Transcript Water Ecosystems

Water Ecosystems
1.03 Explain why an ecosystem can support a
variety of organisms.
• Temperature and precipitation differ
among ecosystems on land. For Earth’s
watery ecosystems, the main difference is
saltiness.
• Lakes, streams, rivers, ponds, and certain
marshes, swamps, and bogs tend to have
little salt in them. They’re all freshwater
ecosystems. Oceans and seas are
saltwater ecosystems.
• In fresh water or salt water, organisms can
be divided into three main categories.
1. Plankton - organisms that float on the
water.
2. Nekton - organisms that swim through
the water.
3. Benthos - are bottom-dwelling
organisms.
Plankton
• Plankton consist of any drifting organisms (animals, plants, or
bacteria) that inhabit the water near the shore. Plankton are defined
by their ecological niche. (Niche – The role of an organism in a
community.) They provide a crucial source of food to larger, more
familiar aquatic organisms such as fish.
Nekton
• Nekton - the larger, aquatic, free-swimming animal life having
movements that are largely independent of currents and waves,
including squids, fishes, and whales.
Benthos
• Benthos - all the plants and animals living on or closely
associated with the bottom of a body of water, esp. the ocean.
Freshwater Organisms
• Many plants live in the shallow waters of
lakes, ponds, and other bodies of fresh
water.
Cattails are tall plants with flat leaves and elongated
flowering spikes that grow best when rooted directly
in water.
Bur Reeds are marsh inhabiting plants,
some growing along the muddy shores of
ponds or streams, while other species are
strictly aquatic, growing in the water with
floating leaves.
Wild rice has long, dark brown or
black, nutty-flavored seeds and live
near water or marshes. Wild rice is
not actually a rice but a cereal grain.
• The Arrowhead Plant is a commonly cultivated
species, being used as a houseplant since the
late 19th century.
Freshwater Organisms (Cont.)
Frog
Turtle
Crayfish
• Also in a pond or freshwater source, you
might also spot a frog, a turtle, or maybe a
crayfish.
Freshwater Organisms (Cont.)
Algae
Protozoa
• Farther out, where the water gets deeper,
are microscopic plankton like algae and
protozoa.
Saltwater Organisms
• Like the freshwater ecosystem, the
marine, or ocean, ecosystem is divided
into several sections.
• The shallowest is the intertidal zone.
There the ocean floor is covered and
uncovered as the tide goes in and out.
Crabs burrow into the sand so they won’t
be washed away. Mussels and barnacles
attach themselves to rocks.
Saltwater Organisms (Cont.)
• The open ocean is divided into two regions. The
first region is up to 200 m (656 ft) deep. In this
upper region are many kinds of fish and
whales. The world’s largest animals--the 150-ton
blue whales--live here.
• The lower region goes from 200 m (656 ft) to
the ocean bottom--perhaps 10.5 km (6.5 mi)
down. At depths greater than about 1,000 m
(3,281 ft), there is no sunlight. It is completely
black!
Saltwater Organisms (Cont.)
• Photosynthetic organisms, like algae, can
only live where there is sunlight. They are
found in the intertidal zone and in waters
up to about 100 m (328 ft) deep. Many
fantastic creatures live on the dark ocean
bottom. Some of these fish “light up” like
underwater fireflies. Other bottom-dwelling
fish are blind. There are even bacteria that
live in boiling water where fiery lava seeps
out of the sea floor.
Can Humans Change Water
Ecosystems?
• People started hunting whales for their meat and
oil at least 4,000 years ago. However, back then
oceans held so many whales that hunting didn’t
have much effect on their populations.
• By 1850 American whalers alone accounted for
the killing of 10,000 a year.
• In 1962 alone 66,000 whales were killed. The
whales could not reproduce fast enough to
replace those that were being killed.
• Many whale species became threatened with
extinction.
• In 1971 the United States banned its
citizens from whaling for profit or even
buying products made from whales. By
the 1990s the IWC had succeeded in
getting whaling countries to reduce or
stop hunting threatened whales.
The End!!!