FreshwaterFreshwater is defined as having alow salt concentration—usuallyless than 1%Plants and animals in freshwaterregions are adjusted to the lowsalt content and would not beable to survive in areas of highsalt concentration (i.e, ocean)
Ponds and Lakes range in size from just a few square meters to thousands of square kilometers ponds may be seasonal, lasting just a couple of months (such as sessile pools) lakes may exist for hundreds of years or more may have limited species diversity since they are often isolated from one another and from other water sources like rivers and oceans
Ponds and LakesTemperature varies seasonally. Summer from 4° C near the bottom to 22° C at the top Winter from 4° C while the top is 0° C (ice) between the two layers is a narrow zone called the thermocline where the temperature of the water changes rapidly with depth
Ponds and Lakes during the spring and fall seasons is a mixing of the top and bottom layers resulting in a uniform water temperature of around 4° C mixing also circulates oxygen throughout the lake many lakes and ponds do not freeze during the winter resulting in the top layer being a little warmer
Ponds and Lakes ice can develop on the top of lakes during winter blocks out sunlight and can prevent photosynthesis oxygen levels drop and some plants and animals may die called "winterkill."
Streams & Rivers bodies of flowing water moving in one direction found everywhere—they get their start at headwaters, which may be springs, snowmelt or even lakes travel all the way to their mouths, usually another water channel or the ocean
Marinecover about three-fourths of the Earth’ssurface and include oceans, coral reefs,and estuariesalgae supply much of the world’soxygen supply and take in a hugeamount of atmospheric carbon dioxideevaporation of the seawater providesrainwater for the land
Oceanslargest of all the ecosystemsdominate the Earth’s surfaceseparate zones Intertidal Pelagic Abyssal Benthicgreat diversity of speciesrichest diversity of species even though itcontains fewer species than there are on land
Pelagic – Open Ocean waters further from the land, basically the open ocean generally cold though it is hard to give a general temperature range since, just like ponds and lakes, there is thermal stratification with a constant mixing of warm and cold ocean currents
What Is a Coral Reef?A structure formed by coral polyps,tiny animals that live in colonies.Coral polyps form a hard, stony,branching structure made oflimestone.New polyps attach to old coral andgradually build the reef.
Estuaries enclosed body of water formed where freshwater from rivers and streams flows into the ocean, mixing with the salty sea water estuaries and the lands surrounding them are places of transition from land to sea, and from fresh to salt water although influenced by the tides, estuaries are protected from the full force of ocean waves, winds, and storms by the reefs, barrier islands, or fingers of land, mud, or sand that define an estuarys seaward boundary
Estuaries are semi-enclosed bodies of water wherefresh water from the land mixes with sea water. Estuaries originate as: drowned river valleys, bar-built estuaries, and tectonic estuaries. Salinity typically grades from normal marine salinity at the tidal inlet to fresh water at the mouth of the river.