Preclassic environmental degradation of Lake Petén Itzá, Guatemala, by the early Maya of Nixtun-Ch’ich’

Abstract

Paleolimnological evidence indicates the ancient Maya transformed terrestrial ecosystems by felling forest vegetation to construct large civic-ceremonial centers and to expand agriculture. Human settlements influenced lacustrine environments but the effects of Maya activities on aquatic ecosystems remain poorly studied. Here we analyzed a sediment core from Lake Petén Itzá, Guatemala, to infer paleoenvironmental changes resulting from Maya occupation of the archaeological site of Nixtun-Ch’ich’. Increases in charcoal and fecal stanol concentrations indicate Maya occupation of the Candelaria Peninsula by the late Early Preclassic period. Geochemical proxies reveal a period of lake ecosystem alteration during construction and expansion of the city’s urban grid in the Middle and Late Preclassic periods. Depopulation of the city in the Terminal Preclassic resulted in a decline in lake trophic state. Whereas previous studies of Petén waterbodies have indicated depressed lacustrine primary production, the core collected near Nixtun-Ch’ich’ shows evidence of ancient Maya lake ecosystem deterioration.

The influence of tropical Atlantic sea-surface temperatures and the North Atlantic Subtropical High during the Maya Droughts

“…In the oldest section of the PI-NC-1 core, high δ 15 N values (Figure 3e) indicate that anthropogenic runoff from the Maya city of Nixtun-Ch'ich' likely influenced the sediment record at our site between 1 and 230 CE (Birkett et al, 2023). After 230 CE, however, δ 15 N declined to levels comparable to values recorded prior to the construction of the Nixtun-Ch'ich' urban grid (Birkett et al, 2023).…”

“…The largest peaks in detrital charcoal during the past 2000 years were between 120 and 140 particles/ cm 3 . This is much lower than during Preclassical settlement of Nixtun'Ch'ich', during which time charcoal concentrations averaged nearly 600 particles/cm 3 and reached a peak of 1480 particles/ cm 3 (Birkett et al, 2023). (d) Fecal stanol concentrations and (e) δ 15 N represent anthropogenic disturbance and runoff of human sewage waste into Petén Itzá.…”

“…δ 15 N and fecal stanols Analyses of bulk organic matter nitrogen stable isotope ratios (δ 15 N org ) and coprostanol and epicoprostanol (collectively referred to here as "fecal stanols") were performed by Birkett et al (2023), following the protocol of Keenan et al (2022), at an average resolution of 5 and 8 cm, respectively.…”

“…A ~3500-year record of detrital charcoal preserved in the PI-NC-1 core showed that charcoal concentrations ranged from approximately 300 to 1500 particles per cm 3 between 2000 and 700 BCE, and likely represented a combination of natural wildfire activity and anthropogenic burning through fire clearance and swidden (i.e. "slash and burn") agricultural practices (Birkett et al, 2023). However, after the establishment of the Nixtun-Ch'ich' urban grid ca.…”

“…The sediment core used for this study (core PI-NC-1; Birkett et al, 2023) was retrieved from the southern basin of the lake (at 16°56′36″N, 89°55′56″W), approximately 200 m south of the Nixtun-Ch’ich’ archeological site – a Maya city that formed and began to be extensively settled during the Maya Preclassic Period (Rice, 2019). The urban center of Nixtun-Ch’ich’ is characterized by a gridded system of six streets (oriented east to west) that intersect with seven avenues (north to south) (Pugh, 2019).…”