Burkolator on the Brown: Part II

We’ve completed our CTD operations for the 2015 Gulf of Alaska OA cruise, but the Burkolator is still running and will collect data all the way to the dock in Kodiak. With this truly groundbreaking system, we have been able to highly resolve the marine carbonate system over the course of this project. The figure below shows the saturation index for aragonite (a form of calcium carbonate; Ω_arag) and the pH (pH_T) of surface water measured as we traveled during our survey (July 14 – July 31, 2015). Blue shades in the saturation index are values where some juvenile shellfish may begin to feel stress from the ocean conditions. We’ve seen these conditions associated with freshwater input at various locations as well as possibly upwelling in areas around southeast Alaska and Kodiak. What is particularly interesting to me are the areas where these conditions caused by freshwater input differ in terms of  pH. In other words, freshwater decreases the saturation index for aragonite, but pH does not always follow this decrease. In the area around Icy Bay (marked on saturation index map), where there is a huge freshwater signal from the largest marine-terminating glacier on North America, the pH actually goes up! We refer to this as a decoupling between saturation index and pH, which is caused in this setting by glacial melt. This is a situation very unique to Alaska in comparison to other US coastal states, and is an important reason not to rely on pH measurements alone to track the occurrence of seawater conditions that may be harmful to marine life such as shellfish. 

2015 Gulf of Alaska OA cruise (July 14 – Jul 31) track maps of the saturation index for aragonite (top; Ω_arag) and pH (bottom; pH_T). For reference, Icy Bay and the Seward Line are marked in the saturation state map. Note that these data are preliminary and should be treated as such. For questions regarding these data, please email wiley.evans@noaa.gov.

Keeping our fingers on the pulse of changing chemical conditions in the Gulf of Alaska is a central goal for the UAF Ocean Acidification Research Center, for the Alaska Ocean Observing System and for NOAA’s Ocean Acidification Program. This trip has been the most extensive OA survey ever conducted in Alaskan waters, and was incredibly important for providing a broad description of conditions that allow us to add context to our long-term efforts on the Seward Line (marked in the saturation index map), in hatchery settings, and from our moorings.  These long-term efforts are incredibly important to resolve the pace of change in Alaskan coastal waters, and cruises such as this provide the broad brushstroke of measurements allowing us to compare and contrast well-resolved regions (Seward Line) with areas less-frequently sampled (Icy Bay). This cruise will hit the dock and the scientists on board will disembark, but the Burkolator will stay on board for the next leg up to the Arctic and then back to Seattle, providing an even broader snap shot of OA conditions around the state of Alaska. 

 - Wiley Evans

Crab Lab!

In our last post, you heard us mention that one of the reasons we do OA surveys is to find out when and where OA events happen, and how they might impact biology. The link between the chemistry and the ecosystem is a big reason why we deploy the Bongo nets. On this project, one of the organisms we are most interested in during this mission are larval crabs.

Some of the larval crabs we have collected during this mission. Photo by Jennifer Questel (UAF).

When I asked Jennifer Questel, one of our ecologists on board how old these crabs were, she told me just a couple of weeks! These larval stages are the most vulnerable for red king crab, the face of the Bristol Bay crab fishery (and one of the types of crab they pull in during Deadliest Catch).  Scientists at NOAA’s Alaska Fisheries Science Center here in Kodiak, Alaska have shown that larval king crab have less than half the survival rate of normal crabs when exposed to ocean acidification levels expected during the next century. This means that fewer crabs would surviving to adulthood, which could shrink the overall adult population.

Lower crab populations likely mean lower crab harvests, and this could be a big challenge for Alaska given that so much of the state’s fishing revenue comes from crabbing. Annually, the crab fishery pulls in around $200 million USD.

Jennifer and Caitlin have been setting aside larval crabs they find in the bongo nets for Dr. Robert Foy of the Alaska Fisheries Science Center, and the informally named ‘Crab Lab.’ These specimens will be carefully examined for any potential physiological impacts of ocean acidification. We’ll also take a look at the spatial distribution of these baby crabs to see if there are any corresponding patterns in ocean chemistry and the presence of these organisms.

It’s important to remember that we still have a long way to go towards understanding the complete impacts of ocean acidification on crab fisheries around Alaska, but there is a lot of current research being done. Dr. Foy’s team is working on laboratory studies that show how acidification impacts king and tanner crabs. This data is then built into models that predict just how much acidification it will take to impact future crab populations. OARC is also working to understand how acidification will play into the overall Alaskan economy.

Want to know more? Check out these links: 

 

Sea Change: Lucrative Crab Industry in Danger

NOAA Alaska Fisheries Science Center Shellfish Research

NOAA AFSC Habitat and Ecological Processes Research Program

Alaska Ocean Acidification Vulnerability Index  

--Jess

Alaska Ocean Acidification Monitoring Network

One of the other exciting bits of scenery we’ve been driving by on this cruise have been our very own buoys! These blue-and-gold surface moorings are the centerpiece of the work done at UAF’s Ocean Acidification Research Center, and are one of our best tools for monitoring Ocean Acidification. (We’re pretty proud of them). On this mission, we’ve visited two of these buoys, one located in Port Conclusion and one just outside of Seward at the entrance to the GAK time series line.  It was dark when we drove past our Southeast buoy, but we got a great shot of GAKOA on a bright sunny day when we visited.
 

View of our GAKOA buoy as we collected our calibration samples. We'll drive by our Kodiak buoy on the way into port! Photo by Jessica Cross (UAF OARC / NOAA).

There are a variety of autonomous sensors on the buoys, designed to measure basic oceanographic variables like temperature, salinity, dissolved oxygen, and fluorescence (a rough proxy for the amount of phytoplankton in the water), as well as sensors that allow us to track pH and the amount of carbon dioxide in the surface water. When we drive by, we’re collecting discrete water calibration samples for the autonomous sensors on the buoy. After we analyze the water we collect, we’ll compare it to the sensor data to make sure everything is working fine. Our ship’s underway systems, like the Burkolator, also provide a valuable comparison tool. Because they collect data constantly, we’ll be able to see how things are change as we approach the buoy, and how well the buoy represents the water around it.

Together, all of these sensors let us monitor seasonal environmental changes. During spring, phytoplankton use carbon dioxide during photosynthesis, and we can watch the concentration go down in the ambient water; during winter, mixing and respiration of organic matter (like when bacteria eat the dead phytoplankton) return that carbon dioxide to the water, and we can watch it build up again. Sometimes, large storms push deeper waters that are naturally rich in CO₂ up to the surface, and we can see that too! In fact, so can you: the data from all our buoys is posted online through the OARC website. Just click on the photo of the buoy you’re most curious about!
 

Our curious cruise participants checking out the GAKOA buoy in the sunshine as we took our calibration samples. Left to Right: Patricia Rivera (UAF); Katie Beaumont (Cornell/UW); Natalie Monacc (UAF OARC); Alex Couturier (OMAO); Rachel Kaplan (UAF); Jessica Pretty (UAF); and Caitlin Smoot (UAF).  Photo by Jessica Cross (UAF OARC / NOAA).

Monitoring these signals helps us identify ocean acidification ‘events.’  These are short periods where the water becomes corrosive to carbonate minerals, usually a combination of natural processes that cause CO₂ to build up and ocean acidification. It’s important that we be able to collect measurements over long periods of time to watch when these events start and end, and if they crop up year after year at around the same time. We also hope to understand how these events relate to the biology around them, and whether consistent events might consistently impact certain development or life stages for fish and shellfish. 

The Alaska OA buoy network has been in place since 2011, so 2015 is our five-year anniversary! In addition to the three Gulf of Alaska moorings, we also support one mooring in the Bering Sea. While OARC runs the project, we receive support from the State of Alaska, NOAA, the Alaska Ocean Observing System (AOOS), the National Science Foundation, and the North Pacific Research Board.

For more information about the Alaska OA mooring program, check out these links: 

OARC Alaska Ocean Acidification Monitoring Network

AOOS Ocean Acidification Project

Alaska Ocean Observing System and Alaska Dispatch News highlight the first buoy deployments

--Jess

Glacier Country (Updated)

***Update:*** More photos at the bottom! 

One of the most enjoyable parts of this coastal monitoring cruise is the wonderful scenery. This morning, there was a great view of Mount Iliamna (see post below), and it got me thinking about Alaska's famously icy landscape. A few days ago, we sailed past Kenai Fjords National Park near Seward, AK. Kenai Fjords is home to a number of glaciers, but the one we can see the best from the boat is Bear Glacier. While it is always great for morale to sail through this area, there’s actually a pretty strong scientific reason for coming through. Glacial melt can have a strong influence on seawater and is one of the natural factors that enhance the region’s vulnerability to ocean acidification, especially as melting of these glaciers accelerates in our warming climate.

View of Bear Glacier (and dark colored moraines) from sea. Photo by Jessica Cross (NOAA/UAF).

While Bear Glacier is stunning to look at, it is a land-terminating glacier and we’re primarily interested in tidewater glaciers that drain directly into the ocean, like Columbia, Bench, or Muir Glaciers. Glacial melt is extremely low in carbonate ions, as you’ve heard us mention before. This type of water can be corrosive to different types of shells, sediments and tests that are made of calcium carbonate. All by itself, this low carbonate concentration already enhances vulnerability of melt-impacted areas to ocean acidification.

However, glacial melt is also very low in carbon dioxide relative to the atmosphere. Do you remember the concept of equilibrium from your highschool chemistry class? It states that solutes want to move from areas of high concentration (like the sugar at the bottom of your coffee cup when you first pour it in) to areas of lower concentration (like the rest of the coffee over the top of it). Because concentrations of carbon dioxide are lower in glacier melt waters than in the atmosphere, the glacial melt wants to pull even more carbon dioxide in!

There’s already a lot of extra carbon dioxide in the atmosphere from human burning of fossil fuels and land use changes, which is slowly dissolving into the oceans. This is what we generally refer to as human-caused ocean acidification. However, glacial melt is what we call a ‘positive feedback,’ where a natural process intensifies the pace and impact of ocean acidification.

In Alaska, tidewater glaciers cover 14% of the total glaciated area, and as our climate warms they are melting pretty quickly. Nearby Columbia Glacier in Prince William Sound has melted back over 19 km, and has lost over 450m in thickness since 1980. Recent research suggests that they might be melting more slowly than other types of glaciers though. It will be critical for our OA research to continue to monitor these rates of melting and where the melt waters end up, so we can keep a good eye on these big acidification signals. 

More on Alaskan Glaciers:  

2014 State of the Climate Report: Mountain Glaciers

Climate News Network: Alaskan Glaciers 

Alaskan Glaciers and Ocean Chemistry

--Jess 

***UPDATE:***
As I was writing this post, we were sailing out of Cook Inlet past Mount Douglas and Fourpeaked Mountain, and had an excellent view of several more land-terminating glaciers along the way. 

Fourpeaked Mountain (left) and Mount Douglas (right), showing four glaciers from this angle.

Mount Douglas and three glaciers. One is melting around a rock at the left.

Mount Douglas and a close-up view of the right-hand glaciers in the photo above.

A close-up view of Fourpeaked Glacier and its prominent moraines. The view just kept getting better as we sailed south.

Fourpeaked Mountain (left; peak hidden by clouds) and Mount Douglas (right) from a slightly different angle, showing more of Fourpeaked Mountain and its glaciers.

A segment from the USGS Map of Katmai National Park, highlighting Mount Douglas, Fourpeaked Mountain and Fourpeaked Glacier.

Mount Iliamna: The Icy Volcano

While sampling in Cook Inlet this morning we passed Mount Iliamna, a glacier covered stratovolcano! We were stunned by its magnificent beauty. Iliamna hasn't erupted since 1876, but there have been plenty of false alarms due to fumaroles on the flank that produce vigorous plumes of gas and water vapor. There was a brief spike in seismic activity in early 2012 that prompted the Alaska Volcano Observatory to issue a temporary advisory, however the activity has since calmed down. If you'd like to learn more about Mt Iliamna, you can do so at the following links:

Alaska Volcano Observatory: Mt Iliamna
Smithsonian Global Volcanism Program: Mt Iliamna

Photo 1: Julian Herndon and Jennifer Questel pose with Mt Iliamna. It's a volcano... covered in ice? Photo by Jennifer Questel

Photo 2: Mt Iliamna, taken by Dan Naber

Photo 3: Mt Iliamna, taken by Dan Naber

Photo 4: Panorama by Jennifer Questel

Successfully Shrunken Styrofoam, Science Style

Photo 0: Science team decorating cups! Jessica Pretty (UAF), Jennifer Questel (UAF), Julian Herndon (UW/PMEL), Rachel Kaplan (UAF), and Jessica Cross (PMEL/UAF)

On Saturday, we had a deep cast at our furthest offshore station, GAK15. We deployed the CTD down to 4200 bd of pressure (just over 4100 meters). The cast, in its entirety, took 3 hours to complete. For the past few days leading up to this station we've had oceanography arts and crafts with decorating Styrofoam cups that would then be attached to the CTD frame. As the CTD gets sunk into the deep abyss the cups shrink and shrink and shrink as the pressure compresses the extra space out of the styrofoam. These cups are quite the tradition for oceanographers. We had a few people get creative with scissors to make octopuses & a jellyfish, and even a few shrunken heads! Below are some photos of the process

Photos 1-2 by Morgan Ostendorf. Photo 3 by Jennifer Questel. Before photos of some of our cups!

 

Photos 4-6 by Morgan Ostendorf. Pat Rivera (UAF), Max Shoenfeld (UAF) and Caitlin Smoot (UAF) decorate their cups

 

Photo 5 by Morgan Ostendorf. Wiley Evans (UAF/PMEL) holding the shrunken head pre-shrinking. The whole science crew chipped in to decorate this lovely lady! Photos 6-8 by Dan Naber






Photos 9-10 by Morgan Ostendorf. Jessica Cross (UAF/PMEL) holding the mesh bag with the finished cups. Photo 11 by Dan Naber, the mesh bag with all of the heads 

Photos 12-15 by Dan Naber. Attaching the mesh bags to the CTD, with guest star Jessica Cross



Photo 16 by Jennifer Questel. Julian Herndon (UW/PMEL) deploying the CTD!

Photos 17-20 by Dan Naber. Post shrinking head!

Photo 21 by Morgan Ostendorf. Wiley Evans (UAF/PMEL) holding the shrunken head for scale

Photo 22-23 by Jennifer Questel. Meet our octopuses & jellyfish! Photo 24 by Pat Rivera, post shrinking cups

Pteropod catch!

I am not kidding when I tell you that Caitlin Smoot (UAF) and Jennifer Questel (UAF), our ecologists on board, caught an absolute /mess/ of pteropods in the bongo nets several times today. They were so thick in her nets that they looked like mud! Often, this is exactly how we find them: very crowded in one isolated patch. It was very cool to find them! 

Caitlin Smoot (UAF) posing with the grey cod-end of the Bongo nets, which collect all the animals that the net filters. The pteropods are the tiny black snails in the white hand-filter. There are so many they look like sand! 

 

This is a close-up shot of the white hand filter, showing the thousands of tiny snails. The animals themselves are dark colored, but the shells are clear. The interspersed red animals are a different kind of pteropod that grows without a shell (and really likes to eat the shelled species). You can also see some ctenophore slime-- jellfish tentacles-- threading through the pteropods!

You’ve heard us mention pteropods before: they are the small snails that are often talked about in conjunction with ocean acidification research. The snail shells are made of aragonite, a mineral variant of calcium carbonate (a more common form is chalk). In order to make these shells, pteropods use free carbonate ions naturally found in seawater. Normally it’s pretty easy, as carbonate is relatively abundant in the ocean. However, in low pH environments, free carbonate ions can be difficult to come by.

At a certain level of scarcity this means that pteropods and other carbonate shell-builders just build more slowly—sort of like you trying to conserve gas when the price of oil goes up—but eventually these shortages can get really severe. Laboratory experiments show that as pH drops, shell building slows… then stops… and then reverses. The shells pit, crack, and start flaking away as they dissolve. Research already shows that this is happening in real life: monitoring cruises just like this one off the US West Coast collected live pteropods with acidification-damaged shells.

Right now, it’s unclear whether or not dissolving pteropod shells will have a major impact on ocean ecosystems, but lots of researchers are on the job! We already know that juvenile salmon love to eat pteropods. If the young salmon can’t replace this part of their diet, they might end up going hungry. In the long term this could mean that they grow up smaller than usual, or that fewer survive to adulthood.

This could be a serious challenge for Alaska. The protein for many native Alaskan communities comes from subsistence salmon fishing, and the state’s economy is built around some shellfish and salmon fisheries that are highly vulnerable to OA. Our program works to understand OA from all these perspectives: our scientists work with shellfish hatcheries and fisheries research facilities, and even economists. For example, we’ll end up sending some of the pteropods we caught today back to the lab for a close look, and that data will end up informing the whole research chain! And it all started here on RB104, with Caitlin and Jenn.

Jennifer Questel (UAF) sorts through some of the zooplankton we collected in the Bongo nets today.

Great catch! 

--Jess