Blue whale with calf. Image credit Andreas Tille.
Blue whale with calf. Image credit Andreas Tille.
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Blue whale ears – more than meets the eye

What’s the first animal that comes to mind when you think of New England’s ocean? Cod? Striped bass? Maybe great white sharks? For me, lately, it’s been the biggest of all the animals that have ever existed – the blue whale. Bigger than any dinosaur that ever pounded the planet or huge ancient shark* that patrolled the warm, primordial sea, their tongues alone weigh as much as an elephant. These leviathans can weigh over 300,000 pounds. You could swim through their heart (but please don’t try).

We may not see them very often, but these endangered animals cruise by here pretty regularly. Why? They take advantage of our very productive waters to fatten up on tiny shrimp-like krill for their long migration from near the poles toward the equator.

Like some of our other, more frequently encountered leviathans, the North Atlantic right whales, blue whales head south for the winter to have their huge babies, but there’s not enough to eat down there (why do you think the water is so clear?), so they head back up when the calves are ready to travel.

Let’s talk about those huge calves for a minute. They measure over 20 feet long, drink about 150 gallons of milk each day from a mother who is on a diet (due to the poor feeding options in the warm calving grounds), and they double in length within 6 months.

That’s all pretty cool, but I know what you’re thinking – why I haven’t talked about anything weird or gross yet? Well, here it is, hot of the presses, new whale ear wax science!

Blue whales’ ears make a long, candle-stick shaped plug of wax throughout the whales lifetime (see below). Scientist are unsure of its function – it might help the whale hear better by channeling the low frequency noises they communicate with to the eardrum.

 

The whale earplug used in the study. Photo credit: Baylor.edu http://www.baylor.edu/mediacommunications/news.php?action=story&story=132825

The whale earplug used in the study. Photo credit: Baylor.edu

 

The wax has “rings” like a tree trunk. There are darker colored rings when the whale is migrating and eating very little, and lighter colored ones when the whale is feasting. This can give scientists big clues about the age of the animal when they harvest the wax from already dead animals. Already pretty interesting, right? But when two scientists at Baylor University recently dug into the biochemistry of the earplug – a novel picture started to emerge.

The wax carries a chemical record of the whale’s life, arranged by year. Hormones produced in the whale’s body are archived in the wax. So the researchers were able to put together never-before recorded pattern of yearly reproductive development and production of stress hormones. Not only that, but pollutants like mercury and pesticides can also be detected in the earplug, giving researchers an idea of what year the whale was exposed to them.

“You have this 100-year-old question: How are we impacting these animals? There is ship traffic, environmental noise, climate change and contaminants. Now, we are able to provide definitive answers by analyzing whale earwax plugs,” said Dr. Sascha Usenko, one of the scientists who developed this technique.

The best part – while the science being used to study the ear wax is new, scientists have been collecting the ear plugs for decades from animals that have been found all over the world. So, knowing the date an animal was found and its age, researchers can figure out what kinds of chemicals the animal was exposed to and possibly link this to our activities on land (for example, increased coal burning or pesticide use), helping us piece together just how much we’re changing this big pond of ours. And, hopefully, we can think even more about how to stop dumping so much ick into our air and water.

Whatever we decide to do with the knowledge – this is a huge new story about the ocean just waiting to be told, from the whales’ ears to ours.

* Please note: megalodons are very extinct, regardless of the Discovery Channels claims to the contrary.

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Ocean Art at its Finest – The Smithsonian Brings It

Categories: Events/Calendar

Soul-enriching opportunity alert! Two very beautiful, very different new exhibits are going on display next week at my favorite Hall of Wonders – the Smithsonian National Museum of Natural History.

Starting Tuesday, September 17th, twenty of Brian Skerry’s most breathtaking and thought-provoking photographs will be featured in a “Portraits of Planet Ocean” exhibit on the 1st floor of Sant Ocean Hall.

Skerry said this about the upcoming exhibit, “I am deeply honored to have an exhibit of my work at the Smithsonian National Museum of Natural History. This creatively designed show will bring visitors into the sea for an intimate look at marine wildlife while highlighting environmental threats and the value of conservation. The show gives a fresh, new perspective to the photographs and I am excited about continuing to reach new audiences about the magnificence of the sea!”

Earlier this year, the Smithsonian asked people to vote for the Skerry image that best represents a “Vanishing World” theme for the display, and the winners have been chosen. I’m happy to see that some “charismatic microfauna” made the cut, in addition to the very compelling seal, manatee, and whale photographs.

Speaking of charismatic microfauna, both Skerry and fine artist Corneila Kubler Kavanagh will be featured in “Fragile Beauty: The Art & Science of Sea Butterflies,” also in the Sant Ocean Hall.

Kavanagh has brought the tiny sea butterfly into our visible world with her soaring, elegant sculptures. She has been collaborating with Woods Hole Oceanographic Institution ocean acidification researcher Gareth Lawson to capture the movement and importance of these imperiled animals, who are showing signs of extreme stress as our seas rapidly change.

Pteropods, planktonic animals including the sea butterflies and their arch-nemesis the sea angels, are some of the most essential prey items in the ocean. As our guest plankton reporter Casey Deiderich said last week, “If the phytoplankton are at the base of the food chain, then the zooplankton are at the first rung.”

Hopefully, this special show can help people understand what is at stake so we can find the political will to dial up our national efforts to combat climate change. Not only that, but if you don’t have a boat and a microscope you may never get to see a pteropod in person, so don’t miss this opportunity to gaze upon their ethereal beauty in these two exhibits.

As if this all wasn’t enough reason to make haste to the Smithsonian, did you know they have two giant squid there? My family had to drag me away when we visited a few years ago. I could have poked around the ocean exhibits for days. And there was only one giant squid then.

We are heading to DC again next month and good luck getting me out of the Ocean Hall this time, because in addition to 100% more giant squid, there is now a high concentration of beautiful ocean art to be lingered over. My kids can head to the Air and Space Museum without me.

Larvae of the spider crab (Maja squinado), the angular crab (Goneplax rhomboides) and the thumbnail crab(Thia scutellata). Each could sit comfortably on the head of a pin. Images copyright of Dr Richard Kirby, Plymouth University. These and other images can be found in the book on plankton, "Ocean Drifters, a secret world beneath the waves."
www.oceandrifters.org
Larvae of the spider crab (Maja squinado), the angular crab (Goneplax rhomboides) and the thumbnail crab(Thia scutellata). Each could sit comfortably on the head of a pin. Images copyright of Dr Richard Kirby, Plymouth University. These and other images can be found in the book on plankton, "Ocean Drifters, a secret world beneath the waves." www.oceandrifters.org
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Not Your Average Drifter – Plankton Part II

Categories: Guest Posters

Last week we met some of our most important New England residents – the phytoplankton. Now, we are happy to introduce their animal counterparts – the zooplankton. These animals drift around in the sea in truly astonishing number and form . If you missed our post on their plant partners – the phytoplankton – you can find it here. Go ahead and read it, I’ll wait.

Okay? Well, those phytoplankton are extremely productive, and they’re eaten by many animals, most of which fall into the category of “zooplankton.”

Microscopic or massive, if you’re an animal that can’t swim against the current you’re part of the zooplankton. Some of these animals drift in the water their entire lives. These are what we scientists (who enjoy inventing and using large words) call the holoplankton (holo = entire, plankton = wanderer). The copepods are a perfect example of this.

Copepods may be the most abundant animal group on the planet, and although they contain considerable diversity, most of them are holoplanktonic. They are also usually gonorchoristic (I know, again with the huge words), which means they come in both the male and female variety. When two of them get together, so to speak, the fertilized egg will develop through many larval stages, until they finally metamorphose into the adult form. But all the way through this life cycle – egg to adult – the copepod will remain drifting along in the water.

The same is true for countless other animals, from the familiar jelly to the bizarre Phronima. All of them spending a life adrift, in a world that seems more like science fiction than reality.

Contrast this to members of the meroplankton (meros = partial), who spend only a portion of their lives in the water column. These animals may not be so foreign to you, as most of the meroplankton are the larval forms of animals that we know and love (and love to eat!). These animals drift around as larvae until they metamorphose and become large enough to swim against the current (at which point they are said to be “nektonic” – like a fast-swimming fish), or until they settle to a life on the sea floor (these animals are “benthic” – like a snail or mussel).

Most fish have larvae, as do barnacles, urchins, lobsters, mollusks, and many others. Some have giant spikes coming out of their heads, others look like flying saucers. But the fact that free-living larval stages exist in most marine animals means that they are (or were) evolutionarily important. Perhaps they evolved for dispersal – to avoid competition or inbreeding. Or maybe larvae evolved as a means to temporarily avoid predation on the sea floor… in truth, we don’t know for sure why the larval form evolved.

What we do know is that they are extremely abundant, and together with the holoplankton they make up an undeniably important and enormous group of animals. If the phytoplankton are at the base of the food chain, then the zooplankton are at the first rung. They are so massive in number that they can sustain huge populations of larger animals, some as large as our own North Atlantic right whales, which filter copepods, krill, and other zooplankton out of the water. But some zooplankton are eaten by their tiny buddies (other carnivorous plankton, like some fish larvae), which can make the marine food web a bit complicated.

And though they can’t swim against the current, they’re on the move. Their ecological importance makes the news of a study showing that climate change has caused dramatic shifts in the distribution of many planktonic species troubling. In the study, the investigators found that phytoplankton and zooplankton were two of the groups whose distribution was changing the quickest. As the authors’ of the study state, “species’ interactions and marine ecosystem functions may be substantially reorganized at the regional scale, potentially triggering a range of cascading effects.”

Translation: As the great drifter Bob Dylan said, “The times they are a changin’.” But that doesn’t mean you have to sit idly by… “If your time to you is worth savin’” then find out how you can help.

Up next in our plankton series – we’ll talk about a really cool citizen science plankton project you can get involved in using little more than your smart phone. Stay tuned!

Casey Diederich is a 5th year PhD candidate in Tuft’s University’s Biology Department, and is conducting his research on slipper-shell snails. We are thrilled to have Casey guest blogging for us about some of the more fascinating plants and animals in our ocean. – Ed.

Diatoms. Photo courtesy of Wikimedia Commons.
Diatoms. Photo courtesy of Wikimedia Commons.
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Not Your Average Drifters – Plankton, Part I

Have you ever accidentally swallowed a mouthful of seawater at the beach? You probably didn’t think much of it, other than “well that was pretty gross.” But you might be surprised to find out just how much you ate in that liquid refreshment! The broad term for the microscopic plants and animals that you’re chowing down on is “plankton,” a group of organisms that we’ve talked about here before, but they definitely deserve a closer look.

Calcareous phytoplankton, SEM

“Plankton” is a term that comes from the Greek meaning “wanderer” and was coined to describe any organism that doesn’t have the ability to swim against the water current. So, technically, even some very large animals like jellies are members of the plankton, but most planktonic organisms are very small, and as the title suggests, the best things come in small packages.

Unlike our favorite New England ice cream, plankton basically come in only two flavors: phytoplankton (plants – the subject of this blog) and zooplankton (animals – I’ll talk about these next time). Both the plant and animal type contain a dizzying array of form and function, and their beauty may be unrivaled in the sea.

Why should we care about phytoplankton? Well, we owe our lives to the horde of single-celled plants that float around in the ocean. Literally – they produce at least half of the oxygen on our planet, and perhaps as much as 80%! Just think about those numbers for a second; amazing production from something so small. It’s obvious, then, that the phytoplankton’s strength is in numbers, which is how they also form the base of the marine food chain.

Phytoplankton provide sustenance to a wide variety of herbivores (including most of the zooplankton), some of which are of great commercial importance, like mussels, oysters, and scallops. As these herbivores are eaten, the productivity of the phytoplankton is transferred up the food chain, ultimately to us.

Those are some pretty good reasons to love plankton, but I’m not done yet. You know all of that carbon that we’re pumping into our atmosphere? Well, phytoplankton take much of that carbon out of the atmosphere through photosynthesis. And when they sink to the bottom, phytoplankton sequester a massive amount of that carbon to the deep sea. Even when they’re long gone they’re important, because their hard bits are preserved in the fossil record, helping scientists to decipher everything from the age of rocks to past environmental changes.

Their importance might be matched by their looks; even in a place renowned for its beauty, phytoplankton stand out. Take the diatoms, for example, which make breathtakingly beautiful skeletons made from silica (the compound used to make glass). Or the dinoflagellates, which are normally harmless but can occasionally bloom and release toxins that form the sinister red tides. There are cyanobacteria, better known as “blue-green algae” that are actually ancient photosynthesizing bacteria. But my personal favorite, and maybe the most curious, has to be the coccolithophores, which cover themselves in buttons made of calcium carbonate. Why would they do such a thing? Scientists aren’t really sure, and debate abounds, but what they are surer of is that more acidic seawater will not be good for the coccolithophores.

In fact, when we look at the big picture, global phytoplankton concentrations have been on the decline for the last century. This is a scary trend, given their importance, and some researchers have even proposed fertilizing large areas of the ocean to cause phytoplankton blooms. Sounds promising, but one of the challenges associated with such large-scale interventions is predicting the unintended consequences. For example, what effect would those blooms have on the zooplankton? Stay tuned, we’ll take a look at those little guys in Part II.

Casey Diederich is a 5th year PhD candidate in Tuft’s University’s Biology Department, and is conducting his research on slipper-shell snails. We are thrilled to have Casey guest blogging for us about some of the more fascinating animals in our ocean. Watch for his close-up look at plankton, Part II, coming soon. You might be surprised at how interesting and important these little guys are! – Ed.

European green crab from Bailey Island, Maine. Photo by David Reed (dreed41) via Flickr.
European green crab from Bailey Island, Maine. Photo by David Reed (dreed41) via Flickr.
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Mean, Green Eating Machines: The European green crab is “one of the world’s worst invasives”!

Categories: Creature Features

The European green crab may look small, but it has an appetite of epic proportions. These tiny 2-4 inch marine invaders can consume up to 40 small clams a day- that’s more than you’d get on your average plate of fried clams!

Why are we so concerned about these crabs? Warming ocean temperatures have allowed green crabs to persist farther and farther north along the North American coastlines. Where cold winter chills used to keep its numbers in check, populations of green crabs are now booming places like the Gulf of Maine, and they are eating their way through our precious local seafood.

The European green crab, Carcinus maenas, is not exactly new to the northeast. In fact, it first arrived in the waters off Cape Cod during the 1800s, from its native range along the European coast and Northern Africa. Green crabs have since expanded their range northward through New Brunswick, and have even made their way over to the west coast, likely hitching a ride in ships’ ballast water tanks, or with commercial shipments of live seafood.

Green crabs dwell in many types of marine habitat, from rocky tidal zones to sandy beach flats, and are extremely good competitors. In a recent study, green crabs were found to be much more successful in introduced regions- including the east and west coasts of the US- as compared to their native regions. Crabs in the non-native study areas were also found to be larger and less affected by parasites, whose numbers were greater in the native region.

The green crab is a professional clammer- able to dig up and crack open young clams and oysters with ninja-like skill. A single crab can consume nearly three-dozen small mussels per day, and will basically try to eat anything around its size or smaller. Other crabs, fish, and even young lobster are all fair game for these tiny eating machines. In fact, green crabs may be the primary culprit in shutting down commercial clam harvesting in parts of Maine. Even worse, some fishermen in Maine are certain that predation from green crabs is responsible for shrinking numbers of other commercially-important mollusk populations – namely, mussels and oysters.

Fishermen worry that once the crabs work their way through shellfish populations, their next target may be lobsters. Green crabs are known to prey upon other species of crab and some fish, and have been shown to prey upon juvenile lobsters in a laboratory setting. The Washington Department of Fish and Wildlife also reports that green crabs are capable of learning and honing their predation techniques- a scary thought for our Maine lobsters!

 

Crachen cranc - Sacculina carcini

A “parasitic castrator” of the green crab – the barnacle Sacculina carcini. Photo by Gwylan via Flickr.

What can we do to defend our coastal seafood communities? Several management strategies have already been put into practice, including trapping and removal programs, chemical controls, and even protective netting for juvenile clams. However, the most interesting, and possibly most controversial, proposed method of control is to introduce a natural enemy. Sacculina carcini is a parasitic barnacle of European green crabs, which impairs its host’s reproductive organs, rendering them unable to reproduce. Parasites that do this are collectively known as ‘parasitic castrators.’ Some sources have suggested utilizing this species to curb crab populations, but recent studies have revealed that the parasite is capable of infecting other species of crabs in addition to the green crab, which may put native species at high risk. This, along with many unknown factors associated with introducing another non-native organism, make this type of biological control an unlikely solution to our green crab dilemma.

CBC News recently deemed green crabs to be “one of the world’s worst invasive species”, reporting problems associated with spikes in green crab populations as far north as New Brunswick. With ocean temperatures rapidly rising, the green crab is likely to continue its territory and population expansions. It is fast becoming one of the biggest threats to New England shellfish populations, and will need continued monitoring and novel control strategies in order to preserve local fisheries and prevent further destruction to our marine life.