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