Browsing by Subject "Paleobotany--Carboniferous"

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    Life in the Carboniferous Coal Swamp Forests: Reconstructing the Paleoecophysiology of the Extinct Horsetail Sphenophyllum
    (2024) Wagner, Sophia; Wilson, Jonathan
    During the Carboniferous Period, there was a radiation of diversity in early plants that were well preserved for study due to the conditions of the Carboniferous coal swamp forests. Studying the coal balls gives scientists insight into the ecosystems of the past. Collaborations with paleoclimate scientists have allowed paleobotanists to line up flora abundances with climatic trends. During the Middle and Late Pennsylvanian period, there were five major intervals of climatic shifts from wet to dry ecosystems and, by the second dry interval at the Late Westphalian D early Stephanian, major plant extinctions took place as the swamp biomes became drier. This paper aims to give context into the species that inhabited the coal swamps and how the ecosystem shifted throughout the period. On a plant scale level, this paper also aims to examine the morphological properties of these Carboniferous plants that particularly make them vulnerable or resistant to the reductions in water availability. This targeted morphological research focuses on a specific understory horsetail genus Sphenophyllum. Sphenophyllum is a particularly unique plant due to its large, wide tracheids and density of bordered pits throughout the xylem making the plant extremely hydraulically conductive while also prone to cavitation. In understanding these plants on a community scale and also an individual morphological scale, we can begin to better understand the past ecosystems and predict how certain plants will respond to climate change in the present and future.
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    Live Fast, Die Young: Examining Hydraulic Conductivity Of The Extinct Lepidophloios And Extant Wollemia Nobilis
    (2024) Korgen, Jessica; Wilson, Jonathan
    The climate is changing at a scale never before seen by humans, and it is impossible to anticipate with certainty how these changes will affect the planet. The best way to attempt to predict how species and ecosystems will respond to our ever-evolving climate is to look to the past. Paleobotany—the study of plant fossils—can inform us about the environment in deep time and how plants previously interacted with, responded to, and influenced a changing climate. The Carboniferous period is the most recent climate parallel we have to today. Although the world looked very different 300 million years ago, with the supercontinent Pangea and so-called “primitive” plants dominating the Earth, there were several similarities to the modern climate. Carboniferous CO 2 fluctuations were within the range anticipated for the twenty-first century and, like we are seeing today, these variations in atmospheric CO 2 were associated with large decreases in sea ice volume, rising sea levels, and the cyclical restructuring of the planet's most extensive tropical forests (Montañez et al., 2016). This was also the last time the planet had complete deglaciation, a phase that we are currently on the trajectory for, so Carboniferous floral transitions during its glacial-interglacial periods could provide insight for what is to come. Several Carboniferous plants are reviewed in relation to their hydraulic efficiency and safety, providing insight to their plant function and the environments they inhabited. An important factor in the hydraulic capacities of plant fossils is the size, shape, and porosity of their pit membranes: the permeable barrier separating xylem cells which water passes through. A larger, more porous pit membrane allows water to pass through the plant quickly while a smaller pit membrane better protects the plant from the entrance of gas and possible embolism. Arborescent lycophytes (lycopsids)—which dominated the first 20 million years of the Carboniferous—are analyzed in particular. Hydraulic elements from lycopsid fossils are measured and considered in the context of the biomes they occupied. The extant Wollemi pine is also measured to contrast with the extinct lycopsid. Consequences for plants with low hydraulic safety when the Carboniferous climate changed and implications for modern plants are discussed.