Human activities and agricultural practices can significantly impact phosphorus (P) cycling by increasing P delivery and eutrophication. Sequential P extractions can resolve uncertainties surrounding P cycling processes by determining if P is mobile, increasing eutrophication, or immobile. This study assesses the nutrient history and current eutrophication status of Lough Carra, a marl lake in western Ireland. Sediment P fractions include Labile-P, iron-bound (Fe-P), aluminum-bound (Al-P), organic (Org-P), calcium-bound (Ca-P), and total phosphorus (TP). Concentrations of P fractions, organic carbon, calcium carbonate, C/N ratios, d13C-Organic C and d13C-CaCO3, were collected from an eight-meter long sediment core representing the past ~600 years of nutrient cycling. The history of Lough Carra is divided into four zones: Zone 1 (1400-1709 A.D.), Zone 2 (1709-1859 A.D.), Zone 3 (1859-1960 A.D.), Zone 4a (1960-2002 A.D.), and Zone 4b (2002-2012 A.D.). Fe-P dominated the majority of LC20 sediment intervals, comprising an average of 68% of TP. Decreases in Labile-P and Fe-P occur in Zone 3, following depopulation from the Great Irish Famine (GIF). Ca-P increases from an average of 6.1 ppm to 81.4 ppm after a massive flood event ~1852. Upcore increases in Fe-P, Labile-P, and Org C and decreases in CaCO3 values from 1960-2002 A.D. demonstrate eutrophication from increased agricultural runoff and fertilizer use in recent years. These findings can inform subsequent lake management strategies. Future work should further investigate Fe sources to Lough Carra.
"},{"label":"Degree","value":["Bachelor of Arts with Departmental Honors"]},{"label":"Administrative Note","value":"Drupal Node ID: 23958