Citation:

Nestlerode, J., Jim Hagy, M. Murrell, B. Jarvis, AND J. Lisa. Using sediment profile imagery to quantify water quality and benthic condition relationships in Pensacola Bay. CERF 24th Biennial Conference, Providence, RI, November 05 - 09, 2017.

Impact/Purpose:

The work presented here is in support of development of alternative, cost effective indicators and endpoints will help improve quantitative relationships between nutrient pollution and support for human and aquatic life uses and, similarly, effects of nutrient pollution on ecosystem condition. The audience that would be interested in this presentation will include conference attendees (scientists and managers) from across the nation.

Description:

We present results from a monthly study in the Pensacola Bay estuary (FL) designed to evaluate the response and recovery in benthic habitats to intermittent, seasonal hypoxia (DO < 2 mg L-1). Samples were collected monthly from June 2015 through October 2017 at seven to nine sites along the estuarine salinity axis, ranging from the oligohaline region near the mouth of the Escambia River to marine waters near the Bay’s outlet into the Gulf of Mexico. Sites covered a range of sediment types (muds to sands) and dissolved oxygen status (high to low dissolved oxygen; intermittent to persistent hypoxia) within this single estuarine complex. SPI sampling took place in conjunction with sediment grab samples to ground-truth sediment type and species of macrobenthic invertebrates observed in the SPI images and CTD water quality profiles to characterize the overlying water column. We evaluated the Benthic Habitat Quality index (Nilsson and Rosenberg 1997), derived from sediment profile images, and the Benthic Index of Biological Integrity, derived from benthic macrofauna samples, across the estuarine transect. Analysis of water column profiles showed that hypoxia was commonly observed in the middle portion of the transect during summer. Sediment profile images provided visual evidence of the integrated effects of hypoxia on sediment physical, chemical, and biological composition. The results of this study are a step toward validating the use of SPI to quantify effect of water quality on benthos in a Gulf coast estuary. Whereas recent water quality management efforts in Florida (e.g., numeric nutrient criteria, marine dissolved oxygen standard) assumed linkages between dissolved oxygen and aquatic life use attainment based on laboratory tests, SPI methods can potentially provide an assessment of these relationships in realistic field settings.

Record Details: