Masters Theses

Keywords and Phrases

eutrophication; lake recovery; macrophytes; Maya; nutrients; trophic state

Abstract

"Paleolimnological evidence indicates the ancient Maya transformed lowland terrestrial ecosystems by felling forest vegetation to construct large civic-ceremonial centers and expand agriculture. The effects of prehistoric Maya land alterations on lake trophic status, however, remain poorly understood. We analyzed a 515-cm-long sediment core from Lake Petén Itzá, lowland Guatemala, to infer paleoenvironmental changes resulting from Maya occupation of the riparian archaeological site of Nixtun-Ch'ich'. Substantial increases in charcoal and fecal stanol concentrations indicate Maya occupation of the Candelaria Peninsula by the late Early Preclassic period beginning ca. 1400 cal yr Before the Common Era (hereafter BCE), despite scant archaeological evidence for settlement at that time. Variations in organic matter geochemical proxies reveal a period of cultural eutrophication in the western arm of the lake between ca. 760 and 20 BCE, during initial construction and later expansion of the city's unique urban grid. Deforestation, soil erosion, urbanization, and human waste efflux enhanced nutrient delivery to the lake, leading to greater primary productivity. During an ~80-year interval, from ca. 20 BCE to 60 CE, there was a decline in lake trophic state, possibly related to partial abandonment of the city in the Terminal Preclassic. Thereafter, shifts in fecal stanol concentrations throughout the Classic and Postclassic periods suggest relatively low, albeit fluctuating, human population densities. Whereas previous studies of long sediment cores from Petén waterbodies have indicated that ancient land clearance led to massive siltation, and perhaps depression of lacustrine primary production, the core collected near Nixtun-Ch'ich' shows evidence of ancient Maya cultural eutrophication"--Abstract, page iv.

Committee Member(s)

Borrok, David M.
Wronkiewicz, David J.

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

M.S. in Geology and Geophysics

Sponsor(s)

National Science Foundation (U.S.); SEPM (Society for Sedimentary Geology) Student Research Grants ; Missouri University of Science and Technology, Dr. Alfred Spreng Graduate Research Award

Comments

Financial support of National Science Foundation (U.S.)13171-21; Financial support of National Science Foundation (U.S.)1949901

Publisher

Missouri University of Science and Technology

Publication Date

Fall 2021

Pagination

ix, 79 pages

Note about bibliography

Includes bibliographic references.

Rights

© 2021 Brooke Amber Birkett, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Thesis Number

T 12215

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