Kelp Forest Food Webs – University of Oregon
Identifying what forces structure food webs and describing how energy flows through the environment are basic questions of ecology. Imported and exported materials that can sustain a community come in many forms: from whales falls that deliver nutrients to the deepest reaches of the ocean, to trace elements that are upwelled to the coastal shelf. Understanding the patterns of these flows allows us to predict responses of recipient habitats on an organismal to community level.
Kelp habitats are some of the most productive on Earth, and are dynamic open systems that export as well as receive nutrients in the form of detrital algae, trace elements, feces, and carcasses. Currently, there is much debate about the relative proportions and importance that particular forms of production including algal primary production and detritus, consumer egestion, and phytoplankton subsidies play in supporting these diverse communities.
As part of my PhD research at the Oregon Institute of Marine Biology, I will be clarifying select pathways of nutrient flow within kelp communities along the Oregon Coast and describing patterns of nutrient production within and adjacent to these habitats. I will test mechanisms and responses of consumers to various forms of nutrient availability with a combination of subtidal SCUBA surveys and lab and field experiments.
What is the diversity and composition of seaweeds along the Western Antarctic Peninsula (WAP), and what is the structure of associated food webs?
With researchers from University of Alabama, University of Alaska, and Texas A&M, the Coastal Trophic Ecology Lab conducted diver video transects at 15 sites across a gradient of latitude and annual mean ice cover along the WAP in Spring of 2019, and collected associated invertebrate consumers for biomarker analyses.
We will use the videos to characterize the seaweed assemblages and analyze seaweed and invertebrate samples for stable isotope and fatty acid content which will allow us to construct food webs of this relatively understudied community.
The Smithsonian’s MarineGEO project is the first global network focusing on long-term monitoring and experimentation of coastal biodiversity. We work with partners in North and Central America, Oceania, and Asia to generate and open-access data set of long-term measurements and coordinated experiments aimed at uncovering processes that modify and are modified in turn by communities of marine organisms. We recently finished a global coordinated experiment called Ocean Bitemap that describes global patterns of top-down control in many common marine habitats. Results of this work were published in PNAS!
The assembly and persistence of ecological communities is a phenomenon that occurs across large spatial and temporal scales. However, the relative effects of regional versus local processes on community structure are not well understood in marine ecosystems. In order to understand how scale can alter processes that drive variation in community assembly it is necessary to determine patterns of diversity across multiple scales. For my Master’s research, along with members of the O’Connor Lab at University of British Columbia, we used invertebrate epifaunal communities in the foundation seagrass species Zostera marina to test:
1. whether this marine community exhibits meadow-scale variability through time, and
2. whether we can identify patterns of connectivity and diversity within and among meadows in the same region.
We found that seagrass epifaunal communities are variable in terms of their rarefied richness, alpha and beta diversity, and evenness among meadows. In addition, differences in these metrics were detected over the course of a summer season. You can find out more in our publication at Ecosphere!
Do sea urchins migrate? Sea urchins in the San Juan Archipelago enjoy a bountiful supply of detrital kelp (their favorite food), that is delivered to them by strong tidal currents. Ageing kelp is stripped from the live kelp thallus and blown across the benthos for consumption. It’s like home delivery for urchins. We wanted to know if the urchins of the San Juan Islands in Washington State moved from shallow waters to deeper waters following the supply of kelp on a seasonal basis, and how that might impact the surrounding community. To find the answer see our published work here in Marine Ecology.