THE AQUATIC ENVIRONMENT

 

 

The surface of the earth is made by 72% of water

 

85% of the oxygen is produce by the marine plants

 

The oceanic plant production is 10 times more the on land

 

The salinity of the ocean is about 3.5%

 

Water need to be present on land for the plant to make photosynthesis

 

TEMPERATURES

 

There are water layers in the sea or lakes, the warmer water is on the top with colder water under. Theses layers of water are called Thermoclines

Cold water sinks under warm water

The average temperature of the ocean is 1C.

 

CURRENTS

 

The main currents in the northern hemisphere flow clockwise with the clock

 

The main currents in the southern hemisphere flow anticlockwise against the clock

 

HOW FAST THE CURRENT FLOWS:

• 1 NAUTICAL MILE = 1852 METRES
• So the speed of one knot is 0.5 per second
• 1852/3600seconds = 0.5 knot

 

• If an object float 9 meters in 60 seconds, the current speed is 0.15knot per second

 

• 9/60 = 0.15 knot

 

• You should never enter in water with 1 knot (1meter per second)

 

• To check if current is present, you must jump in the water with mask and fins

 

• Look at the fishes on the bottom; they always swim against the current.

 

• Look also at the mooring, if current is present, it will be a stream of water in the back of the buoy.

 

LONGSHORE CURRENT

 

• Flow parallel to the shore

 

RIP CURRENT

 

• Is a current who takes you away from the shore

 

 

RIP TIDES

 

• Tides who takes you away (if tide is ebbing ,Down) or to the reef (if tide is flooding , up)

 

If the current push you down, the best is to hold on to the reef.

If the current push you up, the best is to hold on to the reef

 

If you get push away from the reef, there is less current in deep water and it will be easier to ascent.

 

The tides are caused by the moon and the sun position with bigger impact from the moon

 

The best time to dive is when the tide is high and not moving (slack tide)

 

WAVES

 

• Waves are cause by wind
• The highest point of a wave is the crest
• The lowest point of the wave is the trough
• The distance between 2 crests is the wavelength
• How high are the waves is the height
• Waves break when the depth of the water is the same as the height of the wave
• The place where the waves break is the surf zone
• It is always good to observe the waves for 5 to 15 minutes to see their pattern
• Normally it is always 7 big waves and  small

 

BOTTOM TOPOGRAPHY

 

• Is how the underwater terrain look like

 

TAXONOMY

 

• Is the science who organize the plants and animals in group

 

PHYTOPLANKTON

 

• Is plant that are tiny and nearly invisible, and are 995 of the plant production in the sea
• 2 major groups of phytoplankton are :

1. the dinoflagellates
2. diatom

 

• when dinoflagellates blooms, they produce red tides killing reef fishes who cannot pump O2 from the water and they are bioluminescent
• some dinoflagellates produce toxin who are not dangerous for the mollusk who eat them but are poisonous for human who eat them (paralytic shellfish poisoning.

 

• Diatom in the other hand produce siliceous shell which we use in toothpaste and filters.

 

• Toothpaste remove scratches

 

MARINES ANIMALS

 

·       PROTOZOA : mean first animal. They are the zooplankton of the sea.(KRILL FOR THE WHALE SHARK AND MATA RAYS

·       INVERTABRATE : with no backbone :

·       SPONGES : they can be recognize with their holes who filter water from the inside out

·       STINGING ANIMALS : jellyfishes like Portuguese man-of-war, box jelly, fire coral, some anemones ,sea fan, sea pen are in this family. With stinging tentacles

·       CORAL REEF : it requires water temperature from 20C to leave with 22C average. The coral need a symbiotic relation with algae to give him  O2. Algae have a place to leave and the coral benefit from them. The algae give the coral it color. Corals are colonial form, with a coral reef containing many millions of individual anemone-like animals

            They are made by calcium carbonate that is their skeleton structure. Only

            The top of the coral are  leaving creatures. Biorock explaination

·       MARINE WORMS :fireworm can sting with their air-like, Christmas worm and flat worm are the most famous.

·       SOFT BODIED ANIMALS : shells, oysters, squid, octopus, are part of this group

·       ARTHROPOD : shrimps, crabs, lobster are part of this group

 

·       VERTEBRATE : with backbone :

·       Fish, shark, stingray, are part of this group

·       TURTLES SEA SNAKES MARINES MAMMALS

·       NEVER RIDE A TURTLE.

·       Sea snakes are very poisonous but not aggressive

·       CETACEAN: whales, dolphins are part of this group