Ecological turnover in neotropical freshwater and terrestrial communities during episodes of abrupt climate change

Abstract

The last 85,000 years were characterized by high climate and environmental variability on the Yucatán Peninsula. Heinrich stadials are examples of abrupt climate transitions that involved shifts in regional temperatures and moisture availability. Thus, they serve as natural experiments to evaluate the contrasting responses of aquatic and terrestrial ecosystems. We used ostracodes and pollen preserved in a 75.9-m-long sediment core (PI-6, ~85 ka) recovered from Lake Petén Itzá, Guatemala, to assess the magnitude and velocity of community responses. Ostracodes are sensitive to changes in water temperature and conductivity. Vegetation responds to shifts in temperature and the ratio of evaporation to precipitation. Ostracodes display larger and more rapid community changes than does vegetation. Heinrich Stadial 5-1 (HS5-1) was cold and dry and is associated with lower ostracode and vegetation species richness and diversity. In contrast, the slightly warmer and dry conditions during HS6 and HS5a are reflected in higher ostracode species richness and diversity. Our paleoecological study revealed the greatest ecological turnover for ostracodes occurred from 62.5 to 51.0 ka; for pollen, it was at the Pleistocene/Holocene transition. Future studies should use various climate and environmental indicators from lake and marine sediment records to further explore late glacial paleoclimate causes and effects in the northern neotropics.

Evidence of large water-level variations found in deltaic sediments of a tropical deep lake in the karst mountains of the Lacandon forest, Mexico

“…High abundance and similarity of ostracodes, cladocerans, diatoms, and testate amoebae species between fine sand and dark leaf litter layers support the inference of a low lake stage. Moreover, the co-existence of both ostracodes genera Cypridopsis and Cytheridella in dark leaf litter layers suggests warm waters with an electrical conductivity below 1000 µS/cm (Cohuo et al 2020;Pérez et al 2021). A similar situation was observed in February 2019 (Fig.…”

Holocene life and microbiome profiling in ancient tropical Lake Chalco, Mexico

“…Predicted coding genes from the assembly were annotated using the MG-RAST server 5 ⁠ and the SEED ontology 90 . Positive alignments were selected using BLASTp (cut-off values used were an e-value of 1e−10, a minimum identity of 90%, and a minimum alignment length of 15 amino acids, and the best hit was chosen).…”

“…The onset of the recent interglacial (11,700 cal years BP) was marked by substantial climate and environmental changes 1 . Temperature increases during the Early Holocene caused glaciers to retreat, modified landscapes, and reshaped plant and aquatic communities worldwide, even in the tropical latitudes of Mesoamerica 2 – 5 . Thermal regimes and hydrological budgets of lakes changed, and aquatic communities were impacted by these shifts 6 , 7 .…”

Late Quaternary Abrupt Climate Change in the Tropics and Sub‐Tropics: The Continental Signal of Tropical Hydroclimatic Events (THEs)

“…Although all THEs resulted in high species variability as the water level fell and habitats within the lake were drastically altered, THEs 1 and 5 appear to have been the most extreme (coldest and driest). In contrast, THEs 5a and 6 were relatively warm, though still quite dry (Perez et al., 2021).…”