Faculty Candidate Seminar - Jeffrey Drazen

03/22/2017 - 12:00pm
Hubbs Hall 4500
Event Description: 


DATE:     March 22nd, Wednesday, 12 p.m.  

LOCATION:     Hubbs Hall 4500
*Additionally, a “chalk talk” presentation will be held in HH4500 on March 23rd at 12pm

Jeffrey Drazen, Ph.D.
            University of Hawaii

Small particles may form a previously overlooked food source for mesopelagic zooplankton and micronekton

Mesopelagic zooplankton and micronekton (small fishes, squids and crustaceans) are important in mediating vertical carbon flux and for the production of forage for many large harvestable fishes. Currently studies find that the supply of sinking carbon to the mesopelagic ecosystem is much less than faunal carbon demand, indicating alternative sources of nutrition for these communities.  A potentially overlooked food source is small slowly sinking or suspended particles. The nutritional importance of these small particles relative to larger particles can be traced into zooplankton and micronekton using the 15N values of individual amino acids. Our results show that zooplankton increasingly use small particles at greater habitat depths and that the importance of small particles varies seasonally in concert with changes in sinking particle flux. Further some zooplanktivorous and piscivorous species of micronekton exhibit a preferential reliance on a food web based on small particles in the deep mesopelagic. Together these results suggest that there is an important and previously overlooked food web pathway in the deep mesopelagic in which small particles, often thought of as refractory, support a large proportion of the biomass at higher trophic levels. This organic matter partly reconciles mesopelagic carbon and energy budgets.
Faculty Host:  Peter Franks  (pfranks@ucsd.edu)
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