Day 4 What are the roles of the scientist on board?: Christian Halverson
Regardless of the voyage there are certain personnel that are made available, by the Marine National Facility, to the scientists that have applied to do research. I mentioned in the post yesterday one of the geophysicists that works in the Geophysical Survey and Mapping section area supporting Eric’s work. These incredibly talented people set the multiscan sonar units to take measurements of the sea floor at depths of up to 10,000 metres. That, in theory, can go to the bottom of the deepest part of the world’s ocean, the Mariana Trench just off the Philippines—Google Earth the Mariana Trench for a fun half hour.
The team can use other sonar units that act like the biggest fish finders you have ever set eyes on to see what is actually in the water column above the ocean floor. Not only this, but some of the equipment penetrates into the sediments at the bottom of the ocean. Who would have thought that there are two main types of biological oozes, let alone muds, sands, shelly sands and red clays, and all of them have a particular signature that can be ascertained from reflected sound. You don’t have to scoop the stuff up to work out what is there, you just bounce sound at different frequencies at it and record the signature as it rebounds back to the ship—brilliant!
The other group being relied upon at the moment are the hydrochemists—brilliant scientists specialising in the chemistry of water, obviously ocean water in our case. Up on the Monkey Bridge where the animal observations are occurring, we have linked deep into the bowels of RV Investigator to have dissolved oxygen levels, fluoremetry readings, water temperature and soon dissolved ions of trace minerals made available for us to peruse in real time.
What all this information has told me is that there seems to be a link between lots of phytoplankton and zooplankton on the surface, and therefore small feeding fish and predatory seabirds making a simple food chain. It is underpinned by cooler water bringing a burst of nutrient rich waters from deeper ocean areas. Sometimes it is known as an upwelling, at other times it could just be a shift in a current just a few hundred metres below the surface.
I ended today happy that some of the oceanography I taught this year was pretty accurate, but wow has the technology advanced! How lucky are we to have such remarkable people and the tools to put to such great use?