Megan takes light readings in a bed of Ruppia maritima.

Comparing ecosystem function between two habitats or species is an important fundamental goal of ecology and restoration. My master’s research has focused on the ecosystem function of two seagrasses in San Diego Bay. Seagrasses are ecologically and commercially vital components of nearshore ecosystems because they provide a number of ecosystem functions. For example, seagrasses reduce water turbidity, which improves water quality, and they provide structural habitat and food, or trophic support, to a wide variety of fauna. For these, and many other reasons, seagrasses are federally protected under the Clean Water Act.

The seagrass Zostera marina, or eelgrass, is the dominant seagrass in San Diego Bay. During the El Niño event of 1997 / 1998, we noticed a spread in the distribution of the seagrass Ruppia maritima, which was historically a minor species in this ecosystem. My research addressed the question: What would happen to the ecosystem function of the eelgrass beds if they were replaced, or mixed, with R. maritima?

I answered my question by completing a suite of measurements on the quantity, quality, and availability of food provided by both Z. marina and R. maritima. My research suggests that, during periods of maximum biomass, Ruppia maritima can provide trophic support that is, at least, equivalent to that of Zostera marina.

Our lab has on-going research addressing the mechanisms for the distributional shift in R. maritima and on the seasonal variation in biomass of Z. marina and R. maritima.

Megan and Liza conduct fieldwork in San Diego Bay.