Faculty

• Karl Wirth, Macalester College
  
• Carol Mankiewicz, Beloit College
• Steve Ballou, Beloit College

Dates: 10 June to 9 July, 2003 (tentative)

Check out the project website!

Students and Sponsors

• Martin Bevis, Whitman College, Pat Spencer
• Peter Douglas, Pomona College, Linda Reinen
  
• John Patrick Diggins, IV, Beloit College, Carol Mankiewicz
  
• Drew Feucht, Wooster, Grig Wiles
  
• Chelsea Leven, Amherst College, Peter Crowley
  
• Genevive Mathers, Macalester College, Karl Wirth
• Veronica Poteat, Colorado College, Paul Myrow
  
• Alice Waldron, Pomona College, Eric Grosfils

Project Description

Some vertebrate organisms can have a significant impact on the sedimentary processes. One such organism is the tilefish that constructs one- to-two-meter-deep burrows. Some genera of tilefish inhabit shallow-water environments worldwide and build mounds of rubble over their burrows to protect against predators and erosion by high-energy waves. Relatively little is known about impacts of these tilefish on the sedimentary record.
Field area. The coral reefs on the leeward (western) side of Cozumel are part of the extensive barrier reef system that extends from Belize to the Yucatan Peninsula of Mexico. The corals occur primarily in fringing, patch, and shelf-edge reefs. Tilefish mounds are abundant on the sand flats between patch reefs and in sand channels that cut the shelf-edge reefs; most occur in water between 5 and 30 m depth. Mounds vary from 1 to 3 m in diameter; larger ones appear to be more common in shallower waters. Tilefish in Cozumel construct mounds from large numbers (>hundreds) of algal concretions (rhodoliths), or fragments of coral, or conch shells. We will concentrate on the tilefish mounds constructed of rhodoliths because they (1) they occur in shallower waters; (2) growth form of the rhodolith reflects the environment of growth; and (3) rhodoliths actively grow in shallow water and have been reported from Tertiary deposits (therefore, even early tilefish may have had rhodoliths available for armoring their burrows).

The goals of the project are (1) to document the importance of tilefish as geological agents in Cozumel, Mexico; (2) to identify criteria for recognition of tilefish activities potentially preserved in the rock record; and (3) to determine sedimentary features of tilefish mounds that might provide valuable paleoenvironmental (e.g., depth) information.

Potential Student Projects

Field data will be collected as a group. Pairs of students will use the group data and choose one or two research objectives to investigate in greater depth via laboratory work, data analysis, and literature review. Each student pair will write a paper and construct a poster prior to departing Beloit in July.

Specific research objectives addressed by this project include:

• The relationship between mound size (diameter and height) and ambient energy conditions (water depth and sediment size),
• The relationship between mound fragments (dimensions and density, and in the case of rhodoliths, growth form) and ambient energy conditions (water depth and sediment size),
• The distribution and orientation of mounds with respect to bathymetric features,
• A comparison of the types of fragments utilized by tilefish with those that are locally available (e.g., are tilefish selective about the types of materials that are utilized in mound-building, or are the fragments representative of the surrounding debris?),
• A comparison of the magnitude of sediment affected by the mound-building processes relative to other biological and non-biological rates of sediment transport, and
• A comparison of growth form of rhodoliths in mounds relative to rhodoliths surrounding the mounds,
• An evaluation of tilefish mounds as indicators of paleoenvironmental conditions

For more information contact:
Carol Mankiewicz (mankiewi@beloit.edu; 608-363-2371)
Dept. of Geology
Beloit College
700 College Street
Beloit, WI 53511