September 4-5 – sea creatures
September 4
Rosetta Update: Rosetta moved from her sleeping pad in the left-hand corner below the porthole to under a piece of crumpled paper behind her home. Zzzzzzzzzzz!
Scientist Spotlight: Marine Ecologist Vasily Povazhnyy. Vasily usually studies copepods, but on this cruise, he is looking for Polar Cod fish larvae. I had the opportunity to watch Vasily and Physical Oceanographer Nikita Kusse-Tuz pull in two Bongo nets. They are called Bongo nets because they have a similar shape to Bongo drums. Each net has a specific sized mesh to catch the desired sea creatures at depths between 10-100m. The captured creatures are then taken out of the net and put in buckets to be transported to the container lab. Before going into the lab, the creatures are filtered from the bucket and placed in small white tubs. Next, the initial sorting begins with taking out creatures that are of no interest and putting them back into the sea. It is very important to keep the creatures hydrated while working. This can be done with a squirt bottle. Once in the lab, Vasily looks for Polar Cod larvae. This work can be tedious requiring patience, a magnifier, and flashlight. It could be like “finding a needle in a haystack” looking for the minuscule black eyes of the fish larvae. Vasily didn’t find any larvae in this batch, but was rewarded a few days later.
The key motivation for this study is that mammals such as seals and bears are dependent on Polar Cod. Polar Cod hide, hunt and breed under the pack ice. Finding the fish larvae in open arctic water would indicate a change in their habitat. The Polar Cod is a valuable component of the arctic marine food chain. Polar Cod is also important because of the pure omega 3 fatty acids that come from phytoplankton they eat. Phytoplankton are a valuable source for marine life from the bottom of the food chain. The omega 3 fatty acids that phytoplankton contain travel up the food chain unchanged. Polar Cod feed on small crustaceans, amphipods, copepods, fish eggs, and fish fry. Crustaceans in turn feed on phytoplankton.
The following are some of the creatures that Vasily collected:
- Narcomedusae jellyfish (commonly known as “medusa” jellyfish): The deep-sea hydrozoan jellyfish Bathykorus bouilloni has a distinctly Darth Vader-like appearance. The unusual species of jellyfish has not one but two stomach pouches. To fill those pouches with plenty of prey, it will hold its long tentacles out in front of it while it swims. Researchers think this makes them a more effective ambush predator. According to Creature Cast, “Some species of Narcomedusae (affectionately called narcos by the people that study them) can grow inside their own mother who provides nourishment and a safe environment for them. The narcos babies can then leave their mother, find another jellyfish of an entirely different species, attach to its flesh, and thrive on the nourishment and safe environment it provides.” (Jaymi Heimbuch, Mother Nature Network, MNN.com)
- Euphausiid shrimp (krill): Krill are small crustaceans of the order Euphausiacea, and are found in all the world’s oceans. The name “krill” comes from the Norwegian word krill, meaning “small fry of fish”, which is also often attributed to species of fish. Krill are considered important because they are near the bottom of the food chain. They feed on phytoplankton and (to a lesser extent) zooplankton. They convert these into a form suitable for many larger animals for which krill make up the largest part of their diets. Krill are the main prey of baleen whales, including blue whales.
- Carnivorous snail: Gastropods more commonly known as snails and slugs belong to a large taxonomic class of invertebrates with the phylum Molluska, called Gastropoda. There are thousands of species of sea snails and slugs. Gastropods without a shell and those with only a very reduced or internal shell, are usually known as slugs. Snails are those species with an external shell big enough that the soft parts can withdraw completely into it. Gastropods have a worldwide distribution from the Arctic and Antarctic zones to the tropics.
- Copepods: Copepod (meaning “oar-feet”) are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic (drifting in sea waters), some are benthic (living on the ocean floor), and some continental species may live in limnoterrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests, bogs, springs, ephemeral ponds and puddles, damp moss, or water-filled recesses of plants. Many live under ground in marine and fresh water caves, sinkholes, or stream beds. Most copepods have a single median compound eye, usually bright red in the center of the transparent head. Most copepods feed directly on phytoplankton. Planktonic copepods are important to global ecology and the carbon cycle. They are usually the dominant members of the zooplankton, and are major food organisms for small fish, whales, seabirds, Alaska pollock, and other crustaceans such as krill in the ocean and fresh water. C. glacialis inhabits the edge of the Arctic icepack, especially where light (and photosynthesis) is present. C. glacialis comprise up to 80% of zooplankton biomass.
Breakfast: rice porridge, ham and cheese
Lunch: sorrel soup, fried fish, and mixed vegetables
Tea Time: cottage cheese souffle’, apples
Dinner: stewed duck, red cabbage, and salad
September 5
NABOS just completed one of four transects. A transect is a series of stations in a preplanned sequence (line). A station means expedition members from different teams have a chance to collect samples for their research. A station may consist of mooring recoveries and deployments, CTD, UCTD, and MSS casts; and Bongo and net hauls. The chief scientist and co-chief scientists coordinate with the ship’s operation crew to plan the schedule.
It continues to be a very busy time on the ship with team members sleeping and eating at all times of day. There isn’t much of a difference between day or night, especially with the limited darkness between 5:00-9:00 pm.
After going south for a while, we are heading northeast again toward the East Siberian Sea. We are preparing to go on the ice to do some ice studies. This afternoon we will have a meeting with T-ICE Co-Chief Scientist Ben Rabe from Alfred Wegener Institute for Polar and Marine Research. There will be an opportunity for team members to volunteer to help on the ice, and to be on polar bear watch. How exciting is that!
I would like to take some time to get caught up with some photos of our animal sightings. Thank you to Ocean Engineering and Sea Ice Physics student Simon Hummel for providing the beautiful photos.
First, the whales. I mentioned the Northern Minke whale in the August 19 entry while we were in the Barents Sea.
Next, I would like to talk about the Bowhead whale, Balaena mysticetus, meaning “large mustached.” Bowheads are found in arctic pack ice, and are the only baleen whale to spend their entire life in arctic waters. They grow between 11-15 m (35-50 ft), and weigh up to 90,000 kg (200,000 lb), and have the largest mouth of any animal. There are two distinctly separated blowholes behind a peaked ridge. This makes a wide V-shaped blow. Bowheads feed by swimming open-mouthed through schools of copepods, krill, and other marine invertebrates, which are filtered through baleen. They also forage near the seafloor in shallow areas, leaving a trail of mud in their wake. Their far-reaching “songs,” can be heard for several miles underwater.
Breakfast: wheat porridge, ham and cheese
Lunch: Gorsky (lentil) soup, pasta carbonara, and cole slaw
Tea Time: pastries, kiwi
Dinner: roasted chicken, mashed potatoes and salad
