12:44 A Estuaries

Estuaries are semi-enclosed, transition areasWhere fresh water mixes with salt water(called brackish).

U.S. has nearly 900 estuaries, most of whichWee formed at the end of the last glacial period by rising sea level.

Seawater flooded the land and was trappedBy barrier island bays, river deltas andearthquakes

Productivity and biomass are extremely high.Species diversity is directly related to fluctuationsin the characteristics of estuaries.

Salinity – more euryhaline (0-30%) salinity)than stenohaline (30-32%) organisms.Infauna have a more stable environmentthan the epifauna because mud traps salt.

Salt wedges of seawater from under riverrunoff when the tide comes in. This layersthe salinity.

2. temperature – higher in summer; productionIs increased.

3. light/silt – primary producers are sea grasseswho need good light and low sediment.

4. oxygen – depletion can occur in the mud orIn the water column and limits growth

5.Nutrients - come from river runoff and And provides for a detritus based food chain,Inverted energy pyramid increases productivity

12:45 A ORDER SIRENIA - MANATEES

Phylum Chordata; Class Mammalia

Manatees have been protectedBy law since 1893 by the stateOf Florida and by the EndangeredSpecies Act of 1973 – but onlyAbout 1200 still survive

There were 5 populations in the order Sirenia

1. West Indian – Trichechus manatus migratesfrom Brazil to Florida in the ocean, and oftenspends winter in warm rivers

2.West African Manatee

3.Amazonian Manatee

4.Dugong – found in Australia and Indonesia, Has a tail shaped like a mackerel, only horizontal

5.Stellar Sea Cow – hunted to extinction within 276.Years of its discovery in 1741 in the Bering Strait

Manatees are related to the elephant throughBiochemistry and external features.

12:45 B

The average manatee is 10feet long and weighs 1000 pounds. Calves areAround 4 ft. and weigh 60 pounds.

These herbivores may eat 100 pounds ofsea grass a day or 10% of their total body weight.They have large lips to hold plants and replaceable back molars

Manatees like warm shallow water and need fresh water todrink. Their constant eating helpsclear navigational channels ofwater weeds.

However, by inhabiting riversthey encounter boats where50% of their deaths are fromhuman-related boating accidents

Many manatees are identified by their propeller scars.

Flicker

Waving bye-bye

Mammal characteristics:

1.Whiskers (vibrissae) on snout used to rake plants

2.Mammary glands cows nurse young for a year. The glands are located under the flippers.

2.Live births gestation period, 13 months, produce one calf every 3-5 years. They do not reach sexual maturity until 5-9 years old and may live up to 60 years.

4.Large brain, but poor vision5.Warm blooded with a 4 chambered heart6.Stomach has compartments and it ruminates7.Breathes air – may dive for 20 minutes8.Marine mammal tail – horizontal9.Can produce high pitched whistle for communication

Because they have no predators, they haveno social structure, not territorial. Herds have noleader and no permanent bonds are formed for mating

Adopt me please!!!

West Indian With calf

Dugong

The Chondrichthyes or cartilaginous fishes are jawed fish with paired fins, paired nostrils, scales,

two-chambered hearts, and skeletons made of cartilage. They consist of several orders:

Subclass Elasmobranchii (sharks, rays and skates) Superorder Batoidea (rays and skates),

containing the orders: Rajiformes (common rays and skates)

Pristiformes (Sawfishes) Torpediniformes (electric rays)

The shark’s skeleton is entirely composed of cartilage. The skin is covered with tiny scales calleddenticles.

They are similar in structure to teeth and cause theskin to be very abrasive if rubbed in the wrong direction.

Most have gray, brown, white or black coloring; Are not camoflauged but may be counter-shaded.

12:46 A CLASS CHONDRICHTHYES Sharks and Rays

• Only predators are toothed whales and man.

• Puffer fish can accidentally suffocate a shark by blocking water from entering the fills resulting in death for both fish and shark.

• Predation: Efficient, top carnivore of the sick, weak, old and injured. Sharks will not eat Moses sole.

• Jaw is lined with rows of teeth like a conveyor belt.

• Teeth can be replaced ever 24 hours and are used to identify species

• Jaw can be extended out of the mouth for extra reach

• With there diet, it is unusual that they are somewhat resistant to tumors and cancer

• Mote Marine Laboratory in Sarasota, FL is leading research center in shark immunology

• Sharks cartilage has not been proven to prevent cancer, and sharks with tumors have been observed

• Circulation: 2 chambered heart; cold-blooded

• Respiration: Gills are located in muscular slits behind the mouth. They exchange oxygen from the water into the blood.

• Sharks lack swim bladders and must constantly swim upwards to balance their weight. They do sleep

Senses: Vision is good in clear water. Eyelids close from the bottom upwards to prevent injury during an attack.

Smell is excellent. Olfactory lobes compose 2/3 of the brain. Sharks can detect a drop of blood¼ mile away in the water and can determine theDirection of the source.

Hearing is excellent. Sound vibrations can beDetected by the lateral line from 3,000 ft away

The electrical impulses of breathing from a prey can be picked up through the pores in the face.

Reproduction sexual, internal fertilization. Most sharks have live births – dogfish have4-10 pups, tiger sharks may have 80-100At one time. A few species lay eggs

Attacks on humans are rare, but a surfer in awet-suit paddling out on a board, may look like a seal to interest a shark

12:46 CLargest shark:The whale is over 50 ft. long. It is afilter-feeder withbaleen instead of teeth

Most dangerous:Great white sharks are found in temperate and tropical oceansworldwide

Largest Ray:Manta rays may have a 25 foot wide wing span

Most dangerous:Sting rays have a venomous stinger in their tail. Shuffle your feet when wading to avoid stepping on it