Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
  • BCO-DMO Curation Notes
• Data Files
• Related Datasets
• Parameters
• Instruments
• Project Information
• Funding

Survey sites were randomly selected from points generated in ArcGIS by overlaying a 300 x 300 m grid on the continuous seagrass shapefile obtained from the Florida Department of Environmental Protection. Initially 30 sites per bay segment were randomly selected from the intersection of the grid. Due to safety concerns and logistical constraints some sites were not surveyed. At each site propellor scars were quantified along a 50m transect run perpendicular to shore.

All propellor scars that intersected the transect were enumerated, measured (total scar length, as well as the scar width and depth at the point it intersected the transect), and visually assessed for the presence of cut seagrass rhizomes and if seagrass had begun to regrow within the scar. All measurements were taken with either a measuring tape (length and width) or ruler (depth). Scar lengths were measured up to 20m, if the scar extended beyond this or the scar curved a note was made to indicate that the recorded length is an underestimate.

Data was recorded on paper datasheets in the field and manually entered. A different person reviewed the data entry. No other data processing was completed. 

This section documents curation actions performed prior to publication review with the submitter, and additional information relevant to understanding and reusing this dataset. It distinguishes changes made to the submitted (meta)data from unresolved issues and/or enhancements that improve future reuse and interoperability.

CURATION ACTIONS PERFORMED ON DATA

- Loaded survey_propellorscars.csv, treating empty strings, "nd", and "NA" as missing values
- Renamed columns to remove dots for BCO-DMO naming convention: scar.width to scar_width, scar.depth to scar_depth, scar.length to scar_length, cut.rhizomes to cut_rhizomes, seagrass.regrowth to seagrass_regrowth
- Parsed date_time_UTC (format %m/%d/%Y %H:%M) and reformatted as ISO 8601 UTC datetime string (%Y-%m-%dT%H:%M), a pure reformat with no timezone shift since values were already UTC
- Parsed date_time_local (format %m/%d/%Y %H:%M) and set as ISO 8601 UTC datetime string (%Y-%m-%dT%H:%M)
- Created date_time_local_EDT column by copying date_time_local values only where local_timezone equals America/New_York, other rows left missing
- Created date_time_local_CDT column by copying date_time_local values only where local_timezone equals America/Chicago, other rows left missing
- Reordered columns to: uID, date_time_UTC, date_time_local_EDT, date_time_local_CDT, date_time_local, local_timezone, siteID, general_location, latitude, longitude, scar_width, scar_depth, scar_length, cut_rhizomes, seagrass_regrowth, note
- Deleted columns date_time_local and local_timezone
- Replaced blank/missing scar_length values with the value 20, upon submitter request
- Replaced siteID value "271" with "271.0" to match formatting used in uID, upon submitter request
- Output as 1006664_v1_propellor_scars.csv

CURATION ACTIONS PERFORMED ON METADATA

- BCO-DMO's standard metadata entry and text formatting steps were performed.

ISSUES POTENTIALLY IMPACTING REUSE

- N/A

NSF Award Abstract:
This project seeks to determine how ecological memory, shaped by an extreme disturbance, informs the response of coastal ecosystems to multiple stressors at population, community, and ecosystem levels. Seagrass ecosystems are among the most highly productive ecosystems on earth, yet are vulnerable to disturbance by both human activity and natural processes. Hurricane Dorian was a Category 5 hurricane that hit the Bahamas in 2019. By comparing seagrass communities in the direct path of the storm with neighboring areas that were less impacted, this project is evaluating how ecological memory might affect responses of seagrass ecosystems to common human-caused and natural stressors. The investigators are early-career scientists, and results from this study are likely to inform conservation, management, and restoration of seagrass ecosystems. They are providing substantial educational opportunities for students in the United States and in the Bahamas, including virtual and hands-on field research experiences for undergraduate students, some from groups traditionally underrepresented in science. Facilitated by Friends of the Environment, a local NGO on Abaco Island, virtual reality videos and curricula will also enhance STEM educational opportunities for Bahamian high school students

Seagrass ecosystems, a widespread and ecologically important nearshore system, may be shaped by the ecological memory of past disturbances. These legacies may influence how seagrass ecosystems respond to environmental change. The investigators will conduct new research that complements seven years of existing data in a study system in the path of Hurricane Dorian in the Bahamas to assess how ecological memory shapes the response of coastal seagrass beds at multiple levels of biological organization. They are using a combination of modeling, field observations, field experiments, and laboratory analyses to compare highly and minimally hurricane-impacted sites to determine: the distribution and relative abundance of three seagrass species; the relative abundance and species diversity of naturally occurring invertebrate and vertebrate grazers; overall species richness, functional diversity, and habitat complexity of each field site; seagrass growth rates and primary productivity; and abiotic environmental characteristics — irradiance, temperature, and nutrient content— of ambient seawater. They will sample twenty plots per site each quarter—including unaltered controls and experimental plots simulating mechanical damage, increased grazing pressure, and both mechanical damage and grazing. The goal is to provide a better understanding of how ecological memory drives the outcome of current ecological processes, which in turn will inform conservation and restoration efforts as seagrasses continue to decline globally.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

​This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).