Hi all, this is Dr. Edwards, project PI
Our second cruise to the Aleutian Islands has come to a close. On July 23, we finished our last set of dives at Yunaska. Yesterday’s rocking and rolling swell was non-existent; the winds had died down completely, and the sun had come out. Yes... the sun. It had been almost two weeks since we saw a clear view of that yellow star that warms us. We went in and hauled our chambers and the hundreds of pounds of chain to the boat and picked up the sensors. The water was so calm, you could set things down and they did not move. The thick kelp that only the day before had snagged on every edge of our tanks, BCs and regulators, now cooperated as if we were in harmony. You could move through it with ease, but only if you respected it...danced with it. If you took it for granted, tried to change the dance, it would still snag and pull on you, slowing every movement. But with respect, it was like gliding through a photograph.
The kelp was so thick and full of life. There was an understory of kelp so dense you could not see the bottom. There were sponges that covered square meters of rock bottom. Red, yellow, white. There were large nudibranchs plowing through the sponges and eating their fill. There were snails, and bottom fishes of every color you could imagine. Visibility was so good that the only thing that limited your vision was the scenery in front of you. Though you could if you wanted to, it was hard to pass up an infinite number of scenes in front of you that you almost forgot there was a horizon beyond. It made me completely forget the 41 degree water and the holes in my gloves’ fingertips that appeared after two-weeks of deploying benthic chambers, hauling chain, and collecting urchins.
Afterwards we had a day of cleaning gear, packing research equipment, and preparing to disembark from the Oceanus. This is my last shipboard blog for Brenda's and my NSF 2016 and 2017 cruises. In reflection, I look back at what we accomplished. In the past two years, we dove at 15 of the Aleutian Islands (from west to east: Attu, Nizki, Allaid, Shemya, Kiska, Amchitka, Ogliuga, Tanaga, Adak, Atka, Yunaska, Chuginadak, Umnak, Anangula, and Unalaska). My students (Scotty, Tristin, Pike, Sadie and Genoa) and my collaborator Ju-Hyoung pulled off a Herculean amount of work. We deployed nine benthic respiration chambers at each of 11 of the islands; three each in the kelp beds, urchin barren grounds, and in the transition zones between the two. This equated to 99 chamber deployments in total. Each chamber was held down with about 40 pounds of chain, so you can do the math; we deployed and retrieved about 3960 pounds of chain from small inflatables. This, plus the chambers and the sensors…again…Herculean. Together, we did about 250 dives on each of the cruises (about 500 dives total on the project). Conditions ranged from Atka last year where we endured smashing waves and blowing winds in our sites to the calm clear beauty of Yunaska. Water temperatures ranged from 41 degrees to a balmy 46. My students (the SDSU BEERPIGS) more than conquered these tasks and I am grateful and impressed by their abilities, energy, and attitudes. A job well done.
On the ship, Ju-Hyoung and Sadie conducted controlled measurements of invertebrate respiration and algal photosynthesis. Generating photosynthesis versus irradiance (P vs I) measurements requires careful and methodical work. The instruments we use are sensitive to even a single degree of change in water temperature, and to differences in light intensity so small that the human eye cannot make them out. Each measurement for each species requires up to 90 minutes to fully evaluate the photosynthetic responses of the algae to changes in irradiance. Between the two of them, they conducted a total of 150 P vs I measurements across 26 species. In total, this equates to about 225 hours of measurement time (and that’s in just four weeks of ship time). Further, they conducted respiration measurements on dozens of species of invertebrates, and evaluated the relationship between urchin respiration and urchin size across nearly 20 size classes. They also examined the carbon uptake kinetics of 10 species of algae, and helped parameterize our field irradiance measurements with light casts. Another job well done.
On top of deploying and retrieving chambers, Scotty collected tissue samples from about 400 invertebrates, and 101 water samples that were filtered for phytoplankton. Over the next year, he will analyze these for their isotopic signatures to better understand how food webs and trophic energy flow has changed with the widespread kelp loss.
Together with the benthic respiration chamber data I see my next several months of work analyzing and interpreting the results. And then writing up the papers. Not as fun as being underwater, but just as important and rewarding.
The crew of the Oceanus was amazing. From the captain on down, everyone was friendly and incredibly helpful. Our skiff drivers navigated the dense kelp beds, and helped haul heavy chain and chambers into the boats. They were both our drivers and our surface support. The food was awesome, from fresh-caught baked halibut to hot out-of-the-oven cookies waiting for us when we returned from our dives, worn out and cold. We could not have asked for a better crew or ship. I thank the National Science Foundation for providing both the ship and the funding for this research.
So, as I close this blog, I think about the next time Brenda and I will bring our labs here. It has been almost 25 years since I first came here to live for a few months on Shemya; this place is as beautiful and new as the day I first stepped on that tiny island (though I am a little greyer and maybe a step slower). The ecosystem offers an endless avenue of research questions and our research (as most research does) has resulted in as many new questions as it provided answers. So, I think of the last dive at Yunaska, sitting mid-water and looking at the dense kelp teaming with life. I think of the urchin barrens, which at one time looked to me to be devoid of anything other than urchins, but now have revealed themselves to be diverse and full of their own life. What will happen next? How long will the urchin barrens persist? What might cause them to switch back to kelp beds? New predators? Disease? Some as-of-yet unknown factor? The questions remain. I think about the last dive, and I believe the Aleutians are calling me back.
Dr. Matthew Edwards
Hey everyone, Scott Gabara here to describe part of my dissertation working on creating food webs of nearshore and offshore subtidal communities across the Aleutians Islands. In the marine environment, kelps can create the understory and canopy that comprise most of the biomass of kelp forests, providing structure and food resources for their associated communities and can even deliver material to adjacent areas supporting consumers many kilometers away! This is very similar to the plants, bushes, and trees that comprise forests on land (and can deliver leaf litter to adjacent areas).
With the loss of sea otters and subsequent formation of urchin barrens across many locations of the Aleutian Island archipelago, kelp is lost and organisms will either not be able to deal with the loss of food that kelps provided, or they may change their diet to another source of food locally, or rely on food from other locations that drift in. At some locations urchin barrens were formed long ago, but most formed during the late 1990s- early 2000s, giving us communities that lost kelp long ago, many that have lost kelp for about 20 years, and some locations that have had kelp continuously. I wanted to better understand the long term impacts of kelp loss on the trophic ecology of these kelp forest communities that still have kelp or have lost kelp over different amounts of time. To do this I will create and compare food webs using stable isotopes of the dominant community members (producers and consumers) among urchin barrens, kelp forests, and offshore communities at islands across the Aleutian archipelago.
Stable isotopes of carbon and nitrogen are stored in tissues and help us to understand how energy flows through food webs. Stable isotopes act as a hidden tracer that can reveal both where energy is coming from, and the trophic level of a consumer. For example, we can sample the fingernails or hair of people, and using carbon stable isotope values, be able to tell differences of diets based more on rice versus those based more on corn because of the differences in the way rice and corn take carbon up during photosynthesis. We can also identify differences in the diet of people that are vegan, vegetarian, or those that eat more meat, because of differences in the trophic level of the foods that they eat. All of this information is stored in the nitrogen stable isotopes of the food we eat and is then left as a signature in our fingernails and hair.
Food webs help us to understand the connections among organisms and reveal the potential impacts of removing certain food resources (primary producers) that comprise the base of the food web or the impacts of removing the food web members (consumers).
Potential food web resources for kelp forest and urchin barren associated organisms are things in the water such as phytoplankton (that live in the water column) or pieces of algae that break off while algae grow or get ripped off the bottom and drift around, multiple attached algae such as the lower lying green and red algae in kelp forests, and the larger subcanopy and canopy forming brown algae.
To estimate a water column isotopic signature, water was filtered from urchin barrens, kelp forests, and offshore. Filtering water for phytoplankton or algae particulates is no easy task. Water is collected and then needs to either be pushed or pulled through a filter to concentrate the material from the water. To do this I modeled a water filtration setup after the Rohwer lab at SDSU/Smith lab at Scripps developed by Mark Hatay at SDSU. Clear PVC was cut to fit 5 Liters of water, 4 inch adjustable plumbing plugs were used to seal the ends, and tapped plastic valved fittings onto the plugs were used to create a tube that could collect water and be pressurized. A propane pressure regulator and a SCUBA tank was used to create pressure that would push the water through the clear collection tube and then through a glass fiber filter in a holder, concentrating the material from the water on the filter, to be dried and later run for stable isotope analysis.
Locations of nearshore and offshore (grey), kelp forest (green), and urchin barren (blue) water samples.
To estimate algal isotopic signatures, tissues of algae that were living in urchin barrens and kelp forests were collected. To estimate the isotopic signature of nearshore and offshore consumers, invertebrates were collected from surveys or offshore trawls done in collaboration with the Konar lab at University of Alaska Fairbanks. To estimate fish isotopic signatures, pole spears were used to catch fish that were in urchin barrens and kelp forests by divers and by using the trawl to get fish that were living in the deeper offshore areas.
Tissues were prepped and dried on the R/V Oceanus and will be run for carbon and nitrogen stable isotope analysis. The ratio of the heavier to lighter stable isotopes of carbon and nitrogen will help us trace how important local and/or drifting kelp is for organisms in urchins barrens, kelp forests, and offshore areas. By creating food webs of these different communities we may have a better understanding of why certain organisms can survive the transition from kelp forests to urchins barrens and if and how kelp loss in the nearshore affects offshore food webs.
Sadie here with a brief expedition update and a look inside shipboard lab operations!
The next island along our route was Agattu, but inclement weather forced us to head East sooner than expected. After a full travel day, we arrived at beautiful Kiska Island this morning. As usual, the Edwards Lab dive team deployed chambers in three different habitat types (kelp, transition, and urchin barren). A quick refresher on what our lab is doing up here in the Aleutians: we’re comparing ecosystem productivity between these three habitats and among different islands in an east-west gradient along the island chain. For this large-scale project, we use clear, flexible chambers to isolate 0.57m^2 patches of the seafloor for 24-hour periods, meanwhile collecting changing oxygen concentration, temperature, and light data within these chambers. The organisms in nearshore benthic habitats all use or produce oxygen during photosynthesis or respiration, so we use oxygen concentration to assess the activities of algae and animals within the chambers.
These data help us estimate productivity from the community as a whole; however, we want to go deeper into the story! Algae and invertebrate animals from inside the chambers are collected and brought back to the ship and further analyzed to help us understand how individual members of the community are contributing to our large-scale production estimates.
That’s where Dr. Ju-Hyoung Kim and I come in. We’re using small-scale methods at the individual level to add details to the large-scale benthic chambers that give us community-level data. In the shipboard laboratory, we have set up small glass incubation chambers that hold one organism at a time. By controlling temperature and light, we can measure the change in oxygen concentration via photosynthesis (algae) and respiration (animals). Coupled with biomass data from the chambers, we hope tease apart how each species contributes to the larger productivity estimate within the benthic chambers that the dive team deploys in the field.
These experiments in the field and in the laboratory allow our group of scientists to come together and work toward a common goal, which is to understand more about the valuable ecosystems of the Aleutian Islands!
Usually our common goal is research-related, but sometimes we get together and make algae art!
Featured here in an herbarium pressing: Neoptilota asplenoides, Kallymeniopsis sp., Odonthalia setacea, Neinburgia prolifera, Callophyllis sp., and more.
Catch you at the next island!
Hey there, this is Pike coming at you again from the Semichi Islands. Another day, another deployment. We’ve been in the Aleutians aboard the r/v Oceanus for just over a week now, diving in frigid water almost every day now. After trawling on Attu, we began our steam eastward; in the pre-dawn gloom we “dropped hook” in a small island cluster known as the Semichis.
As we stumbled out of our bunks and towards the galley, following the smell of breakfast and hot coffee, a peculiar sight caught my attention; lights in the distance. Deceived by a brain still half-asleep, it took me a minute to process what I saw. Since leaving Adak the last week the only signs of humans we’ve seen have been remnants of WWII and the flotsam that’s washed up on the beaches. Here, in one of the most remote places on the planet, we hardly expect to see another living soul. And yet, what looked like a small city twinkled persistently on the horizon. As the sky began to lighten I realized what we were seeing; the military base on Shemya. During the Cold War the US built a top-secret radar station here, and to this day the ominous “boom box” still listens for ballistic missiles, should they enter US airspace.
But we’re not here in the Semichis to gawk; we have our experiments to deploy and samples to collect. As stated before, the benthic productivity chambers (three in each of three habitat-types) are a beast to deploy. It takes all five divers from the Edwards Lab to set them up; we use lengths of heavy chain and whatever rocks we can find to make sure our chambers, and their respective sensors, stay upright all through the day and night.
For those of you that might have missed it, inside each chamber we mount an oxygen and temperature sensor and a PAR sensor. PAR stands for “photosynthetically active radiation” or, more simply, the specific part of the light spectrum that plants and algae use for photosynthesis. The productivity chambers allow us to gain an understanding of what’s going in a fixed volume of water, which is important when we go to calculate the overall productivity of a system. What do we mean by productivity? We’re essentially looking at the difference between production (measured in the amount of oxygen produced) and respiration (the amount of oxygen consumed). Plants (and algae of course) and animals respire, but only photosynthesizers produce oxygen. Once we have a measurement of oxygen produced/consumed inside the chambers, we can compare that to the data gathered by the sensors we leave outside of the chambers, which are recording what’s going on in the environment.
At the end of the 24-hr deployment, we “ground-truth” our measurements by collecting all of the organisms inside of the chambers when we go to pick them up and measure their biomass aboard the Oceanus. All the while we’re at sea, diving and steaming between islands, a colleague from Kunsan National University in Korea, Dr. Ju-Hyoung, and another Edwards Lab member, Sadie Small, run on-board experiments so we can get measurements on individual species’ rates of oxygen consumption/production.
Alright, I think that’s enough ecology for today. Be sure to check back in, after the Semichis we’re heading east again towards yet another island.
Until then, this is Pike (aka Baron von Urchin) checking in from the Aleutian Archipelago
“This isn’t the end of the world, but you can see it from here”
These words are posted on a sign at the US Coast Guard outpost on Attu. This lonely but spectacular island is the furthest west you can go in North America; technically we’re closer to Russia than anywhere else.
Attu saw a severe battle between the US and entrenched Japanese soldiers during the second World War, but you’d never know it by the vistas afforded to us from our anchorage in Holtz Bay. Most of us, at least from San Diego, were eagerly awaiting our time at Attu. What would it be like all the way west? Would the wind be howling across the Near Strait? Would the water be unbearably cold? What would the rocky reef communities look like?
Attu, if nothing else, was spectacular beyond belief. Our dive sites were in the three different habitats that we are studying: a kelp forest, an urchin barren, and a transition zone. The conditions were exemplary and each midnight sunset was more spectacular than the last. The wind howling through hidden glacier-carved valleys subsided as we launched the small boats to our dive sites. The sun showed itself on multiple occasions, revealing towering snow-capped peaks looming above us. Tussock grass swayed gently in the breeze on the cliffs as murrelets and puffins darted between the water and the sky around us.
Deployment of the benthic experiments went smoothly. We put three benthic chambers in each habitat to measure how much oxygen each habitat is producing. We may expect that kelp forests, because of the abundance of photosynthetic material (ie kelp) in the habitat, are more ‘productive’ ie produce more oxygen than urchin barrens, which are mostly devoid of kelp. Once they are placed on the bottom they sit for most of the time, although we maintain them every six hours, which affords us time to work on other projects. In the meantime, we enjoyed the sites Attu had to offer with breathless amazement. We were even allowed on shore for a brief expedition.
But, all too soon we had to pack up our experiments, stow the small boats on the Oceanus’s deck and begin our steam back east. For the rest of the trip we’ll be running to several more islands as we make our way eastward to Dutch Harbor on Unalaska, and our departure from the Aleutians.
Until next time,
-Pike (aka Baron von Urchin)
Tristin here, greetings from the Aleutian Archipelago!
This week we embarked on our lab’s second voyage to the Aleutian Archipelago to study patterns of biodiversity and ecosystem functioning along the island chain! Our lab was granted NSF (National Science Foundation) funding for a two-year study how biodiversity and ecosystem production have changed following wide-spread kelp loss. We are focusing on three habitat types: Kelp forests, Urchin Barrens, and areas that are in transition between the two. Last year, we traveled from Adak (center of the Aleutian Island chain) towards mainland Alaska. That 21-day cruise on the R/V Oceanus covered a 444-mile expanse, and we surveyed six islands. For a more information on our research goals, and history of the project scroll down to the “Welcome to the Aleutian Islands Blog 2016” at the bottom of this page.
This year, we will expand on the work we did last year and sample the far western Aleutians including the islands: Amchitka, Kiska, Attu, Agattu, and Shemya. The furthest of the islands is Attu (see image), and to put it in perspective, Attu is 1,100 miles from mainland Alaska… and ~450 miles to Russian territory. As a side-note and interesting fact, during WWII, Attu was the only battle fought on American soil.
The expanse of our trip this year will lake us west from Adak to Attu, then back east where we will end our cruise in Dutch Harbor, AK. Team Edwards (Dr. Matt Edwards, Dr. Ju-Houng Kim, Scott Gabara, Tristin McHugh, Sadie Small, Pike Spector and Genoa Sullaway) is back in action, and we are ready for another amazing adventure. Stay tuned for more updates on our research activities over the next couple of weeks!
Genoa here! We just left Amchitka Island and are en route to Attu Island, however it will take us about 21 hours to get there, and we have to steam through Buldir Pass which is a section of exposed Bering Sea...Needless to say we are taking our seasick medicine now!
At Amchitka Island we were anchored next to an old World War II pier and one of our dive sites was littered with bullet casings and an old airplane wing! We need to get back to sorting samples so not much time to write, but here are a few pictures from the island!
R/V Oceanus anchored in Constantine Harbor, Amchitka Island.
It may be cloudy on the surface, but underwater, the subtidal world shows off its vibrant colors. In this photo the Dragon kelp (Eularia fistolusa) sporophylls (reproductive kelp blades) are surrounded by hungry sea urchins. Often, kelp can survive on pinnacles like this because the water speeds up as it goes over the rocks and knocks off the hungry urchins. Additionally, the sporophylls are strong and as they sway back and forth in the wave motion and knock off the sea urchins. But kelps that aren't lucky enough to grow on tall rocks or pinnacles lose their defense from hungry sea urchins.
View from the bridge of the RV Oceanus as we steam through Buldir Pass on the foggy Bering Sea.
R/V Oceanus: Unalaska 6/29 – 7/1
Hi there, Pike here.
We arrived on our 6th and final island sometime in the early morning on Wednesday June 29th. It’s hard to believe that we’ve been living and working on the r/v Oceanus for almost two weeks now. We’ve battled rough seas, challenging dive conditions, and long days working in the field and in the lab. Although the weather only cooperated part of the time, we sampled more islands than we had originally proposed to do this year, so I think that alone makes this first expedition a success.
By the time we went to deploy our chambers in the calm, shallow reefs of Unalaska, we felt as if we could do it in our sleep. Without ripping currents, breaking waves and strong winds, our only challenge was dealing with the thick understory algae. Setting up the chambers, and then later breaking them down, went on without a hitch.
At this point you may be wondering about the design and construction of these chambers, and what exactly makes them so cumbersome. In the months leading up to this trip, the Edwards’ lab has been cutting, stitching and gluing PVC together, along with large sheets of plastic, to make our pyramid-shaped tents. The ocean is a mischievous mistress, and speaking from experience we knew that our chambers had to be sturdy enough to deal with anything the ocean could throw at us (case and point, Atka). However, not only did our chambers have to be sturdy, they also had to be transportable.
Ok so, we have chambers that are sturdy and transportable. Great. To stow them topside, such as on the deck of the Oceanus, we would fold them on themselves to make a 2-demensional triangle. We would transport them to the dive sites like this, and then once anchored, lower them into the water. To deploy them, we swim the triangle to an intended site, and then begin the process of unfurling them. Easier said than done; water is significantly more viscous than air, which means there is a lot more drag working against us. Once the triangle is unfolded, we use a PVC sleeve to secure two of the ends together and voila, we have ourselves a pyramid. But our pyramid also has a lot of drag, and anything not secured to the substrate will eventually be moved by any number of processes in the ocean. To counter this, we lay two lengths of chain around the chamber’s skirt. We riveted loops to the chamber’s skirt to better hold the chain in place; trying to manipulate the chain, skirt and loops while wearing thick gloves is also easier said than done. Before the chain is applied we make sure our sensor arrays are appropriately arranged inside of the tent; after it’s all said and done we have a nice microcosm experiment set up in situ!
Chamber retrieval is basically just the opposite process, which can be a little more tiresome than set up. But if my calculations are correct, across six islands we did a total of 90 chamber deployments and retrievals! At this point I think that makes us chamber professionals. It wasn’t always easy, but the data we gathered will definitely be worth our efforts. Stay tuned for the results!