ZOO CREATION AND SITE SELECTION

only survive at the photic level of the ocean. The photic layer is located close to thewater surface so light can penetrate to facilitate photosynthesis.Discuss the importance of size, turbidity (water clarity) and density tophytoplankton sedimentation rates:SizeSmall particles will sink more slowly than large particleTurbidity High sediment (debris, particle) concentration (high turbidity) results in slowersedimentation rateDensity Low density objects results in slower sedimentation ratesForm resistance -- certain shapes tend to settle slowly. Spines and certain colony shapescan help this (C.S. Reynolds)Reynolds, C.S. 1984. The Ecology of Freshwater Phytoplankton Cambride UniversityPress, New York.Discuss the importance of nutrient availability to phytoplankton populations:In the open ocean, detritus and debris can settle out of the reach of the photic zone. Whenthis happens, their nutrients become unavailable to organisms at the surface. Thusnutrient availability is often limiting for marine phytoplankton. However, manyphytoplankton can survive during periods of nutrient depletion due to adaptations forcapturing nutrients. In certain areas, upwelling brings bottom waters and their dissolvednutrients to the water surface causing rapid growth under conditions of nutrientenrichment. Excess nitrogen levels are available to produce phytoplankton "blooms" tohigh densities, clouding and coloring the water with their profusion. Chronic conditionscan cause an overgrowth of phytoplankton resulting in a reduction of light reaching theocean’s bottom consequences for the rest of the ecosystem including reducing theamount of light reaching the bottom and decreasing the amount of oxygen duringphytoplankton respiration and decomposition.Discuss how zebra mussels, bighead carp and silver carp can remove phytoplanktonwhich disrupts food chains. Disruption may lead to endangered species.24