MSC 111 Lecture Notes - Lecture 14: Nekton, Aphotic Zone, Niche Differentiation

• School: University of Miami
• Department: Marine Science
• Course: MSC 111
• Professor: Peterson Larry

Document Summary

Allows nekton to use more ocean volume and occupy more diverse habitats. Geotaxis: what is up (where light is) Lack of shelter/structure in the open ocean. Resource density declines with depth (less food) Nekton present at depths to 6000 m in abyssal plains. In wake of currents- upwelling- high primary productivity. Just enough light for visual orientation at mid depths. Insufficient ambient light for for orientation in aphotic zone. Access to larger volume of water for foraging for food. Access to specialized habitats and niche separation. Select different habitats for different stages of life history (plankton vs. nekton) Large animals come from single-celled eggs (high fecundity-mortality rate) Small stages of life require different resources (planktonic) Small stages exposed to different and more predators (99% mortality) Old method: tag an recapture (few returns) New methods time - depth recorders (tdrs) Hang out at the surface at night to minimize energy loss. Forage in euphotic zone during the day.