ORCA General Poster Session

Academic Level at Time of Presentation

Senior

Major

Earth Science

List all Project Mentors & Advisor(s)

Dr. Michelle M. Casey

Presentation Format

Poster Presentation

Abstract/Description

Drill-holes found in the fossil record are an important tool to study ecological patterns of the past. It is therefore important to gain a better understanding of the role of extant drilling snails in modern ecosystems. Although traditionally considered a predator, trophic position of 3.0, specimens of the muricid Urosalpinx cinerea from Long Island Sound revealed trophic positions between 2.3 and 2.5, suggestive of an omnivorous diet. This study addresses the generality of this result by examining a U. cinerea population from Wilmington, North Carolina. Preliminary whole body, soft tissue stable isotope analysis of nitrogen and carbon was conducted on five U. cinerea specimens. Isotopic baseline for the study area was calculated using proxy taxa, including Geukensia demissa for the pelagic baseline and Littoraria irrorata for the littoral baseline. Trophic position for these U. cinerea specimens ranged from 2.4 to 2.9. Working hypotheses to explain a trophic position lower than 3.0 in U. cinerea include: trophic omnivory driven by plant consumption, or a lower-than-average nitrogen discrimination factor. Although no studies on the nitrogen fractionation factors of muricids currently exist, the naticid Neverita duplicata from Long Island Sound has recently been demonstrated to have a normal nitrogen fractionation factor and omnivorous isotopic signatures. The difference between the trophic ranges of the two locations may indicate that U. cinerea have a more predatory diet in North Carolina than in Long Island Sound. However, further work is needed to confirm that these values reflect dietary differences, not a below average nitrogen fractionation factor.

Spring Scholars Week 2018 Event

General Poster Session

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INVESTIGATION OF OMNIVOROUS TROPHIC POSITION IN THE DRILLING GASTROPOD, UROSALPINX CINEREA, USING STABLE ISOTOPE ANALYSIS

Drill-holes found in the fossil record are an important tool to study ecological patterns of the past. It is therefore important to gain a better understanding of the role of extant drilling snails in modern ecosystems. Although traditionally considered a predator, trophic position of 3.0, specimens of the muricid Urosalpinx cinerea from Long Island Sound revealed trophic positions between 2.3 and 2.5, suggestive of an omnivorous diet. This study addresses the generality of this result by examining a U. cinerea population from Wilmington, North Carolina. Preliminary whole body, soft tissue stable isotope analysis of nitrogen and carbon was conducted on five U. cinerea specimens. Isotopic baseline for the study area was calculated using proxy taxa, including Geukensia demissa for the pelagic baseline and Littoraria irrorata for the littoral baseline. Trophic position for these U. cinerea specimens ranged from 2.4 to 2.9. Working hypotheses to explain a trophic position lower than 3.0 in U. cinerea include: trophic omnivory driven by plant consumption, or a lower-than-average nitrogen discrimination factor. Although no studies on the nitrogen fractionation factors of muricids currently exist, the naticid Neverita duplicata from Long Island Sound has recently been demonstrated to have a normal nitrogen fractionation factor and omnivorous isotopic signatures. The difference between the trophic ranges of the two locations may indicate that U. cinerea have a more predatory diet in North Carolina than in Long Island Sound. However, further work is needed to confirm that these values reflect dietary differences, not a below average nitrogen fractionation factor.

 

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