Joel Elliott

Updated: July 2020

My research interests are in the ecology and evolution of aquatic organisms. I use both a comparative and integrative approach in my field and laboratory research to address questions at the community, population, organismal, cellular, and molecular levels of organization. Most of my studies have examined predator-prey and symbiotic interactions among marine organisms. Research projects in my lab have examined a wide diversity of organisms, such as the effects of an introduced mussel species on marine communities, effects of wasting disease on sea star populations, biodiversity studies of invertebrates and microbes in anthropogenic sulfide-seeps, potential pathogens of eelgrass, and quantitative surveys of eelgrass beds and bacterial mats.

I have studied predator-prey interactions among a variety of aquatic organisms. Topics of particular interest include: effects of prey size/morphology/color on prey selection patterns by predators, chemical recognition of prey and predators, effects of diurnal activity patterns on predation rates, and the ecological consequences and evolution of prey escape behaviors. We have been conducting a variety of studies on predation by sea stars and crabs on native and introduced mussels in Puget Sound. Recently, we have also been examining the effects of bird predation on intertidal invertebrates (e.g., Rogers and Elliott, 2013) and competition between sea star predators (Rogers, Schultz, and Elliott, 2018).

The introduction of non-indigenous species into marine habitats has had dramatic impacts on the viability of native species and the functioning of food webs. Introduced species are considered to be one of the important environmental threats to the Puget Sound ecosystem.  I have been collaborating with biology professor Peter Wimberger, along with more than 20 of Puget Sound’s biology students, to examine the effects of an introduced mussel (Mytilus galloprovincialis) on intertidal communities in Puget Sound.  The main goal of this research is to determine the factors influencing the distribution and abundance of the introduced mussel, the native mussel M. trossulus, and their hybrids in Puget Sound.  Studies have been conducted to determine the differences in size, shape, and genotypes among the different mussel species in various habitats of Puget Sound (see Elliott, Holmes, Chambers, Leon, and Wimberger 2008).  Other studies have examined the growth and survival rates of the different mussel species in relation to habitat type and competition (see Rensel, Elliott, and Wimberger 2005).

Mussels are important ecosystem engineers in Puget Sound, providing habitat for other marine organisms, and we have also examined the biodiversity of invertebrates living on mussels. Ongoing studies include the effects of predation by sea stars, crabs, and birds on the relative survival of the two mussel species. We have also examined the distribution and abundance of mussel predators (e.g., sea stars) in Puget Sound and the San Juan Islands (Rogers, Schultz, and Elliott, 2018; Eisenlord et al. 2016; Rogers and Elliott, 2013), and how they are influenced by wasting disease and gull predation. The ultimate goal of this research is to determine how the introduced mussel is affecting intertidal communities and food webs in Puget Sound, and to predict what changes may occur in the future.

We have also examined the distribution and abundance of eelgrass beds and bacterial mats in a variety of locations in Puget Sound (Elliott et al. 2006; Elliott and Hannam 2009). We are using intertidal surveys and an underwater video system with laser scaling and GPS (global positioning system) for quantitative analyses, and incorporating the data into a GIS (geographic information system) to produce accurate maps of the eelgrass beds, bacterial mats, and subtidal terrain. The goal of this work is to determine the environmental factors (e.g., substrate type, water quality, microbes) that are influencing where eelgrass and bacterial mats occur in the marine environment.

There is very little known about the effects of wood waste on the environment, and our study was one of the first studies to show a definitive biological effect on the survival of eelgrass in nearshore areas affected by wood waste deposition. Many questions remain to be answered about eelgrass ecology and restoration, biodiversity, microbiology, and sediment chemistry in this system. The bacterial mats discovered in these areas of high hydrogen sulfide appear to be similar to those associated with deep sea hydrothermal vents, and I am collaborating with microbiology professor Mark Martin and a variety of students to characterize the microbial communities found in these areas.

We are also studying a variety of microbes (i.e., bacteria and protists) that live in eelgrass beds and whether they influence the growth, survival, and reproduction of the plants (e.g., Elliott et al. 2019). We use a variety of molecular techniques to identify and quantify microbes (DNA barcoding, high throughput sequencing, qPCR) along with culturing and microscopy (light microscopy, confocal laser microscopy, scanning electron microscopy), to examine microbial community structure.

Potential research projects

Students could examine predator-prey interactions between local aquatic organisms. Of particular interest would be projects that follow up on our previous studies examining factors that influence predation by sea stars and crabs on native and introduced mussels, interactions between native and introduced crab species, and the effects of bird predation on intertidal organisms.

There are many aspects of the introduced mussel study that would provide interesting student projects; e.g., an updated field study of the distribution of mussel species and their hybrids in different habitats, recruitment of mussel larvae, relative growth and survival under different environmental conditions (temperature, salinity).

Students could also become involved in studies of the distribution and abundance of eelgrass beds, bacterial mats, and microbes in Puget Sound. Studies of water quality and sediment quality and their effects on local organisms and communities would also be potential projects.

Studies into the sulfide-seep habitats that we have found in Commencement Bay and other areas may also be of interest. There are many opportunities for research projects on symbioses between different organisms in Puget Sound (e.g., eelgrass and microbes, marine invertebrates or fishes and their microbiome, sulfide-oxidizing bacteria and crabs in sulfide seeps). These studies could involve the collection of environmental samples from field sites along with biogeochemical data, molecular techniques (qPCR, high throughput sequencing) and the use of light and electron microscopy to identify and enumerate members of the microbial communities.



Selected references with UPS student researchers (*):

Joel K. Elliott, Hunter Simpson*, Alex Teesdale*, Amy Replogle, Marianne Elliott, Kathryn Coats, and Gary Chastagner. 2019. A Novel Phagomyxid Parasite Produces Sporangia in Root Hair Galls of Eelgrass (Zostera marina). Protist 170: 64-81.

*Rogers TL, *Schultz HK, Elliott, JK. 2018. Size-dependent interference competition between two sea star species demographically affected by wasting disease. Mar. Ecol. Prog. Ser. 589: 167-177.

Eisenlord ME, Groner ML, Yoshioka RM, Elliott JK, Maynard J, Fradkin S, Turner M, *Pyne K, Rivlin N, van Hooidonk R, Harvell CD. 2016. Ochre star mortality during the 2014 wasting disease epizootic: role of population size structure and temperature. Phil. Trans. R. Soc. B. 371: 20150212.

*Rogers, T., Elliott, J.K. 2013. Differences in relative abundance and size structure of the sea stars Pisaster ochraceus and Evasterias troschelii among habitat types in Puget Sound, Washington, USA. Marine Biology 160:853–865.

Elliott, J.K., K. Holmes*, R. Chambers*, K. Leon*, and P. Wimberger. 2008. Differences in morphology and habitat use among the native mussel Mytilus trossulus, the non-native M. galloprovincialis, and their hybrids in Puget Sound, WA. Marine Biology: 156:39–53.

Elliott, J.K., *Spear E., and S. Wyllie-Echeverria. 2006. Mats of Beggiatoa bacteria reveal that organic pollution from lumber mills inhibits growth of Zostera marina. Marine Ecology. 27: 372-380.

*Rensel M., J.K. Elliott, and P. Wimberger. 2005. Will the introduced mussel Mytilus galloprovincialis outcompete the native mussel M. trossulus in Puget Sound?  A study of relative survival and growth rates among different habitats. Proceedings of the Puget Sound Georgia Basin Conference, Seattle, 2005.