Chemical Oceanography

In this series, educator Deb Greene walks us through some of the science on the ship. She explores the practices of science and how they fit in with the Next Generation Science Standards. Deb has taught and been involved in curriculum development in both the public and private sector for over 35 years. She currently works in Alaska with the Curriculum and Instruction Department for the Anchorage School District.

Another blog post about the Hales lab can be found here

Part 3: Chemical Oceanography

The Hales Lab

The Arctic is a novel environment. It used to be ice covered. Winds did not impact the water column. As the Arctic experiences earlier season breakup and later season freeze-up, there is more open water for a longer period of time. The Hales lab is trying to document the turnover of nutrients that may be a result of wind traveling across all this open water in the late ice-free season.

In the fall when land cools faster than the ocean, winds are created that blow across the water. Dr. Hales’ lab is trying to figure out if the upwelling that is bringing nutrients to the surface is wind induced.

Burke Hales’ Lab is part of Oregon State University, College of Earth, Ocean, and Atmospheric Sciences (CEOAS). The premise that the lab is working on is that with so much open water late in the season, winds blow away the top layer of water on the ocean. In order to fill in this gap created at the top of the water column, deeper water wells up to the surface. This deeper, enriched water provides late season nutrients and CO2 for phytoplankton (organisms that photosynthesize) that have otherwise run out of early season resources.

Dale Hubbard, Senior Faculty Research Assistant, & Dr. Burke Hales with the SuperSucker frame

Dr. Hales wants to examine this new wind induced upwelling phenomena because in the past scientists believe that the ways nutrients were introduced into the marine environment was through ice melt, animal excretions, and runoff.

The questions they are asking involve chemical analysis. What nutrients are present in the Arctic marine environment in the late season and at what concentrations are we finding them throughout the water column?

 A towed profiling vehicle known as the SuperSucker was developed by Dr. Hales to pull in water and send it directly to the lab onboard ship as it zigzags between varying water depths. Because of its ability to draw in water, the SuperSucker provides a fine scale structure (it allows scientists to measure nutrients at almost every meter) as the team looks for the clues that promote late season growth. This data might give clues as to what processes are at play in Arctic waters.

The SuperSucker

The SuperSucker, along with other tools designed specifically for ocean water chemical analysis, test the intake water for chemical attributes of silicate, ammonium, nitrate, and phosphate. These chemical nutrients are analogous to Miracle Grow used to fertilize lawns and gardens. They are the inorganic substances necessary to promote growth. Phytoplankton at the base of the food web need inorganic nutrients just like plants in gardens.

They are also measuring for ammonium. Through the metabolic process, organisms excrete ammonium. If ammonium is present in the water, it is a good signal that organisms are present and metabolizing nutrients available in the system.

The lab is also taking CO2 measurements – looking at both partial pressure CO2 concentrations (gaseous CO2) and comparing these figures with total CO2 concentrations. CO2 is essential to the photosynthetic process in the oceans as well as on land. CO2 drives photosynthesis, which gives plants the energy to grow. This is why industrial farmers pump CO2 into large scale greenhouses. The more available gaseous CO2 in the system, the greater the opportunity a plant has to photosynthesize if all the essential nutrients are present.

If the Hales Lab can identify both the CO2 and nutrient concentrations, they can figure out if there are organisms using these nutrients to grow and photosynthesize in the late season.

The SuperSucker is also capable of measuring temperature, salinity, oxygen, chlorophyll particles in situ.

Data collected will provide a detailed nutrient map of the cross section of the ocean sampled. This information is used to corroborate with the data other teams of scientists are collecting.


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