From the Edge of Darkness to the Black Abyss - Census of Marine Life

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* At about 500 meters (~.3 miles): the Antarctic’s first recorded whalebone-eating worm,Osedax. Seventeen species had been reported on other fallen whales in such places as theshallow northeast Atlantic off Sweden, the northeast Pacific off California and thenorthwest Pacific off Japan. CeDAMar scientists attached whalebone snacks to twovehicles and parked them 550 and 630 meters (~.34-.39 meters) deep near Smith Islandnear the West Antarctic Peninsula. When they raised the parked vehicles after 14 months,they found the same creatures in the Southern and Antarctic Oceans. Analyzing thepopulations crowded onto the parked vehicles they found new species of the whaleboneeatinggenus Osedax. A mat of chemosynthetic microbial fauna and the small marineworm Ophryotrocha that eats bacterial mats covered the raised vehicles.Diversity and abundance in mud: the living skin of the abyssOn the abyssal floor, the deep mud contains biodiversity that escapes detection by videoand photography since most of the animals are only a few millimeters in size and hideamong the sediment particles.“Some scientists have likened deep mud's biodiversity to that of tropical forests. Incollege I was taught that high biodiversity is a function of habitat diversity – many nooksand crannies. It is, however, hard to imagine anything as monotonous, nook-less andcranny-less as deep-sea mud,” says Dr. Carney.Sometimes, the vast majority of creatures collected in mud from the abyssal plains arenew to science, says CeDAMar expert David Billett of UK’s National OceanographyCentre.Of some 680 specimens of copepods collected on a recent CeDAMar cruise (DIVA 2) tothe southeastern Atlantic, for example, only seven could be identified; 99 percent werenew to science. And among hundreds of species of macrofauna (animals about the sizeof an earthworm) collected in different areas, 50 to 85 percent were unrecognized.“The abyssal fauna is so rich in species diversity and so poorly described that collecting aknown species is an anomaly,” says Dr. Billett. “Describing for the first time all thedifferent species in any coffee cup-sized sample of deep-sea sediment is a dauntingchallenge.”(Photo 10, right) What appears to be an ancient gold treasure is amagnified crustacean, a tiny copepod collected this year from theAtlantic abyss.Deep Sea News Release – Page 6
Far rarer than new species in the mud is the capture of a new species of sea cucumber,and rarer still a new genus. However, Dr. Billett and colleagues from the NationalOceanography Centre and the Shirshov Institute, Moscow, accomplished this feat thisyear around the Crozet Islands after steaming for a grueling six days south from SouthAfrica.One of the new sea cucumbers was yellowish-green, a rare find as virtually all othersfound in the global seas are whitish grey or purple.However, what startled researchers most was finding that the most abundant seacucumber around the Crozet Islands – thousands of specimens at abyssal depths – was aspecies never seen anywhere else before, now dubbed Peniagone crozeti.“The distribution of species in the deep sea is full of mysteries,” says Dr. Billett. “Inaddition to the boundaries caused by underwater topography, ridges and seamounts, thereare unseen, and as yet unexplained, walls and barriers that determine supplies of food anddefine the provinces of species in the deep sea.”“There is both a great lack of information about the ‘abyss’ and substantialmisinformation,” says Dr. Carney.“Many species live there. However, the abyss has long been viewed as a desert. Worse,it was viewed as a wasteland where few to no environmental impacts could be of anyconcern. ‘Mine it, drill it, dispose into it, or fish it – what could possibly be impacted?And, if there is an impact, the abyss is vast and best yet, hidden from sight.’“Census of Marine Life deep realm scientists see and are concerned.”Expensive, dangerous work“The deep sea is the Earth’s largest continuous ecosystem and largest habitat for life. Itis also the least studied,” says Dr. German.Sampling at great depths depends on high tech instruments (such as remotely operatedvehicles (ROVs), autonomous underwater vehicles (AUVs), and submarines) or“traditional” equipment (trawls, cores, dredges) that need several kilometers of cable toreach the seabed. For example, 12 km (~7.5 miles) of cable was needed to trawl recentlydown to 4,800 meters (~ 3 miles) depth on the Porcupine Abyssal Plain in the NortheastAtlantic.Earlier this year, CenSeam scientists aboard New Zealand-based Research VesselTangaroa underlined the grueling nature of the challenge of obtaining samples, maps andDeep Sea News Release – Page 7
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From the Edge of Darkness to the Black Abyss - Census of Marine Life

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