Just a few days after scoring a tour into Discovery Hut and a clear view of Mt. Erebus, steaming fumaroles and all, I went to the weekly Science Sunday lecture. This week’s topic was on benthic sea life in McMurdo Sound, which was pretty cool in itself, but it was the presenter that had the entire galley packed.
Paul Dayton started diving in McMurdo in the early 60s, back when they used wetsuits (not the super insulating drysuits of today… wetsuits. In Antarctic water. Under several meters of ice. Badass.) and sat in tubs of hot water between dives to keep from, you know, dying.
Well, he’s back.
He has returned several times over the years to check on his early experiments and do more research. In the forty-plus years since his first dive here, he’s become one of the world’s leading experts on benthic ecology and oceanography (benthic means the lowest level of a body of water such as the floor of an ocean or lake). He is basically a benthic rock star.
And what a nice guy.
His presentation was riveting on so many levels. There was science, history, a ton of humor and humility as he took time out to show slides of his mentors or people in his field that he felt we should know and be able to appreciate how they contributed to our understanding of how oceans work.
He began the presentation with a series of photos not of benthic life but of people, including some of the early explorers. He pointed out that, when he started diving in 1963, it had been 47 years since one of Scott’s guys (or was it Shackleton? Bad me, I should have taken notes… I was too busy being enthralled.) collected specimens of just about everything that lives in McMurdo Sound. And it has been 47 years between his first dive and now. I thought that was a neat way to think about the continuity of science.
There were more photos of McMurdo as it’s changed over the years he’s been coming to the Ice, including ones of the early toilets they used, their wetsuits and underwater images from his first dives that hold their own against modern digital photography surprisingly well.
He brought us into the science gently… you can tell he’s had a career as a successful college professor who taught a lot of first year introductory oceanography classes. He considers McMurdo Sound one of the most interesting environments to study on the planet, for a number of reasons. There is a bay on the west side of the Sound, for example, where currents are pushing water out from under the Ross Ice Shelf and, as a result, the environment looks like what you might find in much deeper water.
The east side of the Sound is full of massive volcano sponges, some the size of an SUV, which are preyed upon by a large but rare white starfish that itself has no predators. Some of his work has investigated why these starfish are so rare in the waters where they appear to thrive, unchallenged, with plenty of monstrous sponges to munch on. And he found out the answer: a much smaller red starfish, which is usually an herbivore, will go to town on the white starfish if it finds one. It becomes not just a carnivore, but a specialist that will latch on to the white starfish and eat nothing else.
The pace of benthic Antarctic sealife is itself interesting… remember how the marine biologists I met last week told me the Emerald cod was “a lazy fish”? Well, it’s not the only one. Growth rates and even consumption rates are staggeringly slow. Dayton and his team observed over the course of three years of diving that a starfish eating a sponge just didn’t move. For three years.
One of the reasons he’s down here again this year is to retrieve some of his earliest experiments, which he placed at a depth now considered too dangerous for divers, so they are using robotic remotes. He and another crazy scientist in a wetsuit placed all kinds of boxes and cages around sponges to see whether they fared better or worse when separated from predators. They also have placed many structures that look like the framework of artificial reefs in an attempt to give organisms a leg up, so to speak. They theorize that many larvae and other juveniles of various species get eaten by organisms on the sea floor… but that, if they land on the predator-free structures, they’ll survive and be able to grow.
Life came to the structures much more slowly than expected, though it got a big boost after the 1976 global oceanic regime shift.
Say what? Regime change in the oceans??
He mentioned that as an aside but you could sense the room take a collective gasp. Yes, apparently, back in 1976, and I know this because I went up after the lecture and asked him, the thermocline of the world’s oceans shifted. (Thermocline is, as I understand, a layer in the ocean water where the temperature differs more sharply from water above and below it than elsewhere in the vertical water column.) No one knows why. No one knows if it’s happened before. He said that back then technology wasn’t really up to the task of figuring out the whys of the 1976 shift, but that with all the money being thrown at climate change now, people are ready and waiting for it to happen again and figure out why.
It was unsettling and fascinating all at once to think about.
Several Kiwis from Scott Base also came to hear the lecture (I told you.. he’s an oceanographic rock star) and I can only wonder what they thought when, during the Q&A, someone asked whether increased commercial fishing in Antarctica could be expected to alter the organisms he was studying (none of which are themselves fished). He just lit into New Zealand’s expanding toothfish industry and said they should be ashamed of what they’re doing, and of course it’s going to have long-term, terrible impacts on the entire Ross Sea ecosystem.
Antarctic Toothfish, by the way, are typically sold as “Chilean Sea Bass” because we can’t get much Chilean Sea Bass any more, due to… yes, overfishing. I did some reading up on the Antarctic Toothfish industry after he said that and learned that the global fishing industry in general is estimated to have depleted 90% of the world’s fish.
We had just better hope that the oceans aren’t planning a global regime change that will knock us off our apex predator throne.