Sunday, December 21, 2014

The Great Pacific Garbage Chowder

The Great Pacific Garbage Patch: it's flashy, disturbing, simple, a great band name, and... is completely misleading. That name was given to an area in the Pacific ocean by Curtis Ebbesmeyer when a colleague reported on the amount of floating plastic in the area. Because the name is so catchy it stuck, and has been used extensively in popular media reports ever since. So what's it look like? Well prepare yourself, below you're going to see a picture from the very heart of this trash zone that's been described as having a surface area twice the size of Texas.

Where's all the garbage?
Courtesy:  ---=XEON=--- via Panoramio

The problem with the term patch is that it suggests a covering, like in a patch of grass; or a lot of big pieces, like in a cabbage patch. Neither of these is what you see in these areas. Really what's happening is that giant ocean currents, called gyres, are concentrating tiny bits of plastic (called microplastic) in their middles. The gyres are more like plastic chowder than a plastic patch. And just like in a chowder the chunks aren't evenly distributed. Different types of plastic have different densities, so they float at different heights in the water column or even sink to the bottom.

This is the North Pacific Gyre. There are two major gyres in the Atlantic and Pacfic,
 and one in the Indian Ocean
Courtesy: NOAA Ocean Service's Making Waves podcast

So why isn't the plastic more evenly distributed, or at the very least why isn't it close to land? Well it has to do with the fact that the gyres are circular currents. When particles sit in water they are partly held up by how fast the water is moving. In swirling water, like the gyres or a cup of tea being stirred, the water at the center is moving slower than the water at the edge. Particles catch on the slow water and are pulled into the center where they stay more or less still.

 Red sprinkles in water before, during, and after stirring: Some sprinkles float, others sink; all concentrate into the center; just like pieces of plastic caught in the ocean gyres.

There are a number of issues associated with plastic in the ocean, and all originate with the fact that plastic doesn't biodegrade. Plastics are designed to last forever; they're stable, cheap, and sturdy. When we throw out plastic it never turns back into the minerals that it came from. Plastics just continually degrade into smaller and smaller pieces, but they stay plastic for functionally forever.
The first problem is that plastic takes up space. Several studies over many years have led to calculations of about 35,000 tons of microplastic and 250,000 tons of larger plastics in the oceans. All of those bits can easily lead to entangled marine animals.

The other big issue is that act of breaking down. As plastics break into smaller and smaller shards they're inadvertently gobbled up by smaller and smaller organisms, entering the food chain at more levels. While they're breaking apart and mixing around in the ocean, the chemically raggedy edges of the plastic grab onto many of the toxins commonly found in sea water. This takes those chemicals from their spread out, and therefore less dangerous, state to concentrated on one of these bits. Some of these toxins are hormone disruptors and there's a growing body of evidence that they can and will affect fish by changing their reproductive organs to those of the opposite sex.

Lastly, when plastic breaks down it becomes much harder to clean up. Imagine trying to separate all the parts out of real chowder, including the spices. Some of it can be picked out pretty easily, but others not so much. The microplastics are so small that we can't go out and grab it all because we'd have to screen the water with nets with really tiny holes. Nets with tiny holes are also how you catch plankton, so to catch the estimated 5 trillion bits of plastic out there we would probably decimate plankton populations.

"A few billion more of these and we can save and destroy the ocean at the same time"
Courtesy: NOAA Photo Library via Flickr

There's also the problem of some plastic sinking. For years surveys of ocean plastics weren't finding as much as researchers expected, but we knew that our waste was making into the ocean, so where was it all going? Well it turns out, straight to the bottom. A three ocean study of deep sea sediments has found significant amounts of microplastic fibers in the depths. A lot of these fibers were rayon and acrylic, materials found in synthetic clothing that probably got into the water from particles coming off as the clothes were washed.

Alright if we can't clean up everything then what do we do? Well the beautiful thing about this issue is that it's entirely in our hands. There isn't a single company or government that has caused all this pollution, so there's no one to fight with to make it stop. We are so powerful in this situation it's unprecedented. The most important thing is to stop using plastic like it has a short life. That tupperware you or your parents bought in the 70's and is still in your kitchen; that's how plastic should be used. Keep that sucker around forever and hand it down to your kids too. Those Legos that have been dropped, washed, stepped on, pummeled, and still haven't broken. Hell yeah that's my kind of plastic. Where you can, eliminate single-use products, and when you're out walking pick up a piece of litter each time. If we do these things we can make a dent in the 30% of all plastic that gets thrown away within a year.

I have to give credit to Edward Humes, author of Garbology for the term "plastic chowder" it really is a perfect metaphor.

References:

Cozar et al., "Plastic Debris in the Open Ocean", Proceedings of the National Academy of Sciences, Vol. 11 No. 28, 2013, DOI 10.1073/pnas1314705111

Ericksen et al. "Plastic Pollution in the World's Oceans: 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea", PLOS ONE, 2014, DOI 10.1371/journal.pone.0111913

Woodall et al, 2014, "The Deep Sea is a Major Sink for Microplastic Debris", Royal Society Open Science, 1:140317, http://dx.doi.org/10.1098/rsos.140317

Rochman, Chelsea, "A Story About Fish, Plastic Debris, and Sex", Deep Sea News, 2014,

Humes, Edward, "Garbology", Ch. 5-6, Penguin Books, 2013

Friday, December 19, 2014

Over 1000!

Imagine my surprise when I logged onto the blog this morning and saw that Depth and Taxa has surpassed 1000 page views! I'm pretty sure my face looked something like this.


I appreciate you all sharing in the exploration of the marine environment with me. This blog has only been active for four months, and I never expected it to get to this point so fast. To everyone in the states, and the folks around the world who have been learning along with us,

Thank you, Dziekuje, Merci, Danke, Tesekkur ederim, Gracias, Dankjewel, Diakuju, and Spasibo.

Sunday, December 7, 2014

The Notorious B.I.G.

"Where does everyone keep getting that number!" I shouted irritably one day while doing some research for the Seattle Aquarium. I was profiling the giant Pacific octopus (Enteroctopus dofleini) and the number that kept coming up was 272Kg/600Lbs. Don't get me wrong, giant Pacific's are well named. They're the largest octopus species in the world, and they can be massive. The largest animal I ever encountered was an octopus named Roland who weighed over 90 pounds and he had an arm span above ten feet.

Giant Pacific octopus also grow incredibly fast. They're short lived, only lasting 3-5 years in the wild, and they go from the size of a grain of rice to broader than a man's height in that time. It's been estimated that they average a gain of 1-2% of their body weight every day. They literally grow exponentially. A well-fed octopus gets bigger today than it got yesterday, and will get bigger tomorrow than it got today.

What had me so flustered about that 600 pound claim is that most giant Pacific octopus never get any bigger than 70 pounds, and the reliable accounts of extremely large animals only weighed around 120 pounds. I found article after article that referenced that size, in both the popular press and the peer-reviewed literature. Six hundred pounds is so far off from what's normally their maximum that I began thinking fish stories might not always be about fish. Many articles even acknowledged that any account above 120ish pounds was probably unreliable.

"I swear it was like two people across!" (Person in this example is defined 
as one elementary aged child) 
Courtesy LAZLO ILYES via Flickr

     Of course it's not not unheard of for a population of animals to shrink over time due to human influence. For example, the dusky grouper (Epinephalus marginatus) from the Mediterranean, is thought to be much smaller than before modern fishing pressure. In ancient Roman murals dusky grouper are portrayed as almost as large as a man, now they rarely get bigger than around 50cm (about 19 inches). Giant Pacific octopus on the other hand haven't really been a targeted catch thanks in part to their chewy texture. It could be that pollution has affected the health of these species, but the reports of truly giant octopus were claimed to be from Alaska where human impact is less significant.

Alright, so where did this number come from? Well lucky for our quest to discover the origins of the "super giant Pacific octopus, TM" , science has a spectacular convention of citation. At the end of every peer reviewed article the authors are expected to cite previous research that informs their experiment and is the basis of their prior knowledge. You can think of it as a built-in BS alarm.

Statistical analypus thinks you should have used an eight tailed test.
Courtesy canopic via Flickr

So I took the opportunity to put on my detective cap and dig around some scholarly research! I have friends I swear, they're humans and everything. Anyway after a little leg work (keyboard work?) I managed to track down the source of the 600 pound octopus in the room. It turns out that in 1975 William High wrote a summary of knowledge about giant Pacific octopus for the National Marine Fisheries Service's annual report. This article was cited by almost every paper I had been looking through, so I suspected it was what I needed. Thankfully the good folks at NOAA keep an online archive of these reports.

In High's summary he discusses how large these animals can get and even he doesn't totally buy the hype at first. He states: "Much larger ones (octopus bigger than 100 pounds) have been reported, but like the Loch Ness Monster, these usually elude the careful photographer or scientist." which is basically the scientific paper equivalent of "cool story bro." But then just a few lines later he goes on to say: "In the late 1950's I interviewed a Canadian commercial diver Jock MacLean... He reported capturing an immense creature weighing 600 pounds and measuring 32 feet from arm tip to top. MacLeans photographs, unfortunately, were of poor quality. Smaller animals, to 400 pounds, were occasionally taken..." Seriously!? Poor quality photos and the testimony of a guy whose job it was to go and get narc'd all the time are all we're going on. You'll have to forgive me if I remain skeptical.

"No you can't be real! The scientific literature doesn't substantiate 
your existence!" -The ship's naturalist
 "Denys de Montfort Poulpe Colossal" by Pierre Denys de Montfort († 1820)
 - Ellis, R. 1994. Monsters of the Sea. Robert Hale Ltd. Licensed under Public domain via Wikimedia Commons  

Sadly it looks like the reports of "super giant Pacific octopus ™" have been exaggerated, even among those who try hardest to avoid hyperbole. Although I can't help but wonder; why is a giant octopus such a universal story? From the legends of the kraken to the creature that supposedly lives under the narrows bridge in Tacoma, Washington; monstrous octopus just capture our imagination. Maybe long ago there were octopus large enough to destroy a ship, or maybe having no frame of reference in the vastness of the ocean led to exaggeration. Either way the real giant Pacific octopus is a huge, magnificent creature that deserves our respect.

References:

Cosgrove, James, & McDaniel, Neil, "Super Suckers: The Giant Pacific Octopus and Other Cephalopods of the Pacfic Coast.", Harbour Publishing, March 2009

High, William, "The Giant Pacific Octopus", Marine Fisheries Review, Vol. 38 No. 9, Sept. 1976
Accessed via: http://spo.nmfs.noaa.gov/mfr389/mfr3893.pdf

Guidetti, Paolo, & Fiorenza, Micheli, "Ancient Art Serving Marine Conservation", Frontiers in Ecology and the Enironment, 9: 374-375, DOI 10.1890/11.WB.020

Sunday, November 30, 2014

Life, uh, Finds a Way

A few hundred years ago we believed that nothing could live in the deep sea. Even as our understanding of the world grew, in some ways we lost our imagination. We began to understand that the deep was incredibly cold, very low in oxygen, and subject to astonishing pressures. So we assumed that this environment was just too inhospitable . Boy were we ever wrong.


A mile and a half down (2560m), on the vent field of an active volcano.
Courtesy NOAA Ocean Explorer via Flickr

More and more, we're seeing that life not only exists in the darkness, but thrives. A few weeks ago we talked about animals up in the water that survive with little light, but now we're headed to the bottom. The above image comes from a deep sea hydrothermal vent community, which in the last few years has become relatively well known. Thanks to programs like Blue Planet and Planet Earth, there is beautiful footage of these ecosystems readily available to the public.

But hydrothermal vents are a small part of the ocean bottom. Other incredibly diverse ecosystems exist, and with the prevalence of the internet, researchers are starting to show them as they're discovered. Some of the coolest environments being found are cold seeps.

There are several types of cold seep ecosystems, but what defines them all, is gasses escaping from underground into the water. Seeps have been found all over the world, from as shallow as 15m (easily diveable) to over 7000m (not easily anything), and even in inland bodies of water. Generally seeps are found on the edges of continental slopes where the earth's crust is bending and folding. Unlike hydrothermal vents cold seeps are not due to magma heating seawater and expelling it back out of the ground. Seeps form in places where a lot of plant and animal matter has settled to the bottom, become buried, and decayed. As that material breaks down it makes a lot of methane gas. Then as the ground bends it squeezes the gas, pushing it closer to the surface through the soft sediments on top. My apologies for being crass, but yes, the earth does fart.


A stream of bubbles escapes from the ground at a cold seep
Courtesy Deepwater Canyons 2013 - Pathways to the Abyss NOAA-OER/BOEM/USGS

The gas alone is not enough to establish an ecosystem; some organism needs to harvest the gaseous bounty to start a food chain. On land and in the surface waters, plants convert the sun's energy into chemical energy using CO2. At cold seeps bacteria and archaea convert the energy in the methane (CH4) coming from underground, and sulfate in seawater, to a type they can use. In a spectacular bit of symbiosis the archaea manipulate the methane and the bacteria manipulate the sulfate, then they use one another's products to complete their energy conversion. The exact nature of this back and forth isn't well understood, but scientists do know it produces hydrogen sulfide.

The hydrogen sulfide is then used by bacteria living inside animals to produce even more energy. These animals (some types of mussels, clams, and tube worms) have little to no digestive system. They get their energy straight from their symbiotic bacteria. At many cold seep sites large mats of bacteria and archaea are surrounded by these animals. Sometimes they even form a bulls-eye of different colors radiating out from the center.


Bacterial mats (white) and mussels (brown/orange) thriving at a cold seep
Courtesy NOAA Photo Library via Flickr

These large sedentary animals draw in small animals that take shelter in the jumbled chaos of their shells. Predators of those small organisms then come hunting. Many animals also feed directly on the bacterial mats, so there don't even have to be larger organisms around them. Entire ecosystems develop from the toots of the planet. Some of the animals that take advantage of cold seep environments are even ones that we eat, like sablefish and crabs. King crabs have even been observed feeding on bacterial mats, leaving, and coming back only after enough time has passed for the mats to regrow!

All of this biological activity helps contain methane (a potent heat trapping molecule) in the sea, keeping the temperature of the earth from rising even more. Also many seeps found in very deep water have low enough temperatures and high enough pressures for solid ice crystals to encase methane molecules. These "methane hydrates" also help keep carbon out of the atmosphere. You can see the biological and geological carbon traps interacting in this adorable video below.



Cold seeps are a good number of deep sea ecosystems, but there's more talk about, and even more to discover. Clearly the ocean bottom isn't quite so lifeless as we once believed. And probably it's even more full of life than we currently understand. Jurassic Park's Ian Malcom knew what he was talking about.

References:

Levin, Lisa, "Ecology of Cold Seep Sediments: Interactions of Fauna with Flow, Chemistry and Microbes", Oceanography and Marine Biology: An Annual Review, 2005, 43, 1-46, Taylor & Francis

Niemann et al., "Methane-Carbon Flow into the Benthic Food Web at Cold Seeps- A Case Study From the Costa Rica Subduction Zone", PLOS ONE, Oct. 2013, DOI: 10.1371/journal.pone.0074894

"Discovery of a New Chemosynthetic Community" NOAA Ocean Explorer

Wednesday, November 26, 2014

A Ray of Hope

Courtesy kathleenreed via Flickr

It's a story that lends itself to hyperbole. An unknown disease causing the literal disintegration of a large group of animals across a wide geographic area. Sea star wasting disease has been on the minds of every marine science professional for the last two years. And amazingly...wonderfully, this issue has captured the attention of the general public as well. Through traditional media, the internet, and personal experience, sea star wasting has become, I think, the most visible issue facing the oceans today.

In case you haven't heard, throughout the North East Pacific, from Alaska to California sea stars have been dying off in large numbers. The animals begin to show signs of distress by curling their rays in unusual ways. Then white lesions (any kind of damage to tissue) appear on the outer skin. These lesions then disintegrate further until holes appear. Eventually the holes grow so large that limbs separate from their bodies, and the animals crumble into piles of skeletal plates. Some reports have stated that the disease causes the arms to walk away from the body, but that is a blatant exaggeration. Partly because stars don't have brains, their limbs can survive for a surprisingly long time after they've been separated from the central disk. So while the disease does cause the arms to come off, it's not what's causing them to keep moving. Sea stars can even deliberately drop off limbs in an attempt to protect the rest of their body from disease and predators. Then they grow a new ray in it's place.

 "We can rebuild him, we have th...." "No that's okay he'll do it himself"
Courtesy Jill Siegrist via Flickr

So why can't the stars regenerate from the damages of the disease, and what the heck is causing it in the first place? Well for the last two years the answer has been a big, fat, "I dunnuh", but that's because researchers have been furiously looking into it, and good experimentation takes time. There has been amazing collaboration between aquariums, research labs, and everyday folks to study the spread and cause of wasting. From this collaboration a new study has identified a virus that is associated with sick stars.

Last year a team of researchers discovered the first virus associated with echinoderms. They found the pathogen inside the tissues of sea urchins on Hawaiian coral reefs. This virus was a type of densovirus which are most commonly found infecting arthropods, like crabs, shrimps, and insects. In the urchins the virus wasn't causing any disease, but as the outbreak of sea star wasting became more severe the scientists wondered if something similar might be at fault. 

First they needed to see if there were any viruses in the stars at all, so the scientists separated virus sized particles from the tissues of sick stars and injected healthy ones with this material. They also boiled samples of those particles before injecting other healthy stars; doing so destroys the DNA that viruses could use infect the organisms. Sure enough the stars that received potentially active viruses became sick with wasting and the ones that received the boiled samples did not.

MMMM Nothing like a nice hard-boiled virus to start the day
Courtesy michelle@TNS via Flickr

From there the team ran a viral DNA analysis on the sick animals and found a densovirus that is unique to stars. They named the pathogen Sea Star associated Densovirus or SSaDV for short, and the more copies of the virus the stars were carrying the more likely they were to start wasting. Interestingly the team found that for most stars, the larger the animal, the greater the viral load, but the opposite was true for the sunflower star (Pycnopodia helianthoides). Sunflower stars were one of the first and most heavily impacted by the disease, so I'm curious if this association may have something to do with that. Through this, and some other lines of evidence, these researchers have found a compelling correlation between this virus and sea star wasting.

So is that it? Can we all wash our hands of this and get on with out lives? In short, no. The study confirms the existence of a virus associated with wasting, but it doesn't look at how the virus interacts with the sea stars' cells. It's extremely likely that the virus alone isn't what's causing the stars to die. Especially since the researchers looked at samples of stars collected as far back as 1943 and found the same viral DNA. And when you think about it that makes sense. When you contract a virus you don't get sick purely because the virus is in your body. You get sick because the virus combines with your stress from work, and the bacteria in your environment, and the fact that you stayed up late having drinks, to tax your immune system until it can't suppress the virus anymore and you get symptoms.

There has been extensive coverage of this study, but the problem is that many news outlets are claiming the answer has been found and they have ignored an important takeaway from the paper's conclusion. From the paper itself: "However it remains to be seen how infection with SSaDV kills asteroids, what the role is for other microbial agents associated with dying asteroids, what triggers outbreaks, and how asteroid mass mortalities will alter near-shore communities throughout the North American Pacific Coast." (Hewson et al. 2014). Essentially the author's are saying " this is a good start, but we have a lot to look into."

It's even possible that disease is a normal means for the
environment to handle overpopulation of echinoderms
Courtesy US Fish and Wildlife via Flicker

It all seems a bit bleak, but like I said before there has been an incredible amount of collaboration, and unprecedented visibility to the plight of West coast stars. Knowing the densovirus is associated with the disease won't stop it, but now we have jumping off point to further our understanding. This is a unique opportunity for you, as an interested person, to participate and keep this research alive.

So if I could ask one thing of you all it's this: Keep paying attention. Stay up to date, visit your local aquarium and ask questions, follow researchers on twitter. You can even go out and survey beaches for wasting stars yourself and scientists will use your data. Together we can develop a strong understanding, citizen and scientist alike, of what this disease is and does. So if you make statement about stars, or upload some pictures to social media I encourage you to attach the hashtag #RayOfHope, and we'll see if we can keep the momentum going.

For more information on the study that identified the virus check out this great summary from Ed Yong with National Geographic. Or read the paper yourself for free on the National Academy of Sciences website. 

References:

Hewson et al., "Densovirus associated with sea-star wasting disease and mass mortality", Proceedings of the Natural Academy of Sciences, Oct 2014, DOI 10.1073/pnas.1416625111  


Sunday, November 16, 2014

Suspiciously Helpful Drifters

I can't contain it any longer! The blog has been active for three months now and we've barely talked about the most amazing, most important, most spectacular group of living things on the planet! Well no more. Prepare yourselves to meet the very reason for life on earth as we know it...

Oh look it's even waving hello
Courtesy Lindsay Waldrop via Flickr

Well not that specifically, that's just a baby barnacle, we'll come back to him/her (I'm not being politically correct, barnacles are hermaphrodites) in little bit. What I'm talking about is plankton. And I'm not exaggerating when I say that plankton are why we have the planet that we do. They've shaped evolution since the beginning of life, and they continue to do so today. So this week we're going to take some time to learn about our magnificent, mostly tiny, benefactors.

The word plankton itself has a pretty cool story. It comes from the same Greek word as planet, Planktos, which means wandering. Planets seen from earth look like stars and they do this weird thing where they kind of meander across the sky. Because of this, the ancient Greeks called them "wandering stars" in their own language. A couple thousand years later a German physiologist named Victor Hensen saw all these living things wandering on currents around the Baltic sea and gave them the name.

Another important part of plankton is the fact that it's not a term to describe how things are related to each other genetically. Saying something is plankton isn't like saying something is a mammal; it's more like saying it's a carnivore. The word describes behavior not biology. That's how algae (referred to as phytoplankton) and animals (called zooplankton) can both be plankton. Any living thing that is moved around by currents, tides, and waves more than it can move itself is plankton.

Pictured: Plankton
Courtesy Ian Sanderson via Flickr

That's right any living thing, so even giant jellyfish are technically plankton. Naturally being very small makes it a lot harder to resist the movement of water so the vast majority of plankton are pretty tiny. Sometimes this means that zooplankton are baby versions of the familiar species we find on the beach.

Take that baby barnacle that we met at the beginning for instance. He/she is a perfect example of meroplankton (they're plankton for merely part of their life). Gravid (the egg-laying version of pregnant) barnacles launch out those tiny babies when they hatch. The babies are then free to spend the next couple weeks cruising the currents eating and growing strong; before settling down to stay in one spot for the rest of their life. These baby, or larval forms as they're known, are actually really important for scientists trying figure out how animals are related to one another. We thought barnacles were related to snails until the mid-1800's when we had good enough microscopes to see that the larvae are more like shrimp.

Of course just because something is small doesn't mean it's a baby. Many living things are plankton permanently. These are called holoplankton (they're plankton for their whole life) and they are incredibly important to the ocean's food web. The two classic examples of this are copepods (pronounced cope-uh-pods) and krill. Both are crustaceans, just like the barnacle, and between the two of them they directly or indirectly feed almost everything in the ocean.

 A copepod (on the left) and a krill (on the right), you've probably seen them in TV and Movies
Courtesy NOAA Great Lakes and Norkrill via Flickr

What these two groups of animals lack in size, they make up for in numbers. Around Antarctica alone it's estimated there are around 500 million tons of just krill! One krill weighs about seven tenths of an ounce. There are literally uncountable numbers of these animals in the ocean. There are so many that we get into numbers that human brains actually have a hard time comprehending. You start to understand how something as massive as baleen whales can live off these two animal groups almost exclusively.

So zooplankton are clearly important to the health of the oceans, but what about the algae, those phytoplankton from before? Well we wouldn't have things like krill and copepods without those phytoplankton, and in fact we probably wouldn't have ourselves either. Like plants on land phytoplankton are at the bottom of almost every ocean food chain. They take sunlight and carbon dioxide and turn it into sugar, which things like krill and copepods love to eat. So the copepods gobble up the phytoplankton, and then they're gobbled up by fish, and on and on, all the way up to you. When you eat a fish you're eating everything that fish ate, plus everything that fish's prey ate, plus everything that fish's, prey's, prey ate. It starts to look pretty important to keep the plankton's tiny ecosystem healthy doesn't it?

Not only do phytoplankton make life work because they're food for other living things, but they provide complex life with something extremely important. Go ahead and take two really deep breaths for me. Nice, long, slow, relaxing breaths from your diaphragm. Feels good doesn't it? All that fresh oxygen to your brain and muscles really does you good. Well amazingly the oxygen in one of those breaths came from phytoplankton.

"You're welcome!"
Courtesy NOAA Photo Library via Flickr

It's been calculated that about half of the oxygen in the earth's atmosphere comes from the ocean. That means that phytoplankton are at least as important as all the terrestrial forests, all the savannahs, and all the shrub lands, combined. Remember how I mentioned that we can't even count the number of krill or copepods? Well to make that many animals you need even more of these algae. There are so many phytoplankton in the ocean that they actually dye huge swathes of the ocean green during the summer, which can be seen from space! Not only does phytoplankton sustain us complex organisms, it's partly responsible for us being here in the first place. 

On the very ancient earth most of the oxygen in the atmosphere was tied in with other gasses, like carbon dioxide, and what was escaping, quickly came out of the air to rust the metals in rocks. But then a group of photosynthesizing bacteria evolved multi-cellularity. All of a sudden there were way more organisms using up the CO2 and dumping out a lot more oxygen than the rocks could absorb, and BAM! They created an atmosphere full of an element that's essential for biological processes in animals.

So that's it for this week. I could write even more about plankton: how they have the single largest migration on earth, how they provide food for the deep ocean with their poop, and I will eventually; but for now let's just appreciate the incredible, essential plankton by looking at this wonderful picture of a spring bloom in the Atlantic.

For scale: that's Ireland at the top middle. This is a real color photo
Courtesy NASA Goddard Space Flight via Flickr

 References:

Carefoot, Tom, "Learn About Acorn Barnacles", A Snail's Odyssey

Sessions et al. "The Continuing Puzzle of the Great Oxidation Event" Current Biology 19, 2009, DOI 10.1016/j.cub.2009.05.054, Accessed via: http://web.gps.caltech.edu/~als/research-articles/2009/sessions_et_al_2009.pdf

Shirrmeister, et al., "Evolution of multicellularity coninsided with increased diversification of cyanobacteria and the Great Oxidation Event." Proceedings of the Natural Academy of Sciences, vol. 110 no. 5, pg. 1791-1796, DOI 10.1073/PNAS.120992710 Accessed via: http://www.pnas.org/content/110/5/1791.full

Krill Facts Center, International Health and Science Foundation



Sunday, November 9, 2014

Drop the (Antarctic Research) Bass

Exterior shot: Antarctic research station over the Ross Ice shelf. Except for a single lamp right outside the door it's the complete inky blackness of the southern winter. Motes of snow billow past through the light and we hear only the sound of rushing wind. The camera slowly zooms in on the entrance. Cut to Interior: Two researchers, a man and a woman, are settling onto cots. There's a dull orange glow from the lamp outside over everything. The woman looks over to the man.

Woman: I can't believe how quiet it is here. Back in Seattle I got so used to hearing the noise from the street that I'd forgotten what it's like in the field.

Man: Yeah everybody reacts a little differently. Some people love the isolation, others start to go a little nuts, start to think they're hearing things. Either way all you'll be hearing for next couple months is wind and creaking ice, so get used to it quick. 

Woman: I'll be fine, I've had enough of civilization lately. I'm ready for the silence.

Man: Good. I wouldn't want you going cracked on me with just the two of us down here. Let's get some rest.

They both settle into their cots and rest their heads on their pillows. The camera pans across the room and settles on the woman's face. She looks slightly unsettled, but calm as she slowly closes her eyes. The camera lingers on her face and all sound from outside dissapears, suddenly we hear this:  
  


And our heroine's eyes snap open! End Scene.

While that may sound like the first scene from yet another reboot of The Thing it's a situation that can actually happen in Antarctica. As ruined by the image on the clip; that sound is not an alien horror, nor the intro to the latest club sensation, but a cuddly seal. (Disclaimer: No wild animal should ever be cuddled, seals have no way of knowing that your hug isn't a grip of death and they will defend themselves, also they usually smell like fish and pee.) Specifically that sound comes from the Weddell seal (Leptonychotes weddellii) which breeds farther south than any other mammal. And they'd have the record for all animals too if it weren't for those meddling penguins. They were first reported on the ice above the Weddell Sea but they have what's called a circumpolar distribution. Basically that means they're found all the way around Antarctica on coasts and ice shelves.

Weddells live much closer to shore than the other Antarctic seals. Although they generally prefer shallower water Weddell seals have been found diving 600 meters down in search of prey! To give you an idea of how far that is, the deepest dive ever done on SCUBA equipment was only half as deep (332m Ahmed Gabr). While it may not be noticeable to us there is a big difference in ice real estate for Weddell seals.

Perfect example; no one wants a bedroom right next to the road
Courtesy Sandwich via Flickr

 Breeding age females and males hang out on ice closer to land than juveniles. The ice closer to shore is called fast ice because it's locked fast and doesn't shift around much. On the ocean side is the more familiar pack ice which gets packed onto and removed from the sheet pretty regularly. As you can imagine a constantly shifting environment isn't great for rearing babies. There's some contention among scientists as to whether or not the adults migrate from the fast to the pack ice, but it looks like most Weddells are pretty site specific.

One of the lines of evidence for this is the presence of the sounds you heard earlier. The trilling noise is unique to male Weddell seals. That sound is thought to be a territorial display since males use it all year round, but ramp up how often during the breeding season. Of course it's always possible that these seals just really love Doctor Who. Either way we know that, during the breeding season, males guard cracks and holes in the ice that females use to access the water.

How you doin'?
Courtesy Sandwich via Flickr

Of course those holes in the ice are also very important for breathing. Even though they can go without fresh air for up to 80 minutes at a time, being mammals means they still need to breathe between dives. In fact both male and female seals put quite a bit of effort into keeping the holes open. Fast ice has fewer gaps than pack ice, so the ones that are free need to be maintained. Weddell seals use their teeth to literally carve out thinner sections of the ice.

It's easy to assume the seals would keep breathing holes to themselves but they've been seen sharing these spaces. So scientists think that some of the underwater vocalizations are seals communicating about the breathing holes. Decoding the Weddell seals' language requires a lot further study; but it could be that seals approaching the surface are letting those already on the ice know they're coming, or seals at the holes telling those underwater where they can be found.

Weddells are the most well studied of all of Antarctica's seals, but we still know so little about them. Why do they have up to 30 different vocalizations? What are they trying to say? Do they get more inspiration from Depeche Mode or Daft Punk? Thankfully, Weddell seals have been relatively unaffected by the loss of ice in Antarctica so far, so there's lots of opportunity to learn the answers to these questions.

References:

Weddell Seal (Leptonychotes weddellii), Wildscreen Arkive

Leptonychotes weddellii: Weddell Seal, Encyclopedia of Life

Doiron et al. "Proportional underwater call type usage by Weddell seals (Leptonychotes weddellii) in breeding and nonbreeding situations." Canadian Journal of Zoology, 2012, 90(2): 237-247, 10.1139/z11-131

Lake et al. "Spatial utilisation of fast-ice by Weddell Seals (Leptonychotes weddellii) during winter.", Ecography, Vol. 28 Issue 3 pg 295-306,  June 2005, DOI 10.1111/j.0906-7590.2005.03949.x 

Sunday, November 2, 2014

Lighting Up The Deep

Happy just after Halloween everyone! And Feliz Dia de los Muertos if you're in Central America! This is one of my favorite times of year, not least of all because I've always had a lot of fun on Halloween. It's one of those few holidays that stay awesome no matter how old you get. When you're young you get to have all the fun of trick-or-treating, and when you're older you get to have parties. I remember one of my favorite things about trick-or-treating was getting to use glow-sticks.

Yeah these things!
Courtesy Timo Newton-Syms via Flickr

Most of the time we humans get to glow for fun, but there are animals in the ocean that glow entirely to survive. So this week we're going to explore some of the beauty of deep sea bioluminescence.  

As I'm sure you know the further down you go in the water the darker it gets. Eventually you lose all light but for a long ways, up to about 1000 meters, small amounts of light still get through. Not all light is created equal though. Different colors have different wavelengths, and therefore have different amounts of energy. Colors like blue and green are very energetic compared to colors like red and orange, so they travel farther through the water. Many a scuba diver can tell you that you don't have to go that far down before everything becomes awash in only blue. This property of light is very important to animals in the deep sea, because it determines what color their bodies are and what  colors their bioluminescence. Watch the video below and see how many different colors of animal made light you can see.

Also, revere the master David Attenborough!

So how many did you count? I'm guessing maybe two if you've got really good eyes or like to be pedantic about blue vs. blue-green. So why do we see basically one color down there? Is the deep sea just racist? Well it comes back to those properties of light; blue literally goes a long way down this far. Communication is one of the important uses for bioluminescence in the ocean and you can signal over a much longer distance with blue light.

Alright so attracting prey and communicating with your own species is a great use for bioluminesence, but there's more you can do with living light. Believe it or not many animals use light to blend in. Even though this seems counter-intuitive animals that do this are using an extension of matching their background like traditional camouflage. Many animals in the region where a little bit of light still lingers, sometimes called the twilight zone, have light emitting organs called photophores on their bodies. The photophores give off the same color of blue that makes it through the water, breaking up their silhouette and blending them in. This is especially true when they're viewed from below because the light comes down from the surface. Many animals do this: from the incredibly numerous lantern fishes (Myctophiformes), to one of my favorite animals, the firefly squid (Watasenia Scintilans

Seen here in a festively appropriate form. 
Actual pictures can be seen here.

Now that we know the things most animals ocean animals do with biolumiescence, let's look at an interesting exception. Three genera (one grouping less specific than a species) of dragonfishes (Stomiidae) have photophores that make red light instead of blue. These special light organs, which are just beneath their eyes, actually beam ahead of them like headlights. The reason they use red instead of blue is two fold. One, most animals in the deep have no reason to see red. Dragonfishes' prey evolved in an environment where red light doesn't exist, so they have no need for the eye proteins that see it. And two, many deep sea animals are red. Weird right? But red is great camouflage against everything except for those three groups of dragonfish. Since there isn't any red light, animals with red skin appear completely black in the depths. These three genera of dragonfish are pointing lights that their prey can't see at animals that are lighting up like beacons.

Why are you weirded out? Only two of them have no bottom on their jaws.
By Erich Zugmayer (died 1939) [Public domain], via Wikimedia Commons 

Even more amazing is the fact one of the species in this group of fish, the Northern stoplight loosejaw (Malacosteus niger), regularly eats copepods (open ocean relatives of shrimp) which eat a bacterium that makes a type of chlorophyll that picks up red light. The stoplight loosejaw takes this chlorophyll and produces the pigment its eyes need to see red light. Think about that for a second; this fish uses the food, of its food, to make what it needs, to find food. Cue the theme song from Inception!

BWWWWWWAAAAAAAUUUUUUGGGGGHHHHHH!


References:

Douglas et al., "Enhanced retinal longwave sensetivity using a chlorophyll-derived photosensitizer in Malacosteus niger, a deep-sea dragon fish with far red bioluminescence", Vision Research, Vol. 39 Issue 17, Aug. 1999, DOI 10.1016/S0042-6989(98)00332-0, Accessed via: http://www.sciencedirect.com/science/article/pii/S0042698998003320

Moser, H. Geoffry & Watson, William, "Order Myctophiformes: Blackchins and Lanternfishes" From NOAA, accessed via: http://web.archive.org/web/20011201063212/http://www4.cookman.edu/noaa/Ichthyoplankton/Myctophiformes1.pdf

Malacosteus niger: Northern Stoplight Loosejaw, Encyclopedia of Life
http://eol.org/pages/224918/details

Watasenia scintillans: Sparkling Enope Squid, Encyclopedia of Life
http://eol.org/pages/399186/details








Monday, October 27, 2014

They're in the Trees Man!

It's autumn here in the Northern hemisphere, and in the Pacific Northwest many of our salmon species are making their return to the rivers they were born in. This amazing phenomenon has been well documented on TV, but there is an incredibly cool piece to the story that's often missing. One that weaves the ocean, the river, and the land together and shows us that nothing is alone in the environment.

Pacific salmon are a pretty cool group of fish, but honestly it can be really hard to agree on just what the heck a salmon is. This confusion comes from old terms for the same fish doing different things. Ever noticed how salmon and trout look almost exactly the same on the outside? Well that's because they pretty much are. All trout, salmon, char, freshwater whitefish, and graylings are part of the salmonid family. Amazingly many of these fish can spend their entire lives in freshwater, or they can spend part of it in fresh and part out at sea. Fish that have a life cycle which takes them back and forth between salt and fresh water are called anadromous (pronounced an-ad-row-muss) fish. Weirdly enough some species have a freshwater exclusive and an ocean going form, and they get different common names because of it. For example a rainbow trout (Oncorhynchus mykiss) lives in freshwater exclusively, but a steelhead (also Oncorhynchus mykiss) goes from fresh to salt and back again. It's genetically the exact same fish, but because steelhead fill up on tasty ocean plankton they get much bigger and their meat turns a lot pinker.  

"I haven't decided which I want to be yet. I'm taking classes in both and seeing which I like more."
Courtesy Ingrid Taylar via Flickr

Honestly the rest of this post could be about what is and what isn't a salmon, but that can get tedious and there's other things to get excited about this week. In general when people talk about Pacific salmon they're referring to one of five different species, which are all in the genus Oncorhynchus which means hooked nose. These are the coho (O. kisutch), pink (O. gorbuscha), chum (O. keta), chinook (O. tsawytscha), and sockeye (O. nerka). Aside from being many species instead of just one, Pacific salmon differ from Atlantic salmon (Salmo salar) by being terminal spawners. After they reproduce all five of the species listed above die. When I first learned this it seemed so sad and pointless to me. After all Atlantic salmon don't die after spawning, but it turns out the deaths of the adult Pacifics bring enormous amounts of nutrients into inland environments. 

"It's cool birds, I wasn't using my eyes anyway."
Courtesy Lewis Kelly via Flickr

When thousands of salmon flood a stream and die there, their bodies begin to decay in the water, but look at that picture above. Where's the shore? That fish is lying out in the middle of the woods. Even if the shore is just off camera a few feet I guarantee that fish didn't have "walk on land" as part of his bucket list. So how'd he get there? Well the answer is probably a bear. 

Bears are good swimmers, they love the fattiness of salmon, and they don't mind scavenging on rotting food. Bears and other animals drag salmon away from the streams to munch in peace and the parts they don't eat mix into the soil. Then plants in the area pick up those nutrients and use them to grow. One study found that trees without salmon nutrients grew about 2/3rds as fast as those with them. So trees are, through salmon, taking nutrients from the ocean and using them to grow; and there are salmon streams that are as far East as Idaho (That's 450 miles in a straight line from the mouth of the Columbia River.) where oceanic nutrients can be detected in the trees. It's not just the trees either; studies have found oceanic nutrients in the shrubs, ferns, insects, birds, amphibians, fish, and mammals of these environments. 

No wonder we call him the King
Courtesy spappy.joneS via Flickr

The way we know know this is pretty cool too. Scientists use isotope analysis to see how much of a certain type of Nitrogen is inside the trees. You can kind of think of isotopes as sub-species of atoms. They're not all unique enough to warrant calling them something else, but they often behave a little bit differently. Different environments favor the production and preservation of different types of each atom. The ocean, as it happens, is very favorable to the form of Nitrogen that has an extra neutron. So researchers are able to burn samples from the trees and use a cool device called a mass spectrometer to figure out how much of their chemical composition came from the ocean. At one site in Canada they found that in some years up to 80% of the Nitrogen available for Sitka spruce (Picea stichensis) came from those years' salmon runs.

It's become increasingly clear that salmon are important for the health of Pacific forests. And the implication is astonishing. If we want healthy trees, that grow more rapidly, create more diverse habitat, scrub carbon from the atmosphere, and produce more lumber, then we want healthy salmon. Amazing large scale projects with that goal in mind are already happening, and keeping salmon streams healthy is as easy as making sure you pick up after yourself when you visit a river. It may be a long time before we see anything close to historic runs again, but so much is being done on every level of the community that I'm confident we can make a difference.

If that seems hard to believe, remember all of these trees are partly made of fish.
The world is way weirder and cooler than we ever expect it to be.
Courtesy ArkanGL via Flickr

References:

"Family Salmonidae: Salmons and Trouts", The Burke Museum online

Reimchen, Tom, "Salmon nutrients, nitrogen isotopes and coastal forests", Ecoforestry, Fall 2001.

Reimchen et al. "Isotopic Evidence for Enrichment of Salmon-Derived Nutrients in Vegetation, Soil, and Insects in Riparian Zones in Coastal British Columbia.", American Fisheries Society Symposium, XX: 000-000, 2002

Moore, J, & Schindler, D, (2004) "Nutrient export from freshwater ecosystems by anadromous sockeye salmon (Oncorhyunchus nerka) Canadian Journal of Fisheries and Aquatic Sciences, Vol. 61, 2004

Sunday, October 19, 2014

Underwater Basket Weaving

Hey everyone, this week we're diving into a bit of a mystery. There's a pretty good chance that by now this little gem has come across your social media feed!


The original of that video had 8 million views on facebook alone last I checked. I've gotta say it's really cool that people are so curious about ocean animals. But the question on everyone's mind seems to be, as my mom succinctly put it: "What the heck is it?" Despite its facehuggerly appearance this is a native of the earth, or should I say the sea? What you're looking is a basket star. I should also mention that I'm not the first to identify this guy/gal. Both the Echinoblog, and IFLScience have tackled this mystery.

First off basket stars aren't actually a true sea star. You may remember from the post on catch connective tissue that sea stars are members of the echinoderm phylum. More specifically the sea stars we're most familiar with make up the asteroidea class (a class is one grouping more specific than a phylum) So if you're feeling pedantic and mischievous you can tell people you found tons of asteroids on the beach and not be lying. However the basket star is not an asteroid! Basket stars are part of a class of animals called ophiuroids (pronounced "off-yer-roids), and are more commonly called brittle stars.

 Jazz Hands!
Courtesy  Paul Thompson via Flickr


Even though most brittle stars look quite a bit like traditional sea stars, being in a separate class means they are as different from a true sea star as a sea urchin is. One of the most notable differences between sea stars and brittle stars is in how they get around. Sea stars use their hundreds of suction cup tube feet to grip tightly to the bottom and cruise along. Their rays (also referred to as arms) act as more of a platform for those strong tube feet to operate from. Brittle stars don't use their tube feet to walk. Instead they pick themselves up on their rays and stroll or slither like something out of the Nightmare before Christmas. Their tube feet lack suction cups and are used to grab food and help move it towards their mouth.


Basket stars are a really cool specialized group of brittle stars. They are well adapted for collecting plankton out of the water with their arms. In the above video you can only catch the view for a second, but at one point the basket star opens all its arms, and you can see the central disk. The disk is pentagonal and one trunk-like arm grows out of each side. Each of those five arms then branches dozens of times to create a wide net. The arms of the basket star are covered in microscopic hooks, a nice coating of mucus, and are capable of coiling around themselves to form traps that hold onto their planktonic prey. Below you can watch as some euphasiid shrimp are added to a basket star's tank at the Seattle Aquarium.


That video is a little sped up, but you can see how those branches form a wide net and are waved back and forth to sweep for more food. Grabbing food out of the water like this is called suspension feeding. Sometimes you'll hear it called filter feeding, but that's a bit different. When there isn't an obvious load of plankton around them, basket stars usually cling to a hard surface or the branches of corals. They curl their rays up above their bodies into the current forming a basket shape. Hence the name.

What a basket ca...I'm not even gonna let myself finish that joke
By Peter Southwood (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons


Once a basket star has enough food trapped on one of their rays they'll slowly move it towards their star shaped mouth. Incidentally brittle stars don't have an anus, so they excrete their waste through the same hole they consume food. Anyway inside the mouth are five sets of comb-like teeth. The star slides its arms over the teeth and the prey are scraped off like frosting from a fork. Am I the only one who does that? I can't be the only one who does that.


Basket stars are found throughout the world from shallow water to the abyssal plane. The one from the original video is probably Euryale aspera which is a shallow living basket star found throughout the Indian ocean and tropical western Pacific. One of the things I think is coolest about basket stars is that they seem to have a strong association with a variety of coral species. Not only do coral branches make a good holding place for adult basket stars, they may even be an important nursery for juveniles. Young of the species most commonly found around N. America, Gorgonocephalus eucnemis, are usually found living just inside the polyps of the sea strawberry coral (Gersemia spp.). While this seems to be some type of symbiotic relationship, it isn't entirely clear if the little basket stars are stealing food from the polyp they're living on, or just using their mouth as a platform to feed from.

References:


Stöhr, S., O’hara, T., & Thuy, B. (March 2nd 2012) “Global Diversity of Brittle Stars (Echinodermata: Ophiuroidea)” PLOS ONE DOI: 10.1371/journal.pone.0031940,
Accessed via http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0031940

"What is that weird thing on facebook???" The Echinoblog
http://echinoblog.blogspot.com/2014/10/what-is-that-weird-thing-on-facebook.html

Gorgonocephalus eucnemis” Encyclopedia of Life, 
http://eol.org/pages/599654/details

"Gersemia” Encyclopedia of Life,