Welcome to this year's blog detailing our field season at McMurdo Station, Antarctica! We are a team of biologists from Portland State University who study the fishes of the extremely cold waters of the Southern Ocean. We will be collecting fish from McMurdo Sound, an icy body of water that borders the Ross Ice Shelf at 78 degrees south latitude. Our studies are focused on the impact of increasing water temperatures on the physiology of these extremely sensitive and ecologically important species.

Wednesday, December 7, 2011

Full on labwork time!

Fishing operations are over, as the conditions of the sea ice have rapidly deteriorated, and traversing cracks and soft ice becomes dangerous. We have been working full-time in the lab, sampling and treating the fish that have filled our tanks. Here's a little more of an scientific explanation of what we do at this point:

 
Once we catch the fish, we allow them to acclimate in the aquarium for at least 48 hours. This is important for several reasons. First, when the fish arrive at the aquarium, they are quite stressed. They have been caught and pulled out of their environment and had to spend two hours in a Pisten Bully riding back to town. After they are transferred to the aquarium, we are able to more closely examine the fish for other signs of stress like gill diseases, parasites or if they are egg bearing females. We do not use these fish in our experiments as their conditions would add another variable to the experiment in which we could not control.

Our experiments are focused on examining how the fish respond to increasing water temperatures. We are trying to determine how they respond at a cellular level. There are many ways of doing this but some of the easiest ways of determining if an organism is under an increased amount of stress is to quantify the amount of stress related proteins they are producing. When a cell encounters an environmental stress, they tend to respond in a universal manner. These stressors can be Ultra Violet Radiation, changes in salinity, increasing temperatures, or toxins. This universal response has been termed Cellular Stress Response or the CSR. When a cell is under stress, it responds by altering the kinds of proteins it makes. These proteins help protect the cell from the different stressors that are acting upon the cell. Some of these proteins are responsible for repairing damaged DNA while others are involved in facilitating proteins to continue to function normally in the face of different stressors. Sometimes, during a stress, cells will stop replicating to prevent damaged DNA from replicating. Stopping (arresting) the cell cycle also allows the cell to re-allocate energy and other resources to other cytoprotective mechanisms. Finally, if a cell or its DNA has become damaged beyond repair, it may actively engage in an automated cell death cycle known as apoptosis. Our team is examining all of these different possible responses that the Antarctic fish could use to survive an environmental stress (such as increasing water temperature).

This year, our team is using both cell preps from hepatocytes (liver cells) and whole tissue samples to examine the cellular response to increasing temperature. Isaac has isolated hepatocytes and exposed them to a range of temperatures and time points. He will be using his samples to examine cell viability (how many cells survive at a certain temperature). He will also be running some of these cells through a flow cytometer to determine what stage of the cell cycle the hepatocytes are in. Finally, he will be staining some samples to determine what percent of the cells have entered apoptosis.

Dan has been isolating liver, gill and white muscle tissue from six different species of fish and exposing them to a range of temperatures and times. Later, he will analyze these samples with a technique called a western blot. This technique helps to quantify the amount of protein is being made at any given time. Dan will determine if the concentrations of a cellular growth arrest/DNA damage protein increases with increasing temperatures. If this protein increases, cells do not continue beyond a certain growth phase and the cell cycle is arrested.
Here is a link to Dan's blog, where he talks about his experiments and includes photos.

These studies are important for several reasons. We hope to help contribute to the building foundation of knowledge that exists regarding how and why cells grow and divide or stop dividing. Further implications from these studies could be used in developing anti-cancer agents. As we continue to learn more about how cells function and what kinds of stimuli cause them to stop replicating will be important details to know as we continue to search out new treatments. 

Thursday, November 17, 2011

Icefish

If you want to watch an excellent documentary about Antarctic fish, we suggest this:
http://www.hhmi.org/biointeractive/shortfilms/


Click on "The Making of the Fittest: The Birth and Death of Genes."


The fish highlighted in this video is the scaleless, hemoglobinless Icefish (family: Channichthyidae). Hence, its gills, heart, and blood are colorless. They are the only known vertebrate to lack hemoglobin. Icefish are not known to exist in the Ross Sea Region (where we are at the moment), but have been documented around Bouvet Island, a small Antarctic Island in the South Atlantic. Still, they are very interesting.
Borks (Pagothenia borchgrevinki) have a cameo in this video. Interviews with Art DeVries and Chris Cheng take place in the Crary aquarium at McMurdo, where we are working now.

Tuesday, November 15, 2011

A day in the life

Yesterday was a beautiful day. The high temperature was 36F. We took the PB out to Inaccessible Island, drilled three holes, and fished for bernies. Here is a time lapse of our day; two hours pressed into a minute and a half:

video

Wednesday, November 9, 2011

That's why it's called "fishing" and not "catching"


Yesterday, Brad and I (Sandwich) went out to check out our various fishing sites. We checked up on fish hut 6 to make sure the hole hadn't frozen over and to see if any borks were around. 

...needless to say, the borks weren't home.







We then cruised over to a new site, Arrival Heights, to fish an open dive hole there. We ran into Henry and Steve, who were in between dives. Henry has been making underwater films this season for Dr Gretchen Hofmann's ocean acidification project, and has worked on many other underwater films in McMurdo Sound and the Ross Sea region. I told Henry that I always thought that fish were attracted to my lure, but would miss it every time I jigged. He offered to film our lures as we fished near the bottom. This would also give us an idea of the fish that were in the area, what the bottom looked like, and what other creatures were there.


It was exactly as I had suspected! The fish in this video are likely T.pennellii, and possibly too small for our hooks, however, Brad did successfully catch one.

We then drove out to Cape Evans Wall for the first time this season. It is a place where we were very successful in catching borks last season. The Cape Evans Wall is at the base of Mt Erebus, where the glacier meets the rock.



After profiling the dynamic crack in the sea ice between Erebus Glacier Tongue and Tent Island, we blazed a trail out to the Wall. The drive was extremely bumpy due to ungroomed sastrugi. We drilled two holes with the jiffy drill, and within 45 minutes caught twenty borks.


Our Pisten Bully at the glacier at Cape Evans Wall


Friday, November 4, 2011

A Fish Glossary

Some photos and profiles of the fish we've been catching at our various sites:

Trematomus bernacchii


T. bernacchii are one of the most commonly caught species of fish in McMurdo Sound. They are primarily benthic, and, like most fish in the Antarctic, live at temperatures of -1.86C. We usually catch them at 70-100 feet deep (with hook and line), however they have been found in depths of >700m. The sizes of the bernies we have been catching are 40g-300g (>200g are usually gravid) with lengths of 15-25cm.

These fish are often dark or pinkish in color, with dark blotches or wide stripes. There are three morphs of T. bernacchii: some exhibit a white patch on their collar/back of head area, some have three white stripes, and some have no distinguishable markings. 


We have also been catching a number of gravid bernies. Spawning takes place around December-January, at a time when we do not have access to the sea ice in McMurdo. Pictured left are a number of gravid females, taken December 2010.


Trematomus pennellii

T. pennellii (formerly T. centronotus) has been a more common benthic species for us this season than in previous seasons as well. The ones we've been catching this season are small: 10-15cm, 20-50g, caught at about 70-100 feet. They have the typical trematomid shape, but are most easily identified by the bright white flecks exhibited on their head and body. 


Trematomus newnesi




                            



 
We have been catching T. newnesi more often these last couple years than in Brad's previous field seasons. We are not sure why they are showing up more now than they have before, especially since we are visiting the same fishing sites.  Newnesi occupy various levels of the water column; we've been catching them on the bottom (at ~70-100 feet) and in the mid-range. The sizes of the newnesi we've caught so far range from 10-20cm, 20-100g. There are a couple morphs of T. newnesi, one with a large mouth and a broad, blunt head, and the "typical" morph, with a more pointy snout (Eastman and Devries, 1996).  These fish differ from other Trematomids in that they lack a large, triangular shaped head like T. bernacchii, pennellii, hansoni, nicolai, etc.  

Trematomus nicolai


T. nicolai look very similar to their Treamtomid relatives. They are often grey with spots on its classic triangular head shape. Their eyes are positioned on top of their head more, so that they seem to look up and not just straight out to the sides. The nicolai we have caught so far weigh in at 50-120g, and are 15-20cm long. We have been finding them at 70-100 feet in McMurdo Sound.  

Pagothenia borchgrevinki
P. borchgrevinki (borks) is a cryopelagic fish, in that they normally live in the thin layer of brash ice that interfaces between the thick (1.5-2m) sea ice and water. We have occasionally found them on the bottom as well. They are long and silver with broad dark stripes, although often their entire body turns completely dark grey as a stress response. Most borks that we have caught this season are about 12 miles from town, and measure 55-135g and 15-25cm.

Weddell seals have been known to blow air bubbles into the brash ice to push out and feed on borks. Although borks are in a different genus than the other fish we study, we are equally as interested in their reponse to changes in temperature.



Gymnodraco acuticeps



G. acuticeps, or locally known as dragonfish, have a "snout" that comes to a sharp point, with an underbite and sharp small teeth. Last season, we caught zero dragonfish, however, this season, we have already caught five and are hoping for more. The dragonfish we have caught at depths of 70 feet range from 55-105 cm long, and weigh 15-25g.   


see also: The Underwater Field Guide to Ross Island and McMurdo Sound, Antarctica

Thursday, November 3, 2011

Rusty, the hut 6 seal

While fishing for borks out in fish hut 6, we had a visitor:


Since the hole in fish hut 6 is large, sometimes seals pop up to breathe. While it is fun and exciting to see a seal in our hut, it usually means all the fish are scared away.
  video

We decided to move a couple hundred meters from the hut, and drill our own holes with the jiffy drill. These holes are big enough for us to fish through, but too small for seals to use as breathing holes.
Drilling holes is hard work. It takes 45 minutes to an hour to drill through 2+ meters of ice. The drill is tempermental, and the wind is biting. Once the holes are drilled, we stand outside in front of the holes to fish. Fish are then transported back to the aquarium in coolers with bubblers attached, making sure that the -2C water is aerated. This site is about a 30 minute (bumpy) drive from McMurdo by Pisten Bully.

Pisten Bully and Fish Hut 6 in the background

Our helpers, Rickie and Keith, jiffy drilling with Mt Erebus in the background


Water!

Fishing, Antarctic style

Bravo 308 uses nothing less than the highest-tech equipment

Monday, October 31, 2011

Winning!

Halloween.
Since Sunday is our only day off during the week, Halloween in McMurdo is always celebrated on the closet Saturday to Halloween. It is one of the biggest events of the year. People mail down costumes months in advance, or make them from locally discarded materials. There is a party in the big gym that begins with a costume contest. There are several categories: best group, best individual, best Antarctic themed, etc.
Of course, as an Antarctic fish team, we decided to dress up as our favorite local fish, Trematomus bernacchii.
As the Best Group category was called onto stage, we jumped up, wiggled, wriggled, and flopped. The crowd loved us. It was a challenge against other groups that worked hard for their costumes, but everyone loved the fish. We were victorious and swam through the crowd all night.