Chapter 9 Marine Ecology ©2003 Jones and Bartlett Publishers.
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Transcript of Chapter 9 Marine Ecology ©2003 Jones and Bartlett Publishers.
Chapter 9
Marine Ecology
©2003 Jones and Bartlett Publishers
Quiz at beginning of lab period.
Not at end of lecture.
Ask me questions!
Ecology
-From greek ‘oikos’ meaning ‘house’.
-The study of organisms ‘at home’.
-More formal definition: The science of the interrelationships between living organisms and their environment (Odum).
9 Marine Ecology
There are two major marine provinces: the benthic (bottom) and the pelagic (water column).
•The benthic environment is divided by depth into the following zones:
– Littoral (<1%) intertidal- between the tides– Sublittoral (8%) low tide to edge of cont. shelf, 0-
200m– Bathyal (16%) 200 – 2000 m– Abyssal (75%) 2000 – 6000 m– Hadal (1%) > 6000 m
Marine Provinces
There are two major marine provinces: the benthic (bottom) and the pelagic (water column).
• The pelagic environment is divided by depth into the following zones:
– Neritic Shallow water overlying cont. shelves.– Oceanic Deep water beyond shelf edge.
• Epipelagic (3%) 0 – 200 m surface, illuminated
• Mesopelagic (28%) 200 – 1000m• Bathypelagic (15%) 1000 - 2000 m• Abyssalpelagic (54%) 2000 – 6000 m• Hadalpelagic (<1%) >6000 m In trenches.
Marine Provinces
Marine Provinces
Light Zones
• Yet another way to classify the ocean
• Photic zone
– light is sufficient for photosynthesis
– to 100 (or 200 m)• Dysphotic zone
– light is too weak for photosynthesis
– twilight zone– < 5% sunlight– 100 to 200 m
• Aphotic zone
– no light
In 1735 Linnaeus developed the taxonomic classification used in zoology.
Kingdom (Metazoa)
-Phylum (Chordata)-Class (Mammalia)
-Order (Primate)-Family (Hominidae)
-Genus (Homo)
-species (sapiens)
• The scientific name of an organism consists of its genus name (capitalized) combined with a species name (lower case), both italicized or underlined.
• Ex. Homo sapiens
Classification of Organisms
The five major kingdoms in the ocean are:
• Monera: single-celled organisms without nucleus (Prokaryotes)
• Protista: single-celled organisms with nucleus (Eukaryotes).
• Fungi : important in decomposition and recycling.
• Metaphyta: plants that grow attached to the sea floor.
• Metazoa: all multicellular animals in the ocean.
Classification of Organisms
Marine organisms can also be classified by lifestyle.• Plankton –float passively, can swim vertically, but not
against currents.
• They can be divided into phytoplankton (plants) and zooplankton (animals).
• Nekton
– active swimmers (marine fish, reptiles, mammals, birds and others)
• Benthos
– live on the bottom (epifauna)– within the bottom sediments (infauna)
• Some organisms cross from one lifestyle to another during their life, for example being planktonic early in life and benthic later (seaweeds, clams, etc).
Classification of Organisms
Classification of Organisms
Epiflora
Epifauna
Infauna
Classification of Organisms
Flounder: Benthos or nekton???
Classification of Organisms
Clam:
Benthos or plankton???
Classification of Organisms
Classification of Organisms:
The 5 Kingdoms
Monera: bacteria-no internal cell membranes-planktonic or benthic-recycle organic material-some photosynthetic
Blue-green algae(photosynthetic)
heterotrophic
Classification of Organisms
Protista: foraminifera, diatom, seaweed-planktonic or benthic-internal membranes-planktonic, benthic, eat or photosynthesize
Foram.
DiatomSeaweed
Classification of Organisms
Fungi: single and multi-cellular-decomposers-planktonic or benthic
Classification of Organisms
Metaphyta: multi-cell plants-primary producers in intertidal-benthic
eelgrass
Salt marsh
MangrovesNot seaweeds!
Classification of Organisms
Metazoa: multicellular animals-planktonic (jellyfish, shrimp), nektonic
(fish,whales), and benthic (crabs, worms).
Fish
jellyfish
whales
•Ecosystem is the total environment including the biotic (living) and abiotic (non-living) physical and chemical aspects.
– Examples of marine ecosystems:• Salt marshes• Mangrove• Intertidal• neritic• Benthic• Or, global ecosystem.
Basic Ecology
•Environmental factors in the marine environment include:
-temperature-salinity-pressure-nutrients-dissolved gases-currents-light-suspended sediments-substrate (bottom material)-river inflow-tides and waves.
Basic Ecology
Basic Ecology
• Temp ranges in ocean between -2 to ca. 40 C.
• More than 90% of ocean is <5 C.
• Can control distribution, degree of activity, and reproduction of an organism
• Temperature controls the rate of chemical reactions within organisms, thus their rate of growth and activity
– Most organism’s are ‘cold-blooded’ or ectothermic.
– 10oC rise in temperature, doubles the activity
Temperature:
Temperature Effects: barnacles
• more activity with higher temperature
Temperature Effects: clam harvest
Salinity Effects
• Can control the distribution or behavior of organisms.
– Epipelagic more S-tolerant than mesopelagic organisms.• Nearshore organisms more tolerant to salinity changes.
– Large S-variations results in tolerant organisms.– Sessile benthic can close shells.
• Availability of dissolved elements (calcium and silicon) can limit an organism’s ability to construct shells.
– Silica depletion results in reduction in diatom production.• Marine organisms’ body fluids have the same
proportion of salts than sea water.
– Sometimes more salt, sometimes less, than surrrounding sea.
– Diffusion, osmosis and osmoregulation.
Salinity Effects: Diffusion
Definition: physical process whereby molecules move from areas of higher concentration to areas of lower concentration.
Salinity Effect: Osmosis
Definition – Diffusion of water molecules through a semi-permeable membrane.
Remember: “salt sucks”
Osmoregulation by Marine and Freshwater Fish
Marine fish must control osmoticwater-loss or fish will dehydrate.
Freshwater fish must control osmoticwater-gain or fish will swell & explode.
• The pressures exerted by a column of water surrounding an organism.
– 10 m column of water = 1 atm.
Hydrostatic Pressure
Hydrostatic Pressure
3 Styrofoam cups sent to 5000 meters depth.
Hydrostatic Pressure
•How do deep-dwelling animals survive high pressures?
•Answer: many have no body cavities containing gasses.(Gasses are more compressible than liquids).
•Fish use gas-filled swim bladders to regulate depth.
Plankton include plants (phytoplankton) and animals (zooplankton).
More than 90% of marine plants are algae and most are unicellular and microscopic.
Selective Adaptive Strategies: Plankton
Phytoplankton photosynthesis
Selective Adaptive Strategies: Plankton size- one way plankton defy gravity to stay suspended in photic
zone
Some Characteristics of Phytoplankton
•Size: 0.5 micron to 1 mm
•Eukaryotes and prokaryotes (bacteria)
•Some motile with flagella (dinoflagellates) some not (diatoms)
•Contain chlorophylls and other pigments for photosynthesis.
•Silica, Calcium carbonate, or no shell.
•Responsible for ½ oxygen production on Earth.
•Major sink for atmospheric CO2.
•Major types:•Diatoms (require silica for growth)•Dinoflagellates (some toxic; symbiotic with corals)•Synechococcus and Prochlorococcus (tropical)
Some Diatoms
General Diatom Structure
Chloroplast
Diatom Cell Division
Phytoplankton “blooms”
Diatoms and other phytoplankton can divide many time per day producing large blooms that are sometimes visible from space.
Zooplankton include the copepods and foraminifera.
•Copepods are small herbivores (plant-eating organisms) that filter diatoms from the water.
•Foraminifera are single-celled animals which build shells of calcium carbonate.
Zooplankton
Zooplankton include the copepods and foraminifera.
Zooplankton
Live foraminifera (size ca. 0.5 mm) Copepod
(size ca. 1-5 mm)
Selective Adaptive Strategies: Copepod feeding
The morphology of fish has evolved to allow them to move through the water easily.
•The fish’s body must overcome three types of drag (resistance)
– surface drag– form drag– turbulent drag.
Selective Adaptive Strategies: Fish
•Surface Drag: Friction between the moving body and surrounding fluid.
– Decrease surface area, decrease surface drag.– Sphere has least surface area for given volume,
so sphere is best shape for reducing surface drag.– But fish aren’t shaped like an orange, so what
else is important?
Selective Adaptive Strategies: Fish
•Form Drag: Proportional to cross-sectional area of fish’s body.
– larger x-sectional area, more water needs to be ‘pushed aside’.
– Narrow pencil-shaped body best for moving through fluid.
– But not all fish are shaped like pencils either, so what else is important?
Selective Adaptive Strategies: Fish
•Turbulent drag: friction arising from turbulent eddies of water that form behind an object moving through a fluid.
– Reduced by having classic ‘torpedo shape’.– Torpedo shape displaced water with minimal
disturbance.– What fish is most superbly adapted for swimming
at high speeds for extended periods of time??
Selective Adaptive Strategies: Fish
Selective Adaptive Strategies: Fish
The Tuna!!
Selective Adaptive Strategies: Aspect ratio
The speed of a fish is related to the shape of its caudal fin:
Aspect ratio, AR = (Caudal Fin Height)2/Caudal Fin Area
High-speed cruisers
Quick, dartingmovement
Selective Adaptive Strategies: Fish classification scheme based on locomotion
Intertidal benthic communities generally are arranged in distinctive bands, termed vertical zonation.
•Zonation reflects the amount of time the area is submerged and the ability of the organism to survive the stress of exposure.
•Benthonic communities also vary in response to substrate (bottom material). Some organisms are adapted to rocky, sandy, or muddy sea bottoms.
9-5 Selective Adaptive Strategies
Banded Benthic Communities
A complex interaction among kelp, sea urchins, and sea otters controls the kelp community.
•Macrocytis is a brown algae that grows up to 40m long in extensive beds on North America’s Pacific continental shelf.
•Sea urchins feeding on kelp detach them from this holdfast and devastate the kelp beds.
The Ocean Sciences: Ecology of the Giant Kelp Community
Kelp Forest Ecology
•Sea otters feed on sea urchins and control the size of their population.
– Where sea otters abound, sea urchins are few, kelp beds thrive and sea otters feed mainly on fish.
– Where sea otters are few, sea urchins abound and kelp bed are thin. Sea otters then mainly eat sea urchins.
The Ocean Sciences: Ecology of the Giant Kelp Community
2-5 Geophysical SurveyingTHE END
•Surface Drag: Friction between the moving body and surrounding fluid.
– Decrease surface area, decrease surface drag.– Sphere has least surface area for given volume,
so sphere is best shape for reducing surface drag.– But fish aren’t shaped like an orange, so what
else is important?
Selective Adaptive Strategies: Fish
•Form Drag: Proportional to cross-sectional area of fish’s body.
– larger x-sectional area, more water needs to be ‘pushed aside’.
– Narrow pencil-shaped body best for moving through fluid.
– But not all fish are shaped like pencils either, so what else is important?
Selective Adaptive Strategies: Fish
•Turbulent drag: friction arising from turbulent eddies of water that form behind an object moving through a fluid.
– Reduced by having classic ‘torpedo shape’.– Torpedo shape displaced water with minimal
disturbance.
– What fish is most superbly adapted for swimming at high speeds??
Selective Adaptive Strategies: Fish