Catherine Fuller: Crossing Boundaries, July 5, 2019

NOAA Teacher at Sea

Catherine Fuller

Aboard R/V Sikuliaq

June 28 – July 18, 2019

Mission: Northern Gulf of Alaska (NGA) Long-Term Ecological Research (LTER)

Geographic Area of Cruise: Northern Gulf of Alaska

Date: July 5, 2019

Weather Data from the Bridge

Latitude: 59° 54.155’ N
Longitude: 146° 18.252’ W
Wave Height: 2 ft
Wind Speed: 12.6 knots
Wind Direction: 264 degrees
Visibility: 1 nm
Air Temperature:  14°C
Barometric Pressure: 1022 mb
Sky: Overcast, light fog

Science and Technology Log

Dr. Suzanne Strom, from Western Washington University, is the team leader for work being done in the wet lab.  Simply put, her team is examining the amount and production rate of phytoplankton (single-celled algae) captured at various depths.  The team uses information from sensors on the CTD during each cast to read light levels and determine the depths at which to collect water samples containing phytoplankton. 

After bottles are filled from the CTD, the team introduce 13C (a heavy isotope of carbon) into the bottles and then packages them in varying layers of mesh bags to recreate light levels at the depths from which they were sampled, simulating 50%, 30%, 10%, 5% and 1% of surface light.  For example, the sample representing 1% of surface light has seven layers of mesh over it.  Depending on the concentration of particles in the water, the 1% sample might range from 20 meters down near shore to 50 meters or more in open ocean. After a 24-hour incubation, the team filters the plankton out of the water samples and has them analyzed for 13C content, which indicates the amount of primary production that has taken place in each bottle (and, by extension, at each depth in the water column). Once the production is known, it can be related to measures of phytoplankton abundance that are obtained from the sensors attached to the CTD.

Dr. Strom is in the process of discovering a way to estimate the production of phytoplankton based on the amount of chlorophyll present in the water.  Currently, on site testing has to be combined with information from sensors and from satellite imagery (which will indicate the amount of chlorophyll present in the surface ocean).  When a relationship between the two is established, it will allow scientists to make accurate predictions about plankton populations and their production without actual sampling.  The spring bloom is a time of greater chlorophyll content and primary production and thus is a critical component of her data set. 

Hana Busse is a graduate student from WWU who is studying under Dr. Suzanne Strom. Her work is based on the perceived distinction between phytoplankton (which photosynthesize) and microzooplankton (which feed on other organisms) and the identification of organisms that cross those boundaries.  These organisms are called mixotrophic, and they can both photosynthesize and feed.  She hopes to find out why particular organisms have developed that ability and how it helps them survive in a varied environment. 

Although mixotrophy has been observed for a long time, it was commonly thought to be an anomalous phenomenon.  However, with better sampling technology, mixotrophy has been discovered to be ubiquitous.  Because this is a relatively new branch in the study of plankton, there are still many questions to be answered. Does mixotrophy promote ‘phytoplankton’ blooms?  Does it promote resilience of species and communities? Can mixotrophs switch strategies, i.e. from photosynthesis to feeding and vice versa? 

As a part of her research process, Hana is incubating a natural community of photosynthetic organisms in gradients of light and added nutrients. 

She will be trying to discover whether ingestion rates change according to the amount of light or nutrients a mixotrophic population is exposed to.  Is the reverse true? Is feeding driven by lack of nutrients or by prey?  Prey concentration experiments?

Because of the relative newness of this kind of a study (it has been growing in importance over the last ten years or so), the results will have important implications for the food web because you have organisms that fit both categories (phytoplankton and microzooplankton) rather than just one or the other.  Hana is working with a modeler on this project to incorporate mixotrophy in models of the ecosystem we are sampling.  Her work also has implications for previous studies that did not take mixotrophy into account.  Although there are different kinds of mixotrophs, she is focused on dinoflagellates, while others, such as Dr. Strom, are looking at ciliates (they “borrow” chloroplasts to photosynthesize).  Hana is also looking at different strategies that organisms use to become mixotrophic. Do they steal chloroplasts? Do they create them themselves when they are in need? Can they switch back?  Her work has huge implications for our understanding of environmental variability, the food web and the dynamics of marine ecosystems worldwide.

Personal Log

There have been more safety protocols in place over the last few days that are noteworthy.  First of all, since we’ve been traveling through fog, the ship must sound fog signals at a two-minute interval to alert other vessels of our presence.  Every two minutes, it sounds like a VERY large angry goose or an annoyed Tyrannosaurus Rex sounds off.  I think most of us have learned to ignore it, although, with the labs being open to the working deck, it is louder in there.  Yesterday for the Fourth of July, Third Mate Artie and the Chief Mate led a safety briefing and demonstration on flares, rockets, projectile line launchers and preventing polar bears from coming on board the ship.

It’s not something we’ll be dealing with, but it is an issue the ship encounters when it goes on arctic cruises.  The line launcher is used to transfer a line over a distance to another vessel or to deploy it to someone in the water. 

Kim, the Chief Steward and head chef on board volunteered to fire it.

To deter bears, two different shells are fired off: one that makes a loud bang and another that makes a loud squeal.

Both are fired from a small pistol at a 45-degree angle (to go over the head of the bear).  A number of the crew as well as the science team took the opportunity to try firing the pistol. 

Being that it was a relatively warm and sunny day (58 degrees outside), and that we were basically circling while one of the science sensors was being fixed, both the science team and the crew were able to enjoy some “overlap” and have a relaxing afternoon together.  Luckily, we were also close enough to land for most of us to be able to text, if not call our loved ones.  We were located in the Copper River plume in fairly shallow water, which meant that the color of the water was close to a tropical green, and was reminiscent of home. 

I’ve decided that I definitely over-packed for the conditions we’ve experienced so far on this voyage.  I expected to find temperatures to be much colder and thus I brought two more jackets than I need.  I brought a combination of short sleeved and long sleeved shirts, planning on layering, but have not had to do much of that yet, although we’ve still got a couple of weeks to go.  I also brought a spare pair of shoes that I haven’t worn yet.  I am glad, however, that I packed workout clothes, as the food on board is so good that I definitely need to exercise!  I discovered the rowing machine in the gym and spent almost an hour on it last night. 

One diversion for a few of us yesterday was rescuing a hummingbird that had gotten into the Baltic Room (which opens onto the main deck) and couldn’t get out.  One of the crew was able to assist by opening the cargo door and the bird flew out.

Birds Seen Today:

Did You Know?

Did you know that the draft of R/V Sikuliaq is less than 10m?

What do you want kids to learn from your research?

Hana: The boundaries that we see in nature are not as firm as people expect them to be.  There is a lot of overlap; everything is related.