Historically, marine populations were assumed to be largely “open” with high dispersal among populations. Such connectivity is thought to have a homogenizing effect on populations, limiting the potential for local adaptation (fine tuning of populations to their environment). However, we now know that local adaptation occurs in the ocean and is perhaps even common (Sanford and Kelly 2011). Local adaptation is important because it changes our view of how species will respond and adapt to climate change.

What environmental forces shape local adaptation in the sea?

We are using oyster drills (Urosalpinx cinerea) to examine how the environment (latitudinal and estuarine) shapes patterns of local adaptation (thermal performance).

The Atlantic margin of the United States experiences the strongest thermal gradient in the world and there have been many reports of adaptive differentiation across latitude (e.g. varying growth rate and thermal tolerance; Fangue et al. 2006, Baumann and Conover 2011). Differences in mean temperature are typically invoked to explain these patterns but mean temperature covaries with the length of the growing season. In this NSF funded project, we are using Atlantic oyster drills to examine how season length and mean temperature drive patterns of thermal performance (growth, consumption, metabolism, tolerance) using common garden lab experiments. These phenotypic traits will be complemented by exploring the population genetics and gene expression of oyster drills, in collaboration with the Molecular Ecology and Conservation Lab at UMass Amherst.

We will sample 13 oyster drill populations across latitude and estuaries for common garden experiments to quantify thermal performance. Physiological measurements will be complemented with RNA-Sequencing to resolve population structure and to identify genes under putative selection.

Are you interested? We are recruiting a PhD student to spearhead the phenotypic measurements!

Work cited:

Baumann, H., and D. O. Conover. 2011. Adaptation to climate change: Contrasting patterns of thermal-reaction-norm evolution in Pacific versus Atlantic silversides. Proceedings of the Royal Society B: Biological Sciences 278:2265–2273.

Fangue, N. A., M. Hofmeister, and P. M. Schulte. 2006. Intraspecific variation in thermal tolerance and heat shock protein gene expression in common killifish, Fundulus heteroclitus. Journal of Experimental Biology 209:2859-2872.

Sanford, E., and M. W. Kelly. 2011. Local Adaptation in Marine Invertebrates. Annual Review of Marine Science 3:509-535.