Emma Langsford, University of Wisconsin-Madison

Class Year:

2024

Mentor:

Jacob Cram , Ph.D.

Abstract:

We investigated the size to volume relationship of Rhizaria, and specifically focused on Collodaria, a Rhizaria morphotype, in the Sargasso Sea during the summertime. Rhizaria, and specifically Collodaria, play an important role in many different biogeochemical cycles through uptake and sinking of elements including strontium, sulfate, carbon, nitrogen, and more. Rhizaria were collected on a research cruise during the month of June at the Bermuda Atlantic Time-series Study (BATS) site in the Sargasso Sea. The samples were collected using plankton tows as well as a Multiple Opening-Closing Net and Environmental System tow. The Rhizaria were sorted, filtered, and weighed to determine the mass of each of the Rhizaria morphotypes. Our method was insufficiently sensitive to measure the mass of smaller Rhizaria, such as Acantharea and Foraminifera; however, we successfully measured the mass of most individuals of the large Rhizaria morphotype, Collodaria. We found a strong linear relationship between volume and mass of Collodaria, suggesting a dry density of 4.3 mg/mm³. This relationship allows conversion of image-based measurements of volume into mass estimates. These data and density estimates will enable future biogeochemical models and studies to better parameterize the role of Collodaria in oceanic biogeochemical cycles. 

Location:

Horn Point Laboratory