Sea star wasting: what is it and why do we care?

Sea star wasting syndrome (SSWS). What the heck is that? It's this:

Holy crap. If you want to skip straight to the sad parts, check out around 4:20. I couldn't find the video to post it here, but somewhere out there is a video of starfish literally walking themselves apart; two arms going in opposite directions, then *boop* three-armed starfish! Awful.

Obviously, that kind of sucks for starfish, but who really cares? They're not pretty like this lovely critter:

Pictured: a male violet-crowned woodnymph. Thanks for the photo, Joseph C Boone of Wikipedia land!

And they eat and poop through the same hole, so they can't be contributing to global IQ levels too much.

Luckily, you don't need brains to eat, and these dudes eat a lot. They are in many ecosystems what is called a keystone species: a species whose effect on its ecosystem is disproportionate to its population size in that ecosystem. Starfish eat shellfish like sea urchins and mussels, keeping their population in check. If you take starfish out of the equation, the shellfish population explodes. This throws the ecosystem out of balance--suddenly you have a plethora of clams roving around, eating all the food and taking all the nice rocks for themselves. But wait, there's more!

Getting rid of the starfish also destroys a food source for several predators: sharks, rays, and sea anemones. Sharks in particular could just eat more regulat, fish-shaped fish, but that would cause the fish, but that would cause the fish population to plummet and the price of tuna would go up and next thing you know Chicken of the Sea costs $20 a can. It's not a great scenario.

Pictured: not worth it.

So why are all the sea stars dying? What is causing this disease, and can you get it by kissing a starfish?

The cause of SSWS has been a mystery since it was first observed in January of this year, but this month research groups at Cornell (among other places) showed some pretty decent evidence that the condition is caused by a kind of virus called a densovirus. The researchers ground up some diseased sea stars and filtered everything larger than a virus out of the sea star puree (mmmm, tasty), then infected healthy starfish with this virus soup. Within a couple weeks, most of the healthy starfish started showing symptoms of SSWS.

The control is boiled starfish puree. From Hewson et al. 2014, PNAS

They also found these little guys in diseased starfish:

From Hewson et al. 2014, PNAS

Using genetic analysis, they determined that this was a type of virus called a densovirus. Densoviruses are small, icosahedral DNA viruses; icosahedral just means they are shaped like an icosahedron, pictured below.

I'm poor, so you'll have to deal with the watermark.

Now that we are reasonably sure what is causing SSWS, what do we do about it? Well, science fans, that question is still unanswered. But at least we know where to start!



Pictures?
I realized that when I link to a picture here, you can just click on it to get to the original source, so I've decided to stop including the links down here. It only took me three blog posts to figure that out!

How do you cool something?

I think we can all agree that refrigerators are made of magic. But, it may surprise you to know that there is also some science sprinkled in for funsies. Since I never got my letter from Hogwarts, I can't tell you about the first point, but I have journeyed far and wide (to the other side of the lab where the physicist--my co-blogger!--sits) to discover the secrets of

Let us begin with a quick refresher on thermodynamics. Hey, get back here! I swear it's not scary or hard. What it is is a great word to use to make your friends think you're smart. Look, we're just going to use this teensy equation, very harmless...

PV = nRT

where P is pressure, V is volume, T is temperature, n is number of molecules and R is the gas constant.

Super easy, right? Pressure, volume and temperature are proportional to each other! So, if we increase the pressure, either volume will decrease or temperature will increase--or, more likely, a little bit of both. Let's pop some numbers in there so you believe me. I'm going to ignore n and R for simplicity.

Let P = 5, V = 6, T = 30

P*V = T, therefore 5*6 = 30 (woo!)

Now, P = 6. Three options:

(1) V decreases to 5

(2) T increases to 36

(3) Mix of 1 and 2

What's that? You'd like a real world example? Alright, science fans, I whipped this one up just for you! Let us turn to our faithful friend, water.

Is that not just fabulous? Doesn't it make you feel good just looking at it?

As you know, if you take a room temperature pot of water and increase the temperature until it boils, it will turn to steam. Now, the temperature of the steam won't rise until all of the water evaporates (for reasons I will not get into because they aren't that interesting to most people). However, you will note that steam takes up a LOT more space than water does, which--oh my goodness here it comes--decreases the pressure.

Did you see what I did there?!

Why does it decrease the pressure? Because the molecules are farther apart! If you take a packed bus full of people and spread them out among 5 buses, those people feel less pressure on them from fellow bus-goers. Same deal with water and steam. Boom. We just proved that PV = nRT, the ideal gas equation, works in real life.

Now, armed with this thermodynamical knowledge, we are fully prepared to battle understand

If you have a refrigerator and you ever bothered to look at the back of it, you probably saw something like this:

What's going on there? I have made this very detailed, scientific, post-modern illustration to explain.

What a great invention. Science!

Pictures!

http://ndpa.org/wp-content/uploads/water-06.jpg

http://upload.wikimedia.org/wikipedia/commons/a/a7/ColorfulFireworks.png

http://images.dexknows.com/cms/images/How_to_Clean_Refrigerator_Coils_0.jpg