Quantification of epiphyte biomass accumulation on artificial seagrass leaves in Culebra, Puerto Rico

This record provides estimates of epiphyte biomass accumulation on artificial seagrass leaves at 13 monitoring stations in Ensenada Honda and Puerto Manglar in the island of Culebra, Puerto Rico.

Currently the island of Culebra is implementing a ridge-to reef-monitoring to assess Land-based sources of pollution (LBSP) mitigation success and identifying adaptive management needs. The goal of this study was to test whether metrics of epiphyte load accumulation on seagrass leaves can be used as a biological response indicator for nutrient impacts on Culebra's nearshore habitats. More specifically identify the presence of spatial patterns and examine potential linkages with nearshore water quality conditions in locations where upland watershed restoration interventions have been implemented vs. locations where no interventions have been conducted.

Artificial seagrass installations were deployed at 13 nearshore fixed monitoring stations downstream from select coastal watershed drainage delivery points, and co-located with water quality, sediment trap, and seagrass monitoring stations. These sites were selected to represent: 1) Repeat locations where nearshore water quality and sedimentation are being monitored. 2) Repeat locations previously sampled in 2014 for water quality and seagrass community status assessment. Epiphyte accumulation was quantified on artificial seagrass following the methods outlined in Virnstein & Curran (1986) with slight modifications At each monitoring station three replicate shoots containing 6 blades each (2 each, approx. length: ~23cm, ~13cm, and ~8cm; approx. width: ~1cm) attached to plastic augers were deployed. Augers were inserted into the substrate and anchored to existing (previously installed) rebar markers. The experiment was run twice and installations remained underwater for 60–90 days: 1) 7 Aug, 2023–7 Nov, 2023; and 2) 11 Dec, 2023–5 Feb, 2024. Recovered artificial leaves were carefully rinsed in fresh water to remove salt, gently scraped with a blade, and scraped material dried at 60 degrees celcius to constant weight. Artificial leaf dimensions were measured to the nearest 0.5 mm and the quadrangular (rectangle / trapezoid) leaf surface area was estimated accordingly. Recovered shoots that were frayed or tattered were discarded and excluded from analyses. Mean epiphyte biomass accumulation was computed in mg/cm2/day

The goal of this study was to test whether metrics of epiphyte load accumulation on seagrass leaves can be used as a biological response indicator for nutrient impacts on Culebra's nearshore habitats. More specifically identify the presence of spatial patterns and examine potential linkages with nearshore water quality conditions in locations where upland watershed restoration interventions have been implemented vs. locations where no interventions have been conducted.

-Virnstein RW, Curran MC (1986) Colonization of artificial seagrass versus time and distance from source> Mar. Ecol. Prog. Ser. 29:297-288

-Stoner A (1980) The role of seagrass biomass in the organization of benthic macrofaunal assemblages. Bull. Mar. Sci. 30: 537-551

-Frankovich T, Fourqurean J (1997) Seagrass epiphyte loads along a nutrient availability gradient, Florida Bay, USA. Mar. Ecol. Prog. Ser. 150: 37-50

-Nelson W (2017) Development of an epiphyte indicator of nutrient enrichment: a critical evaluation of observational and experimental studies. Ecol. Indic. 79: 207-227. doi:10.1016/j.ecolind.2017.04.034

Data include individual estimates of epiphyte biomass accumulation in milligrams per centimeter square per day.

While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.

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Data can be accessed online via the NOAA National Centers for Environmental Information (NCEI) Ocean Archive.

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Artificial seagrass installations deployment, retrieval, laboratory analyses, and accumulation rate computations were conducted by experienced scientific personnel who met a set of minimum standards for field and laboratory work.

Handheld GPS units were used to locate sites and mark site locations.

Handheld GPS units were used to locate sites and mark site locations.

Data gaps originate from: 1) Lost experimental units; installations that were not found at time of recovery. 2) Experimental units that were shredded or tattered probably due to fish predation

-Artificial seagrass leaf length and width were measured to the nearest 0.5 mm and the quadrangular (rectangle / trapezoid) leaf area was estimated accordingly.

Handheld GPS units were used to locate sites.

Survey methods were consistent across all sites.

Quality control occurred at several major stages: 1) Experimental unit construction, deployment, recovery, and post-recovery handling. 2) Mathematical computation error checking. 3) Data entry, and 4) Data management.

--Artificial seagrass installations construction, deployment, retrieval, laboratory analyses, and accumulation rate computations were conducted by experienced scientific personnel who met a set of minimum standards for field and laboratory work.

--The same laboratory instrumentation (i.e., analytical balance and drying oven) was employed to process and analyze all samples.

--Data gaps originate from experimental units that were not found at time of recovery, and experimental units that were frayed or tattered at time of recovery, probably due to predation.

--Survey and analytical methods were consistent across all samples.

Epiphyte biomass accumulation on artificial seagrass