Project Title

Seasonal Primary Productivity and Nitrogen Cycling in Photosynthetic Mats in Lake Fryxell, McMurdo Dry Valleys

Summary

Event Number:
B-047-M
NSF / OPP Award 2445119

Program Director:
Dr. William Ambrose

ASC POC/Implementer:
Ryan Steiner / Jenny Cunningham

Principal Investigator(s)

Dr. Dawn Yvonne Sumner
dawninantarctica.23@gmail.com
University of California Davis
Geology Department
Davis, California

Location

Supporting Stations: McMurdo Station
Research Locations: McMurdo Dry Valleys

Description

This project will evaluate the effect of light and microbial mat activity on biogeochemical cycling in winter and summer in Lake Fryxell within the McMurdo Dry Valleys. The team will evaluate the role of light on microbial mat oxygen production and nitrogen cycling in the system. Divers will deploy microsensors in and immediately above the benthic mats in different months to measure small-scale changes in water chemistry with differing light exposure. Mats will also be subsampled to evaluate changes in microbial gene expression in differing conditions. The proposed research will provide important new insights into the winter behaviors of microbes in mats and how biotic, abiotic, and environmental components of ecosystems interact within specific processes (e.g., redox and nitrogen cycling) to affect the entire McMurdo Dry Valley ecosystem. Results will be used to construct a biogeochemical model for seasonal biomass generation and phenotypic changes in the system.

Field Season Overview

Six participants will deploy from late October through mid-December, residing for 5-6 weeks at Lake Fryxell fixed camp in Taylor Valley. In this final season of this science event, the team will conduct under-ice diving from an Endurance tent positioned on the lake ice to study microbial mats on the lake floor. The aim is to monitor microbial activity in the mats prior to peak photosynthesis in mid-November. The team will collect water and mat samples and recover biogeochemical monitoring equipment and shades that had been deployed over winter. One collaborator from Antarctica New Zealand (AntNZ) will join the group for a week to assist with diving, sample collection and run an underwater remotely operated vehicle (ROV) to collect additional imagery and data.

Deploying Team Members