Going Solar

It seems like the news on energy these days is all about solar. Solar collectors, community solar programs, solar getting cheaper than fossil fuel. Solar, solar, solar. We humans may think we're hot stuff for figuring out how to harvest the energy from the sun for our own needs, but other animals have been using their own kinds of solar panels for eons.

In particular, corals and sea anemones have been acting as green power plants since the times of the earliest dinosaurs. Which is pretty clever when you consider they don't have a brain. Of all the photosynthetic cnidarians out there my favorite has got to be the Aggregating Anemone (Anthopleura elegantissima) AKA the Pink-tipped Anemone.

You can probably guess how it got those names.

Courtesy: Bureau of Land Management via Flickr

If you live on or have visited the Pacific coast of North America, you probably recognize this anemone. They're extremely common very high in the intertidal zone. Which means that if you've ever visited a rocky beach when the tide was even a little low, you've probably encountered these anemones. They're often found in large aggregations, hence the name. These mats of anemones would be astonishing just for their sheer number, but they're even more incredible when you realize each colony is a series of clones.

Have you ever had one of those days where you're so ambivalent about a decision that you wish you could just tear yourself in two and do both? Well aggregating anemones basically have that luxury. They're so good at restoring their tissues after damage that they can literally pull themselves in two different directions and split into separate anemones.

"I weigh a fraction of what I used to, thanks to the elgantissima 
weight loss program!"
Courtesy: Brocken Inaglory via Wikipedia

If the conditions on a particular rock are good enough; one anemone will make many clones, which will make many clones, and so on, and so on until entire sections of beach are covered in copies of the original. These colonies work together to make each individual anemone more successful. Some anemones will specialize in spawning and produce more eggs and sperm than the other clones. Anemones at the edge of the colony will grow more stinging cells than those toward the center, and act as warriors to defend the colony from predators and other aggregating anemones trying to horn in on their turf. If Lenin had a spirit animal, it was probably pink-tipped anemones.

Fight, fight, fight! The white bulbs are sacks of densely packed
stinging cells used to ward of predators and other anemone colonies.
Courtesy: Brocken Inaglory via Wikipedia

Okay so aggregating anemones are pretty cool on their own, but what do all these adaptations have to do with collecting solar energy? Everything. Just under the skin of aggregating anemones live colonies of dinoflagellates, single-celled algae, or both. In the southern portions of the anemone's range you only find dinoflagellates in their tissues, but further north you find a combination of algae and dinoflagellates. We believe that the dinoflagellates are better able to tolerate warm water, and that the algae may help the anemone collect more sun where the days are shorter in fall and winter.

Dinoflagellates (pronounced: dai-no-fla-jell-ates) are a confusing single-celled organism that isn't quite animal and isn't quite plant. Most are a single cell with a wavy appendage like a sperm tail called a flagella. Many can both consume food and produce it via photosynthesis. The dinoflagellates under the skin of aggregating anemones are exclusively photosynthesizers and they're only found living in the tissues of cnidarians.

These individual cells work like the individual panels on a solar array. When exposed to sunlight each cell produces carbon and oxygen, both essential ingredients for the chemistry of life in complex organisms. Aggregating anemones harvest these products from their photosynthetic roomates just like electrical engineers harvest electricity from photovoltaic panels. In turn the anemone maintains the solar power plant by producing carbon dioxide, and waste. Carbon dioxide, which the anemone breathes out, is an essential ingredient in photosynthesis, and animal waste is full of the nutrients plants crave.

The anemone's green-blue color actually comes from the algae
and dinoflagellates in the skin. This clear one probably lives in 
the shade of a large boulder and so doesn't host photosynthesizers.
Courtesy: Peter Pearsall/USFWS via Flickr

Now it's not as easy being a living solar farm as it is being a synthetic one. Human solar arrays can be made of glass and other materials that resist wear and tear, but anemones and their symbiotic solar cells are made of good old squishy, damageable protein.

In order for their symbionts to do photosynthesis, aggregating anemones have to live where there's plenty of sun, hence their high position in the intertidal. However, as any fair-skinned individual can attest, sunlight is loaded with ultraviolet radiation which wreaks havoc on organic tissues. In order survive exposure to all that radiation aggregating anemones have to possess some unique defenses. Thankfully the dinoflagellates secrete a chemical that coats the anemone's cells and acts as a sunscreen. The chemical absorbs the most dangerous parts of the UV and dissipates them as softer visible light.

Of course they say help comes to those who help themselves, and the anemone pulls its own weight in protecting its investments. Along the sides of aggregating anemones are little sticky bumps called verrucae (pronounced: ver-oo-key). The anemone uses its verrucae pick up particles of shell, sand, and other materials. These bits act like a big floppy sun hat to protect the anemone's sensitive skin.

Who Wore it Better? Sandy Beach Edition.
Couretsy: A. Strakey & Diane Main via Flickr

 Even though the anemones have solved the sun exposure problem, there's even more challenges to running a living solar facility. Photosynthesis produces oxygen, which is great if your tide pool is getting hot and losing gas to the atmosphere, but not so great if you're cells start to fall apart from oxidation. Oxygen is a really powerful molecule because it often comes in a form you might of heard of called a free radical. Free radical oxygen has characteristics that make it pull other molecules apart, which is why oxygen is toxic in high concentrations. So if the algae and dinoflagellates are phtosythesizing away, pumping free radical oxygen almost directly into their hosts cells, the anemone could die of oxygen poisoning. Thankfully the anemone's body produces high concentrations of chemicals that bind with free radical oxygen and render it harmless.

The final challenge for an organism trying to run a biological green power facility brings us back to where we started at the anemone's position along the shore. Living high up the beach means that a couple of times a day the tide is going to go out on you. If you're an animal that's normally adapted to living underwater that's a challenge. The shells and sand grains on the anemone's stalk will help block some of the desiccating effects of the dry air, but it's not always enough; so aggregating anemones hold their breath. As the tide recedes the anemones suck as much water as they can into their body cavity to keep them moist and oxygenated while the water is out. If you've ever touched an aggregating anemone and it squirted you, you know what I'm talking about. Careful though, as making them spray their water is kind of like telling your friend to hold their breath and then punching them in the gut. Sure its funny as the air or water comes rushing out, but the anemone/guy who just got punched is left very winded and uncomfortable.

"Anemone Punch" The new album from Olympia punk band: Cnidaria 
Courtesy: Ingrid Taylor via Flickr

More and more, engineers are drawing inspiration from nature for building materials that improve our daily lives. If the flippers of humpback whales can make wind turbines more efficient, maybe we can draw inspiration from nature's original solar plants to improve other areas of green infrastructure. It's a beautiful irony that the fight to save species from climate change might be resolved by looking at the very animals we're trying to protect.

References:

Furla et Al.. "The Symbiotic Anthazoan: A Physiological Chimera Between Alga and Animal", Integrative and Comparative Biology, vol. 45, issue 4, pg 594-604, 2005

Accessed via: https://academic.oup.com/icb/article/45/4/595/636401/The-Symbiotic-Anthozoan-A-Physiological-Chimera 

Lajeunesse, T.C., & Trench R.K., "Biogeography of Two Species of Symbiodinium (Freudenthal) Inhabiting the Intertidal Sea Anemone Anthopleura elegantissima (Brandt)", The Biological Bulletin, vol. 199, no. 2, October 2000

Naut Again

Oh wow, there's some wonderful news that's come out of the US East coast recently that hasn't gotten the coverage it deser....

"NAUT SO FAST PUNK!"

Courtesy: DarTar via Wikimedia Commmons

Oh, god no, not this again. How many weeks am I going to have to go without getting interrupted by a cephalopod? What do you want chambered nautilus (Nautilus pompilius), and did you seriously just use your own name as a pun?

"I'll use my name however I want after you and that wannabe 

Greek hero besmirched it. She should be proud to be 

associated with us nautiluses."

Courtesy: Michael Bentley via Flickr

Alright, alright, I didn't mean to offend anyone. I wrote about argonauts last week since they're a cool family in their own right. I guess I didn't think about how little people know about your family too. Tell you what, I'll make this post all about you, if you promise to tell the other cephs to stop interrupting me. I don't want a ram's horn squid butting in next week.

"Alright deal, but I'm gonna stand here and make sure you do us justice"
Courtesy: OCVA via Flickr

Okay well, if we're gonna give this family the credit it deserves we need to talk about world domination. Don't worry, you needn't imagine a future where shelled overlords subjugate earth's other species, because it already happened. Nautiluses are old, very old, in fact their family members are the OG cephalopods. The first nautiluses to appear had straight shells, but around 400 million years ago they developed the familiar spiral we see today. They were so successful that they, and their cousins the ammonites, would go on to dominate the seas for eons. Nautilus even survived the worst extinction of all time which killed 96% of all life in the sea. Not too shabby for an animal that's essentially a fancy snail.

Even though they ruled the oceans for so long, the nautiluses eventually gave up their family's dynasty to live a life of quiet retirement. Today only two genera of nautilus exist, down from the 75 or so at their peak. Modern nautiluses are found only in the Indian and Pacific oceans in the deep waters at the steep edges of coral reefs. Yet they are some of the most fascinating organisms to occupy those spaces.

Of course what stands out most about nautilus is their incredible shells. Nautilus are the only cephalopod left to still have an exterior shell, which means they don't need all the gaudy color and texture changing flashiness of their cousins. Instead of hiding, speeding away, or out-thinking their predators nautilus prefer the simple life scavenging food off the bottom; and cruising through deeper water at times when predators are at rest.

They're kind of like that friend from college who moves to
 Idaho and starts a goat farm because "It's just easier."
Courtesy: Hans Hillewaert via Wikimedia Commons



Now you might notice that the nautilus' shell is pretty burly. There are hardly any animals with shells that thick that even bother swimming. Other heavily shelled mollusks like clams and snails spend most of their time on or in the ground. So what does the nautilus do that makes it able to hover up in the water like that? Are they just incredibly strong? Not really. When you watch a nautilus puff along by forcing water through its siphon, it kind of makes you want to hand it an inhaler and tell it to go sit on the bleachers. So if it's not pure herculean strength that keeps the nautilus afloat what is it? Well my friends, the nautilus succeeds thanks to the magic of good engineering.

I think like a third of our readers just found their spirit animal
Courtesy: Jason Westley Upton via Flickr

Inside the shell are the structures that put the "chambered" in chambered nautilus. The largest chamber is where the nautilus' mantle is housed, but the others are empty of everything except air and a little bit of water. When a new chamber forms the nautilus walls its previous space off and amazingly, drains the water. See if the chambers stayed filled then the nautilus would get dragged to the bottom thanks to the weight of the water inside the shell. Emptying water from the chambers has the same effect as if the nautilus were to tie balloons to its shell. The air inside pushes up towards the surface while the weight of the shell pulls down, and the two forces balance one another out to make the nautilus neither sink nor float.

You might be wondering: If the nautilus seals the chambers how does it get the water out? Well running through the chambers is a really cool organ with a really cool name, a siphuncle (pronounced: sigh-fun-kull). The siphuncle is a tube that uses water's own physical properties to fill and empty the chambers. See water has a tendency to try and balance the concentrations of different minerals dissolved in itself. So if you put a screen that will only let water through between two solutions and you make one much saltier than the other; the water will cross the screen to the salty side until the two sides' ratios of salt to water are equal. This is exactly what the siphuncle does. When the nautilus wants to remove water from the chambers it adds salt ions to the outer layer of the siphuncle and the water just seeps on out of the chamber. When the nautilus wants to add water to the chambers it does the opposite. This system requires basically no energy on the animal's part, so it's a great strategy for staying properly buoyant.

Who says functional machines can't be pretty? Those little struts in the center 
of each chamber hold the siphuncle in place as it runs through the shell.
Courtesy: Jitze Couperus via Flickr

Of course everyone focuses on the shell of the nautilus, so much so that these animals are being impacted by fisher people catching them for their shells. Many scientists and citizens who care a lot about nautilus are doing everything they can to show the international community that nautilus, not only deserve, but need our protection. The easiest way to do your part is to never buy new nautilus shells. Instead look around antique stores, or purchase nautilus fossils, which have the benefit of being infused with beautiful minerals from fossilization.

Aside from their shells, nautilus are also impressive thanks to over 90 tentacles! These tentacles are much simpler than the complex arms of the nautilus' cousins. They have no suckers and instead use a series of grooves to grip surfaces. They're also incredibly sensitive to scent/taste. As a scavenger nautiluses need to be very aware of where food is sitting, and all of those tentacles act like an array of antennas picking up the fishy signal of food rotting on the bottom.

Okay nautilus, was that a satisfying amount of information for you? We can always come back another week and learn more.

"Well that was better than naut. It'll do for now, and naut to worry,
you've naut seen the last of me."
Courtesy: David Remsen via Flickr

Ugh, the puns man, the puns...

References:

Dunstan, A., Ward, P., & Marshall, N., "Vertical Distribution and Migration Patterns of Nautilus pompilius", PLoS ONE 6(2): 16311, Feb. 2011.
Accessed via: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0016311

Ward, Peter, "Cameral Liquid in Nautilus and Ammonites", Paleobiology, 5(1), 1979, pg. 40-49.
Accessed via: http://www.jstor.org.ezproxy.library.wwu.edu/stable/2400389?seq=1#page_scan_tab_contents

Crook, R., & Basil, J., "A Biphasic Memory Curve in the Chambered Nautilus, Nautilus pompilius L. (Cephalopoda: Nautiloidea)", Journal of Experimental Biology, June 15th 2008.
Accessed via: http://jeb.biologists.org/content/211/12/1992.long

Dunstan et al., "Nautilus pompilius Life History and Demographics at the Osprey Reef Seamount, Coral Sea, Australia" PLoS ONE, 6(2): e16312, Feb. 2011.
Accessed via: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0016312