Development of a benthic foraminifera based marine biotic index (Foram-AMBI) for the Gulf of Mexico: A decision support tool

The Gulf of Mexico (GoM) is an economically important region (e.g. oil and gas, fisheries) and with the expansion of oil drilling, harmful algal bloom events, oil blowouts, dead zones, anthropogenic eutrophication and contaminant loading, it is important that the ecological quality statuses (EcoQS) of different localities in the Gulf are closely monitored. The EcoQS, as implemented by the European Water Framework Directive, is an effective tool for monitoring ecological health and developing reference conditions. One such index used to define EcoQS is the AZTI Marine Biotic Index (AMBI), which pairs species abundance with environmental stressors. Benthic foraminifera are ideal specimens to populate the index due to their varying environmental sensitivities among species, preservation potential, and high diversity and abundance in nearly every marine environment. To calculate the benthic foraminiferal AMBI (Foram-AMBI), species are assigned to one of five groups ranging from sensitive (I) to first-order opportunists (V) based on their correlation to total organic matter and sediment grain size. This study constructs a Foram-AMBI from benthic foraminifera assemblages collected at 59 sites throughout the GoM. This approach provides reference EcoQS for the GoM and will satisfy the need for widespread geospatial coverage in the case of future natural or anthropogenic disturbances. This study provides a master assignment list of 155 species and identification plates of 44 of those species from a depth range of 42 m-2975 m. The development of a GoM Foram-AMBI encourages collaborative partnerships between academic scientists and living resource managers throughout the GoM to operationalize, refine and implement the Foram-AMBI as a decision support tool.