20.4 Aquatic and Marine Biomes

shrub willow is a low-growing plant that dominates the landscape during the summer.

This will show you an overview of the biomes.

Desert, savanna, temperate forest, tropic, tundra are some of the biomes that can be explored further.

Abiotic factors influence aquatic biomes.

The abiotic factors include light, temperature, flow regime, and dissolved solids.
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 be a depth at which the sunlight cannot reach when one descends into a body of water.
There are some abiotic and biotic factors that shade light, but they are not usually permanent features of the environment.
The communities of organisms found in both freshwater and marine environments are dependent on light for their productivity.

Solar radiation warms bodies of water and many have distinct layers of water.

The amount of dissolved oxygen available for respiration is affected by the water temperature.

The movement of water is important.

Even in larger bodies of water such as the oceans, regular currents and tides can affect the availability of food and water resources, even if the organisms are adapted to the constant movement of the water around them.

All natural water has dissolved salts.

Fresh water has low levels of dissolved substances because the water is quickly recycled.
The oceans have a high salt content.
Salt environments vary between freshwater and marine levels in aquatic habitats.
These are water environments.
Lakes located in closed drainage basins can have high salt content that can only be found in a few specialized species.

The ocean is composed of relatively uniform salt water.

It is a weak solution.
Coral reefs are located within the ocean.
Estuaries are coastal areas where fresh and salt water mix.

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 diversity of organisms in the ocean is influenced by the physical diversity of the ocean.

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 left high and dry with each tidal cycle.

Most people think of this part of the ocean as a sandy beach.
In some cases, the intertidal zone is a sandy beach, but it can be rocky, muddy, or dense with roots in mangrove forests.
The intertidal zone is variable because of tides.

Organisms can be exposed to air at low tide and underwater at high tide.

Living things that thrive in the intertidal zone are often adapted to being dry for long periods of time.
A consequence of the pounding waves is that few plants establish themselves in sand or mud.

Sea stars, sea urchins, and mussel shells can be found in the intertidal zone in Kachemak Bay, Alaska.

The neritic zone is where photosynthesis can occur when the water is clear.

The water is well-oxygenated and stable in temperature.
The neritic zone has the highest productivity in the ocean.
The bulk of this primary productivity can be attributed to the large species of algae.
The primary food source for most of the world's fisheries is zooplankton, protists, small fishes, and shrimp.
The majority of the fish are in the neritic zone.

There is thermal stratification in the ocean.

This is a less productive part of the marine environment because of the scarcity of resources.
When the organisms that feed on them die, their bodies fall to the bottom of the ocean where they remain, and the open ocean lacks a process for bringing the organic nutrients back up to the surface.

The deepwater region beyond the continental shelf is the benthic realm.

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 not all of them have photosynthetic organisms.
The hydrogen sulfide and other minerals are used by Chemosyntheticbacteria.
The base of the food chain can be found around the vents, thanks to the use of the hydrogen sulfide as an energy source.

Light penetration, water depth, and distance from the shoreline are some of the factors used to divide the ocean.

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

The Great Barrier Reef is located off the northeastern coast of Australia.
The atolls and fringing islands are circular reefs surrounding a former island that is now underwater.
The calcium carbonate skeleton is produced by the coral-forming colonies of organisms.
These calcium-rich skeletons slowly accumulate, forming the underwater reef Corals found in shallow waters have a mutualistic relationship with unicellular protists.
The relationship gives corals most of the nutrition and energy they need.
Without mutualism, large corals wouldn't be able to grow because there aren't many planktonic organisms to eat.
Some corals living in deeper and colder water do not have a mutualistic relationship with protists; these corals must get their energy by feeding on plankton.

Peter talks about his research on coral organisms.

The coral reefs are one of the most diverse.

More than 3000 fish species can be found on coral reefs.
These species include animals.

Coral reefs are formed by calcium carbonate skeletons of coral organisms.

A coral reef takes a long time to build.
Over thousands of years, the animals that create coral reefs deposit calcium carbonate into the ocean to form their characteristic ocean homes.
The coral animals and their protist 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.

Warmer-than-normal surface water is the main cause of coral reefs dying.
Coral reefs are suffering because of global warming.
The coral organisms expel their protists due to the excessive warmth.

As carbon dioxide is dissolved in the ocean waters, it lowers the pH, thus increasing ocean acidity.

Coral animals build their calcium carbonate homes 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 due to the increased flow of agricultural chemicals into the ocean.
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 1degC-2degC may not seem large, it is very significant to this area.

Changes can cause species to become extinct before they lead to new species.
Many scientists believe that global warming is tipping the balance of the world's coral reefs beyond what they can recover from.

The fresh water and salt water are found in the same area.

Many of the offspring of crustaceans, mollusks, and fish begin their lives in estuaries.
The organisms found in estuaries are influenced by the silinity of the water.
The rate of flow of its freshwater sources affects the salinity of the estuaries.
High tides bring salt water into the estuary.
The current of salt water is reversed by low tides.

The mouth of the Klamath River in California is where fresh water and salt water meet.

The daily mixing of fresh and salt water is a challenge for plants and animals.

halophytes are plants that can tolerate salty conditions.

Plants are able to deal with salt water on their roots.
Some halophytes have filters in the roots that remove salt from the water.
Animals, such as mussels and clams, use a lot of energy to function in a rapidly changing environment.
These animals stop feeding, close their shells, and switch from aerobic respiration to a process that does not require oxygen when exposed to low salinity.
When high tide comes back to the estuary, the animals open their shells and begin feeding.

There are lakes, ponds, and wetlands, as well as rivers and streams.

Humans rely on freshwater biomes to provide aquatic resources for drinking water, crop irrigation, Sanitation, and industry.

Abiotic and biotic factors influence the landscape 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.
The upper layer of water in deep lakes is warm enough to not mix with cooler water during the summer.
The process makes a transition between warm and cold water.
The water in the lake mixes from top to bottom when the cooling temperatures and winds break down the stratification.

Most of the productivity occurs in the warm, well-illuminated upper layer, while dead organisms slowly rain down into the cold, dark layer below where cold-adapted species such as lake trout exist.

The photic layer in lakes and ponds is similar to the ocean's.
The base of the food web of lakes and ponds can be found here.
rotifers and small crustaceans are zooplankton.
Dead organisms that sink to the bottom of lakes and ponds are broken down bybacteria in the aphotic zone.

Nitrogen andPhosphory are important limiting pollutants in lakes and ponds.

They are determining the amount of growth in lakes and ponds.
Light penetration in water can be reduced by Algal blooms.
Plants can't survive in a lake or pond that becomes aphotic.
The water becomes polluted when the algae die.
Oxygen-hungry organisms are more likely to die.

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

Water from the source to the mouth of a lake or ocean is carried continuously by the narrower streams that feed into the rivers.

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

The rivers range from narrow and shallow to wide and slow moving.

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

The source water is usually cold.
Headwater streams are of necessity at a higher elevation than the mouth of the river and often originate in regions with steep grades leading to higher flow rates than lower elevation stretches of the river.

The water in headwater streams is clear because of the fast moving water and short distance from its origin.

The growth of algae on rocks is the main cause of photosynthesis here.
The narrowing of the stream may result in further reduction of photosynthesis.
The shading keeps the temperatures cooler.
An additional input of energy can come from leaves falling into a river or stream from trees and plants that border the water.
The organic material is returned to the water when the leaves break.
The leaves support a food chain that includes insects and fish.
Plants and animals have adapted.
leeches have long bodies and suckers on both ends.
The suckers keep the leech in place.
The freshwater trout speciesphylum Chordata is an important predator in the fast moving and colder river and streams.

As the river or stream moves away from the source, the width of the channel widens, the current slows, and the temperature increases.

The increased volume of water results in the increasing width.
Slowing flow can be attributed to the lower knolls along the river.
As the flow rate slows, the silt can settle and increase the deposition of silt.

It can be suspended in water.

The water won't be as clear as it is near the source.
The water is warmer because of longer exposure to sunlight and the absence of tree cover between banks.
There are worms and insects in the mud.

Waterfowl, frog, and fishes are predatory vertebrates.

The trout in the clear waters of the river are able to see food in the murky waters, but the predatory fishes cannot.
They are more likely to use taste or chemical signals.

When a river reaches the ocean or a large lake, the water slows dramatically and any silt in the river water will settle.

As the silt settles onto the ocean bottom, it will build deltas, lowelevation areas of sand and mud.
The fresh water and salt water mix creates estuarine areas where the ocean currents or wave action are high.

Wetlands are different from lakes and ponds in that they have a continuous cover of vegetation.

There are several types of wetlands.

In southern Florida, there is a vast array of wetlands, including sawgrass marshes, cypress swamps, and estuarine mangrove forests.

There are depressions where water flow is low.

There are areas where there is a clay bottom.
The movement of water through the soil or rocks is called percolation.
Oxygen that is used during the decomposition of organic matter is not replaced because the water is stagnant.
The oxygen in the water is low.
This causes organic acids and other acids to build up and lower the water's pH.

Nitrogen is an important limiting resource and this creates a challenge for plants.

Some types of plants, such as Venus flytraps, capture insects and extract nitrogen from their bodies.
The water in the bogs has low levels of nitrogen and oxygen, which leads to low net primary productivity.

On land, at sea, and in the air there are organisms.

The energy that flows from the base to the top of the food web is lost at each transfer.
The lengths of food chains are limited because there is not enough energy left to support a population.
The fat compounds biomagnify the food chain.

Minerals are used in the environment.

Water, carbon, nitrogen, phosphorus, and sulfur are important.
There are major impacts on the structure and function of the system.
The study and modeling of these cycles is important as human activities have caused major disruptions.
Pollution, oil spills, and events causing global climate change are some of the reasons why the natural biogeochemical cycles have been damaged.
Understanding these cycles and how to protect the environment from irreversible damage is important to the health of the biosphere.

The Earth has both land and water.

The aquatic environments include both freshwater and marine environments.
Tropical rainforests, savannas, subtropical deserts, chaparral, temperate grasslands, and boreal forests are some of the major twinnings.
The same biome can be found in many different locations.
The composition of animal and plant communities are influenced by temperature and precipitation.
There are different seasons with cold and hot weather in the tropics.
Net primary productivity is high in the tropics because of warm temperatures, abundant water, and a year-round growing season.
The deserts and tundra have low primary productivity due to a shortage of water.

There are both saltwater and freshwater aquatic biomes.

The abiotic factors that are important for the structuring of aquatic biomes can be different from those seen in the land.
The role of sunlight in sustaining certain organisms is important in bodies of water that are very deep.
Other factors include temperature, water movement, and salt content.
Depending on water depth, distance from the shoreline, and light penetrance, oceans can be thought of as different zones.
Different kinds of organisms are adapted to different conditions.
A wide variety of species can be found on coral reefs.

Estuaries are found where rivers meet the ocean, and their shallow waters give shelter to many species.

There are lakes, ponds, rivers, streams, and wetlands.
A lack of nitrogen, a lower pH, and standing water are some of the characteristics of bois.

Denitrification bybacteria converts nitrates a.

The neritic zone to nitrogen gas is the aphotic zone.

The following regions would be divided into two zones.

The producer in the ocean is usually a tropical wet forest.

Excess nitrogen in the water is a key feature of estuaries.