The Stefansson Sound Boulder Patch is the largest kelp bed on the Alaskan Arctic coast, but it is not the only one. On Wednesday, Katrin Iken, the Dunton brothers, and I took the RVProteus east to to dive a small kelp bed in Camden Bay.
This was my first time making this run and it was really interesting to see more of the Beaufort Sea Coast. We passed Flaxman Island, the location of Leffingwell’s cabin, from which Ernest de Koven Leffingwell explored the area in the early 1900s, resulting in the first accurate map of the Alaskan Arctic coast and the first scientific description of permafrost.
We dove two sites in Camden Bay. The first site was pretty similar to shallow sites in the Boulder Patch: Lots of red algae, the dominant kelp was Laminaria solidungula.
But the next site was, very unexpectedly, entirely dominated by a different kelp species – Alaria esculenta. There was no Laminaria solidungula to be found!
Alaria esculenta is a relatively widely distributed kelp. It’s fairly common on the coast of Ireland and the UK, where it is harvested for food.
We collected some cobbles from the seafloor as well, and are finding a very different assemblage of algae and invertebrates covering the rocks.
As an ecologist, the differences between these sites are super interesting. Why are they so different if they are so close??? Unfortunately, this is not a question we can answer in one field season. Right now we can only posit that maybe it was the shallower depth…or maybe warmer temperatures…or…
In summer of 2014, I had just finished my first year as a grad student at UT. I had spent the year coming up with questions and designing research projects to carry out for my PhD work. One of the questions I was interested in was “How does the community of algae and animals attached to the rocks in the Boulder Patch come into being? How long does it take for the community to develop?”.
This is a pretty classic ecological question (succession). In marine ecology, scientists usually place settling plates (usually squares of some hard material) in the ocean and monitor what grows on them over time and/or under different biological or environmental conditions (eg El Nino years vs La Nina years). Marine invertebrates and algae mostly have free swimming or planktonic larvae, which settle onto the plates when they are ready to metamorphose into their adult form. These experiments can tell us things like how quickly an ecosystem can recover from disturbance (like a massive landslide), or whether certain species help other species survive in an ecosystem.
So, I decided to deploy settling plates in the Boulder Patch. Because plates lying directly on the ocean floor are vulnerable to benthic predators (like snails) and falling sediment, I decided I wanted them to float above the bottom. I designed my arrays of plates based off of a project looking at coral settlement. Therein lies my mistake and my Arctic newbie naivete… more on that in a second.
That summer, we deployed 20 of these arrays across the Boulder Patch.
In 2015, we went back to recover them and see what had grown.
We found 4 of the arrays.
You see, the shallow, inshore Arctic Ocean waters are not really like the deep waters of a tropical coral reef (YOU DON’T SAY!). In the fall, massive storms blow through, causing massive currents and ice build-up inshore that can tear (very floaty, kite-looking) things off the bottom of the ocean.
So I redesigned my arrays, tying them to very heavy weights, suspended (but not kite-like) just off the bottom. And they are working! I’ve now recovered two years of plates. ( things are growing very slowly… it is the Arctic after all). But I knew those arrays were out there somewhere, floating somewhere is the sea with the help of their GIANT buoys…
And three days ago, a boat caption staying at the same camp as us stopped me in the mess hall: “I think I found some of your equipment today. It’s in the back of our truck”.
It was an array from 2014. It had been found on Pingok Island, about 40 miles west of where it was deployed.
Quite the blast from the past, and a reminder of all the adjustments I have had to make to my plans since I was a first-year. But that is the nature of science! Trial and error, poking at a problem from different angles, and moving forward after a failure. Just maybe with smaller buoys next time.
Hellooo everyone! Welcome to field blog 2017! We are up in Prudhoe Bay working on the Boulder Patch kelp bed (which, incidentally now has its own website: http://arcticstudies.org/boulderpatch/index.html) until the beginning of August, then heading east to Kaktovik for about two weeks, then back to the Boulder Patch for a couple days in mid August.
Onto today’s topic – What is the pH of the freshwater bodies of the Prudhoe Bay area?
I guess I should first explain why we care? Aren’t we MARINE scientists???
Yes, we sure are. BUT coastal ecosystems, like those of the Alaskan Arctic, can be highly influenced by freshwater inputs. Freshwater can obviously make the coastal ocean less saline, but it can also change the pH. You may recall that pH is a measurement of the ratio of hydrogen ions in a solution, which tells you if something is acidic (like lemon juice, pH=2-3), or basic (like bleach, pH=12). Pure water is about 7, which is considered neutral. Sea water is usually a bit basic, around 8.3, but it can really vary by location. You may also recall that pH is on a log scale, so something with a pH of 5 is 10 times more acidic than something with a pH of 6.
Alright now that we have that out of the way… Arley (my awesome labmate) put some pH sensors in the Boulder Patch last year (see this old blog post) that have been recording data through fall, winter, and spring. In the spring, the Arctic Ocean receives a rush of river water known as the ‘freshet’ from melting snow and ice. River water continues to empty into the ocean until temperatures get below freezing again in the fall. We want to know: how does this river input affect the pH of the Boulder Patch? But in order to start figuring that out, we need to know the pH of the river water!
Like good scientists, we wanted to come up with a hypothesis for the pH of the Sagavirnirktok (Sag) River that is adjacent to the Boulder Patch. Like many marine scientists, our river water chemistry knowledge is a little shabby. So we asked our friend Craig, who researches Arctic freshwater inputs. Craig hypothesized (and so we hypothesized), that rather than being ~7, like pure water, the Sag would be ~8-9. He figured that the minerals (especially carbonate) in the rocks the Sag flows over on its way to the ocean would make it basic.
So, hypothesis and pH meter in hand, we set out!
First, we measured the pH of a big gravel pit that was dug into the tundra (green circle on map above) to make some of the roads out here. The pH was 8.01. So far, so basic.
We also measured two pools, one in Deadhorse (dark blue circle), and one further down river (orange circle). The first was 7.87. The second was 7.87.
Pool in Deadhorse
And the pH of the Sag itself (light blue circle)??? 7.87
We also measured the pH of ocean water right near the mouth of the Sag (red circle): 7.77
So, a bit more neutral than we were expecting! Perhaps the rocks have less influence than we thought, or maybe there is some other chemistry going on… we are looking into it.
But in the meantime, we have some real endpoint measurements to help us interpret our sensor data! When we measure the pH in the Boulder Patch in the summer, it tends to be in the low 8s. Will we see a dip below 8 during the freshet?? We will find out soon 🙂
The theme for this year’s Kaktovik Oceanography Program was ‘Exploring our Oceans’. The idea was to expose students to both traditional and state of the art techniques and technologies that scientists use to make discoveries about the ocean.
A very exciting tool we brought to Kaktovik this year is a remotely operated vehicle, or ROV. ROVs are used to explore the depths of the ocean, routinely discovering new species and geological features. You can even watch ROV livestreams: here and here (this is how CoolKids spend their Friday nights).
Kaktovik students learned how to operate and drove the ROV around Kaktovik Lagoon. They came up with ideas on what they would want to explore with the ROV (sharks and shipwrecks were popular answers). This was one of the most memorable activities of the program, shown by the posters students put together at the end of the week.
One of the coolest parts of the Kaktovik Oceanography Program is teaching local students about how the science we do relates to their local ecosystems. This year, fellow UTMSI PhD student Craig Connolly led an activity on groundwater.
In the Arctic summer, water moves through the thawed soil layer and enters the lagoons, bringing with it nutrients that could be important for the base of lagoon foodwebs. Students got to hammer piezometers (basically well points) into the tundra soil until they hit the permafrost layer, they then pumped up the water and collected it in bottles. We also collected a sample from the lagoon, downhill from the groundwater collection point.
Back in the lab, students measured nutrients (nitrate and phosphate) in each of the water samples, demonstrating excellent safe lab technique throughout.
We found that while both the groundwater and lagoon water had similar levels of phosphate, the lagoon had less nitrate than the groundwater. The students deduced, based on a previous lesson, that phytoplankton in the lagoon must be using up the nitrate that comes from the groundwater. Pretty cool!
In my posts here and elsewhere, I mention dataloggers a lot. Dataloggers are the basis of many many types of science. The ones that I use are made to log data on specific environmental variables (temperature, salinity, underwater light, currents) at specific intervals throughout the year (e.g. once every hour). As you may have already guessed, dataloggers are VERY IMPORTANT to our science and we pay a lot of attention to the care and keeping of dataloggers… despite leaving them in the Arctic Ocean for a year.
What do we want our dataloggers to do?
A) Collect accurate data the whole year
B) Let us read that data
C) Be working so they they can be redeployed to collect another year’s worth of data
Some dataloggers provide ‘real-time’ data via cables or satellite connection. Most, like ours, just store the data internally. This means that in order to successfully see that data, you need to FIND your instrument IN TACT*.
*Note: Sometimes, dataloggers are designed so that even if it’s broken, your data might still be there. For example, one of our current meters was a casualty of ice gouging the ocean bottom. When we found it, it was broken in two:
When we opened the sensor itself, it was damp on the inside and the electronics were fried. BUT by some miracle of Posidon, the SD card that held all the data was readable! From that data, we could see the currents measured until that ice gouge happened. Pretty cool.
In any event, we do a lot of work ensuring that we can find our dataloggers next year and that they will still be working. We have to worry about ‘normal’ stuff for ocean deployments: that they are watertight and can stay in place in strong currents. In the Arctic, we also have to worry about ice gouging pushing stuff around or putting pressure on things. So, we make sure our dataloggers are attached to something SUPER HEAVY, and that they are housed in something very sturdy.
And after we’ve spent hours to days making sure that our dataloggers are working right, that they are nice and cozy and secure in their housing, that they are the right buoyancy, we place them in GPS marked locations, wish them well, and abandon them for 11+ months. We fret about them, but at that point their fate is out of our hands.
So dataloggers are our science babies, but we are kinda crappy parents.
The whole reason the Boulder Patch kelp bed exists is because of a large deposit of rocks in Stefansson Sound. These rocks originated in Canada and were dumped by glacial activity in the otherwise silty, muddy Alaskan Beaufort. Over thousands of years, algae and animals began growing on and around these rocks, developing into the diverse ecosystem we see today.
This field season, we are looking closely at these rocks – collecting them via SCUBA diving, taking them into lab, poking at them – to see how what’s growing on them (aka the epilithic community) changes across the Boulder Patch. Do environmental gradients (e.g. near vs far from river input) and/or the presence of certain key species lead to changes in diversity or algal production? We’re trying to find out. Our results will allow for better predictions of what will happen to Arctic Ocean ecosystems with perturbations such as increased storm frequency, increased river runoff, and decreased sea ice.
We see striking differences between rocks from different parts of the Boulder Patch. Observe rock A and rock B:
A. ‘Nearshore’ Rock
This rock was collected from a shallow, nearshore site
B. ‘Offshore’ Rock
Rock A has relatively high amounts of fluffy red algae. It also has a lot of invertebrates growing on it (can you see the silty barnacles?). Rock B, on the other hand, is mostly covered with beautiful, pink crustose coralline algae (CCA), a red algae that makes a limestone skeleton. in the tropics, CCA is known for ‘gluing’ coral reefs together. In temperate kelp forests, it is resistant to the intense grazing that causes urchin barrens. It is usually a very slow grower compared to other algae.
What is causing these differences? It sure seems to be related to distance from shore… but that is intertwined with other variables such as depth, light, and salinity. With the help of these rocks, we hope to untangle which factors are the most important in determining diversity and productivity across Arctic rocky reefs.