A Wild Volvox

Seldom does a day pass when I fail to learn something new from the guests on my tour. Today, a pair of freshwater ecologists from Chicago taught me about the life of Lost and Found Lake.

A dragonfly's-eye view of Lost and Found Lake.

Our dragonflies live four to five years as nymphs, chomping on mosquito larvae and overwintering in lake-bottom muck. They molt from nine to twelve times before finally emerging as royal-blue, winged adults. They fly for one summer before dying in the frosts of fall.

Damselflies go through a similar process but spend only two to three years as nymphs, a stage in which they have three tails and long, wriggly body. We found dragonfly and damselfly nymphs when I scooped lake water into my frisbee. (Just one more reason why you should never leave home without one!)

But the most incredible discovery of all came from the ecologists' daughter who scooped a firm, transparent goo blob from the lake. I'm used to unidentified blobs in the intertidal zone, but in freshwater I was out of my element.

Frog eggs? Nope, we have only one amphibian in Alaska (the wood frog, Lithobates sylvaticus) and its eggs look more like clear grapes with a black dot in the middle.

Snail eggs? Perhaps, though I've never seen a snail in this lake.

Then I looked closer. Thousands of tiny green dots were aligned within the blob, perfectly ordered like soldiers on the march. At the edges of the blob, where upper and lower surfaces overlapped, the dots gave a mossy sheen to the blob.

Could it be... Volvox? The spherical, chlorophytic protist from introductory bio lab?

The ecologists and I leaned in. "Look, it has five gas bubbles trapped inside!" one exclaimed. "I think it's respiring!" Oxygen building up inside was the final clue, and the blob was proclaimed to be Volvox.

A wild Volvox!

I sacrificed my water bottle for our new friend's transport. Back at the field station, we peered through a microscope to see the tiny green dots up close. They didn't look round, but rather like commas, and they jiggled like worms trapped in a force field.

Volvox is an important tool for biology education because it displays both sexual and asexual reproduction. Asexual reproduction is cooler: miniature, spherical daughter colonies form within the parent blob and are released into the world.

Scientists think Volvox switched from a single-celled organism to a communal enterprise about 200 million years ago, and research into that transition is providing clues about how the evolution of cooperation allowed our single-celled ancestors to become the plants and animals of modern times.

It always startles me to see laboratory species in the wild. The same thing happened with slime mold. In high school, I made mazes for slime mold using oats and Petri dishes, then filmed its decision-making with a time-lapse camera. Slime mold was recently featured in Nature for redefining intelligence! Now, on my daily hikes, I notice slime mold inching around the rotting logs of its home, the coastal temperate rainforest.

A banana-yellow slime mold seeks shade in the forest of Peterson Bay Field Station.

Watching slime mold and Volvox do their thing in the wild reminds me of the importance of intact ecosystems. Without old-growth rainforests and healthy lakes, scientists would never have encountered these model organisms that have led to dozens of laboratory-based discoveries and a better understanding of topics ranging from memory to cellular reproduction to our own evolution. 

Imagine how many more organisms are out there in unexplored regions of the Amazon, the Arctic, or the deep sea. Who knows what strange life form is going about its daily business of eating, competing, and reproducing, just waiting to be discovered next?

Share:

Read More

The Dismemberment of an Eight-Legged Giant

Our Alaskan ocean, with its cold year-round temperatures and high oxygen content, is home to some of the largest creatures in the world. One enormous mollusk happens to be as intelligent as she is large, and she's all the more intriguing for her eight arms, hundreds of suction cups, and quaint hobby of collecting shiny objects: the giant Pacific octopus.

These clever invertebrates average 16 feet in length and 110 pounds, but the record-holder was measured at 30 feet and 600 pounds! They also live longer than other octopuses, but don't expect much. They last around four years, with both males and females dying shortly after breeding.

Naturalist Kim points out an octopus den at China Poot Bay.

Octopuses live in dens that are submerged at all but the lowest tides. As a bonus, they prefer dens with two holes: both front and back doors.We were lucky to find this den at low tide. When Kim tickled the entrance with her finger, a red tentacle swooped out to investigate.

When searching for octopus dens, keep your eyes out for the midden, a trash pile of helmet-crab exoskeletons and snail shells discarded by the octopus.

Live octopuses are cool and all, but this blog is about a dismemberment, so let's get to the point!

On June 4th, a dead giant Pacific octopus washed up on Otter Rock.

The limp form of a freshly-dead octopus.

When the tide went out, I descended the rocky shore to investigate.

The octopus was smothered by another of our ocean's giants: sunflower stars! I knew these monstrous, soft-bodied stars to be predators of other sea stars, but I knew nothing of their fondness for octopus meat.

My hand for scale. The tentacles was thicker around than my arm, and the sunflower star could have covered my entire face and wrapped around to the back of my head. (I had no intentions of letting it.)

The octopus was stone-dead, but her sucker still held my finger tight was I pressed on it.

This squishy sunflower star was waiting for the tide to come back in so he could move freely over his meal.

My favorite shot. I love the juxtaposition of tube feet and suction cups: the echinodermatan and molluscan solutions for the tasks of moving around and holding on. 

Here's a video of the tube feet in action!

Three days later, the octopus had disappeared from the low intertidal zone and reappeared high-and-dry upon Otter Rock. The pair of bald eagles were spotted dragging and pecking it. The octopus's carbon was redistributed first to deep waters, then to the crown of a spruce tree, and who knows where else.

Each day I asked one of my visitors to be an octopus model -- for scale and, of course, the cute factor.

June 7th: "There it is, but I'm not touching it!"

June 8th: "There it is! Can I touch it?"

On June 8th, it smelled like bacteria were joining the food chain.

The suction cups, however, were still intact.

June 12th: my octopus models were unwilling to get any closer than this. I thought they were still brave, considering the stench and general goopiness.

June 12th was the last day our dear dead octopus was seen. Whether she got dragged into the woods by a bear or deep under the sea by a seal, or was chewed into goo by microbes during the next few tide cycles, we'll never know.

In theory, I knew that elements are recycled and dead things make up the living. But after watching the swift dismemberment of an octopus into the vibrant life of the intertidal zone I admire daily, I feel included in a secret.

On June 25th, I watched one of the three bald eagle chicks flap his wings for the first time.

Now, when I spy on our bald eagle chicks through my binoculars, I think of the octopus midden. In the chicks' emerging flight feathers, I see helmet crabs that became octopus that became eagle.

Share:

Read More