Maggie Prevenas, May 8, 2007


NOAA Teacher at Sea
Maggie Prevenas
Onboard US Coast Guard Ship Healy
April 20 – May 15, 2007

Mission: Bering Sea Ecosystem Survey
Geographic Region: Alaska
Date: May 8, 2007

Science Log

I’ve been feeling a little sad these past few days because the Healy 0701 mission is coming to a close. There’s been so much data taken, so many measurements done, and more than a few hypotheses tested.  So WHAT has been learned?

The CTD was lowered and fired over 200 times in rough water

The CTD was lowered and fired over 200 times in rough water

This research here, this Bering Sea Ecosystem Study, has been some of the first research done with SEASONAL ice during this time of the year. SEASONAL ice is ice that melts and then reforms each year. The algae blooms occur because the seasonal ice melts, creating a stable freshwater layer, a place for the algae to grow.  The algae take up nutrients, which act as a fertilizer, and explode in numbers. The nutrients are quickly used up. The bloom for that year is over.

Rob tested the water for iron, getting baseline data to see if it is a limiting factor in Bering Sea productivity.

Rob tested the water for iron, getting baseline data to see if it is a limiting factor in Bering Sea productivity.

In areas of the Bering Sea that we visited that were really shallow, like around Nunivak Island, the ice has melted and the nutrients have been used. The bloom is over.

Nancy Kachel collected many samples from the CTD during this research mission.

Nancy Kachel collected many samples from the CTD during this research mission.

What has been a surprise to some of the scientists is that the very productive algae blooms occur at the ice edge, not so much under the ice.

When phytoplankton reproduce very quickly they can actually turn the color of the seawater green. Photo from Ray Sambrotto.

When phytoplankton reproduce very quickly they can actually turn the color of the seawater green.

The algae need sunlight, and the sunlight just doesn’t seem to penetrate ice. Algae explode in large numbers when the ice, under which they have been growing, melts away.

Although this seems to be a small observation, it is actually HUGE!  Or at least it was for me. Look at areas of the Arctic that do not have the seasonal ice.  The flow of energy in that ecosystem is different. The energy transfer from sunlight through the high Arctic permanent ice to the algae that populate the Arctic Ocean is different. Same thing with the Antarctic permanent ice.

This is one of the deepest drops that the CTD made. Over 3000 meters!

This is one of the deepest drops that the CTD made. Over 3000 meters!

If the Arctic or Antarctic holds more seasonal ice, i.e. starts melting, the model of how energy is transferred in the polar region will change. Knowing how seasonal ice acts as a medium to facilitate algal blooms will be very important. Right now is a critical time to research this key component.

TAS Maggie observing the sea ice

TAS Maggie observing the sea ice

I learned a huge amount about ice. I made ice observations many, many times. The scientists on this mission to help them interpret their data will use that information.

The science community has named this an International Polar Year (IPY). What I am doing, in trailing along with scientists, is acting to translate and understand the Bering Sea Ecosystem Study, and to act to educate others about cutting edge scientific research of climactic change. I think I can begin to start telling you the story.