PhD student Rachel Thomas on the blog!

Rachel filters water collected at 500 m in the GOM

Rachel Thomas from Florida State University's Earth Ocean and Atmospheric Sciences Department is a doctoral student in the Knapp Lab and she is our guest-blogger today sharing a bit of her research and cruise goals:

"My personal goal on this cruise is to be able to identify bluefin tuna through a microscope. I’ve never seen fish larvae before, so everything the “fish team” brings up in the nets is new and exciting to me! Most of my previous work is involved in the Southern Ocean, where there are unused nutrients in the surface ocean. This gives us a unique ability to look at how phytoplankton are reacting to different physiological stresses, such as light and nutrient availability."
One of these nutrients, is Nitrate (NO3) which is a form of dissolved inorganic nitrogen that is utilized by phytoplankton in the ocean (Malerba et al 2012). One of the aspects of our project (NF1704 & NF1802 is to examine the dynamics between these inorganic compounds at different depths of the surface water column (0-500 m).

Typical nitrate vertical profile comparison, (modified from A. Nahian Avro)

T. Kelly and Rachel Thomas recover the CTD rosette 

"The Gulf of Mexico has a very different light regime compared to the Southern Ocean, and little to no nitrate in the surface waters. Our research team hopes to explore how these contrasts are expressed in the isotopic composition of subsurface nitrate in the Gulf of Mexico. We will also use the isotopic composition of subsurface nitrate in the Gulf of Mexico to understand the nutrient sources for primary productivity fueling bluefin tuna growth in surface waters." 

Click here for last year's blog post from Rachel's experiences during NF1704.

A bit of trivia: the Southern Ocean is the fourth largest of the world's ocean basins and extends to Antarctica. Psst, how many oceans are there? (click here for an answer)

Rachel Thomas and Alanna Mnich ready to deploy an SVP drifter on the fan tail