Transcript Ocean Ecology and Pollution

Ocean Ecology and Pollution
Major ecological issues
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Photic, aphotic zones
All creatures in ocean, when dead, sink
Movement of nutrients to the bottom
Upwellings bring nutrients back to surface
Shoreline issues
• Substrate type; sand, mud, rock
• Tidal exposure
gure 52.15 Oceanic Biogeographic Regions Are Determined by Ocean Currents
Areas of upwelling
El Nino effects on local
weather
Normal- currents cause
upwelling along pacific
coast – upwelling brings
nutrients to surface
And cold water = rain
In el nino no upwelling, so
No nutrient in water – loss
of fishery, and a lot of rain
as surface water is hotter
and condenses when
coming on land.
Sea is warmer in el
Nino = more rain in
winter as greater
temp difference
water to land.
La Nina years are
colder ocean =
less rain.
Remember, rain in
winter when land is
cold.
Major environmental issues
• Humans can have major effects on the
ocean
• Directly (overfishing, etc.)
• Indirectly (global warming
many of these issues are not quickly
reversable, or are due to population
pressure
Global distribution of coral reefs = warm water
Coral biology
Grow in clear water
No nutrients
Harbor algae in their
tissues- algae make
Food – need
sunlight.
Zooxanthellae in a coral –
give coral color
Threats to reefs
• dynamite to get fish
• cyanide to get fish
• collecting coral
• siltation – river runoff
• algal growth = nutrients
• global warming – coral
bleaching = predicted that
the great barrier reef of
Australia will die in the
next decade – warming
and acidity. Note that
Caribbean coral reefs
already dead.
Overfishing – over use of ocean resources
• hard to census fish ( do it by catch)
• wasteful fishing methods
• food chain effects.
If fishing effort goes up and catch goes
down, the fish are in trouble
Antarctic whale catch.
see progression; biggest to smaller whales.
How to regulate fishing.
1) establish quota for catch.
result – a one day fishing season – everyone goes
out and tried to catch as many fish as possible
2. establish quota per fishing boat – can catch any
time during a longer season – better for safety and
marketing
3. must be international agreement in most cases –
4. prohibit all fishing – let stock recover. What do
fishermen do?
Marine reserve system – areas where no fishing so good reproduction –
hope is it stocks neighboring areas where fishing is allowed.
History of the pollock fishery off the Aleutians
Crab pots – crab fishing dead
Alaskan Pollock
Another case of overfishing
Food chain effects; Steller sea lion eats pollock
Killer whale eat seals
No seals- eat sea otters
Sea otters eat sea urchins
Sea urchins eat kelp – if lots of urchins, kelp cut loose from bottom
Young fish hide in kelp (kelp is a nursery area)
Switch from long line (cheap – mostly developing countries)
To purse seine (more technology – developed countries)
Catch of wild tuna goes down, farming goes up.
Problems with farming – pollution of organics.
Salmon farming issues
• escape and mating with
wild stocks
• disease – to wild stocks
• waste discharge
• fish food
The farmed product is generally softer in texture and is an
unappetizing grey colour. The latter problem is overcome by the
addition of pigment to the food in order to colour the flesh a moreappealing red tone. Although some indicate the addition of such
pigments is not a concern in farmed salmon, high doses of these
colorants can harm the human retina (Baker 2001).
Potrugese Man-o-war, a
floating jellyfish
Jellyfish are a main food
of marine turtles.
Storm water runoff.
Plastics in the ocean
½ year
Blue = U.S. origin,
3 years
Red = Japanese origin
10 years
Oil Pollution
Where is oil shipped?
Where is the ocean most dangerous?
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International convention for
prevention of oil pollution of the
ocean
Doesn’t apply to small vessels
Doesn’t apply to navies
Doesn’t apply to acts of God
Doesn’t apply if crew or cargo in danger.
Originally, only applied to coastal areas.
Is self reporting
• Requires ballast cleaning on shore, not in
ocean
• Requires safety equipment at on-shore
facilities
• Switch to double hulled ships
• Allows damages for oil spills.
Exxon Valdez 10.8 million gallons
of crude oil
Algal bloom in warm water and nutrients
Solutions to sewage issue
• Give tertiary treatment (too expensive)
• Dump further out to sea –
• Storm water runoff – totally untreated still
a problem.
• So; dump chlorine into ocean – kill
bacteria.
Malibu
• La wants to add them to the sewage
system, at a cost per household per
hookup
• Malibu incorporates so as a separate city,
they don’t have to join the sewage system
Enteromorpha (mermaids hair) as an
indication of poor water quality.
Species diversity of algae in So.
Cal.
• 1900 – 60 species
• 1960 – 27 species
• 1970 - 11 species
• Still clean on outside of Catalina,
• Inshore – no so clean
Why are nuclear plants usually near water? Effects??