Dainer, J. S.. Biology Department, San Diego State University, jdainer@sunstroke.sdsu.edu
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HORIZONTAL GRADIENT IN ABUNDANCE OF PLANKTON IN LACUSTRINE SYSTEMS
 
As observed by Michael White that at times of year when small fish (juvenile largemouth bass) were abundant in the nearshore waters of Lake Miramar, large zooplankters such as Daphnia and Mesocyclops tended to move offshore during early morning and back toward the shore in the evening. He speculated that the vertical migration of zooplankters downward in the water column during the day allows them to avoid predation by zooplanktivorous fish while upward movement in the water column during the night allows the zooplankters to maximize access to the phytoplankton. The object of my study was to document the abundance of phytoplankton to test the 'food' gradient part of his hypothesis. Zooplankton samples were collected night and and Phytoplankton during the day, at 8 stations along 3 horizontal transects perpendicular to the shore 50 meters apart at each of two sites 7 times a year. Also two night and day vertical profiles were obtained at each site by collecting zooplankton at 96 m from shore by collecting samples at every two meters from the surface to 22m depth. The horizontal migration appears to be due to a combination of factors including the physical water movement.
 
Day: Thursday, Feb. 4
Time: 02:15 - 02:30pm
Location: Hilton of Santa Fe
 
Code: SS16TH0215H