SEMINAR: MBF STUDENT SEMINAR **TOMORROW -FRI, 11/2 @ 1PM** ADAM GREER & JOHN STIEGLITZ

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

 

PLEASE NOTE THE CHANGE IN ROOM #

MBF Student Seminar Series

 

John Stieglitz

Advisor: Dr. Daniel Benetti & Dr. Martin Grosell

“Impacts of Deepwater Horizon crude oil exposure on pelagic fish: Utilization of marine finfish hatchery technology in toxicology research.”

The Deepwater Horizon (DWH) oil spill in 2010 resulted in the release of approximately 200 million gallons of crude oil into the Gulf of Mexico (GOM), along with significant amounts of chemical dispersants. The aim of the described research is to determine physiological impacts of polycyclic aromatic hydrocarbon (PAH) exposure on various life stages of species representative of GOM pelagic finfish.  Incorporation of advanced marine aquaculture technologies to develop and maintain captive spawning broodstock populations of mahi-mahi (Coryphaena hippurus) will be presented and discussed, as well as techniques used to obtain sub-adult blackfin tuna (Thunnus atlanticus) specimens for use in the toxicological studies. Sub-lethal acute PAH exposure tests are being conducted to assess the aerobic scope and swim performance (U_crit) of some of these pelagic fish utilizing swim chamber respirometry. Results of baseline physiological studies indicate that sub-adult mahi-mahi (105 dph ± 3.5 dph; 208 g ± 8.3g; 26.8 cm FL ± 0.4) have a mean upper critical swim speed (U_crit) of  8.57 ± 0.26 BL s^-1.  PAH-induced swim performance reduction is of particular concern for such high-performance species, due to potential subsequent reductions in migratory, feeding, fleeing abilities and vital physiological functions. Aside from swim performance, other endpoints being tested will be discussed.

 

 

Adam Greer

Advisor: Dr. Robert Cowen

“Plankton dynamics near vertical density discontinuities:

Thin layers and internal waves.”

Biological oceanographers must consider processes operating on a wide range of scales when studying patterns of organisms in space and time. Information relating to fine scale (1m to 100m) structure in the ocean is lacking mainly due to the coarse sampling resolution of many commonly used plankton sampling systems. Using the In Situ Ichthyoplankton Imaging System (ISIIS), we sampled two fine scale oceanographic features, thin layers and internal waves, common to coastal ecosystems. In Monterey Bay, a zero-hurdle negative binomial model showed all gelatinous zooplankton were more abundant with depth, regardless of thin layer presence or absence; however, only Bolinopsis spp. was more abundant in zones of higher chlorophyll-a fluorescence. Copepods clearly avoided regions of the highest chlorophyll-a, especially thin layers, with an overall tendency to be near the surface. At Stellwagen Bank, we sampled on the tidal cycle and documented fluctuations in the chlorophyll-a fluorescence consistent with internal wave activity during the flood tide. During both tidal phases, copepods and larval fishes were predominantly encountered in the shallowest 15m of water column, above the chlorophyll maximum, whereas preliminary analysis suggests the gelatinous zooplankton remained in deeper waters. These two studies demonstrate common vertical patterns of copepods aggregating near the surface, away from peak chlorophyll-a, potentially as a response to avoid gelatinous predators.

 

FRIDAY, NOVEMBER 2, 2012

1:00pm

RSMAS campus, MSC 343

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/