For educational purposes only

1. RG Luis Vincent P. Gonzaga 10-21-2019
BSN 1-5 Environmental Science
Lake Community includes biotic (living) plants, animals and micro-organisms, as well
as abiotic (nonliving) physical and chemical interactions.
Lake ecosystems are a prime example of lentic ecosystems. Lentic refers to stationary or relatively
still water, from the Latin lentus, which means sluggish. Lentic waters range
from ponds to lakes to wetlands, and much of this article applies to lentic ecosystems in general.
Lentic ecosystems can be compared with lotic ecosystems, which involve flowing terrestrial waters
such as rivers and streams. Together, these two fields form the more general study area of
freshwater or aquatic ecology.
Sea Community are the largest of Earth's aquatic ecosystems and are distinguished by waters that
have a high salt content. These systems contrast with freshwater ecosystems, which have a
lower salt content. Marine waters cover more than 70% of the surface of the Earth and account for
more than 97% of Earth's water supply[1][2] and 90% of habitable space on Earth. Marine ecosystems
include nearshore systems, such as the salt marshes, mudflats, seagrass meadows, mangroves,
rocky intertidal systems and coral reefs. They also extend outwards from the coast to include offshore
systems, such as the surface ocean, pelagic ocean waters, the deep sea, oceanic hydrothermal
vents, and the sea floor. Marine ecosystems are characterized by the biological community of
organisms that they are associated with and their physical environment.

2. Forest Types
Forests can be classified according to a wide number of characteristics, with distinct forest types
occuring within each broad category. However, by latitude, the three main types of forests are
tropical, temperate, and boreal.
Tropical
Most tropical forests receive large amounts of rain annually (up to 100 inches), which is spread
evenly throughout the year. However, there are some tropical forests that receive seasonal rainfall
and experience both a wet and dry season. While tropical forests have many layers, most of the
nutrients are held in the vegetation within the canopy; therefore, the soils are typically low in both
mineral and nutrient content. Shallow roots allow for ‘catching’ any nutrients released by decaying
leaves and ground litter.
Temperate
Temperate forests—common throughout North America, Eurasia, and Japan—are primarily
deciduous, characterized by tall, broad-leafed, hardwood trees that shed brilliantly colored leaves
each fall. These forests experience varied temperatures and 4 seasons, with winter often bringing
below freezing temperatures and summer bringing higher heat and humidity. Rainfall also varies,
averaging 30 to 60 inches annually, allowing for soils that are well developed and rich in organic
matter. They also provide habitat for a wide variety of smaller mammal species, including squirrels,
raccoons, deer, coyotes and black bear and many bird species, including warblers, woodpeckers,
owls, and hawks.
Boreal
Boreal forests (also known as taiga) are located just south of the tundra and stretch across large
areas of North America and Eurasia. They are one of the world’s largest biomes, encompassing
about 11 percent of Earth’s land area, but have very short growing seasons with little precipitation
and represent relatively few tree species. The forest is dominated by coniferous trees, which have
needle-shaped leaves with minimal surface area to prevent excessive water loss. These forests
provide habitat for a few large mammal species, such as moose, wolves, caribou, and bears, and
numerous smaller species, including rodents, rabbits, lynx, and mink.