JU marine science faculty and students make strong showing at prestigious national Benthic Ecology Meeting

Their topics may have been about worms and other tiny invertebrates, but make no mistake, this was big stuff. 

A group of JU faculty and students recently presented at the Benthic Ecology Meeting March 20-23 in Savannah, Ga., one of the largest scientific gatherings of premier marine biologists in the world. 

The JU team made a strong showing with three oral presentations and two posters, said Dr. Dan McCarthy, director of the Marine Science Program at Jacksonville University. 

“This is a wonderful chance to see cutting-edge marine science that is not even published yet,” he said. “It’s excellent to help develop research ideas and network with outside researchers, and can help students network and possibly find places to go for work or graduate school.” 

The JU contingent consisted of five undergraduate students (Jodi Coia, Laura Wenke, Tayler Massey, Stephanie Shankle and Anna McClure), two graduate students (Justina Dacey and Kimbe

rly Mann) and three faculty (McCarthy, Lee Ann Clements, Jeremy Stalker). McCarthy also chaired the meeting’s Life Histories session. 

The 42nd BEM meeting was hosted by Georgia Southern University and brought more than 600 registrants, a mix of the nation’s top marine ecologists and up-and-coming graduate and undergraduate students. 

A summary of presentations and posters by JU’s faculty and students is below, with JU undergraduate students in bold: 

ORAL PRESENTATIONS 

Seasonal reef cycles and disturbance in a sabellariid reef in Stuart, Florida

Dan McCarthy, Jacksonville University

Along the Florida east coast, hard bottom habitats dominated by the sabellariid polychaete Phragmatopoma lapidosa provide enhanced shelter supporting diverse marine invertebrate and fish communities. One of the largest sabellariid reefs in the southeast United States is located in Stuart, Florida. Known as Bathtub Reef, it is a popular recreational location for fishing and snorkeling, yet relatively little is known about the seasonal ecology of the sessile species that make up the reef. In this study, we conducted comparisons of intertidal hard bottom communities from 2003 to 2008. Overall, the intertidal hard bottom community was fairly variable with time yet there were some distinct patterns. Phragmatopoma lapidosa was consistently the most common sessile invertebrate present on the reef going through annual cycles of recruitment, growth and decay. In 2004, two hurricanes came ashore in the area resulting in high sediment burial that shifted the dominant sessile organisms to algae and barnacles. However, within two years high P. lapidosa recruitment resulted in abundances of this species being restored to pre-hurricane levels. Thus, unlike conservation efforts that focus on factors that affect adults, efforts to ensure maintenance of healthy worm reefs, might best be directed towards factors that affect early life-history stages. 

Latitudinal variation among populations of Phragmatopoma lapidosa along the east coast of Florida

Tayler Massey; Dan McCarthy, Jacksonville University

The sabellariid Phragmatopoma lapidosa constructs sediment tubes forming sand mounds which enhance nearshore intertidal and subtidal hard bottom habitats along the east coast of Florida. The reefs created are believed to be important as nurseries, foraging grounds, and shelter for many invertebrate and vertebrate species. While the range that P. lapidosa occurs along the Florida coast is considerable (Melbourne to Miami), there has been no comparison of populations along this latitudinal gradient where environmental factors vary considerably. In this study, percent cover, fecundity, egg size, and density of P. lapidosa were collected for four populations along 140 miles of the east Florida coast. We found P. lapidosa percent cover decreased with latitude from north to south while worm lengths were similar among all locations. The density of individual worms was highest at the northernmost site while fecundity there was the lowest. It is likely that environmental conditions at the northern areas of the Florida coast studied are more favorable for survival and growth and thus explain the observed higher densities and coverage there. If the individuals sampled were similar in age, the observed fecundity trends may be a result of site-specific differences in cues to spawning or energy available for reproduction. 

A genetic comparison of populations of the sabellariid polychaete Phragmatopoma lapidosa in the western Atlantic

Joseph Staton (1); Tayler Massey (2); Jeanette Shira (1); Dan McCarthy (2)

University of South Carolina-Beaufort (1); Jacksonville University (2)

The sabellariid Phragmatopoma lapidosa is a reef-building polychaete known to enhance the community of both invertebrates and fish found on nearshore hard bottom habitats in the fairly wide geographic range they are known to occur. While similar in function to that provided by tropical coral reefs, their ecology and robustness is completely different from that of most reef building scleractinians. Past genetic research has focused on broad scale measurements to understand possible species-level diversity, but we recently focused on genetic variation within P. lapidosa to make an assessment of their variability across their range from Brazil to Eastern Florida. We amplified a 710-bp fragment of the mitochondrial cytochrome oxidase subunit I (CO1) and the 420-bp fragment of the cytochrome b apoenzyme (cytb). The CO1 is weakly variable and can be comparable to published sequence data within the species, and the cytb is more variable and is a traditional tool for analysis of population genetic variation. Preliminary analyses of Florida populations demonstrate structuring in cytb variation along the coast (φST = 0.082; α=0.05, AMOVA) with the sample from Bathtub Reef, FL, being a significant contributor. This result may be related to their cycles of decline and reestablishment of reef over time. 

POSTERS

Ophiuroid communities associated with sabellariid polychaete mounds in Palm beach County, Florida

Ashley Knight; Anthony Flock (former JU student ); Lee Ann Clements; Dan McCarthy, Jacksonville University

Sand mounds created by the polychaete Phragmatopoma lapidosa are known to enhance shelter on nearshore hard bottom habitats along the east Florida coast. To date, most research has focused on fish and crustacean species associated with these “worm” reefs. Little is known about the diversity and abundance of other invertebrates that are likely to occur in these habitats. As part of a state funded project investigating the ecological function of nearshore habitats in Florida, P. lapidosa mounds were collected from four depth zones (0-1, 1-2, 2-4, 4-6 m) and two reef types (natural, artificial) during summer 2009. Collected mounds were broken apart and invertebrates encountered were identified and enumerated. In this portion of the study, we focused on the surprising richness of ophiuroids that were collected within these worm mounds. The number of individuals varied considerably between 0 and 18. There was high variability among depth and reef type treatments sampled. Since most brittle stars were small with all arms, they mostly likely were produced via sexual reproduction. However, it is unclear whether most migrated into mounds or recruited there as larvae. Regardless, all are known crevice dwellers and worm mounds in these habitats likely provide important shelter from predation.

The Effects of Elevated CO2 on Arm Regeneration in the Burrowing Brittle Star Ophiophragmus filograneus

Jodi Coia; Anna McClure; Stephanie Shankle; Laura Wenk; Lee Ann Clements; Jeremy Stalker, Jacksonville University

Ocean acidification may impact the calcification and growth of benthic invertebrates. This experiment shows the effect of two levels of increased CO2 on the regeneration of brittle star limbs. We hypothesized that increased CO2 would result in increased skeletal and tissue growth during regeneration. Three CO2 levels (control, elevated and high) were used to alter pH in aquaria resulting in pH differences: control CO2 pH ~8, elevated CO2 pH ~7.5, and high CO2 pH ~7. These pH levels reflect those reported by IPCC estimates. Ten brittle stars, each with one arm surgically removed, were placed in each of nine aquaria in a Latin square design. Temperature, salinity, pH levels, dissolved oxygen, and CO2 pressure were monitored daily and animals were fed every third day. After one month, the dry weight and ash free dry weight of regenerated and non-regenerated portions of each individual were determined. Increased acidity and CO2 levels resulted in increased in arm regeneration and a decrease in overall body mass. Ophiophragmus filograneus are able to utilize the additional CO2 despite the decrease in pH, but there is a metabolic cost which decreases overall body mass.