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?