Natalie Macke, August 23, 2010

NOAA Teacher at Sea: Natalie Macke
NOAA Ship: Oscar Dyson

Mission: BASIS Survey
Geographical area of cruise: Bering Sea
Date: 9/2/2010

Bruce Wing, Invertebrate Biological
Oceanographer “Jelly-man”
Everyone’s Working for the “Jelly-man” …  (at least tonight)     
Weather Data from the Bridge :
Visibility :  10+ nautical miles (Wondering what a nautical mile is??)
Wind Direction: From the NW at 17 knots
Sea wave height: 2-3ft
Swell wave direction: 4 ft
Sea temp:7.7 oC
Sea level pressure: 1025.3 mb
Air temp:  9.5oC
Science and Technology Log: 

The result of each of our trawls thus far on the Oscar Dyson is a sample set of  jellyfish.  There’s at least one man on board who enjoys to see that sort of catch in the net.  (As opposed to our Chief Boatswain, Patrick…) Over this past weekend, the enthusiasm our lead scientist (Ed Farley, Salmon guy)showed for his ability to catch and recover these invertebrates, soared to a new all time high and a record for the Dyson crew.  (Once again, to the dismay of the well-respected fishermen working here on the Dyson  ..  not quite the story they want to bring home.)  On Sunday, our transects had us closer to the western coast of Alaska than our previous sample points.  Our Acoustician, Sandy Parker-Stetter, saw it all coming..  I think she probably said something like..  “Ed, we’re in the jellies…”.  The length of the trawl times can be modified, but how many jellies could there be anyway..  Well, that was quickly answered Sunday morning with a catch of 7,500 lbs of jellyfish (oh.. and a p. cod, salmon and pollock here or there to be fair)

7,500 lb trawl catch ~ “the jelly belly”

So one way to become familiar with the Mellanaster Chrysora is to be knee high deep in them.  From each of our station trawls, Bruce sorts the jellyfish by type and then collects counts, relative size and mass data from up to fifty jellyfish samples of each species type (Fifty..  remember this number…).  The video below is a view of our catch coming down the belt to be sorted by the scientists.  If you listen to the audio you’ll hear Bruce reminding all of us what he needs for his sample set…

As our cruise progressed over the weekend the question of why and how we study jellyfish became my focus.  So I sat down with Bruce and he filled me in on what is known and a lot of what is unknown about these invertebrates.

Measuring the Chrysora Mellanasters

Bruce has been a part of the BASIS cruises for the past 7-8 years.  In terms of changes in jellyfish he simply stated that people are seeming to notice them more, so potentially there may be an increase in their biomass.  This is what he and the scientists are trying to determine.  Just recently, the research community has shown an interest in learning more about their impact in various ecosystems.  The reality with research in this part of the world is that if it doesn’t impact the industries, then money for learning more about them can be sparse.

There are basically four types of jellyfish that are common to the Bering Sea;

  • Chrysora Mellanaster
  • Cyanea Capillate (Lion’s mane)
  • Phacellaphora Kamchatka (Fried egg Jelly)
  • Aurelia Labiata (Moon Jelly)
Cyanea Capillate
Phacellaphora Kamchatka
Aurelia Labiata

This time of year, the jellyfish are in their second (and last) phase.  The opaque regions you see in the center of their bodies are the gonads, the sexual organs of the invertebrate.  Once the jellyfish spawn, (shed their gametes) they die sometime in October in the Bering Sea.  This massive biomass then sinks to the bottom of the ocean where very highly popularized detritivores now have a new food source..  Yes..  it’s crab-feeding time.  Well, that is atleast what the scientists suspect.  It is actually quite difficult to have proof of what is eating the jellyfish since they are >99% water.  Once consumed, the jellies break-down almost instantly.  So an inspection of stomach contents for evidence of feeding on jellyfish is near impossible.  But I think back as to how I acted at the Grand Aleutian with the “all you can eat” King Crab buffet..  and I think the likely-hood of the crabs eating jellyfish during their annual fall buffet is quite probable.

Hauling in the big catch!!

So this brings me back to the enthusiasm of our Chief Scientist, Ed Farley.  Apparently, Bruce had shared the jellyfish / King Crab hypothesis with him…  because, that evening’s trawl (10:00 PM with an amazing sunset for a backdrop)brought us our 10 ton catch of jellies.  Tasking the winch, breaking the net..  I won’t really say how the fishermen reacted.  But the scientists were thrilled.  They had lots to sort through.  Sandy, the acoustician just shook her head.

So the BASIS Cruise 2010 will now go down in infamy for the largest jelly-catch ever.  But on calm seas and a beautiful evening, sorting through jellyfish seems like the perfect thing to do.

Big Jellyfish Trawl
Big Jellyfish Trawl

Personal Log:  

I have certainly learned the importance of wearing the correct fishing gear on board the Dyson.  Every time I think I’m just stepping into the fish sorting room for a look, I wind up with that gelatinous goo all over.  I guess my new found fondness for jellyfish has created a type of attraction not clearly explained by laws of physics.  So, I will in the future save on trips to the laundry by making a more conscience effort to wear the “Bering Orange Rubber Suit”.  (Mine name for it..  not theirs)

For those who have been concerned..  I did indeed find the gym and have been using the elliptical everyday.  Unfortunately, all this had done is provide me the mental freedom to enjoy more than my “Daily Recommended Serving” for Oreo Cookies.  Honestly, I’ve usually exceeded that amount by 9AM.

Lastly, I have taken a number of photographs here on the Oscar Dyson which are worth sharing.  So I will make a page devoted to images I have caught which I’ll update during the rest of our cruise..  Look for the link on the right hand column entitled, “Day on the Dyson”.

I have to say, our team is quite a handsome bunch!!


Richard Chewning, June 17th, 2010

NOAA Teacher at Sea
Richard Chewning
Onboard NOAA Ship Oscar Dyson
June 4 – 24, 2010

NOAA Ship Oscar Dyson
Mission: Pollock Survey
Geographical area of cruise: Gulf of Alaska (Kodiak) to eastern Bering Sea (Dutch Harbor)
Date: June 17, 2010

Weather Data from the Bridge

Position: north of Dutch Harbor
Time: 0830
Latitude: N 54 58.080
Longitude: W 165 58.080
Cloud Cover: cloudy with fog
Wind: 20 knots from SW
Temperature: 6.9 C
Barometric Pressure: 1007.9 mbar

Science and Technology Log

In addition to the Tucker trawl, fish biologists onboard the Dyson also utilize the Methot trawl to catch zooplankton in their study of pollock. The Methot is a single net with a large square mouth (the opening of the net) that is deployed from the stern and towed behind the Dyson. The Methot uses fine mesh with openings slightly larger than the Tucker trawl. This larger mesh size allows the net to be towed at higher speeds. A torpedo looking instrument called a flowmeter is suspended in the mouth of net to measure the flow of water moving through the net. The flowmeter allows the researchers to calculate how much zooplankton is found in a certain volume of water. With its larger mouth and faster speed through the water, the Methot is able to catch the larger zooplankton such as euphausiids the Tucker trawl might miss. Pollock seem to love euphausiids as I have seen firsthand stomachs of pollock caught during Aleutian wing trawls that have had stomachs stuffed with euphausiids.

Deploying the Methot trawl
Recovering the Methot trawl

After the Methot is return onboard, the sample is rinsed and poured through a strainer to separate the zooplankton from smaller algae and phytoplankton. After being weighed, a small subsample is removed and preserved for later identification. The number of euphausiids in a second subsample is counted to calculate the total number in the catch. Several individual euphausiids are also frozen so they can later be analyzed for age and development by examining their eye stalks. In addition to catching the small zooplankton pollock eat, the Methot will also catch some of the largest zooplankton in the ocean: jellyfish. Almost all the Dyson’s trawls have yielded large number of Chrysaora melanaster jellyfish. After being removed from the sample, these jellyfish are also weighed and measured. These jellyfish produce only a mild sting but can be quite frustrating to process in large numbers.

The flowmeter

The Dyson has also been routinely deploying a piece of equipment known as a CTD (conductivity-temperature-depth recorder). This instrument package allows scientists to measure temperature, depth, dissolved oxygen, chlorophyll, light intensity and conductivity. By measuring conductivity (the amount of electricity carried by seawater), salinity can also be calculated, and from temperature and salinity, density can be calculated. The CTD is deployed once every night before dawn and during selected locations during the day. The CTD is attached to a metal frame called a carousel along with other pieces of scientific equipment. Niskin bottles can be attached to the carousel allowing the recovery of water samples from different depths. The Niskin bottle is a vertical plastic tube that is initially deployed with both ends open allowing seawater to flow through. Once the CTD is lowered to the desired depth, the bottle is ‘fired’. Firing signals the bottle to close the openings, sealing the water sample inside. This water can be brought to the surface and filtered to measure the amount of chlorophyll it contains. By better understanding how the properties of seawater such as temperature and chlorophyll concentration relate to the various biological organisms that form the foundation of the Bering Sea ecosystem, researchers can better understand pollock distribution and abundance.

Recovering the CTD

Personal Log

After getting to know the crew over the last week and a half, I have noticed most have a passion for the great outdoors and enjoy a wide range of physical activities such as hiking and skiing when not at sea. Most enjoy hunting and fishing and several enjoy competitive events such as running and cycling. You would think staying active while sharing a platform only 208.6 feet long and 49.2 feet wide with up to 40 people might seem like a daunting task, but this is surprisingly not the case. I have noticed most of crew members from the CO (the commanding officer) to the guest scientists have dedicated time in their schedule to keeping physically fit.

The deck crew has an upper hand in this endeavor as their work often involves moving heavy lines, chains, and gear. Their labor is aided however by powerful hydraulic winches that can lift even the heaviest objects with ease. The Dyson’s acting XO (executive officer) Lieutenant Sarah Duncan was also willing to suit up in her foul weather gear and life vest to give the deck crew an extra set of hands with two late night pollock trawls. Besides the physical workout of retrieving the gear, she told me that working down on deck gives her better appreciation for how the deck crew is affected by the ship’s movements and weather conditions when deploying and retrieving gear. This is very valuable information for Sarah for when she is high in the bridge working hard to direct the ship’s movement so the deck crew can work efficiently and safely in different weather conditions and sea states.

Maintaining one’s physically fitness benefits every member of the crew regardless of station as rough seas can wear the body down physically and mentally in a very short period of time. The rowing machine seems to be the first choice among the crew although the stationary bike and elliptical machine are also popular. The treadmill is the most challenging workout as you are constantly being thrown off balance. I can’t help but wonder what prisoners chained to the oars of wooden ships of old would think knowing that mariners today use large mechanical engines to power the ship and use stationary rowing machines for exercise!

Measuring Chrysaora melanaster jellyfish
Holding Chrysaora melanaster jellylfish

Did you know? The word ‘plankton’ and ‘planet’ come from the same root word? Both names come from the Greek word planktos that means ‘wander’. Plankton is any plant or animal not strong enough to swim against water currents. Examples include diatoms, dinoflagellates, copepods, and euphausiids. Planets were named because they were observed by early astronomers to drift or wander among the stars. Stars appear to maintain the same spatial relationships with each other as they rotate across the sky because they are located so far away. Although they are actually moving, their position in relation to each other appears to be unchanging. This is the reason why the same constellations (pattern of stars in the sky) have been identified throughout human history. Planets on the other hand move through the star field as they are very close in comparison and are orbiting the sun. Thus planets appear to wander among the stars just like plankton drift among the currents of the ocean.

Saving a euphausiid sample
Aurelia labiata