This Week In The Lab

Enrichment plot samples are here!

That’s right, the first 8 week samples from the enrichment plots are in and it’s time to get to work. Here’s what the inside of our lab fridge looks like right now to give you a sense of what lies ahead:

Photo of fridge full of sediment samples

Each one of those bags needs to be sieved, sorted, and analyzed for macrofauna.  I definitely have my work cut out for me!  But I’m excited to see what critters I’ll find in there.  Thanks so much to Rhoda Green and Dave Thoreson for their help setting up the enrichment plots and collecting these samples with me.  And another thanks to Rhoda for coming into the lab to stare at tiny sediment grains for hours on end with me.

More soon!

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This Week In The Lab

Urchin corrals

I have installed the first of what will likely be several different contraptions to contain urchins. It’s an urchin corral! You can see it here in the kiddie pool tanks at MaST aquarium:

Photograph of urchin corral out of the waterClose up of urchin corral

It’s kind of like a little urchin boxing ring!

If you’re wondering why on Earth I’m doing this, you might check out this previous post.  These urchins will eventually be used in a field experiment to test how their feeding affects the subtidal communities on artificial rocky substrates.  In order for the field experiment to work, I need to be able to keep the urchins from wondering off experimental plots.Photo of urchin pressing against edge of corral

Enter little urchin boxing rings… this is likely the first of several iterations of the urchin corral/boxing ring idea.  Over the next week I’ll be trying to figure out whether urchins are escaping and how exactly their doing it.  If I can develop a design that contains urchins effectively, the next Photo of urchin corral in kiddie poolstep will be to put something like this into the field and evaluate whether it seriously alters flow, traps algae, excludes other important critters, or changes some other aspect of the physical environment on seawalls.

In its current form, the boxing ring/urchin corral is constructed from bolts protected by pieces of artificial sponge (thanks to Rus Higley at MaST aquarium for this fantastic idea) and monofilament line (this idea compliments of my advisor, Ken Sebens). I’ll let you know what happens!

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This Week In The Lab

Building a macrofauna library

Vials of representative specimens for my macrofauna library

Beginning of our macrofauna library

Just back from a whirlwind trip to Friday Harbor Labs.  There, with the help of an expert, I was able to begin building my library of the species that live in subtidal soft sediments in the Seattle area. As I drove from Anacortes to Seattle, my vials of macrofauna in ethanol rode along in the passenger’s seat.  Together, we boarded a ferry for San Juan Island, where we spent the next few days looking deep into eachothers’ eyes under the romantic lighting of a dissection scope.

Vial containing Spiochaetopterus worms

Vial of Spiochaetopterus worms!

Thanks so much to Megan Dethier for all her help as I dive into the world of infauna.  You wouldn’t believe how many families of polychaetes there are, or how complicated a dichotomous key for snails can be!  We’ve made good headway though, and I’ve already accumulated a large number of tiny vials containing representative specimens (see photo).

In addition, I’m compiling a written key for lab techs that hopefully will require less time than the all knowing and ever complex invertebrate bible, Kozloff’s “Marine Invertebrates of the Pacific Northwest.”

More soon on my favorite specimens and strangest finds!

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This Week In The Lab

Soft sediments – they’re alive!!!

On Aug 3, I told you about the dives we’d done to collect soft sediments.  Tube of macrofauna in ethanolSince then I’ve spent many an hour in the lab processing the samples we collected.  Processing involves (1) quantifying the volume of riprap-originating algal material in each sample, (2) quantifying sediment grain size, (3) identifying each type of shell hash, and (4) identifying and counting all macrofauna.

Macrofauna are organisms that live in soft sediment.  Until just a few years ago, I had no idea how many critters actually live embedded in sand and mud. From above, the soft sediment landscape appears barren, almost devoid of life.  But it’s actually alive in a way I never imagined – at a tiny scale.  After many hours of picking through sand and mud in my sediment cores, I am again amazed at the density and diversity of macrofaunal life forms.  They come in all shapes and sizes, colors and textures, life histories and strategies.  Worms, clams, snails, amphipods, ostracods, sea cucumbers, and more!  It’s overwhelming.

For now, I’m simply pulling specimens out of sediment samples and storing them in ethanol (as in the photo), but I’ll be identifying them over the coming months and look forward to sharing.  Their stories are bazaar, amazing, surreal – from vicious hunters with exploding mouth parts to little arthropods that spend their entire lives moving about the seafloor in the organic equivalent of a hamster ball. I’ll highlight my favorites as they arise.  Stay tuned!

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This Week In The Lab

Urchins tanks are ready

Last week, I told you about experiments I would be starting at MaST aquarium in Des Moines, WA.  I’m happy to report that the urchin tanks (aka kiddie pools) are up and running! Urchins in kiddie pool A small number of specimens have been moved into the tanks.  I’ll let them acclimate for a week or so to ensure that everything is functioning properly.  Then, it will be time for experiments.

I’ll be trying a variety of different approaches – urchin corrals, sponge barriers, and tethering.  The objective is to find a way to contain urchins without significantly altering physical conditions (such as water flow).  With each method, and particularly with tethering, I’ll be testing whether the technique alters how urchins feed.  This is important because the urchins themselves will later be the experimental treatment in the field when I test whether urchin feeding alters the biological community on subtidal riprap.

Urchins in kiddie pools at MaST aquariumIf you have ideas about how you would contain urchins in a fixed area, I’d love to hear about it!  Submit an idea or drawing on the Contact Me page.  Or, send me your idea at:

Eliza Heery
University of Washington, Department of Biology
Box 351800
Seattle, WA 98195-1800

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This Week In The Lab

Does algae and shell hash from riprap make it into neighboring sediments?

You can find subtidal riprap all over the place in urban marine ecosystems.  It’s often like a patchy network of little islands in a sea of soft sediment.  On each of the islands is vibrant hub of reef-associated species – fish, algae, invertebrates of all shapes, colors, and sizes.  Collectively, these riprap-dwelling species generate a lot of biomass, particularly in the form of algae and shell hash.  Eventually, I’ll be testing whether these materials alter the soft sediment communities nearby.  But for now, I simply want to test whether the materials produced by riprap-dwelling organisms make it into adjacent habitats.

Divers entering water to collect soft sediment

This was my reason for embarking on a series of dives recently at Alki Pipeline and Elliott Bay Marina’s breakwater.  With the invaluable help of two dive buddies, Rhoda Green and Dave Thoreson, I was able to get my hands on lots and lots of dirt!  At each site, we lay out three transects extending perpendicularly from riprap.  We collected core samples at 1m, 7m, and 15m along each transect and put them into plastic bags.  After a lot of heavy lifting, we got the samples back to the lab, where I sit now (procrastinating by writing this) with my work cut out for me.  Over the coming weeks, I’ll be sorting through the sediment, quantifying algae, shell hash, sediment grain size, and macrofauna.

I’ll keep you posted on findings as they arise. For now, it’s time for me to get busy.

 

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Photos of benthic habitat when urchins are present versus absent
This Week In The Lab

Herding urchins

This week in the lab!.. Setting up kiddie pools on the dock at MaST aquarium.  Why you say?  I’m preparing for an experiment with urchins!

Urchins have a very patchy distribution in the Seattle area.  Using field surveys and underwater photography, I have found differences in the marine community between sites where urchins are present and absent (see image above).  Rocky sites with urchins tend to be characterized by encrusting algae, bare rock surfaces, and occasional large blades of kelp.  Rocky sites without urchins are dominated by a diverse range of red macroalgal species, which may support a different suite of mobile invertebrates.

Photos of benthic habitat when urchins are present versus absent

Sample images of the marine community at (a) a site in Elliott Bay where urchins were present and (b) an adjacent site where urchins were absent. Underwater photography allows us to collect data on the flora and fauna at different sites much more efficiently than was possible in the past. Photos are taken on SCUBA dives using a randomized survey design. Back in the lab, we test for differences in the biological community at two sites by quantifying the percent cover for each algal and invertebrate species in the frame and then using multivariate statistics.

Although I was able to detect differences in the biological community at sites with and without urchins, I don’t know whether these differences are actually caused by urchins until I test this hypothesis experimentally in the field. Starting in late August, I will transplant urchins from the kiddie pools at MaST to a site in Elliott Bay where urchins are currently absent. The urchins will be kept there for several months while I monitor the algal and invertebrate life around them and watch for changes in community structure.

Urchins are faster than you might expect and keeping track of them once you’ve transplanted them to a new site turns out to be quite challenging. In a pilot study, I was only able to find 4 out of 10 urchins after they had been transplanted to a new site. In the full experiment, it’s important that I be able to keep urchins on experimental plots. Otherwise, I won’t know whether the plots were actually subjected to urchin feeding. So, I need to develop a way to contain them within a fixed area. That’s exactly what I’ll be experimenting with in the kiddie pools at MaST.

Thanks to the facilities provided by MaST, I can develop and test alternative urchin containment techniques in a controlled setting prior to implementing them in the field. My objective is to find the least invasive urchin containment technique that meets the following criteria:
(1) Contains urchins without significantly altering the physical conditions (such as water flow) of experiment plots
(2) Does not affect urchin feeding
(3) Allows for free movement of other invertebrate species (such as chitons, snails, crabs, etc.) in and out of experimental plots

Tanks should be up by next week.  I’ll keep you posted!

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