Oceans
The world's largest ocean
What is the Pacific ocean?
Coastal development; overfishing; runoff, such as fertilizers, pesticides, and livestock wastes; pollution, such as sewage and spills; habitat destruction; invasive species introduced by humans; and, climate change.
What are major threats to marine systems from human activities?
Where rivers meet the sea are partially enclosed bodies of water where seawater mixes with freshwater as well as nutrients and pollutants from streams, givers, and runoff from the land.
What are estuaries?
Oceans, estuaries, coastal wetlands, shorelines, coral reefs, and mangrove forests.
What are examples of saltwater/marine aquatic life zones?
They help filter toxic pollutants; they provide food and habitats for species; and, they reduce storm damage absorbing waves and storing excess water.
What ecological and economic services do coastal aquatic systems provide?
Aquatic equivalent of biomes where the distribution of organisms is determined by the water’s salinity.
What is an aquatic life zone?
Dams and canals alter and destroy aquatic habitats by reducing water flow and increasing damage.
Flood control levees disconnect rivers from their floodplains, destroy aquatic habitats, and alter nearby wetlands.
Cities and farms add pollutants and excess plant nutrients to nearby streams, rivers, and lakes.
Many inland wetlands have been drained or filled to grow crops or have been covered with concrete, asphalt, and buildings.
What are four ways human activities are disrupting and degrading many of the ecological and economic services provided by freshwater systems?
Because of high nutrient inputs from rivers and nearby land, rapid circulation of nutrients by tidal flows, and ample sunlight penetrating the shallow waters.
Why are coastal wetlands some of the earth’s most productive ecosystems?
Lakes, rivers, streams, and inland wetlands.
What are examples of freshwater aquatic life zones?
Filtering and degrading toxic wastes and pollutants; reducing flooding and erosion; help replenish stream flows; help recharge groundwater aquifers; help maintain biodiversity by providing habitats; supplying valuable products; and, recreation.
What are free ecological and/or economic services that inland wetlands provide?
The warm, nutrient-rich, shallow water that extends from the high-tide mark on land to the gently sloping, shallow edge of the continental shelf.
What is a coastal zone?
Temperature, water flows, and salinity.
What environmental conditions do organisms living in intertidal zones have to survive?
Because of ample sunlight and nutrient inputs from the surrounding land.
Why do the top layers of lakes (littoral zone) have high biological diversity?
Four key factors determine the types and numbers of organisms found in aquatic systems
What are temperature, oxygen content, availability of food, availability of light and nutrients?
Food; drinking water; hydroelectricity; transportation corridors; recreation; and, employment.
What are economic services that freshwater systems provide?
The area of shoreline between low and high tides.
What are intertidal zones?
Human inputs of nutrients from the atmosphere and from nearby urban and agricultural areas can accelerate the eutrophication of lakes.
What is cultural eutrophication?
A lake with a large supply of nutrients needed by producers.
What are eutrophic lakes?
The coastal zone, open sea, and ocean bottom
What are the three major life zones in marine aquatic systems?
Food and oxygen.
What are two things that the limnetic zone of lakes produce that support most of the lake’s consumers?
The amounts of various salts such as sodium chloride dissolved in a given volume of water.
What is salinity?
Precipitation that does not sink into the ground or evaporate.
What is surface water?
Because of their low levels of nutrients.
Why do oligotrophic lakes have low net primary productivity?
Lands covered with freshwater all or part of the time and located away from coastal areas.
What are inland wetlands?
The land area that delivers runoff, sediment, and dissolved substances to a stream.
What is a watershed (or, drainage basin)?