The effects of oiling on salt marsh and mangrove macrofauna communities at the Chandeleur Islands, LA (June and September 2015)

Abstract

To determine the relative abundances, species number, and composition of macrofauna, all plots were sampled at high tide during the growing season (June and October) in 2015 in the Chandeleur Islands, LA. At each sampling location, water depth was measured and density differences between marsh plants (Spartina shoots) and black mangrove pneumatophores were also quantified. Macrofauna were collected within 1 m of the plant/water interface, which is the area known to harbor high organism abundances in salt marsh systems. We haphazardly tossed three 0.17 m^2 plastic cylinders in each plot, whose lower edge was embedded in the sediment. The contents of the cylinders were collected using a gasoline-powered suction pump and all material was retained in a 0.5 mm mesh collection bag. Following collection, samples were removed from the bag and rinsed over a 0.5 mm sieve to remove any extraneous material, then were placed on ice and frozen. Animals were later identified to the lowest practical taxonomic level. Portunid crabs and penaeid shrimp were measured for total length. Biomass (DW = dry weight, ± 0.0001 g) was determined by drying organisms at 70°C to a constant weight. Samples were then muffled at 500°C to obtain ash weight (AW, ± 0.0001 g). Ash-free dry weight was calculated as DW-AW. Samples were placed in a desiccator to cool before any weights were recorded.

Purpose

The purpose of this field study was to evaluate any lasting impacts of the Deepwater Horizon oil spill on relative abundances and community composition of salt marsh and mangrove macrofaunal communities in the Chandeleur Islands, LA

DOI: doi:10.7266/N7B8565W

Suggested Citation

Heck, Kenneth. 2017. The effects of oiling on salt marsh and mangrove macrofauna communities at the Chandeleur Islands, LA (June and September 2015). Distributed by: Gulf of Mexico Research Initiative Information and Data Cooperative (GRIIDC), Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7B8565W

Funded by: Gulf of Mexico Research Initiative (GoMRI)

Funding cycle: RFP-IV

Research group: Alabama Center for Ecological Resilience (ACER)