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Field Testing US M-AMBI Against Regional Benthic Indices of Biotic Integrity in a Northern Gulf of Mexico Estuary: Pensacola Bay (Florida, USA)
Citation:
Paul, J., J. Nestlerode, AND B. Jarvis. Field Testing US M-AMBI Against Regional Benthic Indices of Biotic Integrity in a Northern Gulf of Mexico Estuary: Pensacola Bay (Florida, USA) . 13th National Monitoring Conference, Virginia Beach, VA, April 24 - 28, 2023.
Impact/Purpose:
This presentation is an invited contribution to the 13th National Monitoring Conference (April 24-28, 2023 in Virginia Beach, VA) for Session 25: Using monitoring data to address environmental issues in coastal waters. This session focuses on how monitoring data have addressed environmental issues in coastal regions (estuaries and nearshore waters). This may include new or improved methods, tools, case studies, and partnerships. This conference provides opportunities for water stakeholders – federal, state, tribal and local water professionals, non-profits, academia, industry and water consultants, and volunteer and community scientists – to network, develop new skills and partnerships, and exchange information. In this oral presentation, we present an evaluation of estuarine benthic ecological condition indicators along a transect of Pensacola Bay estuary spanning a salinity gradient and across sites known to experience density stratification and seasonal hypoxia in the bottom layer. This manuscript should be of interest to scientists and managers from across North America, particularly in the Gulf of Mexico region, concerned with monitoring and management of estuarine habitats. The results of this study inform the future use and application of various taxonomic-based benthic indicator tools for describing ecosystem condition.
Description:
Many benthic indices have been created in the last two decades for monitoring coastal ecosystems, however direct comparisons between indices are often difficult. To address this, M-AMBIUS has replaced regional indices used by the US Environmental Protection Agency. Objectives of this study were to evaluate if M-AMBIUS can meet the needs of smaller scale estuarine monitoring in the northern Gulf of Mexico while comparing against AMBIUS and regional indices NCCA2010 and GoMAIBI. Monthly water, sediment, and benthic invertebrates were collected between 2016 and 2017, and abundances used to calculate index score. Generally, indices supported our hypothesis that habitat scores follow a salinity gradient, but they disagreed on habitat condition grades. All indices responded significantly to changes in dissolved oxygen (DO), with M-AMBIU) the most sensitive. Our expectation that hypoxia drives low habitat scores was also supported, albeit with a weaker than expected relationship. The infrequency of discrete water quality measurements could account for mismatch between M-AMBIUS and DO, particularly given the dynamic nature of diel and episodic low oxygen that vary at hourly to daily timescales in Pensacola Bay. Subsequently, this study supports deploying continuous water sensors in areas where hypoxia is known to occur episodically as part of a strategic monitoring program.