TYPES OF SALT WATER LIFE ZONES

Estuaries and Tidal

Coastal Wetlands

Rocky Shores

Barrier Islands

Coral Reefs

Mangrove Swamps

Deep Sea

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High tideLow tide

Coastal Zone

EstuarineZone

Continentalshelf

Open SeaSea level

Sun

Euphotic Zone

Bathyal Zone

Abyssal Zone

Depth inmeters

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Figure 7-6Page 131

© 2004 Brooks/Cole – Thomson Learning

Major Zones in a Marine Ecosystem

David Gallo – Life in the Deep Sea

SANDY COASTAL ZONE

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Barrier beach

Silversides

Blue crab

Low tide

Dwarfolive

Clam

Beach flea

Tiger beetle

High tide

GhostshrimpMole

shrimp

Sandpiper

Peanut worm

White sandmacoma

Sand dollar Moon snailFigure 7-9bPage 134

ROCKY COASTAL ZONE

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Rocky Shore BeachSea star Hermit crab Shore crab

Nudibranch

Monterey flatworm

Kelp Sea lettuce

Barnacles

Sea urchin Anemone

Low tide

Mussel

Periwinkle

High tide

Sculpin

Figure 7-9a Page 134

Coral Reef & Mangrove Swamps

What are coral reefs? What is the importance of coral reefs?What are the general threats to coral

reefs?

What are mangrove swamps?What is the importance of mangroves?

What are the general threats to mangroves?

Coral Reefs

• What are coral reefs?– Massive living calcium carbonate

structures primarily built by corals• Corals are colonies of invertebrate animals

called coral polyps.

Structure of Coral

Brown zooxanthellae inside tentacles of a coral polyp

Reef-forming corals, would be unable to build their calcium carbonate skeletons without the nutrients provided by their zooxanthellae

Because the zooxanthellae are plants, they need sunlight to photosynthesize, so they need to find a part of their host animal which is not regularly shaded, that sunlight can't penetrate

Where are coral reefs located?

The majority of reef building corals are found within tropical and subtropical waters. These typically occur between 300 north and 300 south latitudes. The red dots on this map show the location of major stony coral reefs of the world. Credit:NOAA

Structure (Types) of Coral Reefs

• Barrier- Barrier reefs are platforms separated from the shoreline by a channel or a lagoon. The longest barrier reefs are found along the coasts of Belize and Australia.

Fringing reefs, the most common type, extend outward from a body of land with no water separating the reef from land.

Atolls are coral islands that usually consist of a narrow, horseshoe shaped reef with a shallow, central lagoon.  Over 300 atolls are found throughout the South Pacific.

Function of Reefs• Function as breakwaters• Act as producers and recyclers - they rapidly convert carbon and

nutrients into food through photosynthesis. • Provide food and shelter for plants and animals• “Cleaning stations” - Smaller animals may appear to be "picking"

or "biting" a larger one, with the "victim" doing nothing to defend itself. This is actually cleaning behavior; the smaller fish is removing parasites, debris, or infected tissue from the skin of the larger fish. The cleaner lives in a semi-permanent territory called a "cleaning station", which other fish recognize. Both parties benefit from this relationship: the larger fish gets rid of an irritant and the cleaner gets a meal without being harmed. (Symbiotic relationship – mutualistic)

• Some reef organisms transform biologically unavailable atmospheric nitrogen gas into a form useful for coral and plant growth.

Value of Coral ReefsAccording to one estimate, coral reefs goods and services are worth about 0 $375 billion each year.

Shoreline protection

Source of food

Recreation/Tourism

Diverse communities

Recent report from the Global Coral Reef Monitoring Network estimates that 25% of the world's reefs are already gone or severely damaged and that another third are degraded and threatened. This coral reef crisis is happening here at home in the U.S. and in far away places, in some of the most remote areas of the world.

• overexploitation of resources for subsistence and commercial fishing; • destructive fishing practices that degrade and destroy the habitat itself; • increasing coastal populations, which are expected to double in the next 50 years; • poor land use practices and runoff of pollutants, sediments and nutrients; • disease outbreaks, which may be associated with poor water quality and pollutants; • coral bleaching, associated with increasing seawater temperatures and sedimentation• removal of coastal mangrove forests.

Coral Reefs in crisis – What’s happening to our coral reefs?

Major threats to Coral Reefs

• Overfishing (including aquarium collection)

• Human Population Growth• Pollution• Sediment/Turbidity• Nutrient Enrichment• Invasive Species• Bleaching

What can we do?– Conserve water: The less water you use, the less runoff and wastewater will pollute our

oceans. – Help reduce pollution: Walk, bike or ride the bus. Fossil fuel emissions from cars and

industry raise lead to ocean warming which causes mass-bleaching of corals and can lead to widespread destruction of reefs.

– Use only ecological or organic fertilizers: Although you may live thousands of miles from a coral reef ecosystem, these products flow into the water system, pollute the ocean, and can harm coral reefs and marine life.

– Dispose of your trash properly: Don't leave unwanted fishing lines or nets in the water or on the beach. Any kind of litter pollutes the water and can harm the reef and the fish.

– Support reef-friendly businesses: Ask the fishing, boating, hotel, aquarium, dive or snorkeling operators how they protect the reef. Be sure they care for the living reef ecosystem and ask if the organization responsible is part of a coral reef ecosystem management effort.

– Plant a tree: Trees reduce runoff into the oceans. You will also contribute to reversing the warming of our planet and the rising temperatures of our oceans.

– Practice safe and responsible diving and snorkeling: Do not touch the reef or anchor your boat on the reef. Contact with the coral will damage the delicate coral animals, and anchoring on the reef can kill it, so look for sandy bottom or use moorings if available.

– Volunteer for a coral reef cleanup: You don't live near a coral reef? Then do what many people do with their vacation: visit a coral reef. Spend an afternoon enjoying the beauty of one of the most diverse ecosystems on the Earth.

– Contact your government representatives: Demand they take action to protect coral reefs, stop sewage pollution of our oceans, expand marine protected areas and take steps to reverse global warming.

– Spread the word

Mangrove Swamps• If there are no mangrove forests, then

the sea will have no meaning. It is like having a tree with no roots, for the mangroves are the roots of the sea."

Structure• Mangrove swamps are found

along tropical seacoasts on both sides of the equator. They are named for the Mangrove trees that grow there. Mangrove swamps, to most people, look like muddy, swampy places filled with mosquitoes, snakes and spiders.

• The term "mangrove" refers both to the many species of salt tolerant trees which may be found in a mangrove swamp, and to the actual area in which these salt tolerant trees are dominant.

• Actually, they are a forest community that bridges the gap between land and sea. Mangroves are found along muddy estuaries of large rivers, and in sheltered intertidal coastal settings that include lagoons, bays, tidal creeks and inlets.

To avoid suffocation in the oxygen poor mud, mangrove trees snorkel for air. They develop aerial or air-breathing roots. These take in aboveground air. Only air can get through the lenticels, not water or salts.

All aerial roots also contain large air spaces These not only transport air, but also provide a reservoir of air during high tide when all the aerial roots may be underwater.

The function of aerial roots are to absorb air or/and to provide structural support in the soft mud. Roots for absorbing nutrients are tiny and emerge near the muddy surface.

Function • Mangrove root systems provide a filtering system for

run-off from the guts of our islands, allowing the sediments to be removed before entering open water. This sediment would otherwise cover and kill coral reef colonies.

• Protect land from soil erosion• Pollution control• Flood control• Provide food• Nursery areasIncredible Fact!

If you were to scoop up just one teaspoon of mud from a North Queensland, Australia Mangrove Swamp and look at it under a very strong microscope, you would find that it contains more than 10 billion bacteria -

that's among the highest found in marine mud anywhere in the world!

Bacteria helps break down leaf litter and other bits of natural material. Lots of bacteria tells biologists that these swamps are producing lots of leaves and other sources of nutrition for plants and animals, making Mangrove Swamps an immensely important coastal

habitat.

Value

• Flood control• Nursery for many species of marine life• Pharmaceutical• Economic

– Mangroves are a rich source of timber which can be harvested on a sustainable basis.

– Some mangrove animals, like the proboscis monkeys of Borneo with their unusual noses, are tourist attractions and thus generate income.

Threats to Mangrove Swamps• Clearing: Mangrove forests have often been seen as unproductive and smelly, and so cleared to

make room for agricultural land, human settlements and infrastructure (such as harbors), and industrial areas. More recently, clearing for tourist developments, shrimp aquaculture, and salt farms has also taken place. This clearing is a major factor behind mangrove loss around the word.

• Overharvesting: Mangrove trees are used for firewood, construction wood, wood chip and pulp production, charcoal production, and animal fodder. While harvesting has taken place for centuries, in some parts of the world it is no longer sustainable, threatening the future of the forests.

• River changes: Dams and irrigation reduce the amount of water reaching mangrove forests, changing the salinity level of water in the forest. If salinity becomes too high, the mangroves cannot survive. Freshwater diversions can also lead to mangroves drying out. In addition, increased erosion due to land deforestation can massively increase the amount of sediment in rivers. This can overcome the mangrove forest’s filtering ability, leading to the forest being smothered.

• Overfishing: The global overfishing crisis facing the world’s oceans has effects far beyond the directly overfished population. The ecological balance of food chains and mangrove fish communities can also be altered.

• Destruction of coral reefs: Coral reefs provide the first barrier against currents and strong waves. When they are destroyed, the stronger-than-normal waves and currents reaching the coast can undermine the fine sediment in which the mangroves grow. This can prevent seedlings from taking root and wash away nutrients essential for mangrove ecosystems.

• Pollution: Fertilizers, pesticides, and other toxic man-made chemicals carried by river systems from sources upstream can kill animals living in mangrove forests, while oil pollution can smother mangrove roots and suffocate the trees.

• Climate change: Mangrove forests require stable sea levels for long-term survival. They are therefore extremely sensitive to current rising sea levels caused by global warming and climate change.