University:
York University
Course:
SC/BIOL 2021 | Cell Biology
Academic year:

2019
Views:

170

Pages:

5
Author:

Nick T.

3/31/19 Estuaries. A continuum from river to sea. Segments: Lower, middle, upper. 3 Turbidity peak is due to the interaction of particles in the water with Salinity causing flocculation. Flocculation: process by which particles of clay aggregate into clotlike masses. Four Estuary Types: 1. Coastal plain = drowned river valleys. 2. Fjords = glacial formation 3. Bar-built = shallow and limited connection w/ ocean. 4. Tectonic-built Cause of Tide: Spring and Neap tides Tidal Prism: volume difference between high and low tide. Micro, Meso, Macro, and Hypertidal. → Salinity varies horizontally and vertically • Fine sediments Settles out in middle segment. - Organic material is abundant. * when decomposed, creates anoxic layer in sediment. DO is removed from water by aerobic respiration and. Aerobic respiration. →Freshwater organisms at head of estuaries. polychaetes and Oligochaetes are common in middle. Osmoregulators: maintain internal salinity levels Osmocon Formers: do not regulate internal osmotic cond. Physiological plasticity →Few species spend their whole life in an estuary. * A mojority of energy comes from detritus material. High Abundance of invertebrates. Rocky and Sandy Shores. As particle size decreases, organic matter content increa- ses affecting bacterial abundance and oxygen availab- ility. Dissipative Beaches, have a low slope due to the small particle size. Organic matter can build up and p.p. can be high. Reflective Beaches, have Steep slope w/ large particle Size. • unproductive w/ loW OM. Zonation: Upper is determined by abiotic Factors while lower is determined by biotic factors. →If zonation seems static, they've found equilibrium. Texas vertical zonation is small due to small Atide. Competition vs Predation Hypothesis * Limited resources → Shores are open ecosystems importing and exporting resources and organisms. (import and export). Sandy Shores: Diatoms are the primary producers. Infauna razor clams Meio Fauna = microscopic (<0.5 mm). Neritic Zone beginslends on the continental Shift. Meso < Bathyk Abysso Neustic zone: thin layer on top of water. Photic zone ~ 200 m. Planktons: Passive vs Active Phytoplankton is limited to Eupnotic zone. Meroplankton + Meroplankton. Spend part of their lives as plankton. Spend their whole life as plankton. The coriolis and circulation. and Spatial variability. cause Changes in Temporal Thermocline + Halocline = Punocline. Langmuir circulation: wind driven upwelling above thermo. Continental Shelf: site for commercial Fishing - <500 m deep bottom is unvegetated. * Sources of Organic Matter Plankton Detritus from rivers. • Nearby coastal environment. Oceans Human Sources Aerobic Bacteria = Oz Anaerobic bacteria = processes the organic matter. Macrofauna > Meiofauna Microbiota Bioturbators: polychaete, gastropods, holothurians, crust- Optimal Sediment: fine-grained w/ adequate organic C in. Ecosystem resilience: stable food web w/ recovery →Different species having Same role in diff. comm. Slower currents - Finer sediment Low disturbance to eliminate Species allows species. allow dominates Flourish. High Disturbances allow opportunistics species to