At Sea
Yesterday we made a landing on the South Orkney Islands next to a large colony of chinstrap penguins. There was a steep climb from the boulder-strewn beach, but not nearly as steep as the glacier-carved cliffs on the opposite side of the small bay. And the glacier? Yes indeed, it too was still there, although not nearly as mighty as its former self, the youngster that carved the cliffs. Now, in the autumn of life, it clung tenaciously to a precipitous wall, a frozen cascade, but sluggishly animated as evidenced by recent avalanches from high above that had tumbled sparkling white shards of ice across its snout and the sea. During each shuttle I found myself gazing at the glacier and wondering what lived in the water at the base of this amazing piece of mobile geology. After the landing we took out the ROV, a marvelous technology to satisfy my curiosity, to explore and record, for learning and sharing. We found the bottom at a mere 160 feet of depth, muddy silt, soft and pock-marked from a rain of stones dropped by the fast ice during the spring thaw, but little life and that mostly smothered by the shifting bottom. Disappointed we moved to the base of the cliff. The bottom here was somewhat more stable and the view of a vast field of clam siphons surprised us. What we were seeing was probably the Antarctic soft-shelled clam, judging from the siphon architecture and the habitat. Well adapted to an uncertain environment, not only can this clam burrow relatively deep for protection from iceberg scouring, it can also stretch or dig upwards or downwards as the sediments drift. As a last resort, if the clam is uncovered, it has a unique ability to crawl across the bottom using its muscular siphon and make jerky jumps by producing jets of water. But there is danger on the mud, nomadic predators, sea stars and ribbon worms patrol the bottom, as pictured in today’s web shot. The sea star is Odontaster validus, which I call the scrumming star as we often see them in piles. Small but bold, they will attack much larger animals. As is usual for sea stars, they can feed by everting their stomach out of their body to digest their prey. However, for a large victim a single scrumming star can only inflict a minor wound, but like sharks other sea stars are attracted to the ‘odor’ of the prey’s bodily fluids, not only sea stars, but also the more formidable ribbon worms. The ribbon worms are up to six foot long when fully stretched, but more often they are constricted and thickened to a length of about two feet, a transition they can effect in a matter of seconds…more than somewhat creepy to witness. They have a vast sucking mouth armed with a poison-tipped dart; their bodies are protected by a noxious, toxic slim. Together with the sea stars they are the stuff of nightmares and the stuff of life as the cycle turns once again to the elements and the next tropic level.
Yesterday we made a landing on the South Orkney Islands next to a large colony of chinstrap penguins. There was a steep climb from the boulder-strewn beach, but not nearly as steep as the glacier-carved cliffs on the opposite side of the small bay. And the glacier? Yes indeed, it too was still there, although not nearly as mighty as its former self, the youngster that carved the cliffs. Now, in the autumn of life, it clung tenaciously to a precipitous wall, a frozen cascade, but sluggishly animated as evidenced by recent avalanches from high above that had tumbled sparkling white shards of ice across its snout and the sea. During each shuttle I found myself gazing at the glacier and wondering what lived in the water at the base of this amazing piece of mobile geology. After the landing we took out the ROV, a marvelous technology to satisfy my curiosity, to explore and record, for learning and sharing. We found the bottom at a mere 160 feet of depth, muddy silt, soft and pock-marked from a rain of stones dropped by the fast ice during the spring thaw, but little life and that mostly smothered by the shifting bottom. Disappointed we moved to the base of the cliff. The bottom here was somewhat more stable and the view of a vast field of clam siphons surprised us. What we were seeing was probably the Antarctic soft-shelled clam, judging from the siphon architecture and the habitat. Well adapted to an uncertain environment, not only can this clam burrow relatively deep for protection from iceberg scouring, it can also stretch or dig upwards or downwards as the sediments drift. As a last resort, if the clam is uncovered, it has a unique ability to crawl across the bottom using its muscular siphon and make jerky jumps by producing jets of water. But there is danger on the mud, nomadic predators, sea stars and ribbon worms patrol the bottom, as pictured in today’s web shot. The sea star is Odontaster validus, which I call the scrumming star as we often see them in piles. Small but bold, they will attack much larger animals. As is usual for sea stars, they can feed by everting their stomach out of their body to digest their prey. However, for a large victim a single scrumming star can only inflict a minor wound, but like sharks other sea stars are attracted to the ‘odor’ of the prey’s bodily fluids, not only sea stars, but also the more formidable ribbon worms. The ribbon worms are up to six foot long when fully stretched, but more often they are constricted and thickened to a length of about two feet, a transition they can effect in a matter of seconds…more than somewhat creepy to witness. They have a vast sucking mouth armed with a poison-tipped dart; their bodies are protected by a noxious, toxic slim. Together with the sea stars they are the stuff of nightmares and the stuff of life as the cycle turns once again to the elements and the next tropic level.
