Mark Van Arsdale: Kodiak, September 17, 2018


NOAA Teacher at Sea

Mark Van Arsdale

Aboard R/V Tiglax

September 11 – 26, 2018

 

Mission: Long Term Ecological Monitoring

Geographic Area of Cruise: North Gulf of Alaska

Date: September 17, 2018

Weather Data from the Bridge

This morning 25 knot winds from the NE, waves to 8ft, tonight calm seas variable winds, light rain

58.14 N, 151.35 W (Kodiak Line)

Science Log

Kodiak  

CTD (water chemistry) data visualized along the Kodiak line.

CTD (water chemistry) data visualized along the Kodiak line.

My wife and I have traveled to Raspberry and Kodiak Islands twice.  The island’s raw beauty, verdant colors, and legendary fishing make it one of my favorite places on Earth.  Its forests are dense, with huge hemlocks and thick growths of salmon berries.  The slopes are steep and covered with lush grasses.  Fish and wildlife abound.  As we moved our way down the Kodiak line, getting closer and closer to land, that richness of life was reflected in waters surrounding the Island.  In just fifty nautical miles we moved from a depth of a few thousand meters to less than one hundred.  Seabirds became more abundant, and we saw large groups of sooty and Buller’s shearwaters, some of them numbering in the thousands.  Sooty shearwaters nest in the southern hemisphere and travel half way across the planet to feed in the rich waters surrounding Kodiak.  Fin whales were also abundant today, and could be seen feeding in small groups at the surface. Our plankton tows also changed.  Deep sea species like lantern fish and Euphausiids disappeared and pteropods became abundant. We caught two species of pteropods that go by the common names – sea butterflies and sea angels.  Sea butterflies look like snails with clear shells and gelatinous wings.  Sea angels look more like slugs, but also swim with a fluttering of their wings.  Pteropods are an important part of the Gulf of Alaska Ecosystem, in particular to the diets of salmon.

Sooty shearwaters as far as you can see.

Sooty shearwaters as far as you can see.

In the last decade, scientists have become aware that the ocean’s pH is changing, becoming more acidic. Sea water, like blood, is slightly basic, typically 8.2 on the pH scale.  As we have added more and more CO2 into the atmosphere, about half of that gas has dissolved into the oceans. When CO2 is dissolved in sea water if forms carbonic acid, and eventually releases hydrogen ions, lowering the waters pH.  In the last decade, sea water pH has dropped to 8.1 and is predicted to be well below 8 by 2050.  A one tenth change in pH may not seem like much, but the pH scale is logarithmic, meaning that that one tenth point change actually represents a thirty percent increase in the ocean’s acidity.   Pteropods are particularly vulnerable to these changes, as their aragonite shells are more difficult to make in increasingly acidic conditions.


A nice introduction to Pteropods

Personal Log

I chose teaching

We have been at sea now for one week. I feel adrift without the comforts and routines of family, exercise, and school. There are no distractions here, no news to follow, and no over-scheduled days.  There is just working, eating, and sleeping. Most of the crew and scientists on board seem to really enjoy that routine.  I am finding it difficult.

There was a point in my twenties where I wanted nothing more than to become a field biologist. I wanted to leave society, go to where the biological world was less disturbed and learn its lessons. I see the same determination in the graduate students aboard the Tiglax. When working, they are always hyper focused on their data and the defined protocols they use to collect it.  If anything goes wrong with tow or sampling station, we repeat it. You clearly need that kind of focus to do good research. Over time, cut corners or the accumulation of small errors can become inaccurate and misleading trends.

When I was in graduate school hoping to become a marine biologist, I was asked to be teaching assistant to an oceanography class for non-science majors. Never having considered teaching, the experience opened my eyes to the joys of sharing the natural world with others, and changed my path in ways that I don’t regret. I am a teacher; over the last twenty years it has come to define me. On this trip, they call me a Teacher at Sea, yet the title is really a misnomer.  I have nothing to teach these people, they are the experts.  Really, I am a student at sea, trying to learn all that I can about each thing I observe and each conversation I have.

Bowler's shearwater, photo credit Callie Gesmundo.

Buller’s shearwater, photo credit Callie Gesmundo.

 

Animals seen today

  • Fin whales
  • Lost of shearwaters (mostly sooty but also Buller’s), along with puffins, auklets, skua

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