Infauna abundance from seagrass bed core samples collected in Back Sound, North Carolina in June and July of 2013 (NCEI Accession 0291994)

Acquisition Description:
We sampled 86 sites within seagrass habitats throughout Back Sound, North Carolina, USA (3442’ N to 3439’ N, 7637’ W to 7631’ W during July 2013. Sampling sites were located across 21 seagrass landscapes which were defined by 200m x 80m rectangles (matching common isolated bed size and shape within our system). These landscapes were previously selected to represent independent gradients in both total seagrass cover (260-11,764 m2) and landscape patchiness (1-75 individual patches; Yeager et al. 2016). Sampling sites in the current study were haphazardly placed across all 21 landscapes, but always located within seagrass itself, and not the unvegetated matrix.

Seagrass core sampling and laboratory processing:
One core sample was taken from each sampling site. Each core measured 30 cm in diameter and captured the above ground seagrass habitat as well as the top 10 cm of the sediment surface. All cores were taken within 2 h of low tide and the GPS location of each core was marked with a Garmin 72H handheld unit (Garmin International, Olathe, Kansas, USA). Low-tide depth was measured in situ at each site at the time of sampling to the nearest 10 cm.

Core samples were taken back to the lab and screened using a 500-m sieve; benthic macrofauna were sorted from larger debris and seagrass tissue and transferred to a 70% ETOH solution for storage. These organisms were then identified to the lowest taxon possible. Only polychaetes with intact anterior appendages were identified and counted for density estimates to prevent overestimation and because these are requisite features for accurate identification.

The core (30-cm diameter, PVC) was gently placed by hand at each site and pushed down to a constant depth of 10 cm into the sediment. The core was gently rotated to break seagrass rhizomes, then dug out by hand, lifted, and placed into a resealable 1.5-gallon plastic bag. The sample was transported back to the laboratory on ice.