SEMINAR: MBF602 STUDENT SEMINAR ***TOMORROW 10/5 @ 1PM---Erica Staaterman & Ross Cunning

[Pam Harris <pharris@rsmas.miami.edu>]

 

MBF Student Seminar Series

 

Erica Staaterman

AMP/MBF

Advisor: Dr. Claire Paris-Limouzy

“Modeling orientation behavior in fish larvae”

Larval reef fish possess considerable swimming and sensory abilities, which could enable navigation towards settlement habitat from the open ocean. Numerical modeling studies can be used to explore the outcome of such oriented swimming on larval trajectories and probabilities of recruitment close to the natal reef s. We combined the theoretical framework of the biased correlated random walk model with a high resolution three-dimensional coupled biophysical model to investigate the role of orientation behavior in fish larvae. Virtual larvae of the bicolor damselfish (Stegastes partitus) were released daily during their peak spawning period in the Florida Keys Reef Tract. Larvae began orientation behavior either a few days after hatching or during the flexion stage, increased their swimming speed during ontogeny, and settled on reefs within a flexible window around the mean pelagic larval duration. Only larvae that were within a maximum detection distance from the reefs were allowed to orient. Larvae that began to orient early were more likely to reach reef habitat than those that oriented late, and the most successful larvae possessed the largest maximum detection distance. Orientation behavior also increased the number of larvae that settled near their home reef, providing evidence that orientation is a mechanism driving self-recruitment in reef fish. This study demonstrates that despite their low swimming abilities of the early life history stages, orientation during this “critical period” would have remarkable demographic consequences.                                    

 

 

Ross Cunning

Advisor: Dr. Andrew Baker

“Dynamics of mixed Symbiodinium communities during

coral bleaching and recovery”

The recovery of Symbiodinium communities after bleaching may play an important role in corals’ resilience to climate change by providing an opportunity for symbiont community shifts. Symbiont recovery dynamics may be influenced by the external environment or the diversity and abundance of symbionts remaining in bleached tissues, which depends on how severely a coral has bleached. To investigate these effects on the recovery process, we monitored the structure and function of Symbiodinium communities in fragments of Montastraea faveolata (n=87) for 3 months as they recovered from low, medium, or high severity bleaching treatments (7, 10, and 14 days at 32°C) at either 24 or 29°C. The decline in photochemical efficiency (Fv/Fm) and symbiont density during bleaching depended on the relative amounts of heat-sensitive (clade B) and heat-tolerant (clade D) Symbiodinium within a coral. Corals subsequently recovered with ~80% clade D symbionts when they bleached severely and recovered at higher temperature, compared to ~20% when they bleached less severely and recovered at lower temperature. By elucidating the conditions under which shifts to more heat-tolerant symbiont communities occur following bleaching, these results have major implications for understanding the ability of corals to acclimatize to a changing environment and resist future stress events.

 

FRIDAY, OCTOBER 5, 2012

1:00pm

RSMAS campus, S/A 103

Pamela Harris

Marine Biology and Fisheries

Rosenstiel School of Marine & Atmospheric Science

University of Miami

4600 Rickenbacker Causeway/SLAB-118

Miami, FL 33149

(305) 421-4176

fax - (305) 421-4600

pharris@rsmas.miami.edu  

 

http://www.rsmas.miami.edu/academics/divisions/marine-biology-fisheries/