Journals 2008/2009

John Karavias
Walt Whitman H.S. Huntington Station, NY

"Estimation of Primary Productivity and Particle Export Rates as a Function of Phytoplankton Community Structure in the Bering Sea" United States Coast Guard Cutter Healy, Icebreaker July 3 - July 28, 2008

Journal Index: July 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11        12 - 13 - 14 - 15 - 16 - 17 - 18 - 19        20 - 21 - 22 - 23 - 24 - 25 - 26 - 27        28 - 29 - 30 - 31

July 4, 2008
Happy 4th from the Bering!!

After worrying about taking the O¹⁸ collection for Tom Weingartner, I collected it without incident and now I have the fever! Give me more! It was great to get involved and I thank Tom for having the confidence in me to take his samples.

This is the CTD the scientists will be collecting their water samples from all trip. There are 12, 30-liter niskin bottles on it.

Since it is the 4th of July, we had a barbeque on the ship and it was great. After the barbeque, I had two options. I could look for more fish larvae or whales. I chose whales. Pat hit the racks so I had some time to observe, so I hit the observation tower looking for mega fauna. Gary Friedrechsen, the marine mammal researcher, was welcoming to the company. After about 45 minutes I noticed what I thought to be a few whales. We had "blows" on our port side but Gary did not seem to get excited as he was looking to that side. After 30 seconds, I causally said to Gary, "Aren't those blows over there, Gary?" He looked and instantly got excited; however, I got more excited since this was my first whale sighting ever. He identified the four whales as fin whales by their tall colander blow 12 to 15 feet high. The dorsal fin is trigger shaped, which breeches slightly when the animal breathes. Gary estimated the two adults to be young and about 45 feet long.

When Pat woke up, we finished cleaning the jugs and prepared them for our next Thorium sample. We also set up our satellite link for the sediment trap that we will deploy on Sunday, if all stays on schedule. As compared to yesterday, today was a much-needed "slower" day.

What am I doing with Pat Kelly?

So what does that mean?
We want to know if there is a disruption in the carbon cycle. There is increased sunlight hitting the surface of the Bering Sea and polar waters due to the melting ice.

Why do we want to do this?
Scientists, fisherman, you, and I are concerned about the Bering Sea! It is either the number one or number two most productive American fishing port depending on how you crunch the numbers that reach the billions. With the new algae blooms there is now with less ice, which will affect the Bering Sea. If the Bering Sea is affected, then the Chukchi Sea will be affected, and then the Arctic Ocean will be affected. These waters eventually will affect the North Atlantic. It is not just about money. It is not just about saving the Polar Bears. It is the all too familiar global warming pandemic.

Questions we are trying to collect data to eventually answer:
Is there an increased absorption of carbon in the euphotic zone? The euphotic zone is the vertical water table where light can penetrate so photosynthesis can occur.

Where is the carbon going in the Bering Sea? Is it staying in the euphotic zone, or are the phytoplankton organisms that are absorbing the carbon dying and remineralizing and precipitating to the bottom shifting the carbon cycle to the benthos?

How do we collect and begin to analyze our data?
When the CTD is deployed and retrieved, we are one of the teams that will take water samples. Prior to deploying, Pat Kelly tells the operators at what depths to close the niskin bottles of the CTD.

Once we have our 12 four liter bottle samples of water, the fun begins! We add Potassium Permanganate, Ammonium Hydroxide, and Manganese Chloride. This produces Manganese Oxide precipitate. The seawater solution is filtered through a one inch micron glass filter, which retains the precipitate.

The reason we are doing this is to get the thorium that is in the water to adhere to the Manganese Oxide.

Why do we want thorium?
We want to know the flux of particles sinking in the Bering Sea because the particles tell us how much material (nitrate, phosphate, carbon, etc) is being removed from the water.

Thorium 234 has a 24 hour day half life
Uranium 238 has a half life of billions of years

These two elements behave differently and have different chemistries in seawater. Uranium is conservative, meaning it maintains proportionality with NaCl. Thorium sticks to particles meaning it is particle reactive.

In short and oversimplifying to near inaccuracies, uranium decays to thorium and thorium levels tell us the particle flux which tells us the amount of organic carbon is being exported.

Methods:
The CTD is moving and the Niskin bottles are taking a "snapshot" of a water sample. Since the CTD is being deployed for other studies we take some water to increase our data, however we cannot be sure the water contains particles that are precipitating.

By using a sediment trap we are able to "catch" the particle flux as it is precipitating, thus we know for sure it was precipitating. We deploy the trap for 20 to 24 hours to collect enough material for analysis.