied fish, night­mar­ish loose­jaws with mouths like pray­ing man­tid arms, face­less eels, cook­iecut­ter sharks the length of bak­ing trays – each afloat in its own small preser­va­tory sea. “These are part of our li­braries of life, for peo­ple who are not yet born.”

Gomon is par­tic­u­larly in­ter­ested in tri­pod fish: small, slen­der, sil­very crea­tures that use their elon­gated pelvic fins to prop them­selves on the ocean floor, their noses pointed into the cur­rent. Al­though they have eyes, these are prob­a­bly ves­ti­gial – there is no light in the abyss by which they might see – and they rely in­stead on wa­ter move­ments to push prey past them. Care­fully an­gled pec­toral fins tilt for­wards to form a kind of net, and the fish use their fins to herd any un­lucky crea­tures swept into them to­wards their mouths.

Sit­ting along­side the tri­pod fish is a coffin­fish – a pale, boxy-look­ing crea­ture about the size of a rock­melon – the first of its kind found in Aus­tralia, and pos­si­bly an en­tirely new species. Gomon points out a line of con­spic­u­ous pores that runs from the fish’s mouth to its tail. These form part of a lat­erosen­sory sys­tem that picks up move­ment. In fish from shal­lower wa­ters, these pores tend to be much smaller, bet­ter cov­ered or more sunken, to block out the white noise of ev­ery­day fish life – the crash of waves, and the chat­ter and slosh of thou­sands of other an­i­mals. But in the depths of the abyss, al­though there are cur­rents, there’s vir­tu­ally no white noise, and hav­ing larger pores al­lows crea­tures like the coffin­fish to open them­selves up to lis­ten to the whis­pers and clicks of the deep, dark ocean.

It’s ex­pen­sive to study the abyss. “The num­ber of spec­i­mens in [pre-ex­ist­ing] col­lec­tions is very small for vir­tu­ally all of the species,” says Gomon of the tri­pod fish fam­ily, and this ob­ser­va­tion holds for many of the crea­tures cap­tured by the In­ves­ti­ga­tor.

Ver­te­brate an­i­mals like fish form only a small part of the biota found liv­ing within the abyss. Me­lanie Macken­zie is a col­lec­tion man­ager for marine in­ver­te­brates at Mu­se­ums Vic­to­ria. When we meet, she apol­o­gises for smelling of sea cu­cum­bers. Sea cu­cum­bers, or holothuroids, are her spe­cialty and pas­sion.

Not all sea cu­cum­bers are built alike. The In­ves­ti­ga­tor’s sam­pling brought up spec­i­mens shaped like foot­balls, one with a cape-like velum, and some cov­ered in papil­lae stick­ing out like bris­tles on a hair­brush. Macken­zie pulls out a jar con­tain­ing some ben­thic sea cu­cum­bers, which, as she ex­plains, “sort of work like vac­uum clean­ers, crawl­ing along the bot­tom”. The sea cu­cum­bers are off-white, with tube feet and feed­ing ten­ta­cles. “To be per­fectly hon­est, they al­ways look pretty crud once they’re in a jar,” Macken­zie says cheer­fully, “but when they’re un­der the ocean, they’re pretty cool!”

The ex­pe­di­tion used un­der­wa­ter cam­eras, and some of the ob­served sea cu­cum­ber be­hav­iours were quite un­ex­pected. “I’ve al­ways thought of sea cu­cum­bers as crawl­ing,” says Macken­zie, “but a lot of them can ac­tu­ally jump up enough to get caught in a cur­rent and move along.”

Not all of the spec­i­mens from the abyss were bi­o­log­i­cal in ori­gin. “Un­for­tu­nately, we found quite a lot of rub­bish, even down to 4500 me­tres.” Macken­zie points to a tray of de­bris – bits of old rag, rope, chunks of plas­tic, an old beer can and some fist-sized lumps of rock. “This is coal, and this is clinker from the steam ships.” Clinker is the residue that formed on the in­side of pipes when coal was burned. Steamer crews would have chipped it out of the pipes and thrown it over­board. “You’re talk­ing about a hun­dred years ago,” says Macken­zie. “Once it goes in, it doesn’t come out.” Ad­ja­cent to the rub­bish sam­ples is a jar con­tain­ing two fat ghostly prawns, cov­ered in some kind of sticky, blood-red residue, which the sci­en­tists think is prob­a­bly lead-based anti-foul­ing paint from ships. De­spite the great depths of the abyss, it is not im­mune to hu­man harm.

“We do af­fect it a lot,” says Macken­zie. “Any­thing that’s on the sur­face of the ocean even­tu­ally ends up at the bot­tom.”

A third of Aus­tralia’s marine ter­ri­tory falls within the abyss, and Macken­zie says that while there will be decades of work in the ma­te­rial from the ex­pe­di­tion there’s still a lot more to dis­cover.

“It’s im­por­tant that we keep ex­plor­ing and keep look­ing, but we also need to think about how we as hu­mans are af­fect­ing that en­vi­ron­ment, and about how things like cli­mate change might af­fect it too.

“If we hadn’t been down there and col­lected these an­i­mals now, we wouldn’t be able to go back and say, ‘Oh, these ones are gone,’ or ‘This is what’s changed.’ So it’s im­por­tant to get a snap­shot in time, and in space. And that’s what mu­se­ums and col­lec­tions are about.”

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