NOAA Teacher at Sea
Cara Nelson
Aboard USFWS R/V Tiglax
September 11-25, 2019
Mission: Northern Gulf of Alaska Long-Term Ecological Research project
Geographic Area of Cruise: Northern Gulf of Alaska – currently sampling along the Seward line.
Date: September 19, 2019
Weather Data from the Bridge:
Time: 18:30
Latitude: 59º53.587’ N
Longitude: 149º33.398’ E
Wind: South 15 knots
Air Temperature: 15.5ºC (60ºF)
Air Pressure: 998 millibars
Partly cloudy skies
Science and Technology Log
A major component of the Long-Term Ecological Research (LTER) project is the collection and analysis of physical parameters in the Northern Gulf of Alaska (NGA) and how these abiotic (non-living) factors interact with and impact the biological community. A variety of physical oceanographic research is occurring during the day shift on R/V Tiglax, one of which includes looking at metals in the ocean water.
Mette Kaufmann is the onboard research professional working on the collection of trace metals from the surface water. Specifically, Mette is working to sample and process iron species for Dr. Ana Aguilar-Islas who is the principal investigator for iron biogeochemistry on the LTER study. One might ask, why is there such a focus or interest in iron in the surface ocean water? In the past few decades it has become evident through research that iron is major player in the productivity of the ocean ecosystem. Prior to this, nitrogen was assumed to be the most important nutrient and limiting factor in phytoplankton growth and production. It is now known that iron influx from surface and atmospheric sources is the major limiting factor in our coastal and offshore ecosystems.
Glacier runoff from the Kenai peninsula and the Copper River plume carry this iron into the ocean and allow for a rich spring bloom of phytoplankton over the continental shelf. Sampling the iron levels at different locations helps paint a picture as to the overall availability, transport and use of iron in the NGA. For example, one question the researchers are examining is, do fall storms bring up iron to the surface from deeper water? Additionally, copper samples are being collected for analysis on this cruise, as a factor that can potentially suppress photosynthesis at higher levels.
As I mentioned in my second blog, there is a tool for every job and for iron sampling, it is the “iron fish.” The iron fish looks a bit like a rusty torpedo being dragged next to the boat with a simple plastic hose attached to it. However, looks can be deceiving, as this piece of equipment is quite high tech.
The actual sampling piece of the iron fish is the white tubing that can be seen in the picture below. The tip of the tubing has a red cap and is attached to the weight. This tubing is treated with acid and has an inner lining of Teflon to assure for a “clean” catch of metals.
As we transit between stations the iron fish is towed at 1-3 meters of depth off the starboard side of the boat. The pump, which runs off of the boats air supply, send the water through the tubing and into the “van” on the mid deck. This van is a small connex that is used for trace metal processing. Inside the van, the water samples are processed through a 0.4-micron filter to remove any particulates and then stored in acid for analysis back in the metals laboratory at UAF.
Personal Log
As we started our shift on Tuesday evening heading into Wednesday morning, we knew a gale was approaching. We wanted to squeeze in as many sampling stations as we could before the weather chased us away. It was challenging to manage both the Methot and Multinet in the high seas and building wind, but also a lot of fun. We were handling the waves crashing over the back deck and rushing across us as we sampled and measured and getting really good at pouring off the cod-ends with the rise and fall of the boat in the swell. Unfortunately, by our third station of five, the wind and waves were putting such a strain on the winch that the Multinet couldn’t get an accurate reading or sample. The winch began to not respond and the decision was made to call it for the night, even though it was only 2:30am. We strapped things down and proceeded to make a run for shelter back in Resurrection Bay.
I awoke on Wednesday at around 11am expecting it to be raining sideways and blowing still, but was surprised again by partly cloudy skies and a much calmer sea state. I was pleasantly surprised to hear that we were going to take the afternoon for an excursion to Bear Glacier. We all donned our mustang coats and took three groups in the zodiac to head to shore. We were diverted due to rough breakers to a separate beach away from the glacier but all of us were happy to be ashore.
We had about 4 hours to hike around and explore the shoreline. One of the drawbacks of the beauty of the amazing rocky shoreline along the Gulf of Alaska is that it is littered with human trash. The trash entering from around the Pacific circulates through the ocean driven by the currents. Some of the water gets caught up in the counterclockwise gyre of the Gulf of Alaska current and then gets deposited on land by the storms. Just a few steps onto the shore and plastic water bottles are visible everywhere. What is less visible is the plastics that are broken up into small pieces or micro-plastics that then invade the entire water column. These plastics get ingested by marine organisms, such as seabirds, and can cause death from starvation, as their stomachs are clogged with debris. It makes you appreciate our impact on the oceans and the dire need for a shift in our plastic use and disposal.
Aside from the trash, the beach held other treasures and the walk in the fresh air and sunshine was greatly appreciated.
I did have an interesting case of what the seasoned crew calls “dock rock.” This is when you are used to the motion of the sea and everything on land seems to be moving like the ocean. It didn’t make me land sick but it did throw me off a bit. I wonder how long I will sway when I return!
We boarded the ship in time for another fabulous dinner and prepared to head back out to the Seward line for another night of sampling.
Did You Know?
Dr. Thomas C. Royer is a physical oceanographer who was the first to begin water sampling along the GAK (Seward) line almost 40 years ago. His research led to the discovery of significant coast currents in the Northern Gulf of Alaska that are driven by freshwater input. It was this knowledge of coastal currents that assisted with the prediction of oil spill trajectories during the Exxon Valdez oil spill. His groundbreaking work was the start of the Long Term Ecological Research study that I am assisting with today!
