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Dr. Chris Finelli Faculty Page
of Biology and Marine Biology
University of North Carolina Wilmington
Funding and Projects |
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NSF Biological Oceanography Grant (OCE-0751753) Pumping rates of the giant barrel sponge, Xestospongia muta on Caribbean reefs: size scaling, environmental controls, and bleaching effects Sponges are among the dominant organisms on coral reefs in terms of diversity, numerical abundance, and biomass. Their ability to filter particles (e.g. viruses, bacteria, phytoplankton) from the water column contributes to both water clarity, which is necessary to support corals and other coral reef organisms, and for the transport of carbon from the water column to the benthos, also known as benthic-pelagic coupling. Despite their acknowledged importance, there are only a few mechanistic studies that have quantified sponge filtration rates. This proposal addresses part of that gap in our knowledge by measuring the pumping rates of the most conspicuous sponge on Caribbean reefs, the giant barrel sponge, Xestospongia muta. Specimens of X. muta can comprise up to 60% of sponge biomass on Caribbean reefs, and exhibit a size range (diameter) that spans three orders of magnitude. These sponges, like corals, can be affected by loss of photosynthetic symbionts (i.e. bleaching). Up to 25% of the X. muta population can be affected by cyclic bleaching with unknown consequences for both individual and population level filtration rates. Accurate measurements of pumping rate, and therefore water column filtration rates, are important to assess because sponges have such a profound influence on energy flow on coral reefs. The principal objectives of this proposal are to; (1) measure the excurrent velocities of water from sponges in order to calculate volumetric flow rates; (2) to quantify the scaling relationships between pumping and tissue volume to account for the changes in sponge pumping due to size differences within a population; (3) to describe the temporal patterns of pumping and its relationship to environmental variables; and (4) to determine the effects of sponge bleaching on pumping rates relative to healthy sponges.
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NSF Biological Oceanography Grant (OCE-0715271) The Effects of Water Movement and Zooplankton Escape Behavior on Planktivory by Coral Reef Fishes in Different Microhabitats This study will investigate the effects of water movement on the capture of zooplankton by small fish that live embedded in coral skeletons and are subject to boundary layer effects. The particular focus is on how water movement differs in the microhabitats occupied by two species of blenny (family Chaenopsidae) and the extent to which it affects microhabitat choice by those species. The problem will be approached from two perspectives: (1) the role of water movement in delivering prey to the fish and (2) the role of water movement in determining prey vulnerability to attacks by fish. Water movement will be measured at different scales on reefs where the fish live and, in the laboratory, prey capture will be studied under the patterns and rates of water movement observed in the field. The two fish species have already been shown to live in different microhabitats in the same reef zones, have different metabolic rates, attack prey at different speeds, and have different diets. Their prey capture success varies with degree of water movement and the influence of water movement is different in direction and magnitude for different prey types. Most strikingly, certain calanoid copepods that have exceptionally fast response times to predator signals become more vulnerable with increasing water turbulence. This is believed to be the key to feeding success in blennies and determines where they are located on the reef.
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NSF CAREER Award (OCE-0715272) CAREER: Career Development Plan: Interdisciplinary Research and Education in Marine Habitats Dr. Finelli was awarded a prestigious NSF CAREER award to integrate his interests in interdisciplinary research and student active education. The research funded by this grant examines nutrient dynamics in sedimentary environments impacted by burrowing infauna. Many animals burrow through the mud and sand that covers the sea floor, and this burrowing activity greatly impacts chemical processes deep within the sediment. Importantly, burrow water often contains elevated nutrient concentrations (nitrogen, phosphorous, silicate) that are released to the water column by ventilation of the burrow. The PI and graduate students are investigating the activity patterns and burrow structure of burrowing shrimp common to North Carolina and the Northern Gulf of Mexico, as well as the production and fate of nutrient plumes once released to the water column. Bayouside Classroom. The education component of the CAREER award supports a vibrant K12 education opportunity for students and teachers in South Louisiana, the Bayouside Classroom. Through field activities students montior water quality on various bayous that flow into the Northern Gulf of Mexico. These students have developed a database spanning 7 years for sites throughout Terrebonne parish, and several other parishes in Lousiana. Although all students from 4th grade to 12th grade can participate in the field sampling, there are specialized curricula to address grade-specific learning goals. The program provides field sampling gear and teacher training for participating schools. |
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NC SeaGrant MiniGrant Application of Chemical Cues to Artificial Reef Substrate: Enhanced oyster recruitment or increased predation Continued recruitment of larval oysters to shell plantings and restored reefs is critical to both commercial oyster production and reef restoration efforts. Successful recruitment is a function of two counteracting processes: larval settlement on the reef and predation on settling larvae or post-larval recruits. Chemical cues released by adult oysters have been shown in the lab to induce settlement behavior in competent oyster larvae and may prove efficacious in the field. However, both adult oysters and other benthic organisms consume larvae in the water column and once they are settled. Prelimary data suggested that application of known chemical cues attracted crabs and other predators that actually reduced recruitment on treated substrates. Research supported by this grant examines examines these competing processes through caging experiments in the field. This project is conducted primarily by MarBEL undergraduates.
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Response of the salt-marsh periwinkle, Littoraria irrorata (Say) to the blue crab, Callinectes sapidus: trait-mediated indirect effects on marsh production? The prevailing paradigm of marsh ecology for the past 50 years is that bottom-up forces, such as nutrient availability, solar radiation, and soil salinity, control marsh production. Recent work, however, has provided compelling evidence that the common marsh periwinkle, Littoraria irrorata, can exert strong top-down control on Spartina alterniflora production. Periwinkles ascend stems of S. alterniflora at the onset of high tide to avoid natant predators and for thermal regulation. We have preliminary evidence that periwinkles exposed to blue crabs climb higher on Spartina stems than those not exposed to predators. Moreover, snails that move to higher positions are more likely to occupy unfavorable (drier) microclimate and more apt to cease activity. Thus, by forcing snails to move higher on Spartina stems, crabs may limit the amount of plant stem available for grazing, as well as the amount of time available to graze. We are conducting a series of mesocosm and field experiments to test the hypothesis that salt marsh grass, Spartina alterniflora, is released from grazing pressure by periwinkle snails, Littoraria irrorata, due to the interaction of snail responses to predators (e.g. trait-mediated indirect effects) and microclimate.
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