Pollution: For years, humans have used the ocean as a dumping ground for waste:

Characterizing the intensity of pollution in time and space:

Chronic vs. acute pollution (time)

Point vs. non-point pollution (space)

Assessing the effects of pollution:

Population level declines in abundance and/or diversity

Bioassays that detect the presence of toxins or other chemicals

Some examples of marine pollution:

Toxic compounds used to control "pests" are often harmful

These can harm other species via bio-amplification (e.g. DDT)

Resistance to these compounds often develops quickly in the target species.

Anti-fouling paints inhibit settlement onto ship bottoms and docks.

Copper denatures protein and impairs the function of blood pigments

Tributyl tin (TBT) influences the reproduction of mollusks.

Polychlorinated biphenyls (PCBs) are used as lubricants

These can be highly carcinogenic and can bio-amplify into food-fish

Oil pollution is usually confined to surface waters and shorelines (oil floats)

Petroleum products typically harm sea birds and marine mammals that rely on insulation from feathers and fur.

Detergents used to clean up oil often harms other species

Effects can cascade through an ecosystem as one community after another in affected by a spill.

As in aquatic systems, eutrophication can occur where nutrients are overabundant.

This commonly occurs at the mouths of rivers, in estuaries, and in bays

Acid rain can contribute to eutrophication through the addition of nitrates (sulfur components also decrease pH... sometimes to toxic levels).

What about Carbon pollution in the atmosphere?

CO₂ levels are rising: currently atmospheric concentrations [CO₂]_atm = 400 ppm

projected (depending on what model you choose): 2050: [CO₂]_atm= 480 ppm; 2100: [CO₂]_atm = 560 ppm

While concerns about climate change are valid and frightening, changes in the oceans are also alarming

Sea temperature rise

Temperatures are rising, but as expected for water, more slowly than above the surface.

Biological consequences included: increased rates of metabolism (grow faster, but die earlier?); coral bleaching

Sea level rise - about 6 inches in the last century - (currrently 3.2 mm/yr and speeding up) - predictions of  2.5 - 6.5 feet by 2100.

Biological consequences: changes in shoreline distributions; swamping of current tideflat and estuary habitats.

Acidification

25% of atmospheric CO₂ is absorbed by the oceans

This causes acidification that changes the balance between the amounts of bicarbonate and carbonate

carbonate is necessary for the accretion of CaCO₃

Accretion is zero at carbonate concentrations of ~ 200µmol/kg ([CO₂]_atm~ 480 ppm)

Is this the end of coral reefs?

 

Habitat degradation is often found in coastal areas

Jetties alter the flow of sediment along coastlines.

Run-off and sedimentation can build bars that restrict flow

Use of marine substrate for building

Dynamite is used to kill fish and break up hunks of coral reef

Dams may be the most important reason that salmon stocks are declining in the Pacific NW

 

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