Abstract

Theories regarding the taphonomy of fishes in lacustrine environments have traditionally relied on an anoxic water column to explain the excellent preservation. This concept has never been directly tested in modern lacustrine environments that are thought to be analogous to the lacustrine environments predicted by the Stratified-lake Model. This research tested that model by searching for fish remains in 38 collected bottom samples of six modern lacustrine analogues, including Fayetteville Green Lake, New York. The bottom sediments of a warm, holomictic, shallow, and saline lake (Salton Sea, California) were also examined. Although laminated sediments were found in all of the lakes studied, only the Salton Sea sediments contained fish remains. This was surprising in that one would have expected the opposite: abundant fish remains in the stratified lakes and few, if any in the non-stratified, saline lake.

In addition to the above described study, a preliminary study of the taphonomic processes effecting fish carcasses was carried out at Lake Perris, CA. Fresh fish carcasses were lowered in buckets to the bottom of the lake in both the epilimnion (water temperature >15 deg. c. and oxygenated) as well as the hypolimnion (water temperatureanoxic), directly testing the effects of oxygen content, temperature, and pressure on the preservation of fishes. In the warm, oxygenated water decomposition took place, producing enough gasses in the fish bodies to cause them to float to the surface. In the cool, anoxic environment, decomposition of the fleshy parts was initiated, but not enough gasses were produced to cause the fish to float to the surface. Further study is needed to better understand the separate effects of oxygen content, temperature, and pressure on the taphonomy of fishes.

The results of this research strongly suggest that anoxia alone is not adequate to preserve fish remains and that some other physical, chemical, and/or biological condition may be necessary for the preservation of fishes. The results obtained at Salton Sea suggests that saline, alkaline lake waters may be important in the taphonomic process. Further studies in these environments should be productive.

LLU Discipline

Geology

Department

Geology

School

Graduate School

First Advisor

H. Paul Buchheim

Second Advisor

Leonard Brand

Third Advisor

Lanny H. Fisk

Fourth Advisor

Earl Lathrop

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1988

Date (Title Page)

6-1988

Language

English

Library of Congress/MESH Subject Headings

Paleoecology; Lake Ecology

Subject - Local

Loma Linda University. Geological Sciences program -- Dissertations

Type

Dissertation

Page Count

vi; 39

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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