Researchers say microbial mats fuel a large share of Great Salt Lake's productivity

Bonnie Baxter of the Great Salt Lake Institute presented multi-season field and lab results indicating microbialite mats in the South Arm are major contributors to primary and secondary production in Great Salt Lake.

Baxter summarized comparative microcosm experiments and DNA-based community analyses that found mats consistently outperformed planktonic samples in carbon-assimilation proxies and chemosynthetic measures across seasons. "When you extrapolate...throughout the whole volume of the south arm...the mats are contributing more, both in chemosynthesis and in photosynthesis," she said.

She noted seasonality: winter samples showed high chlorophyll but low measured photosynthetic assimilation, underscoring that chlorophyll alone can misrepresent production in cold conditions. Baxter also described difficulties isolating some mat organisms because they live in tightly associated communities; her team is pursuing genome sequencing to identify genes for dehydration and salt tolerance.

Baxter highlighted one vivid comparison used in the analysis: a former graduate student estimated that, on an annual basis, mats across the lake amount to "the biomass of 7 elephants," an image she said underscores the ecological scale of the mats and the need to keep nearshore water over microbialites so they do not "salt out" or dry up.

She recommended researchers and managers consider microbial mats as distinct ecological compartments that cannot be replaced by planktonic production if they are lost. Baxter offered to share methods and data with colleagues and said ongoing lab work will further clarify rehydration and recovery prospects for degraded mats.