Climate Change, Evolution and Extinction Events, Micropaleontology
Pleistocene to Modern Climate Reconstruction across East Africa
Studying past climates in East Africa is vital in order to provide context for archaeological and paleoanthropological sites that provide information on the evolution and prehistory of modern humans. Our lab studies East African climate along multiple timescales (millions to hundreds of years) at several different sites (Paleolake Suguta, Lake Tanganyika, Lake Nakuru, Lake Malawi) utilizing various methodologies and proxies (ostracodes, geochemical analyses, diatoms). In addition to studying climate, these projects also focus on our understanding of tropical climate systems, processes of biological diversification, and Earth surface (source-to-sink) processes in rift basins. Therefore, our lab’s research conducted in East Africa aim to answer many questions related to the timing of diversification and extinction events and how it relates to molecular phylogenetic reconstructions and paleolimnological events; the role that the history of a lake’s tectonic development and multiple sub-basins may play in the phylogeography of the major groups of endemic invertebrates, especially through multiple lake level cycles of isolation and reconnection; and how changes in climate systems can impact humans and the archaeological record (whether through behaviors, diets, or evolution). Such projects span multiple laboratories, universities, and organizations.
Multi-Proxy Lacustrine Studies on Climate Change and Hurricanes in the Bahamas
Many projects in our lab have focused on reconstructing high resolution records of climatological and anthropogenically-driven environmental change for the past 6,000 years. Using multi-proxy records from sediment cores, we aim to characterize the sedimentation and biotic response to perturbations from climate change, large storm events (i.e. hurricanes) and anthropogenic activities (i.e. deforestation and species introductions). Study questions related to pre-Columbian geomorphology and landscape development related to the settlement and land-use patterns of the Lucayan culture are answered using geochemistry, remote sensing, and ostracodes. Studies related to ostracodes document the species’ occurrences, taxonomy, and geochemical affinities of ostracode species and their lake environments across the Bahamian archipelago using molecular, morphological, and biogeographic variability of certain species to characterize and better understand how quickly natural populations respond to environmental change, how cosmopolitan species might differ from species with narrow niches, and how well ostracodes serve as proxy indicators.
Commensalism across Environmental Change and Extinction Events
The biosphere is a web of interconnected organisms each depending on a set of others for survival. An understanding of how interactions between organisms affects populations of organisms over geologic timescales is a necessary part of the ever-growing picture of the history of life being developed by paleobiologists. With close collaboration with Dr. Andy Bush’s laboratory, members of our lab use specimen-based techniques to study paleoecology and interspecific interactions as they affect evolutionary trends through geologic time as well as the influence of environmental change on ecological interactions. The organisms of interest include a suite of commensal organisms that encrusted and bored into the shells of brachiopods in the Appalachian Basin before and after a pulse of the Late Devonian mass extinction. The purpose of this project is to understand how these organisms responded to changing environmental conditions as well as extinction and turnover within the assemblages of their hosts.
Eocene/Oligocene Climate Responses
About 34 million years ago, Earth’s climate shifted from the warm conditions of the Eocene to the cooler conditions of the Oligocene. As the climate changed, organisms adapted in a myriad of ways: changes in different taxonomic groups; species diversification; changes in community organization; migratory changes; differences in relative abundances; and others appear to have changed very little to not at all. Our interest in this topic focuses on whether there is a broad disparity in when or how marine vs. terrestrial systems responded to changing conditions in the late Eocene and early Oligocene. Ostracodes, which are found both in marine and terrestrial (lacustrine) environments, are a superb organism to study as they provide a direct comparison for the responses of organisms between the two environments. Collaborators on this project include various museums that have provided access to collections across the Western Interior of the US and the International Ocean Discovery Program (IODP) where ostracodes were picked from core samples.
Lake Faunas through Time
In 2003, Dr. Park Boush initiated a database project to examine how clades of organisms invaded continental ecosystems via estuaries through geologic time. The examination of records of clade invasions through time suggests that an “estuary effect” created a gateway or filter through which faunas invaded the continental realm. Since discovering and documenting this phenomenon, Dr. Park Boush on the role of osmoregulation within specific clades such as mollusks, ostracodes, conchostracans and fish, in their adaptation from marine to freshwater conditions, which will allow her to better understand how and why clades radiated after invading the continental realm, and may provide clues about modern diversity patterns.
Modern Hydrochemistry and Seasonality in Southwestern Angola
Reconstructing past climate using lake sediments is benefitted from an understanding of the modern lake processes including where the water comes from (i.e. surface water, precipitation, ground water), the water’s chemical composition, and possible seasonal changes in water chemistry. This project attempts to understand seasonal changes in hydrochemistry in southwestern Angola in order to reconstruct historic changes in hydrochemistry. This project represents a collaboration between archaeologists, hydrochemists, micropaleontologists, and climatologists at the University of Connecticut, the University of Tübingen in Germany, and the Universidade Mandume Ya Ndemufayo in Angola to use geochemistry, hydrochemistry, meteorology, speleology, and micropaleontology to understand more about seasonality, hydrochemistry, and climate in southwestern Angola. This preliminary project represents the first steps for larger climate projects spanning deeper into the Holocene, but also provides extremely practical teaching opportunities for local, Angolan students to learn more about field techniques and water quality. This extremely collaborative project aims to decipher climate and hydrochemistry in southwestern Angola while focusing on increasing field skills for local geology undergraduates.
Mesozoic Moenave Formation
The Park Boush lab has been working with Dr. Celina Suarez at The University of Kansas and Dr. James Kirkland at the Utah Geological Survey to investigate an ostracod fauna from lacustrine sediments of the Lower Jurassic (Hettangian) Whitmore Point Member of the Moenave Formation, well known for its rich, Late Triassic?–Early Jurassic fossil record. Five ostracod species, all belonging to the Suborder Darwinulocopina, were identified from sediments of probable Early Jurassic (Hettangian) age: Suchonellina globosa, Suchonellina liassica, Prasuchonella? sp. 1, Whiplella sp. 1 and Whiplella? sp. 2. The diversity and composition of the Whitmore Point Member ostracod fauna is in sync with previous interpretations about the paleoenvironments of Lake Dixie and nearby paleoenvironments as shallow lakes, where darwinulid species survived probably by asexual reproduction by parthenogenesis. The Lake Dixie region, in its geographical and climatic isolation, may represent the last dawn of darwinulid dominance in freshwater environments before the Late Jurassic diversification of the cypridocopine/cytherocopine modern ostracods.