July 12, 2005
I was back to sampling from CTD casts just like my second day at sea. We sampled along the LD line for chlorophylls and nutrients. It made for a quick day since I was involved in every cast. Dr. Trick's group was also very busy sampling from the "FISH". A trace metal collection pump system that resembles a rocket, it collects water at a four meter depth, and is towed from the rear starboard side of the vessel. The sample water is then pumped from the ocean through a hose into the clean room, better known as the "bubble." Eric Roy (UM), a chemist, works in the bubble and analyzes the samples for iron and copper ions. Previous iron experiment research has shown that the presence of iron is linked to the ability for phytoplankton to uptake carbon (in the form of carbon dioxide). Dr. Trick (UWO) explained to me that the production of domoic acid (the neurotoxin) by Pseudo-nitzschia might be due to its need for iron is needed to maximize photosynthetic production. The lack of iron would cause the phytoplankton to produce domoic acid (DA). The presence of DA allows for the uptake of copper which would in turn allow for the uptake of available iron in seawater. It is thought that iron cannot be taken up by Pseudo-nitzschia until there is enough copper within phytoplankton cells. Eric's work will help to check against what Liza, Ben, Keri, Vera, Brian, and Jessica would see under a microscope. Iron is made available to coastal waters from terriginous sediment blown to the sea from nearby continents.
During the day, we completed the LC line (CTDs 36-38) and started on the LD line (CTDs 39-48). I finished my work for the night and left test tubes ready for Brian Bill, who will be relieving me. I cleaned up and took in a movie in the lounge.