Sediment accumulation rates and constituents in Culebra, Puerto Rico from sediment trap monitoring surveys conducted from 2022-08-30 to 2024-02-06

This record provides sediment trap monitoring data collected periodically between 30 August 2023 and 6 February 2024 at 13 nearshore monitoring stations on the island of Culebra, Puerto Rico, as part of Culebra's Ridge-to-Reef Monitoring and Evaluation Framework to assess the effectiveness of the NOAA strategies and actions in priority watersheds to reduce land-based sources of pollution (LBSP) impacts to the nearshore marine ecosystems of the island.

Monitoring stations were co-located with nearshore water quality monitoring sties and long-term seagrass monitoring transects. Monitoring stations were selected to identify watershed discharge points, coastal hydrodynamics, as well as the existing level of LBSP exposure and anticipated changes to LBSP exposure due to management actions. Nearshore monitoring stations were designated based on their land based sources of pollution management implementation status (LBSP Treatment Group), as follows: 1) LBSP Restoration stations: Located downstream where land-based pollutant management has or is being implemented. 2) LBSP Control stations: Represent a range of land-based pollutant impairments, including sites with no LBSP management, no known direct discharge of LBSP but are representative of the range of external factors that may be encountered at the LBSP Restoration stations. 3) Negative Reference stations of know significant -anecdotal and quantified- LBSP impairment. 4) Positive Reference stations of low LBSP impairment.

Two replicate sediment traps were deployed at each monitoring station. Traps were constructed and installed following Storlazzi et al. (2011) with an added honeycomb baffle at the top to reduce turbulence in the trap and prevent sample disturbance by aquatic organisms. Traps were retrieved and redeployed periodically (30-Aug-22 to 6-Feb-23; 6-Feb-23 to 1-May-23; 1-May-23 to 07-Aug-23; 07-Aug-23 to 6-Nov-23; 6-Nov-23 to 6-Feb-24). In the lab, the accumulated sediment from one trap was dried and weighed to estimate accumulation rates (mg/cm2/day). The contents of the second trap were separated into coarse (<2 mm-63 um) and fine (<63 um) fractions, dried and weighed to the estimate accumulation rate, followed by a sequential loss on ignition procedure (following Edmunds & Gray 2014, Heiri et al. 2001) to assess the terrigenous, carbonate, and organic composition. Laboratory analyses were conducted at University of Puerto Rico at Rio Piedras. Please review the Culebra Sediment Trap Monitoring Work Plan (Vargas-Angel 2024) for a complete methodological description.

The data presented herein was collected with financial support from NOAA Restoration Center and NOAA Coral Reef Conservation Program, and the National Fish and Wildlife Foundation (NFWF). The research questions, survey design and monitoring localities were specific to this study and the associated water quality data is unsuitable in a regulatory framework.

References:

Edmunds, Peter & Gray, Sarah. (2014). The effects of storms, heavy rain, and sedimentation on the shallow coral reefs of St. John, US Virgin Islands. Hydrobiologia. 734, 143-158. https://link.springer.com/article/10.1007/s10750-014-1876-7

Heiri, O., Lotter, A. F., & Lemcke, G. (2001) Loss on ignition as a method for estimating organic and carbonate content in sediments: Reproducibility and comparability of results Journal of Paleolimnology, 25, 101-110. https://doi.org/10.1023/A:1008119611481

Storlazzi, C. D., Field, M. E., & Bothner, M. H. (2011). The use (and misuse) of sediment traps in coral reef environments: Theory, observations, and suggested protocols. Coral Reefs, 30(1), 23-38. https://doi.org/10.1007/s00338-010-0705-3

Vargas-Angel B (2024D) Culebra Sediment Trap Monitoring Work Plan: Developing a nearshore sediment trap monitoring program to evaluate changes in LBSP exposure in Culebra, Puerto Rico. Available at: https://www.ncei.noaa.gov/data/oceans/coris/library/NOAA/CRCP/NMFS/OHC/Projects/30033/Culebra_LBSP_RidgeToReef_Monitoring_Program/Vargas-Angel2024d_Sediment_Trap_Monitoring_WorkPlan.pdf