Publication Date

Spring 2016

Degree Type


Degree Name

Master of Science (MS)


Moss Landing Marine Laboratories


Jonathan Geller


California, Fouling Community, Invertebrate

Subject Areas

Ecology; Climate change


Increasing average global sea temperatures are one of the most direct and alarming consequences of climate change, yet it is still unclear how sessile marine communities will respond in the near- and long-term. In addition, it is unclear if warming ocean temperatures will facilitate marine invasions or primarily benefit native species. To simulate the effects of increasing ocean temperatures on sessile communities, heated settlement plates (n=7) were used in an in situ field experiment to investigate how an increase in substrate temperature (2.5°C above ambient) would affect recruitment and community development as compared to unheated control plates (n=9). Experimental treatments were deployed in the municipal harbor of Monterey, California, which was characterized by an assemblage reflecting a mix of native and invasive species (mainly bryozoans, sponges, tunicates, and tube worms). Following three months of community development in the field, heated plates experienced significantly higher rates of initial recruitment, 33% increase in wet weight, increased percent cover of native and invasive species, and an increase of species with both historically southern and northern range limits. This study reinforces the need for in situ experimentation to understand the effects of temperature on the dynamics shaping marine communities. In situ studies are valuable because they incorporate all ambient factors and are therefore a more reliable predictor for defining the consequences of climate change.