SEMINAR: MBF STUDENT SEMINAR --TOMORROW @ 1PM-- XAYMARA SERRANO & PAUL JONES

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

 

MBF Student Seminar Series

 

Xaymara M. Serrano

Advisor: Dr. Andrew Baker

 

“Vertical genetic structure in a broadcast spawning Caribbean coral

despite high levels of horizontal connectivity”

The Deep Reef Refugia hypothesis (DRRH) suggests that deep reefs can act as local recruitment sources for shallow reefs following disturbance. To begin testing this hypothesis in the Atlantic region 9 new DNA microsatellite loci were developed for the broadcast spawning coral Montastraea cavernosa. These loci were used to assess vertical connectivity in >600 coral colonies collected from 3 depth zones (<10m, 15-20m and >25m) at sites in Florida (within the upper Keys, lower Keys and Dry Tortugas), Bermuda and U.S. Virgin Islands. Overall, cluster-based analyses revealed significant genetic differentiation by depth in Florida (but not in Bermuda or USVI), despite high levels of horizontal connectivity between different shallow sites separated by up to 1,700km. Principal component analyses further partitioned differentiation by depth within regions in Florida, with higher vertical connectivity in the Dry Tortugas compared to the lower or upper Keys. Finally, allelic richness measured at both deep and shallow sites revealed a similar level of genetic diversity at all geographic locations, suggesting that deep reefs are not genetically depauperate compared to their shallow water counterparts. Together, these findings suggest that significant potential exists for shallow reefs to recover from deep water refugia, but that this potential varies between sites as a consequence of local hydrology.

 

 

Paul R. Jones

Advisor: Dr. Andrew Baker

“Vectored inoculation of reef corals with different algal symbionts (Symbiodinium spp.) using tissue plugs”

Reef corals are mutualisms between invertebrate animals and diverse dinoflagellate algae (Symbiodinium spp.). Breakdown in coral-algal symbiosis (“bleaching”) can disrupt these communities and lead to shifts in favor of stress-tolerant symbionts. However, very few studies have investigated whether communities change in the absence of acute stress, and none have tested whether the exogenous introduction of different symbionts can influence community changes in response to the environment. We investigated this for the first time by conducting an experiment using replicate cores (N=70) of Montastraea cavernosa (N=5 colonies) that we had previously manipulated to be dominated (>99%) by either Symbiodinium C3 or D1a.  We conducted a reciprocal tissue swap between cores that contained the same and different Symbiodinium, and used highly sensitive quantitative PCR (qPCR) assays to study the symbiont community structure in both the core and its implant when maintained under different environmental conditions (22oC vs. 29oC) for 1, 2, 3 and 6 months. We found that, at 22oC, communities that were originally D1a became increasingly dominated by C3, and that this change was more pronounced at the boundary between the core and implant. Communities that were already C3-dominated remained unchanged. In contrast, at 29oC, communities exhibited a reduced dominance (~20%) of their original symbiont, suggesting that C3 is still competitive with D1a at higher temperatures.

 

FRIDAY, FEBRUARY 15, 2013

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/