Sites and Critters

Sea Lions as urban megafauna

Sea Lion pup in restaurant booth (c) Mike Aguilera

Sea Lion pup in restaurant booth (c) Mike Aguilera

The owners of the “Marine Room” restaurant in San Diego were certainly in for a surprise this morning, after an eight-month old sea lion pup found her way into their establishment overnight and decided to set up shop. She was quite obviously grumpy when a marine mammal rescue team arrived to take her away (right). You can read the full story and see the video of her deportation here from the LA Times.

(c) The Cave Store

(c) The Cave Store

Oddly enough, this was not the first strange sea lion encounter in San Diego this year. Back in January, another California Sea Lion pup (left) climbed up 145 steps from the beach below to colonize a gift shop in La Jolla; the desperado allegedly would only vacate the premises upon being bribed with salmon. In addition, this young sea lion decided to hitch a ride with a random paddle boarder near the Coronado Bridge back in October, though no ransom was reported for the high jacking:

If you’re thinking to yourself: ‘Why on Earth are sea lion pups moving into restaurants and gift shops?’ you’re not alone. Representatives from Sea World suggest that high tides and high sea surface temperatures associated with El Niño have reduced the food supply for California Sea Lions. Indeed, coastal areas in the Pacific have experienced abnormally warm temperatures as of late, and a recent paper from Bernardo Shirasago-Germán and colleagues in Mexico highlights that pups and young adults are particularly vulnerable to environmental fluctuations like higher sea surface temperatures. But further science on the matter has yet to hit the primary literature as far as I can tell. While the pup who found her way into the restaurant last night was apparently tiny for her age, it’s not clear to me whether her journey, and that of her gift shop- and paddleboard-invading comrades can be effectively linked to climate-induced food shortages.

(c) Takashi Hososhima

(c) Takashi Hososhima

Marine mammals may well serve as the canary in the coal mine for large-scale ecological changes in the ocean, but perhaps a different species would be a better representative for such an important task… one that’s not inherently so curious and unruly. California Sea Lions have lived and interacted with humans in heavily urban areas for as long as I can remember. When I was a girl, they took over a popular tourist destination in San Francisco and have remained in charge there ever since (left). In Seattle, they do just as they please on the buoys and barges operated by the port (at the top of this post). And when I’m underwater, they generally seem quite keen to make their presence known (below).

Perhaps it’s best to think of them like other urban wildlife, such as raccoons and coyotes – natural in a sense, but there in large part because of their ability to thrive in dense urban centers. This is all conjecture, of course, as much work would be needed to confirm whether California Sea Lions are indeed the type of generalist consumer the has adapted to urban life. Just something to ponder next time a sea lion wanders into your neighborhood coffee shop or corner market.

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Sites and Critters

Winter is coming

Winter is coming… well, it’s here really. January is a time of change and rebirth for many species in the seasonal seas of the Pacific Northwest. Perhaps this is true for none more so than the Giant Pacific Octopus, Enteroctopus dofleini. As the largest known octopus species in the world, these graceful giants are prominent inhabitants of Seattle’s underwater environment and serve as a captivating icon of local marine ecosystems for many Seattleites.

Despite their considerable size, Giant Pacific Octopus are thought to live only 3 years on average. And they’re semelparous… meaning they reproduce only once before they die. In their final year of life, the male presents a spermatophore to the female using a special tentacle called a hectocotylus. She carries the spermatophore around delicately for some time. Then, as winter descends, she establishes her clutch of fertilized eggs in the safety of her den. For months, she works tirelessly to keep them clean and protect them from predators. She doesn’t eat or leave their side. They remain her focus for the remainder of her life. With luck, she’ll survive to see the eggs hatch and her offspring swim off into the great blue world that awaits.

In the video below, you’ll see fertilized octopus eggs in a den we found last year under a fiberglass boat that was resting on the seafloor at a depth of about 50ft (in south Seattle). My video skills are admittedly horrific. Though the mother’s body isn’t visible in its entirety, you’ll see her flush the eggs with the end of her tentacle repeatedly (if you look very closely).

However, for a very sweet and far better visual exploration of an octomom’s final days, see the beautiful video by Drew Collins (below):

 

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Sites and Critters

All that lives in a handful of mud

Most coastal cities are built at the mouths of rivers and in estuarine systems where soft sediment was the dominant marine habitat type historically. Though we’ve added all sorts of artificial structures to these landscapes and altered urban shorelines considerably, mud and sand habitats are sometimes still evident in some coastal cities, either at low tide, or if you look carefully through the water to the seafloor below from piers and boardwalks. Initially, this soft sediment substrate will probably look rather boring and featureless, not to mention “icky.” There couldn’t be much living in that stuff, right?

Believe it or not, soft sediment environments are incredibly diverse. In a single sediment core sample (a cylindrical area of sediment that’s only a few inches wide and maybe half a foot deep), I find more invertebrate species than I typically find on an entire artificial reef in Puget Sound. They’re modest creatures – small and unassuming, often cryptic, and typically not as colorful as their ostentatious, rock-dwelling counterparts. Regardless, soft sediment organisms, termed “infauna”, are an important part of urban marine landscapes.

Over the last few years, I’ve had the pleasure of becoming more closely acquainted with some of these critters as I’ve sorted through sediment samples from West Seattle. The samples are part of a larger experiment that I promise to report more about soon, but in the meantime, I want to share with you some of my favorite “infaunal” organisms. Specifically, they are the current winners of 3 categories for which I’ve had running lists over recent years:

Category #1: Most frightening

WINNER: Glycerid worms

If I were a marine organism about the size of an ant, there is little I can imagine that would be more frightening than a glycerid worm. These fierce predators construct complex networks of burrows in soft sediment, which they move through rapidly. Remember the movie Tremors from the early 90s? This is like Tremors the real version. When glycerids find their prey, they shoot out their pharynx complete with four terrifying fangs (pictured to here). They’re known as bloodworms. This is said to be because of the ceolomic fluid you can sometimes see through their body wall, which contains hemoglobin and is the color of blood. I wouldn’t be surprised is the true origin of their name is more morbid than that, though. At least they seem to want blood when I’m handling them in the field… Remind me not to re-watch Tremors anytime soon.

Teeth of a glycerid worm. Photo: Marcos Daniel

Teeth of a glycerid worm. Photo: Marcos Daniel

Glycerid worm, Photo: David Fenwick

Glycerid worm, Photo: David Fenwick

 

Category #2: Most adorable / cutest

WINNER: Euphilomedes ostracods

Since teddy bears weren’t in the running, we have the next best thing. Ostracods are tiny crustaceans that live inside a little circular house; sort of like a seed with legs. The genus I tend to encounter is Euphilomedes spp. and is relatively large, reaching well over a millimeter in diameter. It may not sound like much, but in the world of ostracods, these are giants. Life for Euphilomedes ostracods tends to consist of puttering around between sediment grains, presumably in search of food.

Ostracod, Photo: Ajna Rivera

Euphilomedes ostracod, Photo: Ajna Rivera

 

Category #3: Most elegant

WINNER: Tellina clams

Though clams in Puget Sound come in all shapes and sizes, one stands out with its elongated figure, smooth, shiny shell, and occasional radiating pink patterns. Though the Tellinid pictured here is from the Bahamas, it’s Puget Sound relatives are no less elegant.

Tellina radiata, Photo: Bill Frank

Tellina radiata, Photo: Bill Frank

 

These are just a small selection of the many critters that inhabit muddy and sandy marine habitats. The softs sediments we see in urban marine environments may look like a lonely place to call home, but these critters are by no means alone. It’s amazing to see all that lives in a handful of mud!

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Happenings, Sites and Critters

Green Seas in the Emerald City

If you’re a barnacle, clam, mussel, or any other filter feeder in Seattle, you’re likely rejoicing right now in the recent profusion of food! Just as terrestrial plants throughout the northern hemisphere have exploded with new leafy growth and flowers, photosynthetic plankton have proliferated in the springtime sunshine. As a result, the seasonal seas of temperate coastal cities like Seattle are now a deep, soupy green, and marine invertebrates are having a feast!

Here’s a video I compiled from recent dives in Seattle. Everyone in the underwater environment has joined in on the celebratory affair. Orange sea cucumbers shove plankton-covered tentacles into their mouths. Serpulid worms collect passing food particles with their colorful branchial crown. Tubesnout fish hover in a milieu of green plankton, sucking in food as they go. Barnacles frantically fan the water with their feathery feeding appendage in an effort to get the most from the surrounding bounty while it lasts.

Now is the time for marine organisms to take up as much energy as possible and store it in their tissues or send it off as offspring. Within a few weeks, the plankton bloom will have run its course. The water will once again become clear and blue, making each fanning motion a bit less lucrative for barnacles and their filter-feeding compatriots. As dying plankton sink to the bottom and blanket the seafloor, detritus feeders like the California sea cucumber (Parastichopus californicus, below) may continue to lie about in satiation well after the party has ended. But for everyone else, it’ll be back to life as usual, as clear waters restore order to the underwater cityscape.

Parastichopus californicus, (c) James Watanabe

Parastichopus californicus, (c) James Watanabe

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Sites and Critters

Urban Dweller: The Giant Pacific Octopus

Giant Pacific Octopus in riprap den

Giant Pacific Octopus (GPO) in artificial boulder habitat  in Elliott Bay, Seattle

Coastal cities are not just home to high densities of humans. Octopus may also come to dwell in urban landscapes in large numbers.

This is what we’re finding in an underwater study we initiated earlier this year. We conducted video surveys at a series of paired, neighboring dive sites where artificial structures were abundant vs. sparse. The addition of artificial structures to the marine environment is a major part of urbanization in coastal cities. Artificial structures can consist of anything from sunken cars to old toilets to discarded garden gnomes.

Giant Pacific Octopus in some junk

GPO in south Seattle, in a den made out of an old iron hatch

Without revealing the full punch line (we’ve yet to submit our findings for publication), I can say that octopus densities tend to be higher at sites where there’s more junk. This may come as no surprise to long-time divers in the Puget Sound region. Scientists also have been aware of the use of artificial structures by octopus for some time. What’s so striking is the extent to which artificial structures appear to increase octopus abundance in even the most heavily urbanized locations.

Here’s a great video from UW research diver, Ed Gullekson, of octopus and several other critters that live just off of downtown Seattle, in Elliott Bay:

For more great videos from Ed “Sharkman” Gullekson, check out his Vimeo page here!

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Sites and Critters

The aesthetic delight of Aurelia aurelia

A quick tribute to a common urban marine organism that I think is particularly beautiful: the Moon Jelly, Aurelia aurelia. Here’s a video I took recently of one in Seattle’s Elliott Bay:

Jellyfish have probably been a source of inspiration for artists and designers for as long as humans and jellies have coexisted (ie – all of human history; jellyfish have been around from some 500 million years or more). They’ve served as study subjects for all sorts of work, from Ernst Haeckel’s lithographic prints to Dale Chihuly’s organic glass forms. In Björk’s current exhibit at MOMA, she explains that the ancient, pulsing, fleshy creatures connote feelings of calmness and satiation that come with finding love (though it seems jellyfish imagery has had other uses in her work as well: link). Others seem captivated by the silent, toxic danger jellyfish pose to their prey, or simply by their beautiful, primal form and the aesthetic experience of observing them in their environment.

Beyond artistic expressions past, jellyfish might also provide inspiration for technological innovations of the future. Could knowledge of the way in which Aurelia propels itself help us develop more efficient forms of underwater propulsion or better medical technologies? John Dabiri at Cal Tech believes so. Or perhaps the peculiar qualities and molecular structure of jellyfish tissues could facilitate advances in material sciences, as noted by Steven Vogel in Comparative Biomechanics.

As coastal ecosystems become ever more urbanized and the planet undergoes rapid changes, we may need to look to nature for examples of physical designs that are tried and true. Few organisms have the track record of jellyfish, with 500 million years of adaptation and counting. What luck that they’re aesthetically endowed too.

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Happenings, Sites and Critters, Uncategorized

Urchin barren video

Last fall, I posted photos from an urchin barren at Elliott Bay Marina. It’s taken me forever to compile video from the same dive, but here it is in all its glory – video of the urchin barren at Elliott Bay Marina from November 2014:

I’ll return to the site as this year’s kelp begins to establish to see whether we can expect the kelp forest to return. More on that soon!

In related news, here’s a an article from National Geographic about what researchers are seeing in California in the way of urchin populations. Though major increases in urchin densities have been observed locally following sea star wasting syndrome, it’s interesting to see that’s not a uniform trend.

 

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Tire covered in green urchins
Happenings, Sites and Critters

Urchin take-over?

Plastic penguin statue (Seacrest Park, Jan 2015)

Green urchins, Strongylocentrotus droebachiensis, on a plastic penguin statue (Seacrest Park, Jan 2015)

There’s been much talk in the local dive community recently of an urchin take over in Puget Sound’s urban waterways. Divers at some of Seattle’s busiest dive sites have noticed a sudden influx of green urchins, Strongylocentrotus droebachiensis. They travel in hungry mobs, marching with the help of lots of little tube feet, presumably in search of greener pastures. At dive sites like Seacrest Park, in West Seattle, you can see them covering submerged objects by the hundreds, clearing the substrate of algae and smaller invertebrates as they go.

Traffic cone (Seacrest Park, Jan 2015)

Urchins on a traffic cone (Seacrest Park, Jan 2015)

Long-time divers note this is the first they’ve seen green urchins out in such force. What’s more, the apparent invasion seems timed with the recent die off of large sea star predators due to sea star wasting syndrome. In particular, the sunflower star, Pycnopodia helianthoides, was hit hard by the disease in the fall of 2013, and is known to be an important predator of green urchins. Any diver who’s seen green urchins clambering over one other in response to an approaching Pycnopodia will agree that urchins take the threat quite seriously. So perhaps the two events are connected….

Has the absence of Pycnopodia caused the urchin population to explode?  To address this, here are a few points I think are important to consider:

– The majority of green urchins that I’m seeing at sites in Seattle are 25-30mm in diameter or larger. Here’s the size frequency distribution I found back in November (below) when documenting the urchin barren that recently formed at Elliott Bay Marina Breakwater. The urchins I’ve seen at Seacrest Park are of a comparable size range.

Size frequency distribution of Strongylocentrotus droebachiensis at Elliott Bay Marina Breakwater in November 2014.

Size frequency distribution of Strongylocentrotus droebachiensis at Elliott Bay Marina Breakwater in November 2014.

– Based on published growth parameter estimates for S. droebachiensis (below; see Chapter 18 by Scheibling and Hatcher in  Edible Sea Urchins), we know that individuals of this size range (25mm in test diameter or greater) are at least 2-3 years of age. Green urchin recruitment occurs in the winter and spring, so we expect baby urchins that have settled since Pycnopodia populations disappeared in fall 2013 are no bigger than 15mm across at this point.

Growth curve for Strongylocentrotus droechiensis based on  published estimates of von Bertalanffy parameters.

Growth curve for Strongylocentrotus droechiensis based on published estimates of von Bertalanffy parameters.

Therefore, we cannot conclude that the high urchin densities we’re seeing at some sites are the result of an increase in population size. While juvenile urchins could very well be experiencing lower predation rates in the wake of sea star wasting syndrome, those that have actually arrived since the disease hit are not the ones we’re seeing out in force at dive sites like Seacrest Park.

So what is going on?

It’s important to note that urchins of all kinds are commonly found in very patchy distribution patterns. In some cases, this is the clear result of patchiness in predation, as Jane Watson and Jim Estes have documented beautifully in their work on red urchins around Vancouver Island (Watson and Estes 2011). In other cases, the reasons for their patchy distribution pattern are unclear.

It’s possible that the mass mortality of Pycnopodia has shifted the behavior of green urchins, allowing them to aggregate and travel more freely from one location to the next. The formation of urchin mobs may just as easily be the result of a localized depletion of algae and other food resources, however. Since we don’t even know where these urchin aggregations were living before they showed up at common dive sites, it’s quite hard to tease apart what caused their mobilization in the first place.

Lastly, I’ll add that patchiness in the distribution patterns of species like green urchins is a phenomenon that occurs over both space and time. Who knows what green urchin populations looked like 100 years ago, or even 500 years ago. If in fact the increase in urchin densities proves to be widespread and persistent, we can certainly expect to see some changes in the community of species that dominate Seattle’s subtidal ecosystems (urchins are quite effective at clearing space on hard structures and facilitate high turnover rates of sessile invertebrates and macroalgae). Whether such changes are “desirable” or “undesirable”, “natural” or “unnatural”, “destructive” or “restorative”, depends very much on your perspective and your objectives and goals for how urban marine ecosystems, which are in a sense our own creation, should function.

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Sites and Critters, This Week In The Lab, Uncategorized

What’s out there?

What lives out there in Seattle’s underwater landscape? That’s been the question of undergraduate interns in the Sebens Lab over the last 2 months, as they’ve analyzed photos from our recent benthic surveys.

This work was no small undertaking. It required learning hundreds of new species and species codes, and spending many many hours zooming in and out of digital photos to identify invertebrates and algae, and quantify their relative abundance on photographed surface. The curious critters they’ve encountered at times seem stranger than fiction and offer a window into Seattle’s vibrant, underwater world. Here is a compilation of their favorite finds of the quarter:

Balanus nubilis

Balanus nubilis, (c) Minette Layne

Balanus nubilis, (c) Minette Layne

Most people wouldn’t call barnacles interesting, and truth be told, I can understand why. Barnacles aren’t exactly the most thrilling things in the ocean; they aren’t as dangerous as sharks, they aren’t as beautiful as angelfish, but just because they aren’t as flashy as their mobile compatriots doesn’t mean they are any less interesting. In particular, the Giant Acorn Barnacle, Balanus nubilis, is an intriguing creature. Growing up to approximately six inches in diameter and twelve inches in height, the B. nubilis is a filter feeder related to shrimp, and has the largest known muscle fibers in the animal kingdom. Also, the “glue” that these, and other, barnacles produce cannot be dissolved by either acidic or alkaline solutions. This has piqued the interest of some researches in the medical field, particularly dentists, in hopes of developing new medical adhesives. Giant Acorn Barnacles also provide important habitat even after they die. The shells of dead acorn barnacles sometimes form reef like structures and can act as nurseries for small fish. So although barnacles aren’t the supermodels of the ocean, they are important parts of the ecosystem and are worthy of study.

– Christopher Scott Mowers (Class of 2018)

Chris Mowers

Chris Mowers

 

Cryptochiton stelleri

Cryptochiton stelleri, (c) Jerry Kirkhart

Cryptochiton stelleri, (c) Jerry Kirkhart

Cryptochiton stelleri, also known as the Gumboot Chiton or the “Wandering Meatloaf,” is the largest species of chiton. It lives 20-40 years, weighs up to 4.4 pounds, and grows up to 14 inches long, and is found throughout the coast of the northern Pacific Ocean. The Gumboot Chiton has armored plates along its back, which help it bend and attach to curved surfaces. It is red because approximately 20 species of red algae live on it and because red algae makes up much of the gumboot chiton’s diet. Its tongue-like radula, used for scraping algae off rocks, has teeth tipped with magnetite, a magnetic mineral! One defense mechanism used by the gumboot chiton, as well as other chiton species, is to curl up so that its soft underside is protected from predators. Because of this, chitons are sometimes called “sea cradles”. An interesting fact is that about 25% of Gumboot Chitons have small segmented worms living on them, near their gills. These worms help clean the gills by eating material found there.

– Maia Tian Sebek (Class of 2015)

Maia Tian Sebek

Maia Tian Sebek

 

Metridium farcimen

Metridium farcimen, (c) James Watanabe

Metridium farcimen, (c) James Watanabe

Metridium farcimen is a species of sea anemone that is more commonly known as the Giant Plumose Anemone. It is native to the west coast of the United States and Canada. Metridium has enormous plumes and striking white, red or reddish-brown coloration that makes it impossible to miss. Large Metridium farcimen are also known to drive away other organisms and capture prey with its large tentacles. Additionally this particular species is able to reproduce sexually and asexually, through pedal laceration, leading to dense populations of the anemones. These organisms can survive for centuries. One specimen in particular lived for more than one hundred years in captivity before human error lead to its death. This species is an enormous, highly adapted filter feeder that dominates the substrate when present.

– Jack Berrigan (Class of 2019)

Jack Berrigan, UW Class of 2019

Jack Berrigan, UW Class of 2019

Parastichopus californicus

Parastichopus californicus, (c) James Watanabe

Parastichopus californicus, (c) James Watanabe

Parastichopus californicus is a large sea cucumber that can be up to 50 cm in length and about 5 cm wide, with large cone-shaped pseudo spines, and tube feet on the underside for movement. Their body is soft and cylindrically shaped, with reddish-brown to yellowish, leathery skin and an endoskeleton just below the skin. They feed upon organic detritus and other small organisms by eating bottom sediments, and pooping out sand. Occasionally, they will position themselves in a current where they can use their tentacles to catch food (such as plankton) the floats by. Typically found in the low intertidal zone down to about 90 m depth (although occasionally as far down as 250 m), they are generally loners that are active at night. A few interesting things about P. californicus is that they have the ability to regenerate all parts of their body, similar to their relatives, the starfish. When threatened, they can expel all the contents of their stomach (instantaneous poop!) or a sticky white substance that confuses predators. They are a commercially fished species that is popular in Asian markets in the United States and overseas, which has led some areas to be overfished.

– Dejah L. Sanchez (Class of 2015)

Dejah Sanchez

Dejah Sanchez

 

Pugettia producta

Pugettia producta, (c) James Watanabe

Pugettia producta, (c) James Watanabe

Pugettia producta, the Northern Kelp Crab, is a ubiquitous feature anywhere kelp grows. It does not decorate it’s carapace to the same extent that other majid crabs do. There is speculation that when it does attach items to it’s carapace, it is doing so to eat them later. It is omnivorous, but mainly feasts on algae–only when this food source is scarce will it resort to a eating barnacles, mussels, hydroids, or bryzoans. P. producta is at times parasitized by the barnacle, Heterosaccus californicus, which modifies their behavior and physiology. The crab becomes sluggish, and during their next molt, the barnacle pushes it’s reproductive sack through the crab’s abdomen. The crab’s gonads are damaged severely if not destroyed. In some cases, male kelp crabs exhibit female morphology after being parasitized, including carapace and claw modifications, and even production of eggs in addition to sperm.

– Ian McQuillen (Class of 2015)

Ian McQuillen

Ian McQuillen

 

 Serpulid worms

Serpulid worm, (c) Jim Lyle

Serpulid worm, (c) Jim Lyle

The rocky subtidal substrate lining the bottoms of our waters is teeming with life. My personal favorite creatures are the serpulid worms. These suspension feeders bind to solid substrate and extend their beautifully patterned feathers in order to sift nutrients floating through the water around them. If startled, they quickly retreat into their shell like home. If enough of the worms live together, they can form a cool, reef-like structure. As urban structures are being developed closer and closer to the shoreline, we disrupt their fragile habitats.  They are definitely small and easy to miss but fascinating nonetheless.

– Rianne Peterson (Class of 2018)

Tritonia festiva

Tritonia festiva, (c) Kevin Lee

Tritonia festiva, (c) Kevin Lee

Tritonia festiva (also known as the Diamondback Tritonia), is a nudibranch of the family Tritoniidae. They are distributed all the way from North-Central Alaska to Baja California, and are 2-3cm in length. Tritonia festiva use their sensitive frontal veil to hunt their prey, carefully positioning their mouth over expanded polyps of octocorals before swiftly attacking. If you ever get the chance to look at an octocoral colony after a Tritonia attack, you will see holes where the missing polyps have been torn out by the nudibranch. I would say Tritonia festiva is definitely one of the prettier sea slugs, though there are over 3,000 sea slug species. Like other sea slugs, they are hermaphrodites, and so can mate with any individual passing by them.

– Ashley Pierson (Class of 2018)

Ashley Pierson

Ashley Pierson

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Sites and Critters

Urchins destined for great things

Green urchins

Green urchins, Strongylocentrotus droebachiensis, on an artificial boulder covered in barnacles and pink coralline algae

Sea urchins may not seem like they’re destined for great things in life, but the marine environment would really by quite different without them.

These prickly creatures, which are related to sea stars, spend most of their time eating. Eating for them involves scraping rocky surfaces of algae and other life forms with 5 rather vicious looking teeth. Though they are typically characterized as “grazers” (eating primarily algae), former Sebens labbie, Robin Elahi, and others have noted that they eat pretty much anything small and sessile (attached) that’s unlucky enough to be in their path.

Many researchers have noted the importance of sea urchins in maintaining invertebrate-rich marine ecosystems. By consuming leafy algal species such as kelps, which can dominate rocky surfaces, urchins may facilitate a higher diversity of invertebrate species that would otherwise be out-competed.

Painted Greenling on riprap

Painted Greenling on artificial boulders with barnacles and jingle shells, at a well-grazed site (where urchins are present)

Such a shift in community composition at the proverbial hands of urchins has been documented in other, less urban ecosystems. However, we’ve found that Seattle’s rocky, subtidal ecosystem is dominated by a different suite of algal players. Red leafy algae tend to be much more successful in Seattle than the brown kelps that are dominant at rural, higher flow sites in the region.

We’ve conducted a survey of the invertebrate and algal community in Seattle, and it appears that urchins may be reducing red algal abundance at sites where they’re present in moderate numbers. In the presence of urchins, we find organisms like serpulid worms, jingle shell clams, and coralline algae. We think this may be because urchins are clearing space for these species to settle. Without urchins, red macroalgae appears to take over and leave little room for the more delicate characters you see here.

This findings, however, are observational. Until we test the hypothesis presented here, there will be no way of knowing whether urban urchins truly are destined for big things in life. More to come on that front!

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