44.4 Aquatic Biomes

A series of abiotic factors influence aquatic biomes.

Water has different physical and chemical properties than air.
The water in a pond or other body of water absorbs light even if there are no suspended particles.
There will eventually be a depth in the water which the sunlight cannot reach.
Abiotic and biotic factors can obscure light in the environment, but they are not permanent features of the environment.
The communities of organisms found in both freshwater and marine environments are dependent on light.
In freshwater systems, the most important abiotic factor is the density of the water.
Major impacts on global climate and weather patterns can be found in the thermal properties of water, which are significant to the function of marine systems.
Large-scale physical water movements, such as currents, are less important in most freshwater lakes.

There are several areas or zones in the ocean.

The majority of the ocean is aphotic.

The deepest part of the ocean is called the Challenger Deep and is located in the western Pacific Ocean.
The average depth of the ocean is 4267 m or 14,700 ft deep.
The freshwater lakes are relevant to the realm and zones.

Water depth and distance from the shoreline are used to divide the ocean.

The ocean is large.

It is a continuous body of salt water that is relatively uniform in chemical composition, but it is a weak solution of mineral salts and decayed biological matter.
Coral reefs are a type of marine environment.
Estuaries are coastal areas where fresh and salt water mix.

Plants, animals, and other organisms are influenced by the ocean's physical diversity.

The ocean is categorized based on how much light reaches into the water.
Each zone has its own group of species that are adapted to the biotic and abiotic conditions.

The intertidal zone can be rocky or muddy in some cases.

The intertidal zone is very variable because of the ebb and flow of water.
Organisms are exposed to air and sunlight at low tide and are underwater most of the time.
The intertidal zone has adapted to being dry for long periods of time.
The organisms found on the shore of the intertidal zone are adapted to survive being hit by waves.
The shoreline crustaceans are tough and protect them from desiccation and wave damage.
A consequence of the pounding waves is that few plants establish themselves in the constantly moving rocks, sand, or mud.

The intertidal zone in Kachemak Bay is home to sea urchins, mussel shells, and starfish.

Light can penetrate this depth and still reach the neritic zone.
The water here is well-oxygenated and stable in temperature.

The base of the food chain for most of the world's fisheries are zooplankton, protists, small fishes, and shrimp, which are found in the neritic zone.

The warm and cold waters mix because of ocean currents.

This is a less productive part of the marine environment because of the scarcity of resources.
The bodies of the organisms and protists that feed on them fall to the bottom of the ocean when they die.
Most of the open ocean doesn't have a process for bringing the organic nutrients back up to the surface.
The majority of organisms in the aphotic zone include sea cucumbers and other organisms that survive on the dead bodies of organisms in the photic zone.

Sand, silt, and dead organisms are found at the bottom of the benthic realm.

As water depth increases, the temperature decreases.
The dead organisms that fall from the upper layers of the ocean make this a rich part of the ocean.

The abyssal zone is very cold and has high pressure and low oxygen.

There are a variety of animals and fishes found in this zone, but the lack of light makes the abyssal zone not have plants.
The hydrogen sulfide and other minerals that are emitted from the vents are utilized by the chemosyntheticbacteria.

The base of the food chain can be found in the abyssal zone, thanks to the use of the hydrogen sulfide as an energy source.

They are found in the north and south of the equator.

The reef is located off the northeastern coast of Australia.
Other coral reef systems are circular reef systems surrounding a former landmass that is now underwater.
The coral organisms are colonies of saltwater polyps that produce a calcium carbonate skeleton.
The underwater reef is formed by the slowly accumulating calcium-rich skeletons.
Corals found in shallow waters have a relationship with unicellular algae.
The relationship gives corals most of the nutrition and energy they need.
Without mutualism, it would not be possible for large corals to grow in the poor waters in which they live.

Some corals living in deeper and colder water do not have a good relationship with algae, they use stinging cells called cnidocytes to capture prey.

The National Oceanic and Atmospheric Administration has a video about Dr. Peter Etnoyer's research on coral organisms.

More than 4,000 fish species live on coral reefs.

It takes a long time to build a coral reef.

The animals that create coral reefs have evolved over millions of years to deposit calcium carbonate in their ocean homes.
The coral animals and their symbiotic algal partners evolved to survive at the upper limit of ocean water temperature after being submerged in warm tropical waters.

Climate change and human activity are threats to the long-term survival of the world's coral reefs.

Coral reefs are suffering due to global warming.
If the symbiotic zooxanthellae is lost, the coral animals will die and the reefs will lose their characteristic color.

As CO2 is dissolved in the ocean waters, it lowers the pH and increases the acidity of the water.

Coral animals build their calcium carbonate shelters when acidity increases.

Animals lose food and shelter when a coral reef dies.

The decline of coral reefs poses a serious threat to coastal economies.

Humans have damaged corals in other ways.

Some of the once-clear tropical waters have become cloudy as a result of the increase in the amount of agricultural chemicals in the water.
The predator species that eat corals have been allowed to go undetected because of the overfishing of popular fish species.

Although a rise in global temperatures of 1-2@C in the coming decades may not seem large, it is very significant to this area.

When change is rapid, species can become extinct.
Many scientists believe that global warming is tipping the balance of the world's coral reefs beyond what they can recover from.

Fresh water and salt water are found in the same area.

Estuaries form protected areas where many of the young offspring of crustaceans, molluscs, and fish begin their lives, which also creates important breeding grounds for other animals.
The organisms found in estuaries are influenced by the silinity of the water.
The rate of flow of its freshwater sources can affect the salinity of the estuaries.
High tides bring salt water into the estuary.
The current of salt water is reversed by low tides.

Plants and animals that live in estuaries are challenged by the short-term and rapid variation in salinity due to the mixing of fresh water and salt water.

halophytes are plants that can tolerate salty conditions.
Plants adapted to deal with saltwater on their roots are called halophytic plants.

Some halophytes have filters in the roots that remove salt from the water.

Oxygen can be pumped into the roots of other plants.
Animals, such as mussels and clams, use a lot of energy to function in a rapidly changing environment.
When these animals are exposed to low salinity, they stop feeding, close their shells, and switch from aerobic respiration to anaphylactic respiration, a process that does not require oxygen and takes place in the cytoplasm of the animal's cells.
When high tide comes back to the estuary, the animals open their shells and begin feeding.

Lakes and ponds, as well as rivers and streams, are freshwater biomes.

Wetlands will be discussed later.
Humans rely on freshwater biomes to provide benefits such as drinking water, crop irrigation, and industry.
Abiotic and biotic factors influence the ecology of lakes and ponds.

The lakes and ponds range in size from a few square meters to thousands of square kilometers.

Living things found in lakes and ponds are affected by temperature.
In the summer, thermal stratification of lakes and ponds occurs when the upper layer of water is warm by the sun and does not mix with cooler water.
Light can enter the photic zone of the lake.
Dead organisms that sink to the bottom of lakes and ponds are broken down bybacteria in the aphotic zone.

Nitrogen andPhosphory are limiting in lakes and ponds.

They determine the amount of growth that takes place in lakes and ponds.
Light penetration in water can be reduced by Algal blooms.
They may taint the drinking water taken from that source.
Plants cannot survive in a lake or pond that becomes aphotic.
The water becomes polluted when the algae die.
Fishes and other organisms that need oxygen are more likely to die.
Lake Erie and the Gulf of Mexico are freshwater and marine habitats.

An algal bloom has been caused by the growth of algae.

Large amounts of water are carried from the source to a lake or ocean by rivers and streams.

The Nile River in Africa, the Amazon River in South America, and the Mississippi River in North America are the largest rivers.

Along the length of the river or stream, there arebiotic features.

The source water is usually cold.
The current is often faster here than at any other point in the river or stream.

The water is usually clear and free of debris when the water is fast.

The growth of algae on rocks is the main cause of photosynthesis here.
An additional input of energy can come from leaves and other organic material that fall downstream into the river or stream, as well as trees and other plants that border the water.
The organic material is returned to the water when the leaves break.
Plants and animals have adapted.
The bodies and suckers of the leeches are found on the anterior and anterior parts of the body.

The suckers keep the leech anchored in place and are also used to attach to their prey.

The trout speciesphylum Chordata are an important predator in the fast moving rivers and streams.

The width of the channel widens as the river or stream moves away from the source.

The slow moving water is caused by the decrease in the gradient and the increase in volume.