Sunday, May 13, 2018

Graves Light

Kristina rolled onto her side and peered back at me. She crossed her arms over one another across her chest and slowly drifted forward in the current. In that position, with her black drysuit and neoprene hood, she looked very much like an otter. I giggled at the thought of her cracking urchin shells on her chest with a rock.

I beat my own fins and swam forward to join her. The seafloor beneath us was covered in boulders - giant, impossibly heavy rocks that played host to amazing biodiversity. I kept running into rocks throughout the dive, not because I was struggling to control my buoyancy (this dive was the first time I actually have felt in full control of my buoyancy in my drysuit), but because I was too curious about what was living on the stones. I would hover over one, exhale to sink, and get my face as close to the organisms as my mask would allow. There were giant ribbons of kelp rippling in the water. Every rock was covered in thin, branching strands of red algae, and attached to the algal fronds were ascidians, or sea squirts. One of the species in particular caught my eye. It was white and had very small zooids (small individuals in the colony). It reminded me of Didemnum vexillum, an invasive sea squirt that I'll have to collect for a project later this summer. I concluded that it must be Didemnum albidum, the sister species that is native to New England. It lived in small blotches on fronds of red algae. I made a mental note that the easiest way to collect Didemnum specimens would be to just rip up bits of the algae. That could help during my project later this year.

Elsewhere on the rocks, Kristina and I noticed numerous small black objects, again clinging to the red algae. We both stopped swimming for a second and hovered there, placing one hand each on the rock to steady ourselves in the current. We debated what the black things were in a way that only SCUBA divers can. Speech was precluded by the presence of a regulator in each of our mouths, so we used hand signals. I shrugged at her to ask "What are they?" We each took a look. We exchanged signals for "clam?" and "I don't know." Then Kristina opened her hand and wiggled it like a fish swimming out of a cave. I had no idea what she meant, so we moved on. Back on the surface, with speech to our aid, she clarified she had meant to say "egg." I actually believe the tiny things were blue mussels, Mytilus edulis. They were all gaping, as mussels often do when feeding, with their fleshy insides and siphons exposed to the current. The ubiquity of adult shells strewn on the seafloor indicated that M. edulis certainly occurs at the site, and the little guys may have been this year's recruits.

Altogether, Kristina and I did two dives at Graves Light, a lighthouse on a rocky island that marks the entrance to Boston Harbor. It was a marvelous day. Every time I go out diving, especially if it's on a small boat, I go through the same series of thoughts. First, I am nervous for the dive and make sure I have all of my gear no less than 15 times. I am hot, queasy, and uncomfortable on the boat and start to ask myself why I ever bother to dive at all. I tug at my neck seal and gripe at my weights and get frustrated by the number of things that snag on my straps (SCUBA gear is not comfortable to wear on surface.) But then, as soon as I am underwater, every negative thought melts away. My mammalian dive reflex kicks in, my pulse slows down, my breaths lengthen, and I am mesmerized by the seafloor beneath me. Submerged habitats in New England have about the same level of biodiversity and fill the same function for me as the intertidal did in Oregon. It is where I go to decompress, to re-focus, to remember why I fell in love with the ocean in the first place.

On our second dive, Kristina and I again swam along the rocky seafloor, but we ventured a little farther than before. We found an area with even larger boulders and a sheer rock wall that rose from 15' depth to the surface. We ventured out over the sand a bit, too, and what we found there was a most impressive sight. Northern moon snails (Euspira heros) crawled across the sand with their fleshy, pale purple feet extended in a radius around their shells. I had always heard about moon snails but never seen them in person. Hovering there, watching the graceful mollusks glide along the sand, I felt like an alien visitor to another world. I could survey the planet's life forms from low altitude, but I was incapable of staying in their world for long.
A quintessential post-dive photo. Kristina still has her hood
on and is giving the "OK" symbol (used frequently underwater).
One of my braids has fallen out and my face is sun-kissed, but
we are euphoric. Graves Light is in the background.

Eventually, we began to get cold, and we were running out of gas. We found our way back to the boat's anchor, let air out of our suits and buoyancy compensators, and swam for the surface. I could feel the pressure release in my ears as we rose, not unlike during take-off in an airplane. We rolled onto our backs at the surface and paddled to the boat - now mimicking otter behavior almost perfectly. I took my gear off and settled down on the deck. The post-dive haze is a marvelous feeling, equal parts satisfaction, comfort, and euphoria.

We had two excellent dives to the bottom of the ocean. It was an awesome day.

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