Module 4:

Biomes of the World(Part-II)

Aquatic Biomes

1. Freshwater– Wetlands – Rivers and streams

2. Coastal and Marine Three-fourth of the

Earth's surface– Coastal– Estuaries– Open Ocean

Freshwater Biome

0.8% of the Earth's surface, which is 0.009% of its total water ;

3% of the global net primary production from Freshwater E

41% of the known fish species occur in this biome

Provide the majority of our nation's drinking water resources

Water resources for agriculture, industry, sanitation, as well as food including fish and other aquatic life

Recreational opportunities and a means of transportation

THREATS : Runoff from agricultural and urban areas,

The invasion of exotic species

The creation of dams and water diversion. 

Overexploitation and pollution of groundwater supplies. 

Freshwater- Wetlands

• Areas of standing water that support aquatic plants. – Lakes, Ponds, Marshes, swamps, and bogs are all

considered wetlands. • Highest species diversity of all ecosystems.• Many species of amphibians, reptiles, birds.• Plants/Hydrophytes: Pond lilies, cattails,

sedgesSpecial category of wetlands: Salt marshes that have high salt concentrations. These support different species of animals, such as shrimp, shellfish, and various grasses.

Freshwater- Rivers and Streams

The characteristics of a river or stream change during the journey from the source to the mouth.

Source: Cooler temperatures; Clearer water; Higher oxygen contents - Freshwater fish such as trout and other heterotrophs can be found there.

Middle Part: Width increases; Greater species diversity – Numerous aquatic green plants and algae can be found there.

Mouth: Murky water; less light penetration; less diversity of flora – Catfish and carp can be found there.

- Greatly influenced by their catchments- Characterised by unidirectional flow- The current is the primary determinant of community structure.

Vegetation- Freshwater

Biodiversity use of freshwater system

Marine and Coastal Biome

•..

THE MARINE BIOME IS THE LARGEST BIOME IN THE WORLD, COVERING ABOUT 70% OF THE WHOLE EARTH

.

The coastal zone provides…Home to more than half of

the world’s population

Two third of world’s largest cities are located on the coast

Two third of the global fish production are from the coastal and marine habitat

Half of the global tourismearnings are from the coastal zone

In terms of its ecological and biodiversity value, the coastal and marine areas supports habitat and

ecosystems representing…

• Major productive estuaries

• Deltaic mangrove systems

• Coastal lagoons

• Productive salt marshes

• Coral Reef systems

• Productive mudflats

• Seaweed and seagrass beds and

• Sand dunes

Coral Reefs• Massive structures made of limestone

• Corals: Algae (zooanthellae) + tissues of animal polyp

• Coral reefs support over twenty-five percent of all known marine species: 4,000 different species of fish, 700 species of coral and thousands of other plants and animals

•Microorganisms, invertebrates, fishes, sea urchins, octopuses, sea stars.Hydrothermal vents

Corals: types

• Hard corals:

Brain coral and elkhorn coral. • Soft Coralssea fingers and sea whips,

The Structure of Coral Reefs•Coral reefs begin to form when free-swimming coral larvae (planulae) attach to the submerged edges of islands or continents. As the corals grow and expand, reefs take on one of three major characteristic structures—fringing, barrier or atoll.

•Fringing reefs, which are the most common, project seaward directly from the shore, forming borders along the shoreline and surrounding islands.

•Barrier reefs also border shorelines, they are separated from their adjacent land mass by a lagoon of open, often deep water.

•If a fringing reef forms around a volcanic island that subsides completely below sea level while the coral continues to grow upward, an atoll forms.

Coral Reef- Distribution

• Reef-building corals are restricted in their geographic distribution. This is because the algal-cnidarian symbiotic machinery needs a narrow and consistent band of environmental conditions to produce the copious quantities of limestone necessary for reef formation.

• The formation of highly consolidated reefs only

occur where the temperature does not fall below 18°C for extended periods of time.

Coral reefs

Coral polyp provides Zooxanthellae provide

protection oxygen

living space food (e.g. glucose, amino acids) - up to 90% 

nutrients (CO2, NO3-, NH4

+)  increased calcification

The symbiotic association between corals and zooxanthellae

Corals and its associated fauna

SPECIES Indo-Pacific Atlantic

Hard coral species 700 60

Mollusc species 5000 1200

Fish species 2000 600

3ary consumers Eels, Octopus, Barracudas

2ary consumers Anemones, Urchins, Crustaceans, Starfish, Gastropods, Parrotfish, Butterfly fish

1ary consumers Corals, Clams, Sea Urchins, Crustaceans, Brittle-stars, Gastropods, Grazing Fish

1ary producers Zooxanthellae, Calcareous Algae, Algal mats, Phytoplankton, Epiphytes

Strong relationship between corals diversity and its associated species

Read more on Coral Reefs here http://fishtalesindia.org/?page_id=4

Estuary• An estuary is a partially enclosed body of water formed where

freshwater from rivers and streams flows into the ocean, mixing with the salty sea water.

• Estuaries and the lands surrounding them are places of transition from land to sea, and from fresh to salt water.

• Although influenced by the tides, estuaries are protected from the full force of ocean waves, winds, and storms by the reefs, barrier islands, or fingers of land, mud, or sand that define an estuary's seaward boundary.

• Estuaries come in all shapes and sizes and go by many different names, often known as bays, lagoons, harbors, inlets, or sounds.

A very interesting and informative 5-minute video for a good understanding of an estuary by UESPAgov http://www.youtube.com/watch?v=XLumSN4G5P4  

Estuaries

• Areas where freshwater streams or rivers merge with the ocean. This mixing of waters with such different salt concentrations creates a very interesting and unique ecosystem.

• Microflora includes algae. Macroflora includes seaweeds, marsh grasses, and mangrove trees (only in the tropics).

• Estuaries support a diverse fauna, including a variety of worms, oysters, crabs, and waterfowl.

Watch an interesting and informative video on YouTube http://www.youtube.com/watch?v=XLumSN4G5P4&feature=related

Inter-tidal mudflat

Mangrove forests

Read more on Mangroves here http://fishtalesindia.org/?page_id=95

“Mangroves are among the oldest and most productive wetland forests of our planet. Found in the intertidal zone they are uniquely adapted to survive highly saline and anoxic conditions. They are ideal habitats for many terrestrial and marine species, carbon sinks and natural barriers against storm surges and coastal erosion. mangroves provide invaluable services but have been declining worldwide as a result of anthropogenic and other threats” Mangroves4theFuture

There is no better way to learn about the mangroves and the ecosystem services provided by these ecosystems, than to watch this 30-minute film “Guardians of the Coast”, produced by Mangroves for the Future- IUCN and Riverbank Studios with the financial support of Norad and Sida.

Watch Guardians of the Coast!

Marine- Open OceansZones: Intertidal, pelagic, abyssal, and benthic

• Intertidal: algae, mollusks, herbivorous snails, crabs, sea stars, small fish, seaweeds

• Pelagic: surface seaweeds, whales and dolphins

•Benthic: seaweed, bacteria, fungi, sponges, sea anemones, worms, sea stars, and fishes

•Abyssal: invertebrates and fish, Chemosynthetic bacteria in Hydrothermal vents

Click here

References

• Campbell, N.A. 1996. Biology, 4th Edition. The Benjamin/Cummings Publishing Company, Inc., Menlo Park, California.

• http://www.ucmp.berkeley.edu/exhibits/biomes/marine.php

Explore Further

• A Blog about India’s Coastal and Marine ecosystems http://fishtalesindia.org/

• Coral Reefs- Polyps in Peril http://www.youtube.com/watch?v=Jn5-ARXmQlQ&feature=player_embedded#!

• http://deepakapte.com/

- What is the significance of the concept of biodiversity hotspots?

- Is there any risk involved in using the concept of biodiversity hotspots for prioritizing conservation at global and national level?

Food for Thought