This poster was presented at the 2024 UCSB EEMB Research symposium.

Algae plays a crucial role in aquatic ecosystems, serving as both a primary producer through photosynthesis and a food source and habitat for macroinvertebrates, which in turn supports larger organisms. The abundance and composition of algae and macroinvertebrates are influenced by environmental factors such as salinity, temperature, pH, and dissolved oxygen.

This ongoing study investigates the dynamics of a temporary open-closed estuary in the North Campus Open Space Devereux Slough. Monthly water quality data and algae samples are collected from three sites to assess the types of algae present and variations in macroinvertebrate abundance. Preliminary findings reveal several genera of algae, including but not limited to Tribomena, Phormidium, Ulva, and Oscillatoria. Tribomena exhibits the highest abundance of macroinvertebrates and species diversity. 

These findings have enabled a more targeted exploration into local microalgal salinity tolerance, primarily through measurements of algal cell wall density, extent of motion, and color in response to regularly increasing salt concentration. Algae samples were collected from Phelps Bridge and introduced to a controlled aquarium environment in which oxygen and temperature levels were kept relatively constant, while 0.25 ppt of salt was introduced to the system every three days over the course of seven weeks. After each addition, the cell structures and behavior of the algae were examined with microscopy. This yielded results aligning with expectations of algal health deterioration with higher salinity. This research highlights the complex interactions between algae, macroinvertebrates, and environmental factors in estuarine ecosystems.