Project: RAPID: Effects of Hurricane Irma on shallow-water marine ecosystems: Assessing resiliency of sponge and macroinvertebrate communities in the Florida Keys

Hurricane Irma was a massively destructive storm that traveled directly over the lower Florida Keys. While the above water damage was obvious, effects from the hurricane on shallow benthic marine habitats in the Florida Keys is unknown. Shallow water habitats, which are important nurseries for economically important fisheries, likely experienced the strong effects from the storm. Sponge communities in these ecosystems perform vital ecological functions due to their feeding behavior, which involves pumping large quantities of water and filtering material from the water column. The project tests important hypotheses about sponge responses to ecological disruptions that are caused by hurricanes. Sponges are abundant in many reef ecosystems, and play essential ecological roles, so learning about system responses to sponge community disturbances is important. The work trains undergraduates in field research, data management and analysis, and science communication. Some of the activities developed as part of this project are incorporated in the University of Richmond Integrated Science Experience (URISE), and the first-year Science, Math and Research Training (SMART) course, both of which are designed to increase participation in STEM disciplines by individuals from underrepresented groups. Furthermore, the research is presented in a variety of public forums to disseminate as widely as possible.

Sponges represent a significant benthic-pelagic coupling point in tropical reef habitats. The recently proposed sponge loop hypothesis predicts that these animals release detritus as a function of their biofiltering capabilities, which is then consumed by organisms at the base of the food web. Hurricane Irma may have disrupted components of the sponge loop, and the investigators are exploring four hypotheses related to the storm's effects. First, the proposed work tests whether sponge damage from the storm was non-random, disproportionately affecting larger sponges. The second hypothesis examines the effects of the storm on macroinvertebrate communities in these habitats. This work builds on sponge and macroinvertebrate surveys conducted by the investigators in the years preceding the storm. Thirdly, the hypothesis that the hurricane influenced bacterioplankton populations through disruption of sponge feeding is tested. The PIs also compare pre- and post-hurricane plankton structure via flow cytometery using inhalant-exhalent water samples collected as part of an on-going study of sponge feeding behavior. Finally, inhalant-exhalent water samples are collected from shallow-water populations of several sponges from different size categories to determine if feeding behavior shows any demographic shifts based on the size of the sponge. Samples are processed to examine the retention efficiencies and prey selectivity of the host sponges using flow cytometry. Initial surveys are conducted of sponges (size, density, diversity) and macroinvertebrates in December, 2017. Preliminary sponge pumping activity occurs then too. Extensive surveys take place again in May-July, 2018 with further monitoring to occur in subsequent years.