Seward Line Transects – NOAA Teacher at Sea Blog

September 17, 2018October 4, 2018

Mark Van Arsdale: What Makes Up an Ecosystem? Part IV – Jellies, September 16, 2018

NOAA Teacher at Sea

Mark Van Arsdale

Aboard R/V Tiglax

September 11 – 26, 2018

Mission: Long Term Ecological Monitoring

Geographic Area of Cruise: North Gulf of Alaska

Date: September 16, 2018

Weather Data from the Bridge

Mostly cloudy, winds variable 10 knots, waves four to six feet during the day, up to eight feet at night

57.27 N, 150.10 W (Kodiak Line)

Science Log

What Makes Up an Ecosystem? Part IV Jellies

Ever seen a jellyfish washed up on the beach? Ever gotten stung by one? Most people don’t have very favorable views of jellyfish. I’m getting to spend a lot of time with them lately, and I am developing an appreciation. We have a graduate student on board studying the interactions between fish and jellies. Her enthusiasm for them is infectious.

Graduate student Heidi photographing a phacellophora (fried egg) jelly

Jellyfish really aren’t fish. They belong to a group called Cnidarians, along with corals, sea anemones, and hydras. It’s one of the most primitive groups of animals on the planet. Ancient and simple, Cnidarians have two tissue layers, a defined top and bottom, but no left and right symmetry and no defined digestive or circulatory systems. Jellies have simple nerves and muscles. They can move, but they are unable to swim against oceanic currents and therefore travel at the whim of those currents. Jelly tissue is made of a collagen protein matrix and a lot of water. I have heard one scientist call jellies “organized sea water.” That’s really not too far off. Seawater has a density close to one kilogram per liter, and when you measure jellies, their mass to volume ratio almost always approaches one.

Despite their simplicity, jellies are incredible predators. When we scoop them up with the Methot net, they often come in with small lantern fish paralyzed and dangling from their tentacles. Jellies possess one of the more sophisticated weapons in the animal kingdom. Located in their tentacles are stinging cells, called cnidocytes. These cells contain tiny, often toxic harpoons, called nematocysts. The nematocysts are triggered by touch and can deploy as fast as a rifle bullet, injecting enough venom to kill small fish or to give the person weighing the jellies a nasty sting.

Me holding a Chrysaora (sea nettle) jelly. — Holding up a Chrysaora (sea nettle) jelly.

Jellies have not been thoroughly studied in the Gulf of Alaska, and the work onboard the Tiglax may take us closer to answering some basic questions of abundance and distribution. How many jellies are there, where are they, and are their numbers increasing in response to increasing ocean temperatures?

In order to sample jellies each night, four times a night we deploy a Methot net. The Methot net is a square steel frame, two and a half meters on each side and weighing a few hundred pounds. It is attached to a heavy mesh net, ten meters long. Even in relatively calm seas, getting it in and out of the water takes a lot of effort. We have already deployed it in seas up to eight feet and winds blowing 20 knots, and that was pretty crazy. The net is attached by steel bridle cables to the main crane on the Tiglax. As the crane lifts it, four of us guide it overboard and into the water. We leave it in the water for 20 minutes, and it catches jellies – sometimes lots of jellies. On still nights, you can sometimes see jellies glow electric blue as they hit the net.

As we retrieve the net there are a few very tense moments where we have to simultaneously secure the swinging net frame and lift the jelly-filled cod end over the side of the boat. A few of the hauls were big enough that we had to use the crane a second time to lift the cod end into the boat.

Smaller ctenophores (comb jellies) caught in the Methot net.

Once on board, the jellies have to be identified, measured, and weighed. Assuming catches stay about the same, we will measure over one thousand jellies while on this cruise. I don’t know how all of this data compares with similar long-term ecological projects, but on this trip the trend is clear. Jellies are true oceanic organisms, the further we go offshore the larger and more numerous they get. Go much beyond the continental shelf and you have entered the “jelly zone.”

Personal Log

Seasick teacher

Last night was tough. During our transit from the Seward line to the Kodiak line, things got sloppy. The waves got bigger, and their periods got shorter. To make things more uncomfortable, we were running perpendicular to the movement of the waves. I retreated to my bunk to read, but eventually the motion of the ocean got the better of me and I made my required donations to the fishes. The boat doesn’t stop for seasick scientist (or teacher) and neither does the work; at 11:00 last night I dragged myself from bed and reported for duty.

The work on the Tiglax is nonstop. The intensity of labor involved with scientific discovery has been an eye-opener to me. We live in a world where unimaginable knowledge is at our fingertips. We can search up the answer to any question and get immediate answers. Yet we too easily forget that the knowledge we obtain through our Google searches was first obtained through the time and labor of seekers like the scientists aboard the Tiglax.

The goal of this project is to understand the dynamics of the Gulf of Alaska ecosystem, but one of the major challenges in oceanography is the vastness of its subject. This project contains 60-70 sampling stations and 1,800 nautical miles of observational transects, but that is just a few pin pricks in a great wide sea. Imagine trying to understand the plot of a silent movie while watching it through a darkened curtain that has just a few specks of light passing through.

“Pinpricks in the ocean,” Transect lines for the North Gulf of Alaska Long-term Ecological Research Program.

Did You Know?

Storm petrels periodically land on ships to seek cover from winds or storms. They are one of the smaller sea birds, at just a few ounces they survive and thrive in the wild wind and waves of the Gulf of Alaska.

Last night we had a forked-tailed storm petrel fly into the drying room as I was removing my rain gear between zooplankton tows. A softball-sized orb of grey and white feathers, it weighed almost nothing and stared at me with deep black and nervous eyes as I picked it up, wished it well, and released it off the stern of the boat. It was a cool moment.

Animals Seen Today

Fin whales
Lots of seabirds including Storm Petrels, tufted puffins, Laysan and black-footed and short-tailed albatross, flesh footed shearwater, and an osprey that followed the boat for half the night
Mola mola (ocean sunfish), which was far north of its normal range

September 13, 2018October 4, 2018

Mark Van Arsdale: What Makes Up an Ecosystem? Part I – Chemistry, September 13, 2018

NOAA Teacher at Sea

Mark Van Arsdale

Aboard R/V Tiglax

September 11 – 26, 2018

Mission: Long Term Ecological Monitoring

Geographic Area of Cruise: North Gulf of Alaska

Date: September 13, 2018

Weather Data from the Bridge

Clear skies, variable winds, swell 4-6 ft

59.58 N, 148.38 W (Gulf of Alaska Line)

Science Log

What Makes Up an Ecosystem? Part I Chemistry

CTD (water chemistry) data visualized along the Gulf of Alaska Line.

The scientists aboard this ship are trying to understand the working parts of the North Gulf of Alaska ecosystem. Since Descartes, the western approach to science has required that the understanding of complex systems begin with the reduction of a system it to its simpler working parts. For example, to understand the clock, you must take it apart and try to understand the mechanism of each piece separately. The Gulf of Alaska is huge, and its ecosystem is both highly complex and highly variable. Changes take place because of weather, season, and climactic regime. Nonetheless, the first step to understanding it is to understand its chemistry.

The CTD gets dropped or “cast” at each station. On this boat, that means four people shoving it out the back door while trying not to fall out themselves. There is more than $100,000 worth of equipment attached to the CTD Rosette and there is a moment in each cast where the CTD swings precariously before the winch lowers it down into the water. When the CTD comes back up, all of that data is run through a computer and it paints a picture of what conditions are like at depth.

Inside the "van" where water samples are processed for trace medals — Inside the “van” where water samples are processed for trace medals

CTD stands for conductivity, temperature, depth. In reality, it tests for those things plus salinity, dissolved oxygen, nitrates, pressure, and florescence (which is a measurement of the chlorophyll in phytoplankton). The CTD also has a camera onboard that takes gray-scale images of particles and plankton in the water column as it goes down. Most of our CTD “casts” are showing a water column that is highly stratified, with a surface layer that is relative warm (34^o Celsius), lower salinity, and a chlorophyll maximum around twenty meters. The CTD shows a thermocline (rapid change in temperature) around fifty meters. Below that, the water is colder and has a higher salinity, both of which results in water with a higher density. The density differences between these two layers make it so that they don’t easily mix. The stratification effect had been intensified by the recent stretch of sunny weather and light winds. Stratification by density “traps” phytoplankton at the surface in waters ideal for photosynthesis except that in September, the availability of nutrients needed for growth is quite low. Nitrates, nitrites, and silica have been used up by growing phytoplankton earlier in the summer and their absence now limits growth.

Catch from a Multi-net, mostly small euphausiids (krill)

We have scientists on board measuring the surface waters for trace metals – iron in particular. It’s a common joke on board that the smaller the subject you study, the greater the equipment needs. Whale watchers just need binoculars but the chemists have their own lab set up inside a twenty-foot shipping container or “van” strapped to the top deck. The metals team drags a missile shaped device along the side of the boat known as an “iron fish.” The iron fish, is connected to a long plastic tube and pump that provides them a constant stream of surface water. Samples are continuously collected and frozen for later analysis back in Fairbanks. Months of work will be required to process all of the samples collected on this trip.

Our plankton catches were much less variable last night. The Multi-net caught almost exclusively small euphausiids (krill.) The Methot net caught four kinds of jellies, including one moon jelly that the jelly expert was very excited about – perhaps a species not described in Alaska before. The Methot net also caught a lot of small fishes swimming at the surface. One of which was the three-spine stickleback. This was exciting for me because the three-spine stickleback is a species we use in my AP Biology class as an easy to understand and highly local example of natural selection. The three-spine stickleback is a small fish, around 1 inch in size, found in both fresh and saltwater. In saltwater, they have three large spines that discourage predators from eating them. Out here in the ocean, the spines give the fish a selective advantage. During the last ice age, some sticklebacks were trapped in fresh water ponds and lakes in South Central Alaska. There, they underwent a change. The spines which were such a great defense in the ocean were a disadvantage to them in freshwater. Aggressive dragonfly larva use the spines like handles to grab the small fish and eat them. Over time there was a selective advantage to have smaller spines, and today freshwater sticklebacks have greatly reduced pelvic spines as compared to their saltwater cousins. Natural selection did not design a better fish, it simply picked which variants were more likely to survive and reproduce in its environment.

Personal Log

Cetacean acoustic recording buoy recovered by the Tiglax.

My second night shift was not any easier, but it was more pleasant. Just before sunset, we took a slight detour from our transect line to recovery a buoy for a scientist from Scripps Institution of Oceanography. An acoustic recorder, designed to count whales by their unique calls, it had been deployed a year earlier in 900 meters of water. The crew had onboard a device that would talk to the buoy and signal it to release from its mooring. It took about a half an hour, but eventually there we saw it bobbing at the surface. Luckily the seas were pretty calm, and we were able to pull it through the side door.

The seas and weather continue to be excellent. Last night we were treated to a display of the aurora around 3:30 AM. It was so calm and so quiet that at one point, we could hear whales breathing around us. Both served as distractions to the routine of net deployment, net retrieval, sample containment, repeat.

As we traveled the ten nautical miles between stations, the flood lights on the front deck were turned off and I would sit down to watch the stars. To ancient mariners, the clear night sky was a map that could direct you across an ocean. It made me think of the Polynesian navigators tracking their small canoes across the Pacific. It also made me think about Ptolemy, who thought the Earth was encased in a perfect glass sphere with stars painted along its interior. I could see how you would think of such a sky as art.

Did You Know?

Did you know the Earth is round? It seems silly to have to say, but as a science teacher, the battle against the fantasies and fallacies of the Internet are never ending. Last year was the first year in twenty-one years of teaching that I was challenged by a student to prove to him that the Earth is round, and it happened twice. So here goes. On a boat in the Gulf of Alaska on a clear day, you know the Earth is round because as you move slowly away from the mountains, they disappear from the bottom up. By the end of the day we had traveled far enough from shore that we saw just the snow-covered tips of mountain peaks.

Sunset, it must be time to go to work. — Sunset with the mountains receding in the background, it must be time to go to work.

Animals Seen Today

Dall porpoise
Lots of seabirds including black-footed and Laysan albatross, sooty shearwater, puffins and fulmars.

September 13, 2018October 4, 2018

Mark Van Arsdale: Night Work, September 12, 2018

NOAA Teacher at Sea

Mark Van Arsdale

Aboard R/V Tiglax

September 11 – 26, 2018

Mission: Long Term Ecological Monitoring

Geographic Area of Cruise: North Gulf of Alaska

Date: September 12, 2018

Weather Data from the Bridge

Partially Cloudy, Variable Winds, Seas to 3ft

59.43 N, 149.21 W (Gulf of Alaska Line)

Science Log

Night Work

Most of day one was spent loading, sorting, unpacking, and storing gear. Scientists do not travel light. There were more action packers on board than I have ever seen in once place. At midday, we had a safety training, which consisted of learning how to put on a survival suit and how to use the coffee machine without flooding the galley. For night work, I was assigned a mustang float coat, a water activated flash light, and satellite locator, so that they could find my body if I went overboard.

After dinner, work shifted to putting together various nets and the CTD which I will describe in more detail later. We got underway at about 8:00 PM, just as the sun was setting. I slept for an hour and was woken at 10:30 to begin my shift doing zooplankton tows.

The first tow uses a Methot net, which is a large square steel frame attached by d-rings to a heavy mesh net, ten meters long. The net ends in a plastic sieve tube called a “cod end” that keeps any jellies from escaping. The net is quite heavy, and it takes four of us to guide it as a crane raises it off of the deck and then lowers it over the side. The net is dragged at the surface for twenty minutes. In the darkness of night, it glows slightly green as ctenophores and other bioluminescent jellies smash into it.

Dave demonstrating the proper technique for putting on a survival suit

After the Methot net is retrieved and secured on deck, we leave the collected jellies for a few minutes to go deploy the next net, called a Multi-net. The Multi-net is a steel box about the size of a dishwasher with a funnel entrance and five separate fine-mesh nets hanging off of the back. The net also has a heavy “fish fin” that acts to drag it down and keep it moving straight. The four of us work the net to the edge of the boat, open the back gate, and use two winches to lower it overboard. Once in the water and if the bottom depth allows it, the Multi-net gets dropped to a depth of two hundred meters and the first net is opened. The Multi-net allows you to “carve up the water column.” Each net can be triggered remotely to open and collect a horizontal sample of zooplankton at a specific depth. The electronics also allow you to measure how much water volume flows through the net. Each net is about two meters long, made of a fine mesh that funnels plankton into a soft sieve or “cod end”. While the Multi-net is “fishing,” we sort, classify, and measure the jellies collected in the Methot net tow.

The Seward Line Transect is made up of fifteen stops or stations. Each one designated as GAK1, GAK2, etc. Once we finish sampling a station, the boat speeds up and drives us ten nautical miles to the next station. Last night we managed to sample four stations, finishing the last one just as the sun rose around 7:00 AM. When daylight comes, the Tiglax makes its way back to the place the night shift began. All of the day-time sampling has to be done at each of the stations we sampled the night before. The day-time sampling uses different tools, the main tool being the CTD Rosette Sampler. The Rosette is a steel cage with water collecting “Niskin Bottles” and lots of other instrumentation strapped into the cage. There are fifteen bottles and each is triggered by computer to close at a specific depth. This allows the scientists on board to measure a variety of physical and chemical properties of the water at depth.

Personal Log

The night shift was surprisingly dark. That may sound obvious, but after a long Alaskan summer, with campfires and hikes that often went past midnight in perfect daylight, dark is an adjustment. The night was beautiful and warm, but the work of deploying and retrieving nets was tedious and physical. By morning I was exhausted, but I was reminded repeatedly that there are no cutting corners. No matter how tired you get, each sample needs to be meticulously cared for.

After the sun came up, I forced myself to eat some breakfast and then I fell in bed for a hard sleep. I could only stay there for a couple hours before my well-trained, morning-self wanted to greet the day. The day was flawless, picture-perfect, sunny and calm, the kind of days you don’t often seen in the stormy Gulf of Alaska.

Animals Seen Today

Dall Porpoise
Lots of seabirds, including black-legged kittiwakes, pelagic cormorants, and sooty and flesh-footed shearwaters.

Shearwater taking off, photo credit Callie Gesmundo

September 7, 2018September 7, 2018

Mark Van Arsdale: Flexibility, September 5, 2018

NOAA Teacher at Sea

Mark Van Arsdale

Aboard R/V Tiglax

September 11 – 27, 2018

Mission: Long-Term Ecological Research in the North Gulf of Alaska, aka The Seward Line Transects

Geographic Area of Cruise: North Gulf of Alaska

Date: September 5, 2018

Latitude: 61.3293° N
Longitude: 149.5680° W
Air Temperature: 60° F
Sky: Clear

Logistics Log

When I read the instructions for my application to NOAA Teacher at Sea, they emphasized the necessity for flexibility. Alaskans, in my mind, epitomize flexibility. The climate demands it. When the weather changes, you have to adjust to it. Not doing so can put you or others at risk.

My original cruise should have departed this weekend into the Bering Sea, but NOAA Ship Oscar Dyson developed problems with its propulsion system. Rather than sailing this research cruise, she will be in Kodiak under repair. I was pretty bummed when I got the news, but I really feel for all of those PhD students whose thesis projects needed the data from that trip.

The wonderful folks at NOAA told me that they were working on a new assignment, most likely in Southeastern US. I tried to wait patiently, but I was thinking about how much I wanted to teach Alaskan kids about the ocean just a few miles from them. Meanwhile, I had to cancel my substitute teacher. My sub has done some biological fieldwork, and when I talked to him he was very understanding. The funny thing was I got an email from his wife the next day, saying that she might have a berth for me. It turns out she works for the North Pacific Research Board and was familiar with most of the fisheries and ecological research going on in coastal Alaska. The berth was on the R/V Tiglax (TEKH-lah – Aleut for eagle). The Tiglax is not a NOAA vessel. It is owned by U.S. Fish and Wildlife Service and operated jointly by the National Science Foundation. NOAA Teacher at Sea does occasionally partner with other organizations. After a few days of waiting, I was told that this cruise met the NOAA Teacher at Sea criteria.

Bringing an end to my long logistical story, I leave Monday on a trip into the Gulf of Alaska for seventeen days aboard the Tiglax.

Science Log

The science behind my new project is pretty exciting. The Seward Line Transects have been run every summer since 1997 – every May and every September. Weather permitting, we will repeat the Seward Line Transect (seen below in black) along with four other transects. Each transect begins at a near shore location and makes it past the edge of the continental shelf into the deep waters of the Pacific. At each transect station, water is collected using a CTD to test the physical and chemical properties of the water at that location. A variety of plankton collection nets will be also be deployed. One of these sampling stations (GAK-1) has been sampled continuously for plankton and water chemistry for forty-eight years, representing an incredible wealth of long term ecological data.

Here is Caitlin Smoot (who will be on board with me) talking about how Zooplankton is collected aboard the R/V Sikuliaq, another vessel that operates in the Gulf of Alaska.

Personal Log

The transect lines that make the North Gulf of Alaska Long Term Ecological Research Project

My job will be working the night shift, helping to collect plankton. I go out of my way in all of my classes to look at plankton. I even wrote a lab using diatoms to investigate a suspicious drowning death for my forensic science class. I’ve been collecting and examining freshwater plankton around my home in Eagle River, Alaska with my science classes for years, but rarely have I gotten to look at marine plankton. I’m excited to learning how plankton is collected at sea and how those collections are used to calculate relative abundance of plankton in the Gulf of Alaska from these samples.

In my classroom, I am always on the look out for how to better connect students to the science I am teaching. I’ve taught Oceanography for fifteen years but never been on an oceanographic cruise. I am hopeful this trip gives me a depth of experience that my students will benefit from.

As I get closer, I am not without some anxieties. I’m the very definition of a morning person, so working the night shift is going to be an adjustment. Just being aboard the Tiglax is going to be an adjustment. At a length of 120 feet, the Tiglax is a small research vessel with pretty limited facilities and no Internet connection. I’ve been in a lot of boats, but I don’t recall ever being beyond the sight of land. Those transect lines go way out into the ocean, and I wonder what it will feel like to be 150 miles from shore.

Did You Know?

The average depth of the ocean approaches 3,700 meters (12,000 feet.) The Seward Line transect begins in water only 100 meters deep and moves into water greater than 4000 meters in depth.