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Aquatic Ecology Biodiversity in Aquatic Ecosystems

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					Aquatic Ecology: Biodiversity in Aquatic
Ecosystems




                  Environmental Science
What are the two major types of aquatic life zones?


                                         Saltwater, or marine, life
                                          zones include estuaries,
                                          coral reefs, coastlines,
                                          coastal marshes, mangrove
                                          swamps, and the open
                                          ocean
                                         Freshwater life zones
                                          include lakes, ponds,
                                          streams, rivers, and inland
                                          wetlands
What are the main kinds of organisms in aquatic life zones?


                                     Plankton are weakly
                                      swimming and free-floating
                                      organisms
                                     Nekton are strongly
                                      swimming consumers, such
                                      as turtles, fish, and whales
                                     Benthos are bottom dwellers
                                     Decomposers are mostly
                                      bacteria
What are some major differences between life on land and life in water?


                                         Aquatic habitats:
                                                provide buoyancy,
                                                act as a thermostat,
                                                have great dissolving power,
                                                help disperse larvae to new
                                                 habitats,
                                                make water readily available
                                                 to organisms,
                                                filter out UV, dilute toxic
                                                 chemicals,
                                                 support a wide variety of life,
                                                provide intricate and
                                                 complex food webs,
                                                and are difficult to study
What factors limit life at different depths in aquatic life zones?


                                            Important environmental factors
                                               determining the types and
                                               numbers of organisms found in
                                               the surface, middle and bottom
                                               layers are
                                                  temperature,
                                                  access to sunlight for
                                                   photosynthesis,
                                                  dissolved oxygen content,
                                                  and availability of nutrients
Why are the oceans so important?


                                    Saltwater oceans cover about
                                     71% of the planet’s surface
                                    Oceans are important habitats
                                     for 250,000 species, and they
                                     disperse and dilute many
                                     human-produced wastes
                                    Oceans have a coastal
                                     zone,which is warm and
                                     shallow, and an open sea zone,
                                     which is colder and deeper
What are estuaries and coastal wetlands?


                                            An estuary is a coastal zone
                                             where seawater mixes with
                                             freshwater and nutrients from
                                             rivers and streams
                                            There is constant water
                                             movement in estuaries and their
                                             associated coastal wetlands
                                             which stirs up nutrients, making
                                             them some of the earth’s most
                                             productive ecosystems
What impacts do human activities have on estuaries and coastal wetlands?


                                        Since 1780, about 53% of the
                                           area of estuaries and coastal
                                           wetlands in the US have been
                                           destroyed or damaged due to
                                           dredging, filling in, and/or
                                           contamination
What are rocky and sandy shores?




                                    The area of shoreline
                                     between low and high
                                     tides is called the
                                     intertidal zone
                                    Some coasts have
                                     steep, rocky shores
                                     pounded by waves
                                    Other coasts have gently
                                     sloping barrier beaches,
                                     or sandy shores
What are barrier islands?


                             Barrier islands are long, thin,
                              low offshore islands or sediment
                              that generally run parallel to the
                              shore
                             They are found along the
                              Atlantic and Gulf coasts of North
                              America
What are coral reefs?



                         Coral reefs form in clear,
                          warm, coastal waters of the
                          tropics and subtropics
                         They are some of the
                          world’s most biologically
                          diverse life zones
                         Today, the biggest threats to
                          the biodiversity of many of
                          the world’s coral reefs come
                          from human activities
What biological zones are found in the open sea?


                                                    The open sea is divided
                                                     into the:
                                                    Euphotic zone, where
                                                     sunlight penetrates and
                                                     photosynthesis occurs
                                                    Twilight zone, which is
                                                     dimly lit and
                                                    Deep ocean, which is the
                                                     dark, lower zone that is
                                                     very cold, and has
                                                     enough nutrients to
                                                     support about 98% of the
                                                     250,000 species living in
                                                     the ocean
What life zones are found at freshwater lakes?



                                                  The littoral zone which
                                                   consists of shallow sunlit
                                                   water near the shore to the
                                                   depth at which rooted plants
                                                   stop growing
                                                  The limnetic zone, which is
                                                   the open, sunlit water surface
                                                   layer away from the shore
                                                  The profundal zone, which is
                                                   the deep, open water where it
                                                   is too dark for photosynthesis
                                                   and
                                                  The benthic zone, is the
                                                   bottom of a lake
How do plant nutrients affect lakes?


                                        A newly formed lake
                                         generally has a small supply
                                         of nutrients and is called an
                                         oligotrophic lake
                                        Lakes with excessive
                                         sediment built up in the them
                                         are called eutrophic lakes
What seasonal changes occur in temperate lakes?


                                        Water of different
                                         temperatures forms different
                                         layers in lakes, this is called
                                         thermal stratification
                                        In the fall and the spring
                                         these layers mix and
                                         distribute oxygen and
                                         nutrients throughout the lake
What are the major characteristics of freshwater streams and rivers?


                                             Precipitation that does not
                                              sink into the ground or
                                              evaporate is surface
                                              water, it becomes runoff
                                              when it flows into streams
                                             The land area that
                                              delivers runoff, sediment,
                                              and dissolved substances
                                              to a stream is called a
                                              watershed, or drainage
                                              basin
Why are freshwater inland wetlands important?


                                       Inland wetlands are lands
                                        covered with fresh water all or
                                        part of the time and are located
                                        away from coastal areas
                                       They provide food for many
                                        organisms, they filter nutrients
                                        and pollutants in the water, and
                                        they reduce flooding and
                                        erosion by absorbing excess
                                        water
What impacts do human activities have on inland wetlands?


    About 53% of wetlands are drained, dredged, filled in, or covered
     over
    Wetlands and people
Why is an understanding of aquatic life zones important?


                                         Everything is connected
                                         Most aquatic life zones are
                                          connected by flows of water and
                                          nutrients from one type to
                                          another
                                         Nutrients and pollutants flowing
                                          from the land and deposited
                                          form the atmosphere affect the
                                          ecological processes of aquatic
                                          ecosystems
How sustainable are aquatic ecosystems?


                                       Water is purified by natural
                                          hydrologic processes, nutrients
                                          cycle in and out and populations
                                          of biological organisms can be
                                          replenished, given sufficient
                                          opportunity and time
       The End!
                  Thank you for your attention!




Homework:
Read “Why Should We Care About Coral Reefs,” on page 152
and comment on it with a few sentences.
Critical thinking questions
Page 172
#’s 4, 5, 7, 8

				
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posted:3/10/2012
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