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The application of fossil diatom assemblages in reconstructing mid to late Holocene climate in the neotropics: The paleolimnology of Huarmicocha and Lake Ayauch1, Ecuador

Riedinger, Melanie Ann, Ph.D.

The Ohio State University, 1993

UMI 300 N. Zeeb Rd. Ann Arbor, MI 48106 THE APPLICATION OF FOSSIL DIATOM ASSEMBLAGES

IN RECONSTRUCTING MID TO LATE HOLOCENE CLIMATE

IN THE NEOTROPICS : THE PALEOLIMNOLOGY OF

HUARMICOCHA AND LAKE AYAUCHI, ECUADOR

DISSERTATION

Presented in Partial Fulfillment of the Requirements for

the Degree Doctor of Philosophy in the Graduate

School of The Ohio State University

Melanie A. Riedinger, B.S., M.S.

*****

The Ohio State University

1993

Dissertation Committee: Approved by

D.A. Culver

R.A. Stein

R.E.J Boemer Adviser M. Steinitz-Kannan Department of Zoology Copyright by Melanie Ann Riedinger 1993 Dedicated to

Virginia Mary Zeis Riedinger ACKNOWLEDG EMENTS

There are many people who have contributed their time and encouragement to this work, and for their support and efforts I am very grateful. I am indebted to Dave Culver, Roy Stein, Miriam Steinitz-Kannan,

Ralph Boerner and Tom Hetherington for their assistance in the last phases of this process, for without their help I would not have completed. I would like to thank Miriam Steinitz-Kannan for stimulating my interest in diatom ecology, for her advice, enthusiasm and encouragement throughout all phases of this research, and for graciously welcoming me into her lab. I also would like to thank Paul Colinvaux, my major professor throughout most of this project, for his support, patience and advice. This work has benefited from many stimulating discussions with Paulo de Oliveira on diatom ecology and paleoecology and I am grateful for both his friendship and his interest in this research. I look forward to many years of collaboration with him in the future. , Mike Miller, Mark Bush and Mark Brenner provided many important insights into my data, and I thank them for their time. Ramahurthi Kannan read and re-read many versions of this draft, and I thank him for his

iii comments and observations. Throughout this project I have been fortunate to have had the opportunity to work with many bright and promising scientists, who kindly sh