Honors Theses
Date of Award
Spring 5-8-2026
Document Type
Undergraduate Thesis
Department
Chemistry and Biochemistry
First Advisor
Colin Jackson
Second Advisor
Saumen Chakraborty
Third Advisor
Stephanie Otts
Relational Format
Dissertation/Thesis
Abstract
Microbial extracellular enzymes are critical for the breakdown of organic matter and nutrient cycling in aquatic ecosystems. Extracellular enzyme activity serves as an indicator of nutrient turnover rates, metabolic states, and nutrient limitations within an ecosystem. Coastal ecosystems are especially dynamic as the influx of freshwater from inland runoff or seawater intrusion from storm surges can lead to fluctuations in salinity which can restructure microbial communities and alter enzymatic activity. Despite the ecological significance of these changes, few studies have explored the effects of short-term salinity shifts on microbial extracellular enzyme activity in coastal waters. This study investigated the effects of manipulated salinity shifts on the activity of three microbial extracellular enzymes (β-glucosidase, NAGase, and phosphatase) in controlled laboratory coastal seawater microcosms over a five-day period. Activities of NAGase and phosphatase showed little variation across salinity treatments and with the main pattern being changes in enzyme activity over time. The activity of these two enzymes was slightly correlated, suggesting a linked demand for nitrogen and phosphorus. β-glucosidase activity also changed over time but showed some sensitivity to natural freshwater inputs. This study highlights the importance of temporal variation on microbial extracellular enzyme activity and offers a building block on understanding how microbes adapt to short-term changes in salinity.
Recommended Citation
Ariyoshi, Natali, "Impacts of Salinity on Microbial Enzyme Activity in Coastal Waters" (2026). Honors Theses. 3588.
https://egrove.olemiss.edu/hon_thesis/3588