Biomechanics, Ecological Physiology and Genetics of Intertidal Communities

photo credit: Peter Taylor

Hopkins Marine Station, Stanford University

This course will be offered June 15 to July 10, 2009. Application deadline is April 1, 2009.

Course Description

Intertidal communities have been used as a model system in community ecology for decades. Many of the factors responsible for structuring these communities are abiotic variables such as wave exposure, temperature, wind speed, and light. Therefore, a full understanding of community ecology demands an interdisciplinary approach that includes biomechanics and physiology. The physical and biological environment also sets the geographic scale for dispersal, adaptation and gene flow. This four-week summer course is designed to offer experimental ecologists theoretical and hands-on instruction in cutting-edge methods in biomechanics, physiology/biochemistry/molecular biology, and genetic investigations of dispersal, as applied to questions in community ecology.

For additional information, please request a course prospectus from the Instructors, at the above address and see http://www-marine.stanford.edu/HMSweb/mech.html.

Course Organization and Objective

The structures of marine ecosystems are governed by a host of biotic and abiotic interactions. The former types of interactions, for instance, predator-prey interactions, have received the greater share of attention in experimental marine ecology in rocky shoreline habitats. However, to acquire a comprehensive understanding of these complex ecosystems, it is critical to appreciate how abiotic factors influence the distribution patterns, recruitment success, rates of growth, reproductive capacities, and individual longevity of wave-swept organisms. Among the abiotic factors of importance are wave exposure, temperature, wind speed, and light. Each of these factors either impinges directly on organisms (wave-induced hydrodynamic forces, for example) or leads to significant secondary effects (for instance, temperature, solar radiation, and wind velocity may interact to promote desiccation). The physical environment also sets the scales for natural selection and dispersal, which then interact to produce levels of local adaptation.

This course offers lecture and laboratory analyses of several abiotic factors in the context of rocky shoreline marine communities. The basic objectives of the course lectures are three-fold: (i) to describe how different abiotic stresses influence (stress) marine animals and plants, (ii) to analyze adaptive responses to these stresses, and iii) to show how genetic neighborhood scales can be assayed. The role of this adaptive variation in establishing distribution patterns (for instance, vertical zonation from the subtidal to high intertidal zones) will be emphasized. The primary goal of the laboratory portion of the course is to provide the participants with new sets of tools for studying abiotic effects. Separate, yet complementary, laboratory exercises using oceanographic-biomechanical and physiological-biochemical-molecular techniques are intended to introduce participants to a wide spectrum of methods in genetics and physiology that may allow them to extend their ecological studies in productive new directions. Below, we describe in more detail the biomechanical, physiological-biochemical-molecular and molecular genetics components of the course.

Biomechanics: The lectures will introduce students to the fields of fluid dynamics, solid mechanics, thermal mechanics, and materials science as applied to wave-swept organisms, providing the basis for a mechanistic approach to life in the intertidal zone. Topics will include (i) an in-depth analysis of "wave exposure" and the many physical factors that are directly or indirectly tied to wave-induced water motion, (ii) the evolution of and physical limits to size and shape in intertidal organisms, (iii) heat-budget models and the prediction of thermal and desiccation stress, (iv) the theory of tides and how their long-term fluctuations might affect intertidal life, (v) and the statistics of environmental prediction.

The laboratories will provide students with hands-on experience in the techniques and equipment of the biomechanical approach to nearshore ecology. These include: (i) how to design and build force transducers, (ii) how to measure lifts and drag both in the field and in the laboratory: beam theory, strain gauges, and bridge amplifiers (iii) how to measure wave heights and water velocities both in the field and in the lab: drag-sphere transducers, acoustic Doppler techniques, electromagnetic flow meters, flow visualization, (iv) the do's and don'ts of flumes and wave tanks, (v) measuring temperature, irradiance, and wind in the field: thermocouple technology, computerized data recording, (vi) spectral analysis and its application to the study of scale, (vii) measuring material properties: static and dynamic testing, work of fracture.

Ecological Physiology: The lectures will focus on how a number of physical and chemical factors, including temperature, solar radiation, salinity and oxygen content affect the physiological processes of organisms and, thereby, influence their distribution patterns, rates of metabolic activity, and growth. The lectures will describe: (i) how each environmental factor perturbs critical physiological systems, and (ii) how organisms adapt to these perturbations over evolutionary time periods and during shorter-term acclimatizations, in concert with seasonal- and tidal cycle shifts in environmental factors. Particular emphasis will be placed on adaptations that affect a species' environmental tolerances and, thus, its biogeographic patterning.

The laboratory exercises are designed to acquaint ecologists with a variety of physiological, biochemical and molecular tools that may be of relevance for gauging the physiological status of natural populations and understanding the mechanisms that establish environmental optima and tolerance limits. Laboratory exercises include solid phase immunological detection of stress proteins (western analysis) and DNA microarray ("gene chip") methods for studying alterations in gene expression in response to changes in the environment.

Molecular Genetics: Lectures focus on state-of-the art tools for studying the population genetics and species phylogeny of marine taxa. We will discuss how dispersal is measured, how dispersal balances natural selection to produce adaptation, and how phylogenetic methods can help resolve questions of species adaptation.

Laboratories will let students move through every step of molecular data collection from DNA isolation to sequencing to analysis. In some cases, students may arrange to stay beyond the course period for further independent lab research. 

Prerequisites

There are no formal prerequisites for this course, other than an interest in studying marine ecosystems using a wide suite of approaches. The instruction will emphasize basic principles that are accessible to students with limited backgrounds in biomechanics and physiology.

Logistics and Financial Support

This course is supported by the David and Lucile Packard Foundation and the Gordon and Betty Moore Foundation. Participants will be provided with a block grant of up to $3,000 to be used in support of travel, lodging, and tuition. The course charges a non-credit fee of $2,760. Enrollment for credit is optional; if the student wishes to obtain Stanford University credit for the course (4 units), an additional fee of $112 is charged. Please go to the housing web page for information about available lodging.

Independent research

After the completion of the course, interested students may be able to remain at the marine station to conduct independent research under the auspices of one of the faculty. Space for this is limited and restricted to cases in which prior arrangements have been made with the appropriate instructor.

Application Procedure

To apply, send by April 1, 2009 (1) a curriculum vitae with statement of research interests, and (2) a short essay explaining your reason for wanting to participate in the course. Announcements of acceptance will be made before the middle of April.

Send to:

Dr. George Somero
Hopkins Marine Station
Oceanview Blvd
Pacific Grove, CA 93950

or Email to somero@stanford.edu.

RSS Facebook

Questions? Comments?
Please contact us!