PHYSICAL FACTORS THAT AFFECT LIVING

ORGANISMSKL OCEANOGRAPHY

UNIT II: OCEAN PLANET

PHYSICAL FACTORS

• PHYSICAL FACTOR= ANY PART OF THE PHYSICAL ENVIRONMENT THAT AFFECTS LIVING THINGS.

• SAME IDEA AS AN ABIOTIC LIMITING FACTOR

1. LIGHT & TRANSPARENCY

2. TEMPERATURE

3. SALINITY

4. SOUND

5. HYDROSTATIC PRESSURE

6. BUOYANCY

7. MOVEMENT & DRAG

8. CURRENTS

I. LIGHT ZONES & TRANSPARENCY

LIGHT & TRANSPARENCY

• OCEAN WATER IS FAIRLY CLEAR WHICH ALLOWS SUNLIGHT TO PENETRATE UP TO 200M (PHOTIC ZONE) THIS IS WHERE PHOTOSYNTHESIS TAKES PLACE.

• EUPHOTIC ZONE= TOP UPPER ½ OF THE PHOTIC ZONE, BETWEEN 0~70M, IS THE AREA OF GREATEST PHOTOSYNTHESIS.

• DYSPHOTIC ZONE= THE LOWER ½ OF THE PHOTIC ZONE, BETWEEN 70-200M. LIGHT IS PRESENT, BUT NOT ENOUGH TO DRIVE PHOTOSYNTHESIS.

• APHOTIC ZONE= FROM 200M AND LOWER, WHERE NO LIGHT PENETRATES

I. LIGHT & TRANSPARENCY

• TRANSPARENCY IS LIMITED BY THE NUMBER & SHAPE OF PARTICLES FLOATING IN THE WATER.

• MORE PARTICLES=LESS LIGHT

• PARTICLES ABSORB LIGHT OR SCATTER LIGHT.

• PARTICLES= SEDIMENT, ORGANISMS (BOTH ALIVE AND DECAYING) AND OTHER DEBRIS (GARBAGE, PLASTIC, ETC.)

• THE GREATER THE TRANSPARENCY, THE GREATER THE AMOUNT OF LIGHT ENERGY CAN BE ABSORBED CREATING HEAT

• THIS CAUSES THE PHOTIC ZONE TO BE WARMER THAN THE APHOTIC ZONE

I. LIGHT & TRANSPARENCY

WHY IS THE OCEAN BLUE/GREEN?

• WATER ABSORBS COLORS AT THE RED END OF THE VISIBLE SPECTRUM

• REFLECTS THE BLUE END OF THE VISIBLE SPECTRUM WATER APPEARS BLUE/GREEN

• MOST VISIBLE LIGHT IS ABSORBED IN THE FIRST 100M BELOW SEA LEVEL…EVEN THE BLUE WAVELENGTHS ARE ABSORBED BY 300 M.

II. TEMPERATURE

TEMPERATURE= MEASURE OF KINETIC ENERGY

• THE CHEMICAL REACTIONS THAT DRIVE LIFE PROCESSES ARE INFLUENCED BY HEAT/TEMP.

• THE GREATER THE HEAT, THE FASTER THE REACTIONS CAN TAKE PLACE ESPECIALLY CELLULAR METABOLISM (PROCESS OF RELEASING ENERGY TO RUN CELLULAR FUNCTION).

• FOR COLD BLOODED ORGANISMS, METABOLIC RATES DOUBLE FOR EACH 10ºC INCREASE IN WATER TEMPERATURE

• METABOLIC RATE IS PROPORTIONAL TO HOW QUICKLY AN ORGANISM MOVES & REACTS.

• OCEAN TEMP. VARIES WITH DEPTH AND LATITUDE

• TEMP RANGE IS BETWEEN 0º-30ºC

II. TEMPERATUREECTOTHERMS OR POIKILOTHERMS= COLD BLOODED ORGANISMS THEIR BODY TEMPERATURE ADJUST TO THEIR SURROUNDINGS

PRO:

• CAN SLOW DOWN METABOLISM IN COLDER WATER REDUCES THE AMOUNT OF FOOD THEY NEED TO CONSUME

CON:

• THE COLDER THE WATER; THE SLOWER THE ABILITY TO MOVE

• SOMEWHAT HABITAT DEPENDENT

• EX> ALL MARINE FISH AND INVERTEBRATES

II. TEMPERATUREENDOTHERMS OR HOMEOTHERMS= WARM BLOODED ORGANISMS THEY HAVE A CONSTANT BODY TEMPERATURE THAT ALLOWS FOR A CONSTANT METABOLIC RATE, REGARDLESS OF THEIR SURROUNDING TEMPERATURE (FOR THE MOST PART).

PRO:

• THESE ORGANISMS CAN LIVE IN A WIDER VARIETY OF TEMPERATURES AND HABITATS THAN ECTOTHERMS

CON:

• ENDOTHERMS DEMAND A LARGER FOOD SUPPLY AND TEND TO HAVE MORE EFFICIENT MECHANISMS FOR GAS EXCHANGE.

• EX> MARINE MAMMALS

III. SALINITY

SALINITY= CELL MEMBRANES ARE SENSITIVE TO CHANGES IN SALINITY.

• FLUCTUATING SALINITY CAN PHYSICALLY DAMAGE MEMBRANES. TOO MUCH SALT CAUSES CELL DEHYDRATION.

• CONCENTRATED SALT CONTENT CAN ALTER PROTEIN STRUCTURE AND FUNCTION.

• SEE OSMOREGULATION NOTES

IV. SOUND

SOUND = ENERGY THAT TRAVELS IN PRESSURE WAVES… CAN ONLY TRAVEL THROUGH MATTER.

• SOUND TRAVELS ABOUT 1500M/S IN WATER (5XS FASTER THAN AIR) AND FASTER THAN LIGHT TRAVELS THROUGH WATER.

• SOUND ALSO BOUNCES OFF SUSPENDED PARTICLES & OTHER OBSTACLES IT ENCOUNTERS.

Echolocation= the use of sound to sense and locate objects in the water… natural sonar.• Used by toothed whales to

determine an objects size, distance, density and position.

• Echolocation involves the emission of sound and reception of its echo. 

• The sound is emitted in the head region and focused by the melon. 

• The received echoes pass through special sound conducting tissue in the lower jawbone to the inner ear.

IV. SOUND

• ECHOLOCATION IS USED BY TOOTHED WHALES, SOME PINNIPEDS (SEALS, ETC), BATS, AND APPARENTLY, SOME HUMANS!... CHECK THIS OUT:

• HTTP://YOUTU.BE/TB_YRWPPP0C

• BEN UNDERWOOD WAS HIS NAME… IF YOU ARE INTERESTED IN CHECKING IT OUT FOR YOURSELF

V. HYDROSTATIC PRESSURE

• HYDROSTATIC PRESSURE= THE CONSTANT WEIGHT OF THE WATER COLUMN ABOVE A CERTAIN DEPTH PRESSING DOWN ON AN OBJECT OR AREA.

• IT DIFFERS FROM ATMOSPHERIC PRESSURE, WHICH IS THE WEIGHT OF THE ATMOSPHERE PRESSING DOWN ON YOU OR ANY OTHER OBJECT.

• WATER IS HEAVIER(MORE MASS) THAN AIR, SO HYDROSTATIC PRESSURE IS GREATER THAN AIR PRESSURE

• IT “FEELS” HEAVIER

HYDROSTATIC PRESSURE ATMOSPHERIC PRESSURE EXERTS A FORCE OF 1KG/CM2 = ONE ‘BAR’ = ONE ATMOSPHERE

(‘ATA’)

• PRESSURE INSIDE AND OUTSIDE THE ANIMAL EQUAL OUT THEY HAVE ADAPTED TO WITHSTAND THIS IMMENSE PRESSURE.

• PRESSURE HAS BEEN THE BIGGEST LIMITING FACTOR TO OUR EXPLORATION OF THE SEA

• 100 M IS THE DEEPEST DEPTH EXPERIENCED DIVERS CAN TYPICALLY WITHSTAND 20ATA

VI. BUOYANCY

BUOYANCY= ABILITY TO FLOAT

• ARCHIMEDES’ PRINCIPLE= OBJECTS IMMERSED IN LIQUID (OR GAS) ARE “BUOYED” UP BY A FORCE EQUAL TO THE WEIGHT OF THE LIQUID (OR GAS) DISPLACED.

• THE DENSITY OF SEAWATER = THE DENSITY OF MOST LIVING TISSUE; SO ORGANISMS ARE BUOYED UP BY A FORCE THAT IS EQUAL TO THEIR OWN WEIGHT.

• EX> 2000 KG WHALE DISPLACES 2000 L OF WATER IN ORDER TO FLOAT

VI. BUOYANCYHOW DO MARINE CRITTERS AVOID SINKING?

ORGANIC TISSUE LIKE BONE AND SHELL OFTEN HAVE > DENSITY THAN WATER, SO ORGANISMS MADE OF LOTS OF BONE OR SHELL TEND TO SINK WITHOUT ASSISTANCE.

• MARINE ORGANISMS HAVE DEVELOPED ADAPTATIONS TO OFFSET THIS PROBLEM:

• SWIM (OR GAS OR AIR) BLADDERS-

• BALLOON LIKE STRUCTURE ALLOWS BONY FISH TO FLOAT WITH REDUCED ENERGY SPENT

• LIGHT CARTILAGINOUS SKELETONS

• SHARKS, RAYS, SKATES

• PRODUCTION OF OIL IN TISSUES

• SHARKS HAVE HUGE OILY LIVERS

• DIATOMS PRODUCE AN OILY SUBSTANCE TO HELP THEM FLOAT

VII. MOVEMENT & DRAG

WATER HAS A FAR HIGHER VISCOSITY THAN AIR, SO IT RESISTS MOVEMENT MORE THAN AIR.

• DRAG= THE RESISTANCE TO MOVEMENT CAUSED BY FRICTION.

• IT INCREASES WITH VISCOSITY AND THE SPEED, SHAPE OR SIZE OF A MOVING ORGANISM.

• SWIMMING ORGANISMS HAVE DEVELOPED ADAPTATIONS TO DECREASE DRAG:

• VERY SLOW SWIMMING SPEED

• MUCOUS SECRETIONS TO LUBRICATE ORGANISM SO THAT IT SLIPS THROUGH THE WATER

• FUSIFORM BODY SHAPES (TORPEDO SHAPED) STREAMLINING BY REDUCING TURBULENCE

I’m big & slow

I’m slimy

I’m fusiform

VII. MOVEMENT & DRAG

VISCOSITY AFFECTS MICROORGANISMS LIKE PLANKTON DIFFERENTLY.

• PLANKTON ARE SMALL IN SIZE, HAVE LITTLE STRENGTH, YET HAVE THE NEED TO STAY SUSPENDED IN THE PHOTIC ZONE TO SURVIVE.

• THEY HAVE DEVELOPED ADAPTATIONS LIKE PLUMES, FILAMENTS, RIBBONS, SPINES, AND A VARIETY OF APPENDAGES TO INCREASE THEIR DRAG TO HELP THEM RESIST SINKING.

VIII. CURRENTS… MORE IN CH 9

THERMOHALINE CURRENTS= DEEP OCEAN CURRENTS CAUSED BY DENSITY DIFFERENCES BETWEEN TEMPERATURE AND SALINITY

• CIRCULATE NUTRIENTS

• CREATE OCEAN CONVEYOR BELT

• DISPERSES BOTH LARVAE AND ADULT ORGANISMS TO NEW HABITATS

VIII. CURRENTS… LAST ONE!SURFACE CURRENTS= CURRENTS GENERATED BY THE PRESSURE GRADIENT FORCE CREATED BY WIND, THE CORIOLIS EFFECT AND THE ROTATION OF THE EARTH

• CREATES WAVES AND TIDES

• FURTHER CIRCULATES NUTRIENTS & DISPERSES LARVAE