Surface distributions are commonly collected to assist with overwash interpretation; however, many of these are first established immediately after a major overwash event as part of a post-event field survey. This study documents the impacts of Hurricane Irma, a Category 5 storm, on nearshore sediments off the coast of Anegada (British Virgin Islands) using distributions of Homotrema rubra, an encrusting foraminifer with a defined provenance in coral reef ecosystems. Over four sampling intervals spanning 2 years, from six months pre-Hurricane Irma to 18 months post-Hurricane Irma, surface sediment was collected from three shore-perpendicular transects on both the northern and southern shores of Anegada. Partitioning Around Medoids cluster analysis using the Homotrema data revealed that Hurricane Irma introduced an influx of well-preserved fragments into the reef flat (10% increase along the Windlass Bight transect and 13 % increase along the Soldier Point transect, the two northern transects) and homogenized the sediments, limiting the foraminifer’s utility as a known sediment transport indicator. The homogenization of sediments along the two northern transects (i.e., reef proximal) persisted for 7-18 months, at which point Homotrema distributions returned to near pre-Hurricane Irma conditions. However, the southern transect (i.e., absence of reef), where Homotrema concentrations are significantly less, failed to recalibrate within the time period assessed by this study. Post-event recalibration intervals will vary based on site and event, however, our results suggest that a waiting period of at least 18 months is recommended before collecting surface sediment samples from nearshore environments offshore Anegada.
","abstract_html":"<p>Surface distributions are commonly collected to assist with overwash interpretation; however, many of these are first established immediately after a major overwash event as part of a post-event field survey. This study documents the impacts of Hurricane Irma, a Category 5 storm, on nearshore sediments off the coast of Anegada (British Virgin Islands) using distributions of <em>Homotrema rubra</em>, an encrusting foraminifer with a defined provenance in coral reef ecosystems. Over four sampling intervals spanning 2 years, from six months pre-Hurricane Irma to 18 months post-Hurricane Irma, surface sediment was collected from three shore-perpendicular transects on both the northern and southern shores of Anegada. Partitioning Around Medoids cluster analysis using the <em>Homotrema</em> data revealed that Hurricane Irma introduced an influx of well-preserved <em>fragments</em> into the reef flat (10% increase along the Windlass Bight transect and 13 % increase along the Soldier Point transect, the two northern transects) and homogenized the sediments, limiting the foraminifer’s utility as a known sediment transport indicator. The homogenization of sediments along the two northern transects (i.e., reef proximal) persisted for 7-18 months, at which point <em>Homotrema</em> distributions returned to near pre-Hurricane Irma conditions. However, the southern transect (i.e., absence of reef), where <em>Homotrema</em> concentrations are significantly less, failed to recalibrate within the time period assessed by this study. Post-event recalibration intervals will vary based on site and event, however, our results suggest that a waiting period of at least 18 months is recommended before collecting surface sediment samples from nearshore environments offshore Anegada.</p>","abstract_has_math":false,"creators":["Mitchell, Stephen"],"institution":null,"degree_name":"Master of Science (MS)","degree_level":"Masters Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Dr. Davin Wallace","Dr. Jessica Pilarczyk","Dr. Jeremy Deans"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-12-01T08:00:00Z","date_published":"2020-12-01T08:00:00Z","updated_at":"2026-07-24T05:45:19Z","subjects":["surface distributions","Homotrema rubra","Anegada","taphonomy","Partitioning Around Medoids cluster analysis","recalibration interval","Geology","Oceanography","Paleontology"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://aquila.usm.edu/masters_theses/777","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Dr. Davin Wallace","Dr. Jessica Pilarczyk","Dr. Jeremy Deans"]},{"key":"dc:creator","label":"Author","values":["Mitchell, Stephen"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2022-10-08T07:00:00Z"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Masters Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (MS)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["surface distributions","Homotrema rubra","Anegada","taphonomy","Partitioning Around Medoids cluster analysis","recalibration interval","Geology","Oceanography","Paleontology"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://aquila.usm.edu/masters_theses/777"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Surface distributions are commonly collected to assist with overwash interpretation; however, many of these are first established immediately after a major overwash event as part of a post-event field survey. This study documents the impacts of Hurricane Irma, a Category 5 storm, on nearshore sediments off the coast of Anegada (British Virgin Islands) using distributions of Homotrema rubra, an encrusting foraminifer with a defined provenance in coral reef ecosystems. Over four sampling intervals spanning 2 years, from six months pre-Hurricane Irma to 18 months post-Hurricane Irma, surface sediment was collected from three shore-perpendicular transects on both the northern and southern shores of Anegada. Partitioning Around Medoids cluster analysis using the Homotrema data revealed that Hurricane Irma introduced an influx of well-preserved fragments into the reef flat (10% increase along the Windlass Bight transect and 13 % increase along the Soldier Point transect, the two northern transects) and homogenized the sediments, limiting the foraminifer’s utility as a known sediment transport indicator. The homogenization of sediments along the two northern transects (i.e., reef proximal) persisted for 7-18 months, at which point Homotrema distributions returned to near pre-Hurricane Irma conditions. However, the southern transect (i.e., absence of reef), where Homotrema concentrations are significantly less, failed to recalibrate within the time period assessed by this study. Post-event recalibration intervals will vary based on site and event, however, our results suggest that a waiting period of at least 18 months is recommended before collecting surface sediment samples from nearshore environments offshore Anegada.
"]},{"key":"dc:title","label":"Title","values":["Assessing the Recalibration Interval for Nearshore Sediment Assemblages after Hurricane Irma: implications for Developing Long-term Records of Overwash Deposits"]}]}],"canonical_facts":{"dc:contributor":["Dr. Davin Wallace","Dr. Jessica Pilarczyk","Dr. Jeremy Deans"],"dc:creator":["Mitchell, Stephen"],"dc:date.available":["2022-10-08T07:00:00Z"],"dc:description.abstract":["Surface distributions are commonly collected to assist with overwash interpretation; however, many of these are first established immediately after a major overwash event as part of a post-event field survey. This study documents the impacts of Hurricane Irma, a Category 5 storm, on nearshore sediments off the coast of Anegada (British Virgin Islands) using distributions of Homotrema rubra, an encrusting foraminifer with a defined provenance in coral reef ecosystems. Over four sampling intervals spanning 2 years, from six months pre-Hurricane Irma to 18 months post-Hurricane Irma, surface sediment was collected from three shore-perpendicular transects on both the northern and southern shores of Anegada. Partitioning Around Medoids cluster analysis using the Homotrema data revealed that Hurricane Irma introduced an influx of well-preserved fragments into the reef flat (10% increase along the Windlass Bight transect and 13 % increase along the Soldier Point transect, the two northern transects) and homogenized the sediments, limiting the foraminifer’s utility as a known sediment transport indicator. The homogenization of sediments along the two northern transects (i.e., reef proximal) persisted for 7-18 months, at which point Homotrema distributions returned to near pre-Hurricane Irma conditions. However, the southern transect (i.e., absence of reef), where Homotrema concentrations are significantly less, failed to recalibrate within the time period assessed by this study. Post-event recalibration intervals will vary based on site and event, however, our results suggest that a waiting period of at least 18 months is recommended before collecting surface sediment samples from nearshore environments offshore Anegada.
"],"dc:identifier":["https://aquila.usm.edu/masters_theses/777"],"dc:subject":["surface distributions","Homotrema rubra","Anegada","taphonomy","Partitioning Around Medoids cluster analysis","recalibration interval","Geology","Oceanography","Paleontology"],"dc:title":["Assessing the Recalibration Interval for Nearshore Sediment Assemblages after Hurricane Irma: implications for Developing Long-term Records of Overwash Deposits"],"thesis:degree_level":["Masters Thesis"],"thesis:degree_name":["Master of Science (MS)"]},"updated_at":"2026-07-24T05:45:19Z"}