Repost from Wired.com: Sea Creatures Hint at Recent Trans-Antarctic Seaway

The discovery of nearly identical sea creatures on either side of a now solid Antarctic ice sheet — 1,500 miles wide and over a mile thick — points to an open ocean passage there as recently as 125,000 years ago.

A schematic of a seaway created by the partial collapse of the West Antarctic Ice Sheet (on left).

The new evidence adds to geologic clues indicating the West Antarctic Ice Sheet has collapsed at least once in the last million years, and could do so again in a warmer climate. The complete collapse of the West Antarctic Ice Sheet would raise global sea level by 11 to 16 feet.

“The West Antarctic Ice Sheet can be considered the Achilles heel of Antarctica,” biologist David Barnes of the West Antarctic Survey, lead author of the study, said in a press release. “Our research provides compelling evidence that a seaway stretching across West Antarctica could have opened up only if the ice sheet has collapsed in the past.”

As part of the Census of Antarctic Marine Life, scientists were looking at the distribution of different species of bryozoans, small filter-feeders that are attached to the sea floor as adults (top image). They found that the populations of bryozoans were remarkably similar in two different seas separated by the ice sheet, the Weddell and the Ross.

“Because the larvae of these animals sink and this stage of their life is short — and the adult form anchors itself to the sea bed — it’s very unlikely that they would have dispersed the long distances carried by ocean currents,” Barnes said. “Our conclusion is that the colonization of both these regions is a signal that both seas were connected by a trans-Antarctic sea way in the recent past.”

“This biological evidence is one of the novel ways that we can look for clues that help us reconstruct Antarctica’s ice sheet history,” Barnes said. The study appears in Global Biological Change.

The West Antarctic Ice Sheet is already considered to be highly vulnerable to climate change, but estimates of when it might collapse vary from a few hundred to a few thousand years.

Read More http://www.wired.com/wiredscience/2010/08/antarctic-passage/#ixzz0yH1cDspW

Fish Getting All Hot Under the Collar

This was a recent Science Daily story. The following excerpt gives a sense of what the article is about:

“Experiments with two species of young damselfish on Australia’s Great Barrier Reef have shown for the first time that some reef fish are either consistently timid, or consistently bold, and that these individual differences are even more marked as water temperatures rise.

A slight lift of just one or two degrees may have only a small effect on some fish but the behaviour of others can be transformed — leading them to become up to 30 times more active and aggressive.”

Check out the original article “Fish With Attitude: Some Like It Hot” for more info.

So science has already brought to our attention fish that can change sex seemingly almost at will, what’s a little aggression? Although with the possible warming trends, it seems all too possible we could have lots of little aquatic hulks on our hands… “fishy SMASH!”

Ocean Acidification – The “Other” Inconvenient Truth

The National Resources Defense Council (NRDC) has just produced a film called “Acid Test: The Global Challenge of Ocean Acidification.”  The short film, which clocks in at about 21 minutes, features narration by Sigourney Weaver who also lent her voice to the recent Planet Earth series (although I happen to have the David Attenborough version, as I have a great deal of reverence for him and his narrative skills).

Most of us think of “carbon” as a buzzword intimately connected to the concept of global warming (the more apt word really is “climate change” as increased CO2 can, through complex and interesting ways, actually lead to cooling trends; but that’s a whole other topic…) but in terms of the ocean can lead to other unfortunate repercussions. The ocean has always been a major sink for CO2 and for quite some time has resisted strong ill effects due to its natural buffering system. A buffering system in chemistry terms allows a liquid (in this case, our “liquid” would be the entirety of the world’s oceans) to resist changes in pH when either acids or bases are added…. to a point. At some level, the system becomes “overwhelmed” and can no longer resist radical changes in pH.

The phenomenon’s name, “ocean acidification”, indicates the oceans are dropping in their pH, increasing in Hydrogen ions, and becoming more acidic in their composition. As more carbon pours into the sea, free carbonate ions (CO3) which are part of the oceans buffering system end up being tied up by the addition of extra CO2 (for the chemistry of this, check out the Center For Ocean Solutions’ Ocean Acidification page – the link is provided in resources at the end of this post). Unfortunately, carbonate is also a very necessary ingredient for the formation of the shells of a variety of organisms – corals, shellfish, pterapods, some types of plankton, etc. The lack of a supply of these carbonate ions actually can cause the shells of these creatures to dissolve, greatly increasing these species’ mortality.

The decalcification issue is also thought to be a stressor in what has been suggested as the return of the ocean to a primordial state, marked by a decrease in marine biodiversity and among other things, an increase in gelatinous marine organisms, most notably jellyfish. There are certainly a mix of reasons for the increase of jellies, but the decrease in shelled organisms helps release their gelatinous counterparts from competition for resources.

According to the Center for Ocean Solutions, other negative impacts include acidosis (a build-up of carbonic acid in marine organisms’ tissues leading to decreased immune response and other health consequences) and changes to the way sound travels underwater, resulting in the absorption of low frequency sounds which can inhibit communications and other uses of sound between sea creatures.

It’s yet another real and present danger we’re facing in today’s oceans.

Resources:

Chemtoons: Animations about how acids, bases, and buffers work

Center for Ocean Solutions: Decalcification

Center for Ocean Solutions: Ocean Acidification

Karl Grossman: The Jellyfish Revenge

NRDC – Ocean Acidification: The Other CO2 Problem

Sperm Whales Get a Bum Rap – Who are you, the carbon police?

Okay, so just a warning, the first half of this post is a mini-lesson on carbon in the ocean for those over achievers who just need to know. To get to the Sperm whale nitty gritty, jump to the section after the asterisks.

******************************************************************

So the name of the game with this climate change thing is carbon – the movement and interchange of carbon in and out of major reservoirs.

This ocean is massively important in the storage of this life sustaining element, and serves mostly as a sink for carbon (in terms of carbon, sinks are where it goes, and sources, where it comes from). It can hold roughly 50 times the amount normally held in the atmosphere.

There is however is robust carbon interplay between the ocean and the living things in it. All the living “stuff” in the ocean can be both sources of carbon (Respirers, like the creepy heavy breather on the other side of the phone line…) or can help move it along into deeper ocean depths where it tends to stay for an extended vacay. The movement of carbon to the ocean bottom is called the biological pump (note, I describe this in simplified terms. Carbon can take little forays off of this cycle – to see what a full cycle looks like, search for biological pump in google images).

Generally, plankton (oh yes, I know there is a definite possibility you are now picturing an ugly, one-eyed bad guy from the enthralling world of sponge-bob, but these are actually real, not just animated-real), the minuscule  plants and animals in the ocean, drive the pump. Copepods, tiny planktonic crustaceans, release feacal pellets (read: poop) after eating that hopefully sink to the bottom. Also carbon can help increase plankton populations, and when plankton die (I wish I could insert a clip of taps that played right when you read this…), they sometimes sink to the bottom as detritus, moving alot of the carbon that was just hanging out in the surface down to the sea floor. Carbon in deep waters has a residence time of approximately 1000 years. For it to stay longer, it needs to actually be sequestered (fancy word for “buried”) in sediments, which happens to less than 1% of the carbon entering surface waters. (Note: it’s been suggested injecting carbon into the deep sea or sediments can solve our human carbon-emissions problem, but it comes at a price. See my post on ocean acidification, or my upcoming article on the subject that will be in the spring issue of the online Gulf of Maine Times.)

So, now you know…

And knowing is half the battle….

******************************************************************

According to this article – Sperm Whales as Carbon Sinks -, there were rumors going around that Sperm Whales were respiring out a large amount of carbon being introduced into the Southern Ocean.  So they were essentially playing the role of carbon source rather than sink while oblivously swimming around and doing that whale thing they do.  But as often happens, we’ve allegedly gotten better at the math, and now it appears they may be more helpful than deleterious in keeping the carbon where it’s supposed to be. When they dive into colder,more nutrient-rich waters to eat squid (See my blog entry on squid, it’s rockin) they bring some of the nutrients back with them which stimulates plankton growth. When the plankton die and sink (or release feacal pellets that sink), they’re setting the balance right and bringing carbon way down deep.

And the best part is these mammoth creatures glide about in their day to day lives, blissfully ignorant of their role in life, the universe, and everything.

Ew… just Ew

So, I’ve definitely heard of some of this kind of phenomena…marine “snot” if you will. There can be all kinds of conglomerations of detritus (the dead stuff, the small particles sinking down to the ocean bottom). But not sure if I’d want to be swimming/snorkeling with it.

And these blobs are apparently on rise due to warming trends. Suprise, suprise these mucousy plumes harbor bacteria, sort of like some marine cold…