Apes ch 8
• Key Concepts
• Factors that influence aquatic systems
• Saltwater life zones
• Freshwater life zones
• Human activities that affect aquatic systems
• Aquatic Environments
• Marine systems: Saltwater systems
• Estuaries, coastlines, coral reefs, coastal marshes, mangrove swamps and oceans
• Freshwater systems:
• Lakes, ponds, streams, rivers and inland wetlands
• Aquatic Organisms
• Plankton: Weak swimming of free floating organisms, key component of the aquatic food web
• Phytoplankton: Photosynthetic plankton (plant-like)
• Zooplankton: heterotrophic plankton (animal-like plankton)
• Ultraplankton: Photosynthetic bacteria no more than 2 micrometers
• Aquatic Organisms
• Nekton: Strong swimming organisms (fish, turtles, and whales)
• Benthos: Bottom dwelling organisms (barnacles, oysters, worms, lobsters and crabs)
• Decomposers: Mainly bacteria that break down the organic compounds of dead organisms of their wastes
• Limiting Factors
• Limiting factors make “life zones”
• Temperature, sunlight, dissolved oxygen, dissolved CO
2
, nitrogen, phosphorus
• Euphotic zone: Area where sunlight can penetrate
• Aphotic zone: No light

• Dissolve oxygen is highest in the upper layers while dissolved CO
2
is highest in lower levels
• Limiting Factors
• Shallow water such as streams, ponds, coastal waters are high in nutrients
• Open ocean is very low in nutrients such as nitrates, phosphates and iron which limits net primary production (NPP)
• Upwelling redistributes nutrients from ocean floor into upper zones
• Deep ocean organisms depend mainly on dead organisms for their food source
• Saltwater Life Zones
• Coastal zone: High tide mark to the continental shelf
• Less than 10% of the oceans but contain 90% of all marine species
• Estuaries: area where freshwater mixes with seawater
• High productivity from nutrients coming from fresh water rivers and streams
• Important nursery ground for fish
• Estuaries and Coastal Wetlands Are Highly Productive
• Important ecological and economic services
• Coastal aquatic systems maintain water quality by filtering
• Toxic pollutants
• Excess plant nutrients
• Sediments
• Absorb other pollutants
• Provide food, timber, fuelwood, and habitats
• Reduce storm damage and coast erosion
• Saltwater Life Zones
• Coastal wetlands: Land areas covered with water all or part of the year
• Inlets, bays, sounds, mangrove forest swamps, salt marshes
• Wide fluctuations in temperature and salinity

• Mangrove forest swamps
• Buffers from storms
• Filter water
• Build new land
• Saltwater Life Zones
• Intertidal zones: The area between low and high tide lines
• Very harsh environment
• Out of the water for part of the day
• Changing salinity
• Crashing waves
• Rocky shores with tide pools
• Barrier beaches
• Barrier Islands
• Barrier islands: Low, narrow, sandy islands that are parallel to coastline
• St. Pete beach, Clearwater beach
• Protect coastal zones from storm waves
• Made from long shore currents
• Coral Reefs
• Coral reefs form in clear, warm tropical and subtropical waters
• Biologically diverse
• Important nursery ground and key component in food web
• Can only live in 18-30 o C (64-86 o F) water
• Coral bleaching can be caused by a 1 o C increase above the maximum
• Open Ocean Zones
• Open sea: From the edge of the continental shelf out

• Euphotic Zone: Upper zone where phytoplankton carry out photosynthesis
• Bathyal zone: Dimly lit middle zone that does not contain producers
• Abyssal zone: Lower zone with no light, very cold and high pressure
• Freshwater Life Zones
• Fresh water life zones: Salt concentration less than 1%
• Lentic: Standing water (lakes, ponds, inland wetlands)
• Lotic: Flowing water (streams, rivers)
• Freshwater Life Zones
• Lakes: Large natural bodies of standing water fill depressions in the earth’s surface
• Causes of depressions:
• Glaciation: Great Lakes
• Crustal displacement: Lake Nyasa in East Africa
• Volcanic: Crater Lake in Oregon
• Freshwater Life Zones
• Littoral zone: Top shallow sunlight area from the shore to depth which rooted plants stop growing
• Limnetic zone: Open sunlight layer to the depth light can penetrate
• Profundal zone: Deep open water where light cannot penetrate, low O
2
levels
• Benthic: Bottom of the lake
• Nutrient levels and PP
• Oligotrophic: Nutrient poor lakes
• Deep
• Steep banks
• Clear with little sediments
• Young lakes
• Eutrophic: Nutrient rich lakes

• Shallow
• Shallow banks
• Murky
• Older lakes
• Nutrient levels and PP
• Cultural eutrophication: The acceleration of the eutrophication process caused by fertilizers, big problem in Florida
• Meotrophic: Lakes that fall between oligotrophic and eutrophic
• Water Flow
• Surface water: Precipitation that does not sink into ground or evaporate
• Runoff: When surface water flows into streams
• Watershed: Land area that delivers runoff to a stream (A.K.A. drainage basin)
• Water Flow
• Source zone: Headwaters of mountain streams
• Cold, clear, fast moving water , attached plants
• Low nutrient, high O
2
levels
• Transition zone: Wider deeper rivers
• Warmer water supports producers
• Gentler slope, river run straighter
• Floodplane zone: Widest and deepest zone
• Water flow slows down
• River is silted
• River meanders and can form oxbows
• Inland Wetlands
Wetland: Land covered by water all or part of the time (excluding lakes, reservoirs, streams)
• Marshes: Dominated by grasses, reeds

• Swamps: Dominated by trees, shrubs
• Prairie potholes: Glacial depressions
• Floodplains: Flooded land
• Seasonal wetlands: Underwater only part of the year
• Freshwater Inland Wetlands Are
Vital Sponges
• Provide free ecological and economic services
• Filter and degrade toxic wastes
• Reduce flooding and erosion
• Help to replenish streams and recharge groundwater aquifers
• Biodiversity
• Food and timber
• Recreation areas
• Human Impacts on Wetlands
• Dams, diversions and canals
• Flood control levees and dikes
• Pollution and Eutrophication
• Wetland destruction
• Case Study: Dams, Deltas, Wetlands, Hurricanes, and New Orleans
• Coastal deltas, mangrove forests, and coastal wetlands: natural protection against storms
• Dams and levees reduce sediments in deltas: significance?
• New Orleans, Louisiana, and Hurricane Katrina: August 29, 2005
• Global warming, sea rise, and New Orleans
• Human Activities Are Disrupting and Degrading Freshwater Systems
• Impact of dams and canals on rivers
• Impact of flood control levees and dikes along rivers

• Impact of pollutants from cities and farms on rivers
• Impact of drained wetlands
• Case Study: Inland Wetland Losses in the United States
• Loss of wetlands has led to
• Increased flood and drought damage
• Lost due to
• Growing crops
• Mining
• Forestry
• Oil and gas extraction
• Building highways
• Urban development