Post on 20-Dec-2015
Ocean Ecology and Pollution
Major ecological issues
• 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
Figure 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 more-appealing 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.
½ year 3 years 10 years
Blue = U.S. origin, Red = Japanese origin
Plastics in the ocean
Where is oil shipped?
Where is the ocean most dangerous?
Oil Pollution
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??