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Lipid Biomarkers Record Shifts in Prehistoric Sinkhole Communities
Get PDFLipids are utilized as biomarkers for ecosystem conditions because their variable structures reflect shifts in species abundance and diversity. This study examines lipid profiles from cores taken from Drinkwater Sinkhole in the Bahamas, which is affected by sea level variations. Sinkholes preserve allochthonous and autochthonous sediment deposition over time, making their stratigraphic accumulations useful as paleoenvironmental records. Transitions from lacustrine groundwater fed systems to marine flooded sinkhole systems are visible in the sedimentary record and forced by sea level fluctuations. The characteristic refractory organic molecules produced by different communities in these changing ecosystems were analyzed using gas chromatography (GC) and mass spectrometry (MS). Samples were taken from identifiable zones of stratigraphy corresponding with certain Greenland Stadials (GS) and Greenland Interstadials (GI) to contextualize them in a preexisting record of hydroclimate fluctuations. In our analysis we found fluctuations in the preserved polar lipid content. Of the fatty acid components tested, a continuous record of just palmitic, stearic, lauric, myristic, arachidic acid were present. The Drinkwater polar lipid record contains broad changes in total lipid concentration per organic weight percent and C/N ratio, which corresponds with GI and GS episodes. Our record also clearly documents MIS-3 terrestrial ecological changes during the shift from GI-8 to GS-8. In our principal component analysis, while there are clear variations in organic matter input which can be seen between stadials and interstadials, there is no definite characteristic lipid composition which separates them. Changes in environmental and hydroclimate conditions certainly altered the concentrations of lipids deposited, but more intensive sampling and analysis of the lipids in the stratigraphy may reveal a precise trend. Our results demonstrate that lipids can be useful for examining hydroclimate variability in the subtropical North Atlantic
RCFA on Non-Operated Vertical Pump Breakage (Coupling Torsional Failure by Sudden Shaft Seizure Following Pump Dry Spinning)
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By the Border
No full textArchitecture can be articulated in different ways such that a building serves to depict the intricate relationship between building and culture. A theme within the discipline of architecture that closely works with the concept of the building becoming a part of the art of living includes architectural conservation, heritage buildings, and adaptive reuse. As described by Danla Misirlisoy, heritage buildings serve as an important aspect of being able to transfer the cultural identity of a region (Misirlisoy & Gunc, 2016). This design project intends to establish a design paradigm for local public libraries beyond the traditional standards of library design by incorporating the cultural heritage derived from living on the border of Texas and Mexico. The adaptive reuse strategy of incorporating a historical building for a public library located in the city���s downtown district showcases the diverse spatial potential of an existing building and its relevance in the regeneration of an area
