Wednesday, July 31, 2013

Leeah: Week 4

          Primarily the focus for this week was on molecular work. Over the past month I have frozen a plethora of pilidium larvae. On Monday I ran the biggest extraction I have ever done before. This DNA extraction consisted of sixteen previously frozen individuals. Terra had some business to attend to on Tuesday and I was left to my own devices for most of this week. She gave me a list of high tides and low tides so I could plan some plankton tows. I was also entrusted to run a PCR on a few samples she had left with me. It was exciting to see the pictures she had taken of the larvae and have a face to match with the glowing band on the gel tests.
           I know that it is rather confusing to explain molecular work here. I now have access to pictures which will help explain the process.
As I mentioned before, we use a product called Instagene for larval samples which has little beads that hold everything but DNA. The beads need to be stirred using the Nuova stir plate as shown below.

A pipetman is used to transfer the Instagene to the larval sample.

This is one of the incubators used in the DNA extraction process

After incubation, the samples need to be centrifuged so the beads will accumulate at the bottom of the tube.

Then the supernatant liquid which contains the DNA can be removed and put in a new container.

Extraction complete now moving onto the PCR.
I split up the samples based on the gene regions we study, 16S and CO1. I had 16 samples and now I have 32!

I put a few microliters of my extracted DNA within and some Master Mix to get the reaction going. Then it goes in a machine which is has programs that run at temperatures specific to the gene regions and the reactions.

Time for an agarose gel test. This process is called gel electrophoresis.
This is the gel rig that holds the agarose containing a chemical that binds to DNA called Ethidium Bromide.

The gel is melted and then poured into the rig. It is then allowed some time to set.

Combs help to mold the gel and provide a place to load the samples. It is important to check for any bubbles between the teeth of the comb.

Then buffer is added to the rig. It must have complete coverage over the gel.

Then the combs are removed so we can load the gel with our samples.

Small quantities of the samples are added to each place left behind by the comb. A ladder or molecular weight size marker is also inserted as to show the quantity of DNA when the gel is placed in the imager.

The rig is then hooked up to a current, running from black to red, which will pull the negatively charged DNA to the positive end.

After about 30 minutes, the gel is ready to go into the gel imager.

Agarose gel test completed! Now the troubleshooting begins.

 On another note I have taken a break from drawing worms this week. I was excited to find a Sea Otter skull in the Birds and Mammals classroom and I decided to draw from it. One interesting thing about otters is that their lower jaws cannot detach from the upper part of the skull. Evolutionarily this makes sense as otters routinely eat hard kinds of prey which would be easy to dislocate one’s jaw on. The upper image of this drawing depicts the underside of the otter’s skull where the mandibular condyle on the otter’s jaw is completely interlocked with the mandibular fossa. The scientific name for Sea Otter is Enhydra Lutris which literally translates to “Otter in water”.

Tuesday, July 30, 2013

Zac - Tools and tricks of the trade

My work in the Maslakova lab involves using morpholinos to suppress the products of specific genes in M. alaskensis larvae.  After the morpholinos begin taking effect, we use a number of techniques to identify the differences between morpholino treated larvae and untreated larvae. These differences can be attributed to the suppression of these genes, and thus give us clues as to the mechanistic function of these genes. However, these are microscopic larvae and oftentimes this research requires peaking into individual cells. So how do we do it?

Bright-field vs DIC imaging, pictures by Zac Swider
For one, we use extremely powerful microscopes capable of differential interference contrast imaging (DIC). This imaging technique takes advantage of the properties of polarized light to make  a high-contrast image out of an otherwise transparent object. The image to the right shows a bright-field image of one my cheek cells (top) as well as a the exact same image with the DIC prisms in place (bottom).  Although this is a handy technique for taking pictures of our otherwise transparent larvae it is still extremely limited in its ability to visualize sub-cellular components. For this purpose can utilize fluorescent protein probes to mark specific tissues or sub-cellular components.  Since we are already injecting these larvae with a solution of morpholinos, it is no big trick to add a solution of mRNA to the needle and co-inject it with the morpholino. These cells will take the injected mRNA and express the protein that it codes for in great quantities. Once the protein has been produced it will bind to its target molecule and mark its location within the cell. We can choose specific proteins that, for example, bind specifically to DNA or specifically to microtubules, or actin.  You name it and somebody has probably made a probe for it.

Nemertean Embryo Expressing Microtubule Label
Image by George von Dassow

The image to the left shows a nemertean embryo expressing a fluorescent label for microtubules (orange) - image by George von Dassow. Microtubules are significant component of the cell "skeleton" and watching the changing behavior of these macromolecules can tell us a great deal about a cell. These images of fluorescently labeled larvae are generally obtained using laser scanning confocal microscopy.  Confocal microscopes essentially just use a laser and a pin-hole to take extremely thin scans through a specimen, and then compiles these individual scans to create a crisp image with no out of focus blurring. The image series below shows the significant difference seen between confocal microscopy and compound microscopy.  The difference in image crispness is significant between the image to the left (confocal) and the image series below (compound).  This is largely due to out of focus light that the compound microscope simply cannot filter out.  

Five day old M. alaskensis larva expressing mEos - images by Zac Swider
The image series above shows a five day old M. alaskensis larva expressing a fluorescent protein called mEos. This fluorescent protein is attached to a histone, one of the components that helps package up DNA in the nucleus, which means that it will accurately label the location and shape of every single nuclei in the the subsequent larva. It also has the neat feature of being photoactivatable. This means that the protein starts out with a green emission peak but it can be irreversible converted to have a red emission peak by exposing the protein to a 390nm laser light.  The image series above shows the larva using DIC imaging (left), epifluorescence imaging before laser exposure (middle) and epifluorescence imaging after laser exposure (right). For the sake of this picture I just exposed the entire larva to UV light, but the photoconversion can be done under much more controlled conditions to alter the emission spectrum of a single nucleus and leave all others intact.  By doing so one could photoconvert, for example, just one of eight cells (in an eight cell embryo), to red and put it back in a dish to grow.  After a couple weeks the resulting larva would show a number of red nuclei - each one a direct progeny of the originally altered cell. Needless to say this has a number of implications in allowing us to study the development of these larvae.

Spionid - Image by George von Dassow
However injections of mRNA are not the only way to label specific parts of a larva, another popular technique involves permanently fixing the larvae (using formaldehyde) and staining for specific molecules using fluorescent antibodies. Antibodies are components of the vertebrate immune system that that recognize and "tag" foreign entities for destruction. The match between an antibody and its "target" it boasted to be one of the most specific chemical matches within the cell. Biologists can take advantage of this specificity to "probe" for just about any molecule imaginable. The image to the right (by George von Dassow) demonstrates the contrast and complexity achievable by staining, even with a relatively large animal.

I know I promised some fluorescence microscopy pictures of my own larvae this week, but unfortunately the last batch could not have turned out any worse. We are trying again this week (using a different buffer, and new antibodies) and will hopefully see some better results. Again, stay tuned for some fluorescence pictures and (hopefully) some tentative results next week!


Zac - Shore Acres Botanical Garden

Weekends are frequently a good time for hard-working interns to get into the field and experience some of Oregon's natural beauty.  This past weekend we went for a short hike along the Oregon coastline to the Shore Acres Botanical Garden.  The image below shows a taste of the dramatic coastal scenery.

Oregon Coastline
The title of this post is slightly ironic in that I did not actually take any pictures inside the botanical gardens. I found that the diversity of flora and fauna on our hike to the garden far surpassed that found within. The sun was in and out through the light cloud cover during our hike, but there was enough of it to encourage a healthy abundance of bumblebees.  See below is a common species of bumblebee (Bombus sitkensis) perched atop a "coastal sneeze-weed" (Helenium bolanderi).

Sitka Bumblebee - Bombus sitkensis
Another relatively common wildflower (albeit invasive, and slightly more prickly) were the thistles. The bush seen below had attracted a host of hoverflies.  These harmless insects look similar to a wasp or a bee but they are actually flies - closely related to mosquitos or the common housefly. The coloring on these insects is a classic example of Batesian mimicry - when a harmless animal mimics the coloration and/or behavior of a poisonous one.
Hoverfly - F. Syrphidae

Yellow-bellied Racer - Coluber constrictor mormon
Another big hit on the trail was a snake (everybody loves snakes). I am a big fan of the insect world (as you may have already guessed) and can only tentatively identify this as a yellow-bellied racer. It is relatively common in the pacific northwest and fits all of the criteria - but the scale pattern on the head seems to be a little bit off from most of the pictures that I have seen.  Hmmm...
Seen below is a wasp moth nestled into the coastal undergrowth. The only thing that I was not able to capture in this picture is the bright iridescent blue coating on the body of these distinctive moths.

Virginia Ctenucha - Ctenucha virginica
Seen below is a common wasp (yellow-jacket) likewise enjoying the summer sun.

Common Wasp - Vespula vulgaris

I still had some time left of on my beautiful Sunday afternoon to capture an image of the nemertean seen below. As you may remember from previous blog posts, the Maslakova lab (my place of work) is largely consumed with characterizing the phylogeny and development of the Phylum Nemertea.  Not surprisingly, there are hundreds of nemertean worms being kept in the lab sea table and the species seen below (Micrura verrilli) is by far one of the most striking.  It also happens to be a very close relative to the species that I am studying - Micrura alaskensis.

Nemertean Worm - Micrura verrilli

More adventure blogs to come soon! If I ever find some time to get out of the lab before dark ;)

Natasha Christman: Along the San Juans

This week, I took part in ongoing oceanographic research based in the San Juan Islands. As a component of  the continued monitoring of the region's health and ecology, research cruises on the University of Washington's vessel the R/V Centennial occur periodically throughout the year. The cruises focuses on the waters to east of San Juan Island and to the west of Lopez and Shaw Islands.

The Centennial docked at its home port
 of Friday Harbor Labs.

The Centennial started out life as a commercial fishing boat in the Gulf of Alaska but later was converted to a research vessel. Today, when not out at sea, the 58' vessel resides at the University of Washington's Friday Harbor Labs on San Juan Island. With its formidable size, the ship can accommodate the navigation crew, the scientists, students, and the citizen-scientists that accompany the cruise. With so many different experiments and sampling going on at once, having a solid amount of space on the ship is important to keep track of it all.

The deck of the Centennial.
The picture on the left shows the deck of the Centennial as viewed from the navigation cabin. Like Shannon Point's vessel the R/V Zoea and many other oceanographic ships, the Centennial also has a CTD to take water samples at fixed depths and profiles of the water column. The long transect of water the cruise investigates is broken up into several regions. At the edge of each region, the CTD is lowered down to several meters above the seafloor bottom to record a detailed profile. This gives us better insight to the conditions and characteristics of the area's water, helping to establish the ecological makeup of the region.

Dr. Apple and the captain working to lower the net
Apart from the CTD and related data collection like nutrient and chlorophyll samples, a group of citizen-scientists also come aboard the vessel to tally the populations of birds and marine mammals they see along the transect. Additionally, water from a small plankton tow is taken to isolate and fix some of the phytoplankton from the column for later analysis. To sample and account for the important zooplankton populations, a very large plankton net is lowered into the water by a crane. There are pretty substantial differences in the phytoplankton tow size and the zooplankton tow size; while the metal rings that support the phytoplankton net are about the size of a dinner plate, the zooplankton tow rings are akin to hula-hoops in size. This difference is related to supporting the different mesh sizes that target each group of plankton. The wider meshes are great for capturing the larger zooplankton, while more fine, thin net is best for the tiny phytoplankton.

Data from this contributes to the understanding of the whole ecological chain; from the tiny phytoplankton and zooplankton to the cormorants and seals, the data gives us a pretty good idea of the current condition of the food web. With so many factors that contribute to the region's natural environment, research like this is important to understand and monitor what exactly is happening or has happened to the ecosystem. Overall, it was a fine day out on the water and contributing to this research. Next month, I will go out on the Centennial again for the next series of this experiments. Until then, I resume my research of Bellingham Bay and the environment there!

And a big thanks to the University of Washington and all the people at Friday Harbor Labs!

Natalie Week 5 Shrimp Nirvana

This week at Hatfield I was able to help Brett complete his collections of the shells bags that were placed in the Zostera japonica sea grass beds and I also helped him sort through the samples. We found many more shore crabs, Hemigrapsus oregonensis, than we did Dungeness crabs which was consistent with the other sites that were closer to the mouth of the bay. I also helped Katelyn Bosley complete her survey of the mud shrimp Upogebia pugettensis by shrimp coring.  This process starts by selecting 10 random points throughout the mudflat in low, medium, and high density beds and navigating to those points with our GPS unit.  We then sink the core, a large metal device, into the mud and count the number of shrimp burrows inside the sample area.  We then use a shovel to dig out the sediment and place it into sieves.  We can use our hands or water to rinse away the sediment and expose the shrimp, which we then collect and freeze so Katelyn can extract lipofuscin from their brains later. 

This week I was also give the amazing opportunity to go to a behind the scenes tour of the Oregon Coast Aquarium located right next to Hatfield.  The educational program director Wendy took us on a tour and showed us the jellyfish propagating room, the brine shrimp growth area, the freezers where they keep the restaurant-quality seafood they feed the marine mammals, and the tops of the passages of the deep tanks.

I also progressed with my gastric mill slides, which I was able to polish with the help of Tom Murphy, a scientist working in Dr. Jessica Miller’s lab.  Though I am waiting on a compound scope camera to document my slides I have located an area of the lateral ossicle attached to the lateral tooth that looks promising for growth rings and hopefully I will decipher what these lines mean next week.

Monday, July 29, 2013

Aaron Nelson- week 5- Progress in the missing plankton case

 Those of you who have viewed my recent posts know that I've been struggling to keep track of my tiny zoo-plankton research subjects. I place them in the turbulence generator (see pic below) where they enjoy a leisurely two-hour swim and when I remove them there is invariably a smaller number that come out than went in! Sometimes the difference is small (~5%) and sometimes it's not so small (~50%!). This last week I began to work methodically at isolating the source of their mysterious disappearing act. To do this I have become an experimental detective of sorts and I'm satisfied to report that I have some very strong leads in this case!

My detective work has partially consisted of breaking up the larger experiment into smaller pieces and doing counts of plankton before and after. There are many places in the experimental process where the plankton (Artemia salaria) could go missing and since they're so small (~.5 mm long x .2 mm wide) you can't just peer around with a flashlight for them!

One of the first things I decided to look into was whether or not the A. salaria  could squeeze though the mesh screen partitions in the turbulence generator. The mesh has holes that are only 100 ┬Ám wide (.1 mm). I assumed that the A. salina larvae, while small, were at least a few times larger than this. However, when I peered through a dissecting scope at A. salina placed directly on top of the mesh (see photo above), I realized that the width of the A. salina perhaps only two times larger than the mesh holes and perhaps not even that. This might not seem like a cause for worry by itself, but when the turbulence pumps are on they create a suction effect through the screens, which may be all that is needed for this soft-bodied prey to pass over to the other side of the screen partitions. When I ran my first experiment, I recovered 80 out of 100 A. salina: disappointing, yet a pretty average outcome thus far. Since I originally only rinsed out the central chamber where the A. salina  were placed, I decided to rinse the pump chambers and siphon out the water from there. To my relief, I didn't find a single sea monkey! ("Sea monkey" is the common name for A. salina.) I decided to let the 100 um screens off the hook, at least for the moment.

Turbulence generator- the white partition screens separate the central chamber from the two pump chambers on the side.

After running a second full turbulence experiment I had result consistent with the first: 77 out of 100 A. salaria recovered from the tank. I realized when I was counting them under the dissecting scope that some of them were rather mangled; sometimes this meant they lost a lot of tissue and sometimes I would just find a loose head of one of the poor buggers! I realized that if some of them were in this marginally recognizable state, then perhaps some had gone past it, disintegrating into a mess of unfamiliar fragments.

I realized that the siphoning process is the roughest obstacle in the A. salarias' course, so I did some little tests. I placed 40 A. salaria in 2 liters of water and siphoned them through a 43 um filter to concentrate them. After doing this twice my results suggested that I found the source of the missing A. salina: I only recovered 33 and 36 out of the 40.

I squeezed in a third and final trial run last week and decided that i would siphon out the water (and A. salaria) as gently as possible, so as to prevent the mangling. The results were very promising: I recovered 99 out of 100! (Although, one was very mangled and two were partial.) The main trick was to slow down the flow speed of the siphon. This was accomplished by using a skinnier hose (~3/8") and by using a much smaller height difference between the ends of the siphon hose. I going to run the same experiment a few times this week and hopefully get the same results. Then I'll add some copepods to the mix and see if they are recovered as easily. I'll be sure to let you know how it turns out. In the meantime, go easy on your plankton!

Tiny Creatures Bonus!
Polyorchis Sp. spotted during its commute in the small boat basin

Tube feet of a juvenile Pycnopodia helianthoides reach for the moon

Katlyn: Week 5

A Kinetic Sculpture and Its Creator
This last weekend a bunch of my fellow interns from Hatfield and I went to Da Vinci Days in Corvallis. It was a fun Art and Science festival that had a lot of informational booths as well as live performances. Some of the Science booths included a wave energy booth, a Sea Grant booth, a Remote Operated Vehicle (ROV) booth, a Geology booth, an Equine dentition booth, a local honey booth, and many more. The live performances included two juggling acts that were very entertaining and a Big Bad Voodoo Daddy concert. There were other performances, but those were the ones I went to. The swing band concert was a lot of fun because our whole group was dancing during it. Another event at this festival was the kinetic sculpture races, which is where people make man-powered sculptures that they then race through different challenges including a mud-pit and a float down part of the Willamette river. It was interesting to see how different people planned to meet the challenges. Over all, this festival made for a great Saturday!

Chris, Shelby, Ella, and me (right bottom) at the Siletz river

On Tuesday Ella and I were able to go to the Siletz river and collect freshwater snails with two other interns, Chris and Shelby, and one of their mentors, Kym Jacobson. It was very exciting to be able to get out in the field! The beautiful river and sunshine made this a wonder day. After we collected the snails, we took the big ones back to the lab and put them each in their own Petri dish with water and a chunk of lettuce. The next day, after they had settled for a little while, we took each dish and looked at it under a dissecting scope to see if any parasites that had been on the snail had come out. If we found any parasites in the dish, then we would write down what we saw so Kym would know what to look for when she used these samples to show parasites to students in Corvallis.

Kym, Shelby, Ella, and me (left) in the lab
examining the snails

Lately, I have been able to enjoy the natural beauty of Newport by walking down to the beach after work. These walks make me appreciate how lucky I am to be living here on the Hatfield campus this summer where we are only a little over a mile away from the beach! Such a beautiful summer experience and it is sadly more than half way over.

Sunday, July 28, 2013

Luc - Week Five

The more time I spend living here the more I realize that the concept of "Hatfield time" does exists. Watching week five fly by confirms this assumption. The week started with a bang as I accompanied my good friend/coworker Kristen Simmons on a sampling trip to Florence, Oregon. The hour journey south was beyond beautiful, once passing through the city of Waldport, highway 101 becomes epic! The entire stretch of road between Waldport and Florence represents what the Oregon coast looks like; empty coves,  looming headlands, and endless twists and turns. Although, upon reaching Florence not a single shellfish interview took place due to there not being a single crabber present on the docks. This surprised me because of a rather large population of fishermen residing in the area. 

A new experience this week was learning the art of “the pursuit” as my supervisor Justin Ainsworth calls it. Since at this point in my data collection I have a sufficient number of land based crabber interviews but hardly any boat based interviews, Tuesday and Wednesday I  primarily targeted crabbing boats. This involves a bit more skill than land surveys since you first must locate a boat actively crabbing and then intercept it right as it reaches the marina. Not as easy as it sounds! Since usually I may only get one boat interview in an hour where as in the same amount of time I could possibly get 10+ land crab interviews from the piers, it’s worth spending the energy in obtaining boat interviews because it makes for a more diverse composition of information. This makes my data more accurate and certainly more informative.

Towards the end of week five I had the opportunity to take a behind the scenes tour of the Oregon Coast Aquarium thanks to Ichung, the COSEE mentor. Seeing the ins and outs of the aquarium was such a treat! I will not soon forget seeing the shark exhibit from the rafters and I’d be lying if I said I wasn’t a little scared of falling in. Yikes! 

-Me being a goof during the tour.

-A look inside the massive walk-in freezer on site at the Oregon Coast Aquarium.

Anna Russell- Prep, Prep and More Prep

The majority of Week Five was spent assisting UW Friday Harbor Labs in doing eelgrass health surveys. On Sunday and Monday, we went out to different islands in the San Juans to measure densities, phenolics, epiphyte growth, grazer abundance, and presence and extent of Labyrinthula spp. (the disease I have been working with this summer). On Tuesday and Wednesday, we focused on sites around Fidalgo Island. Eelgrass with Labyrinthula spp. infections were scanned for further analysis. 
In between helping the UW Friday Harbor Labs, I have been busily prepping for the last stage of my experiment: the infection stage. For the last four weeks, my eelgrass has been growing in some outdoor tanks. Two of the tanks had isopods and snails but the other four have been growing in (hopefully) stress-free conditions. Today, all the eelgrass was taken out, scraped of diatoms, cut, and placed into petri dishes. Tomorrow, at the start of Week Six, we will infect half of these pieces with Labyrinthula spp. by clipping them to inoculated pieces of eelgrass. The other half are going to be clipped to eelgrass pieces covered with sterile seawater. 
To prepare for the inoculation, I have been growing the Labyrinthula spp. cultures in both SSA broth and agar media. On Thursday, I counted the number of cells in the SSA broth using a hemocytometer. A hemocytometer is a special microscope slide that has a set volume, so by counting the number of cells, one can calculate the concentration. The same number of cells has to be used in each inoculation to ensure that no piece of eelgrass is more exposed to Labyrinthula than another. 
Tomorrow, I need to centrifuge the vials and remove the SSA broth so that Labyrinthula infects the eelgrass instead of eating the broth. After that, I need to replace the SSA broth with sterilized sea water. This is where the hemocytometer comes in. By knowing the concentration of cells in the broth, I can calculate how much sterilized sea water to put in so that every vial has the same concentration of Labyrinthula. 
I did a practice run of this procedure on Friday and so far a couple of eelgrass pieces show Labyrinthula which is a good sign. Hopefully everything will run smoothly tomorrow and my eelgrass will be successfully inoculated! 
144 petri dishes of eelgrass waiting to be inoculated in the culture box

Friday, July 26, 2013

Ella- WEEK FIVE: festivitals, clamming, parasites and boats

A racing "kinetic sculpture"
This super busy week five started out with Da Vinci days, a festival celebrating science and art in Corvallis, Oregon. One of the main features were the kinetic sculpture races. Over the course of the weekend, these people powered sculptures raced through town, over sand dunes and down the Willamette river. All of the vehicles had to have their flotation gear on board the entire time, and the time it took to transfigure the sculpture into a boat was counted as part of the race. Although I somehow missed the start and end of all three different races, I still got to see them lining the streets, in all their creativity, waiting to disembark on the next race.
OSU slocum glider

Inside the festival, there were many booths with educational displays from organizations around Oregon and also many booths from different departments at OSU. One of the booths was representing the glider to the right. This device is used to measure oceanic conditions, recording data such as temperature, salinity and dissolved oxygen levels, which is used in understanding upwelling and hypoxia. The great thing about the glider is that it is self propelled, using something similar to a swim bladder, taking on and off sea water as needed to propel itself in a porpoise-like way along transects off the Oregon coast. This is extremely useful as the glider can amass a great deal of data and periodically sends all its information on via satellite, all on its own! Here is the link to the OSU's glider wepage:

Back at Hatfield, all of the interns had the opportunity to tour NOAA's  R/V Bill M. Shamata and The University of Washington's R/V Thomas G. Thompson, both of which were docked in Newport for a few days.

Scale and fish ruler talk to computer:
this setup makes weighing and measuring
large amounts of fish on the Shamata super efficient!
The Bell M. Shamata does fish surveys from
California to British Colombia. Currently,
they are specifically monitoring Hake and anchovies. 
R/V Thompson with ROPOS ready to decend. ROPOS: Remotely Operated Platform for Ocean Sciences.  Image from'12+Cancelled

On the Thompson: this sophisticated machine is used to
survey Ocean floors up to 5000 meters deep! It is equipped with lights and cameras as well as remote controlled "hands".

Source: Trematodes of North America by Stewart C. Schell. 
Lettuce, snails and parasites
 (not visible with the naked eye)
Next on the itinerary was a snailing adventure on the Selitz river, collecting fresh water snails for a fellow intern's REU project with Kim Jacobson's parasitology lab. As many of the beam trawls in our data set have come from the mouth of the Selitz river, it was neat to be able to do some data collection in this river, and the weather was beautifully perfect as well! The objective of the trip was to collect some hundred of these freshwater snails in order to identify the various trematodes living inside of them. Back at the lab, we could see that most of them did have at least one type of trematode, as they came out of the shells over night and wriggled around in the Petri dish in cercaria form (see diagram above). If the snails had still been in the river, these trematodes would then have found a salmon to latch on to or be eaten by (depending on which species of trematode they were). In the salmon they would live and thrive in the posterior kidney until the fish got eaten by a some bird or mammal, such as a dog. At this point, a harmful bacteria which would have been living on the trematode the entire time would cause the dog to be very sick, also known as "salmon poisoning". This is why it is never a good idea to let your puppy eat raw salmon!
A cercaria medusa found in one of the Petri dishes.
The individual cercaria prefer forming this mass, as being bigger attracts hungry fish better, a major goal at this stage in the lifecycle of the trematode.You can't tell here, but the ends of all the "arms" are wiggling
about frantically, quite the sight  when seen under the microscope! 

Speaking of smaller organisms living within larger ones, this is a Pea Crab found within a gaper clam destined for dinner last night.
The tragic end to a commensal relationship
While researching these little crabs, I came across this COSEE blog entry from 2010:
Check it out the link! It is a very concise and helpful description of the little guys.
My very first fishing licence: watch out shellfish!
The amazing neck of a Gaper clam found in
the mudflats of our front yard
Crying cockles and muscles alive alive oh!

A beautiful and tasty way to end the week.
I am so grateful to have been able to experience
 wild harvesting the bounty of Oregon's coast.
This week was a landmark in our data entry project as I finished the first binder of beam trawls from 1978! Next week is NOAA's fish cutting party: where lots of scientists get together to dissect salmon and each take home a part to study for their respective projects. This is an event all interns are strongly encouraged to attend, and it will be interesting to see the salmon kidneys full of the next life cycle of trematodes.