How do humans affect the marineenvironment both directly and indirectly?
For each effect, discuss how it affects a specificmarine environment and why this effect isharmful to marine life. For one effect,discuss how it can have an impact both locallyand across an entire ocean.
Effects of humans on the marine environment
•Direct effects•Indirect effects
Minamata Disease:methyl
mercurypoisoning,
Japan,1950s &
1960s
Greenhouse effect and global warming
One of major greenhouse gases is CO2
CO2 + H2O O2 + C6H12O6(glucose)
Sources of CO2respiration by plants and animals on landrespiration by marine plankton, algae,
animalscombustion of fuel (industry, cars,
burning of forest)volcanic eruptions
Greenhouse effect and global warming
Planet is warming+ 0.5 degrees C (0.9 degrees F) 1900-2000UN predicts +1.0 to 5.8 deg C (2.1-11 F)
byend of 21st century CO2 up 25% since 1850
Predicted Consequences of warmer temperatures:
more storms, flooding, climate changesea level rise (ice caps, expansion of water)
1-5 feet by 2030?
Sea level rise Cause: melting of ice caps,expansion of warmer water
Predicted rise of 1-5 feet by 2030Netherlands, Florida, New Orleans
will be much smallerIsland nations may disappear
(Maldives, Kiribati)Coral reefs and mangroves will be under
deeper water
Predicted effects on global warming on marine life
Coral bleaching and diseaseChange in ocean currents
Gulf Stream moves: NW Europe colderFlooding of mangroves and estuariesChange in species that are fishedPlankton hurt by radiation in Antarctica (ozone hole)
indirect effects on rest of life there
Coral Bleaching:
symbiotic algae(zooxanthellae)
expelled
Bleachedpolyps
of anemone
CFCs (Chloroflourocarbons) used in sprays andair conditioners:
CFCs:are a greenhouse gasDestroy the ozone layer (O3) that cuts out UV
Ozone hole over Antarctica was 3X size of USA in 2000
Predicted effects on global warming on marine life
Coral bleaching and diseaseChange in ocean currents
Gulf Stream moves: NW Europe colderFlooding of mangroves and estuariesChange in species that are fishedPlankton hurt by radiation in Antarctica (ozone hole)
indirect effects on rest of life there
What can be done?
1) Kyoto Climate Change Conference (1997)
Agreed to 6% to 8% reduction ingreenhouse gases from 1990 levelsby 2012
Requires consumers and industriesto cut use of fossil fuels and CFCs
USA withdrew from agreement in 2001
What can be done?
1) Kyoto Climate Change Conference (1997)
2) Fertilization of oceans (Iron is limitingfactor in oceans)
•Photosynthesis uses CO2, gives off O2 CO2 + H2O O2 + C6H12O6 (sugar)
•Increase photosynthesis by fertilizing oceanand phytoplankton.
Figure 18 p.422
Figure 18 p.422 (right)
European green shore crab introduced SF 1989
Spread along Pacific, NE USA,Australia, South AfricaCan live in wide range of salinitiesVoracious predator
Comb jelly (Mnemiopsis leidyi) from N and SAmericaDevastated fishery in Black Sea, also in SF Bay
Zebra mussel from Europe to Great Lakes 1988
San Francisco Bay: 250 introduced species
Busy port (ballast water of ships brings in non-native species)
Highly disturbed habitatinvasives (weeds) more tolerant of fluctuating
physical conditions, pollutionDiseases of non-natives transferred to native species(Still unclear why non-native species often do so well and outcompete native species)
Cultural bias against introduced species?
Toxic Algae Blooms
Increasing worldwideAccumulate in fish, shellfishCan sicken or kill people
Artificial reefs
What can you do to save the oceans?