Freshwater Regions
Freshwater is so called because of its extremely low salt
content. It exists in various forms such as lakes, rivers,
ponds, swamps, or wetlands such as the Florida everglades, and
is host to a wide variety of plants and animals.
As the Earth warmed up
following the Pleistocene era, or ice-age, the accumulation of
melted ice went on to form the various lakes which are
found around the globe. Because lakes are generally
separated from one another, they are home to few species and
plant life. While lakes can exist for centuries, other
inland bodies of water such as ponds tend to dry up
fairly quicker. Because of that factor, the species which
breed and inhabit these areas are often threatened by
extinction, especially when major change is brought on my human
expansion.
Lakes and ponds, are like the
oceans, in that they are divided into separate zones which are
defined by their distance from the shore. The littoral
zone, which is closet to the shore is host to a wide variety
of species due to its warm, shallow environment. Various
species of invertebrates, crustaceans, plants and amphibians
thrive in this environment, and in turn provide food for
predators such as birds, reptiles and other creatures inhabiting
the shoreline.
The limnetic zone, the
open water near the surface of a lake or pond, is home to a
variety of phytoplankton, and zooplankton, which play an
important role in the food chain. Several species of freshwater
fish such as bass and lake trout can also be found this area,
mainly feeding on insects and plankton. The deeper
region of a lake or pond is called the profundal zone.
This zone, shrouded in darkness, and serves as a repository for
dead plankton, and is inhabited by creatures which feed mostly
on decaying organisms. Because freshwater biomes are
inland, they are more subject to seasonal changes
Other areas of still waters, or wetlands, such as glades,
swamps, and marshes support a large variety of aquatic flora and
fauna. Aside from plants such as sedges and pond lilies,
the wetlands also support a few types of trees, such as cypress,
which are highly adapted to the high humidity of these
regions. The wetlands are rich in life forms, from
reptiles, to mammals, to amphibians and birds, to hundreds of
insects. Some wetlands, such as the ones found in the
San-Francisco Bay area, are host to shellfish, shrimp, and other
marine creatures due to their high salt content.
Rivers and streams mostly
get started from mountainous ice and snow melting and
springs. Ultimately, rivers and streams end up at the
ocean or another waterway. Since this water is in constant
motion, it is quite different in fauna and flora to that of
lakes and ponds. animals and plants which thrive in lakes
would have trouble surviving the colder water and limited
shorelines of rivers. Some fish, such as river trout, and
small scavengers such as crayfish can be found in various areas
of the river; usually depending on water temperature and the
exposure of a riverbank to sunlight. The colder areas are host
to salmon and other more vigorous fish, whilst the warmer areas,
rich in sediment and decaying matter are inhabited by catfish,
carp, and other bottom feeders. River plants include floating
weeds and algae, mostly found forming around rocks and submerged
tree roots.
The area where freshwater meets
saltwater, is called an estuary; this area usually
features unique characteristics, trees and algae, seaweed, wetland
flora, and various species of invertebrates, birds, reptiles and
crustaceans congregate into a complex ecosystem, serving as a
"trade center" to the world's aquatic biomes.
