Big Ideas

Urbanization and evolution

Galapagos finches, drawn by John Gould (1804-1881)

Galapagos finches, drawn by John Gould (1804-1881)

Urbanization may affect many aspects of marine ecosystems, but as ecologists we often ignore the potential evolutionary consequences of urban development. Several years ago now, there was a great study on just this by Andrew Hendry and colleagues in Proceedings of the Royal Society. They studied the most famous of model species for evolution: Darwin’s finches (the ground finch, genus Geospiza).

Specifically, Hendry et al. were studying two morphs (right)

Two finch morphs (Photo by A.P. Hendry, 2014)

Two finch morphs (Photo by A.P. Hendry, 2014)

of the Medium Ground Finch (Geospiza fortis) on the island of Santa Cruz in Galapagos. The two morphs had different beaks sizes (used for eating different foods), different songs, and tended to mate preferentially within their morph (ie – with other birds that looked like them).

By documenting the differences between these two morphs, Hendry and colleagues expected they were in the process of observing a speciation event. But then something strange happened: in areas on the island where there were lots of humans, the morphological differences between the two morphs diminished. In particular, the “bimodal” (distinct large and small) beak sizes of the two morphs fused and beak size became widely variable in more urban locations. Why would this happen? Human activities had made a wider variety of food sources available to the finches (see photo of finch on cereal box). The little birds indulged in the anthropogenic cornucopia urbanization offered, and human food of all shapes and sizes was sure to satiate regardless of one’s beak morphology. Selection against intermediate beak size was thus eliminated, allowing birds of all beak sizes to thrive in urban areas. As Hendry describes it, humans were causing “reverse speciation”.

Galapagos finch on a cereal box (Photo by A.P. Hendry, 2014)

Galapagos finch on a cereal box (Photo by A.P. Hendry, 2014)

This is old news really, as it was published almost a decade ago. Two things have led me to post about it now: (1) I recently came across this blog post by Hendry on eco-evo, which I highly suggest, and (2) Hendry’s findings were featured in Episode 3 of Galapagos, which was made available on YouTube earlier this month. (The episode in its entirety is worth making an evening of! But skip forward to 36:08 if you just want to hear about urban finches).

To my knowledge, there have yet to be any comparable examples documented in the marine environment. Other human activities are known to influence evolutionary traits in marine organisms. For instance, fishing can lead to an earlier age or smaller size at which marine fish become reproductive. But evolutionary consequences from marine urbanization specifically are poorly understood.

With time and further study, we hope to know more!

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Sea Lions In Elliott Bay
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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Big Ideas, Recent Research

CASU

Figure 1 from Loke et al. (2014) - A screenshot from CASU.

Figure 1 from Loke et al. (2014) – A screenshot from CASU.

Here’s a neat tool that could be of use to urban planners and restoration ecologists – CASU, the “Complexity for Artificial Substrates” program. CASU is open source software developed by Lynette Loke at the National University of Singapore and colleagues in Singapore, the Netherlands, Brazil, and the United Kingdom. The program allows users to design and visualize artificial substrates for urban waterfronts that are more complex than traditional, uniform surfaces we currently see on most bulkheads and seawalls. Since substrate complexity is tied to biodiversity of intertidal ecosystems, more complex substrates like those generated by CASU may serve as “ecological enhancements” for urban waterfronts.

Loke and colleagues originally developed CASU as part of a project aimed at increasing biodiversity on seawalls in Singapore using molded concrete tiles. By manipulating the topographic complexity of the tiles and deploying them in the field, they wanted to test whether more complex tile designs would increase the diversity of intertidal organisms. The problem is that you can define complexity in number of different ways. What specific aspects of habitat complexity actually affect intertidal diversity most and which are most important to include in your design?

CASU allows the user to modify 5 variables that affect complexity: (1) the number of object types, (2) relative abundance of object types, (3) density of objects, (4) variability and range in the objects’ dimensions, and (5) their spatial arrangement. In the case of their molded tiles, these 5 variables altered the arrangement and configuration of depressions in the tiles’ exposed surface (which are the “objects” that alter habitat complexity in their study).

Loke and colleagues describe CASU in further detail in a recent article in PLoS One. Indeed, after deploying their tiles in the field for 13 months, they did find that tiles with more complex surfaces supported greater diversity of intertidal organisms. Their subsequent work teasing apart which components of complexity are most influential for intertidal diversity on Singapore’s seawalls appears to be in press at the moment, so stay tuned for that. In the meantime though, you can download CASU using the links at the bottom of this page.

Figure 2 from Loke et al. (2014) - their caption reads: "3D models (AutoCAD drawings) of tiles with a single structural component (square-pits) at two levels of complexity generated via CASU. (A) ‘simple tile’ and (B) ‘complex tile’. (C) a fabricated 40×40×6 cm^3 concrete tile mounted onto a seawall (photograph taken one month after deployment)."

Figure 2 from Loke et al. (2014) – their caption reads: “3D models (AutoCAD drawings) of tiles with a single structural component (square-pits) at two levels of complexity generated via CASU. (A) ‘simple tile’ and (B) ‘complex tile’. (C) a fabricated 40×40×6 cm^3 concrete tile mounted onto a seawall (photograph taken one month after deployment).”

 

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Big Ideas, Ecosystem Services, Recent Research

Engineering for the greater ecological good

Photo of eagle statue at Redondo Beach, WA

Invertebrate-encrusted eagle statue with a Metridium anemone growing on its wing

As coastal cities become increasingly urbanized, the surrounding waters are littered with a plethora of artificial structures. An “artificial structure” can be anything from seawalls and breakwaters to an abandoned garden statue, like this eagle (right) in South Seattle, which ended it’s long terrestrial journey at the bottom of the ocean. Though colonized by a colorful variety of organisms, artificial structures are rarely added to underwater landscapes with clear, coordinated, and ecologically-oriented goals in mind. The undersides of coastal cities can therefore become ecosystems of happenstance, a chaotic patchwork of opportunistic marine species that may or may not promote the conservation agenda of urban residents or the ecosystems services upon which urban residents rely.

But does it have to be this way? This was the question posed by Dr. Katherine Dafforn and colleagues in a recent publication in Frontiers in Ecology and the Environment (link). Using a series of case studies, they explore how artificial structures might instead be designed, or engineered, to meet specific ecological goals. For instance, to combat pollution, artificial structures could be “seeded” with seaweeds that absorb contaminants, and bivalves that filter organic pollutants. If we want to promote local biota, we could design artificial structures to mimic natural conditions, and restore natural coastal barriers, like wetlands and other shoreline features. (Here’s one such example documented by other UW biologists at the Olympic Sculpture Park in downtown Seattle. The video below shows the kelp forest ecosystem that formed at the site after old artificial structures were rebuilt with more natural materials.)

Though ecological engineering is not a new idea, Dafforn et al. are among the first to emphasize how the approach could help us realize the “multifunctional potential” of artificial structures in urban marine environments. Indeed, anyone who spends time observing marine life in cities is aware of the diversity of life these structures support and the benefits they could offer, both ecologically, and for people, if developed intentionally and with clear objectives in mind. As Dafforn and colleagues explain, these objectives do not need to be singular, as a multifaceted coastal management plan that incorporates a variety of ecological engineering projects and techniques could provide many benefits simultaneously. Perhaps it’s not too grandiose to conjecture that forward-thinking design initiatives could even realign the trajectories of humans and marine ecosystems in coastal cities so that they converge onto a single, more sustainable path forward.

 

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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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Happenings

Research Blitz – Science for Adaptation Planning

I’m en route to the Friday Harbor Labs for a much anticipated research blitz – a 72 hour research intensive with fellow graduate students in the IGERT Program on Ocean Change (IPOC). Over the course of the coming weekend, we hope to make considerable progress on an interdisciplinary collaboration we started last fall. Our objective: Use a case study approach to identify how scientists can best support the planning process undertaken by coastal cities as they adapt to rising sea level.

From the IPCC's 2013 Report (see link in text)

From the IPCC’s 2013 Report (see link in text)

For many years now, the Intergovernmental Panel on Climate Changes (IPCC) and concerned scientists have warned of the impending rise of global sea level and the risks it poses to coastal communities, particularly in high density, urban areas. Projections published by the IPCC in 2013 suggest that sea level could increase by more than 3 feet by the end of the century. But more recent research suggests that the threat may be much more extreme and immediate in some locations due to geographic unevenness in the rate at which sea level is rising. Cities like Miami are already beginning to experience periodic inundation from the surrounding ocean, and record-breaking storm surge events like that from Hurricane Sandy now pose considerable risks to New York and other low-lying metropolitan areas. For many coastal cities, sea level rise is no longer a possibility in the distant future; it’s a process that is already underway, with very real social and economic consequences.

The question many coastal cities therefore face is not how to prevent sea level from rising, but how to adapt to the additional increase we’re already fairly certain will occur. Adaptation plans are under development in most major coastal cities, with the Dutch leading the pack. Many of these plans employ both traditional engineering solutions, like the construction or reinforcement of seawalls and dikes, as well as “soft engineering” approaches, such as restoring wetlands that serve as barriers from encroaching seas. Though economists, social scientists, policy buffs, and the design and urban planning community have already made extensive research contributions to the field of adaptation planning, we’d like to know what more natural scientists (climatologists, oceanographers, biologists, ecologists) could do to help.

Adapting to sea level rise will most certainly require creative approaches that draw on expertise from a wide range of disciplines. What better way to learn about adaptation planning and the science behind it than with an interdisciplinary group of IPOC fellows!

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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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Aurelia aurelia
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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