Morehead State University
Examining Mcrobial Diversity in a Paleocene Wilcox Group Coal from Texas
Institution
Morehead State University
Faculty Advisor/ Mentor
Jen O'Keefe; Michelle Johnston
Abstract
The distribution and ecological niches of fungi found in coals are poorly understood. Organic petrography and palynology are used in tandem to study fungi preserved in a Wilcox Group Coal and associated sediments from Texas. Fungal remains are a common petrographic component of the coals (up to 8.5%), and fungal palynomorphs are very common and diverse components of the palynological spectrum, ranging from 6–71% of the total. Saprophytic, parasitic, and mutualistic forms are all present, as are abundant hyphae. Samples are dominated by hyphae, Monoporisporites, Diporisporites, with some containing abundant Nigraspora. When the dominant taxa are excluded from statistical analyses, four groupings can be made: 1) samples containing high-diversity, low-abundance assemblages, including Fusiformisporites; 2) very low diversity, low-abundance assemblages; 3) assemblages that are enriched in Dicellaesporites; and 4) assemblages that contain Fusiformisporites and Lacrimasporites. The Fusiformisporites contained in this coal are morphologically identical to Atrotorquata lineata, known to occur only as a saprophyte on Juncus stands, and Lacrimasporites forms are indistinguishable from an unnamed associate of A. lineata. Groups 1 and 4, which occur at the top of each seam indicate deposition in a salt-marsh environment. Petrographically, groups 1 and 4 are also the most densinite enriched, pointing toward significant aerial exposure of the peat prior to incorporation in the mire. Thus, there is strong evidence for increased peat decomposition up-section within the coals coupled with a transition from peats formed in freshwater swamp environments to those formed in marshes that may have been impacted by brackish waters.
Examining Mcrobial Diversity in a Paleocene Wilcox Group Coal from Texas
The distribution and ecological niches of fungi found in coals are poorly understood. Organic petrography and palynology are used in tandem to study fungi preserved in a Wilcox Group Coal and associated sediments from Texas. Fungal remains are a common petrographic component of the coals (up to 8.5%), and fungal palynomorphs are very common and diverse components of the palynological spectrum, ranging from 6–71% of the total. Saprophytic, parasitic, and mutualistic forms are all present, as are abundant hyphae. Samples are dominated by hyphae, Monoporisporites, Diporisporites, with some containing abundant Nigraspora. When the dominant taxa are excluded from statistical analyses, four groupings can be made: 1) samples containing high-diversity, low-abundance assemblages, including Fusiformisporites; 2) very low diversity, low-abundance assemblages; 3) assemblages that are enriched in Dicellaesporites; and 4) assemblages that contain Fusiformisporites and Lacrimasporites. The Fusiformisporites contained in this coal are morphologically identical to Atrotorquata lineata, known to occur only as a saprophyte on Juncus stands, and Lacrimasporites forms are indistinguishable from an unnamed associate of A. lineata. Groups 1 and 4, which occur at the top of each seam indicate deposition in a salt-marsh environment. Petrographically, groups 1 and 4 are also the most densinite enriched, pointing toward significant aerial exposure of the peat prior to incorporation in the mire. Thus, there is strong evidence for increased peat decomposition up-section within the coals coupled with a transition from peats formed in freshwater swamp environments to those formed in marshes that may have been impacted by brackish waters.