TROPICAL FUNGAL PALYNOLOGY OF EARLY-MIDDLE MIOCENE SEDIMENTS FROM NORTHWESTERN PERU

Fungal communities provide vital terrestrial ecosystem functions. Understanding how they respond to climate change is necessary for predicting future assemblage dynamics. Sediments deposited during the Miocene Climate Optimum (MCO), 18-13 million years ago, provide an opportunity to examine fungal responses to a warming event with CO₂ values both similar to those today and in line with forecast climate change. Few fungal datasets exist for tropical regions during the MCO, and only one uses modern methods to identify fossil fungi and complete paleoecological inferences. To date, none have completed paleoclimatological reconstructions using the nearest living relative method. Two past studies examined fungal diversity in northwestern Peru. However, these did not utilize stratigraphically controlled samples, without which it is impossible to explain how fungal communities changed prior to, during, or following the MCO. For this study, new samples with stratigraphic control were collected in Summer 2022 and are being studied for fungal content. Here we present extended preliminary results of fungal diversity from the lowermost part of the section to the uppermost. Samples from the lower part of the section contain a sparse, low-diversity assemblage, while the uppermost part of the section contains an abundant, diverse assemblage, suggesting that fungal diversity increased during this period of climate change.