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!

Big Ideas, Recent Research


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).”


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.


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


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!


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!

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.

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.


Photo banner from the website
Big Ideas

Blue Urbanism

Recently, while browsing in a small bookstore in my hometown of San Francisco, I came across this new fantastic read: Blue Urbanism: Exploring Connections Between Cities and Oceans, by Timothy Beatley. Upon reading even just the dedication at the beginning (“Dedicated to all of the marine life we don’t (usually) see and the many individuals in cities who work tirelessly to understand and protect it”), I knew I was hooked.

Cover of Blue Urbanism, by Timothy Beatley

(c) Island Press, 2014

In a Places Journal essay (available here), Beatley notes, “Blue urbanism — an emerging set of ideas and perspectives — would mean that cities would seriously evaluate and carefully regulate their effects on marine environments; and city planners are potentially on the front lines of this new movement.” Because cities have jurisdiction over nearshore environments, he argues, they also have the power to actively manage these environments and mitigate the effect of city development on marine ecosystems. This may be done through a suite of management tools, including reducing pollution and “urban detritus” (such as plastic wastes), changing regulatory guidelines for ports and shipping, and curbing greenhouse gas emissions. Even simply incorporating maps of “ocean sprawl” into city planning may allow for considerable progress.

But Beatley’s exploration goes well beyond regulatory tools, eventually developing a completely new vision for how we interact with urban marine environments. If you’re a sci-fi fan, an urban dweller, a lover of marine habitats, or all of the above, I suspect you’ll find this vision to be an appealing one. Floating cities, underwater buildings, soft urban edges, and public spaces that integrate the shoreline are just a few of the ideas Beatley considers…. Did you know there’s already a restaurant in the Maldives where you can dine 5m below the sea’s surface (link)? And a luxury resort in Fiji where you vacation (for the cost of an entire college education) entirely underwater, at 12m depth, in the bottom of a tropical lagoon (link)?

These of course are venues most of us will never have access to, and who knows the extent of their environmental impact, but they stimulate consideration of a novel concept that I think is helpful: Perhaps we, as part of coastal food webs and marine ecosystems, could live our lives in a way that is intentionally and visibly integrated with the marine environment. Whether we’re purposeful about it or not, we are actively shaping and recreating urban marine landscapes. Why not do this in a way that promotes sustainability, helps marine ecosystems thrive, and enriches our own awareness and sense of well being?

Blue Urbansim, by Timothy Beatley. Check it out!



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.