Topic 3 Aquatic Environments Ecosystem Communities of living

Topic 3: Aquatic Environments

• Ecosystem – Communities of living and non-living components in relationship with each other and their environment – Examples of aquatic ecosystems • Continental shelf • Intertidal zone • Open ocean • Benthic zone • Estuary • Freshwater lake

• How do organisms survive in their own ecosystems? – Adaptations • Physical behavioral characteristics of a species that increases its chances of survival • Eg. Gills – Allow aquatic organisms to extract oxygen from the water

Assignment 3 A • Research your selected aquatic environment • Prepare your answers to the following questions: – Describe the environment • Example of specific location • Type of water • Type of climate • Zones within environment – Highlight the organisms that call that environment home • 3 plants & 4 animals • Adaptations • Share your information with the class

• Which would have a greater diversity of organisms – freshwater or saltwater? • Saltwater – Covers ~2/3 of earth – Oceans are large in size – Have many different types of environments – Have many different abiotic factors – 2/3 of all major types of organisms in the world live at least a part of their lives in saltwater

• Intertidal Zone – Where earth, water & air interact – Divided into 4 zones: • Lower – Only dry during the lowest tides – Contains the highest biodiversity • Middle – Regularly covered with sea water • Upper – Covered by water during high tide so it experiences dry periods daily • Spray zone – Survives on the mist and spray of the ocean

– The most common organisms are small and relatively simple • Often have attachment devices – suction cups, hooks • Often have protective coverings - shells • Intertidal zone is an extreme environment – Supply of water is intermittent – Organisms must be able to withstand pounding waves – Extreme temperature range – High salinity » Salt water trapped in rock pools evaporates leaving behind salt deposits

• Continental Shelf – Land that extends out from the edge of the continent – Water is warmer than in open oceans – Light penetrates all the way to the bottom – Warm water + light + nutrients = area very rich in life • Plants – herbivores - carnivores

– Because areas are shallow, organisms are generally small • Large organisms may only be present during high tides

• Estuary

– Formed where freshwater from rivers and streams flows into the ocean, mixing with the salty sea water • Creates brackish water

– Are places of transition – Are influenced by the tides – Partially enclosed • Protected from the full force of ocean waves, winds, and storms

– Support unique communities of plants & animals • Specially adapted for life at the margin of the sea • Organisms have to be able to tolerate brackish water • Rich in bird life because of the available food and shelter

– Adaptations? • Able to withstand ranges of salinity • Able to withstand tidal movements

• Open Ocean – Far from shoreline • Few nutrients available directly – 2 subzones • Upper layer (Photic) – Receives light – Main producer is phytoplankton • Middle layer – Some light penetration – Many different kinds of fish, jellyfish, squids, octopus, shrimp, etc.

– Adaptations? • Good swimmers • Able to evade predators • Good senses – hearing, ecolocation

• Benthic – Receives no light • No plants – Contains little oxygen – Immense water pressure – Animals live on waste that drops down – Organisms that live in this zone are unique

– How do producers make food with no sunlight? • Chemosynthesis – Producers are able to use chemicals instead of sunlight – Chemicals come from deep sea thermal vents

– Adaptations? • • Different body shape – low, flat to disperse pressure Feelers instead of eyes Able to feed on dead/decaying matter – scavengers Unique ways of hunting – angler fish

• Freshwater – Upper • From shore to where plants stop growing • Organisms include plants, small fish, clams, insects, snails, frogs – Middle • Open water with light penetration • Organisms include phytoplankton and fish (can move between zones) – Lower • Little light • Food comes from waste that falls from upper and middle zones

– Adaptations?

• Other adaptations – Water temperature • Fish are cold-blooded – they extract heat from the water • Warm water fish can’t extract enough heat from cold water • Cold water fish overheat in warm water

– Pressure • Increase in depth = increase in pressure • Organisms that are adapted to deep water can’t survive in shallow water because their bodies can’t function at lower pressures – Salinity • Too much salt – draws fluid out of organisms – causes dehydration – Water movement (current) • Strong currents – need to be able to attach to a surface