threats to biological diversity 4: environmental factors

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Threats to biological diversity4: Environmental Factors

Sam HopkinsBiodiversity and Conservation

Biology

Pollution

Litter

Oil Spills

Pesticides

Fertilizers

Light

Global Warming

What Are The Environmental Factors What Are The Environmental Factors Causing Loss Of Biodiversity?Causing Loss Of Biodiversity?

100s of different pesticides exist

Many are worldwide contaminants as they have been carried in the air and water

Have been seen as agent of evolutionary change in some species

PesticidesPesticides

These pesticides all have

Chemical stability

High mobility

High solubility

Toxicity

A well known example of a chlorinated hydrocarbon pesticide is DDT

Pesticides: Chlorinated hydrocarbon Pesticides: Chlorinated hydrocarbon pesticides (CHs) pesticides (CHs) 11

Discovered in 1939

First used to kill mosquitoes

Used to control against pests such as the elm bark beetle

DDT does not just affect the target species

DDT is still used in some developing countries

Pesticides: DDT Pesticides: DDT 11

Has been seen to bioaccumulate and biomagnify throughout the trophic levels in the environment

An example is seen in a study by Boykins (1967) 2

Worms were absorbing DDT

The worms kept the DDT 18 months after spraying

Birds absorbed the DDT from the worms when they ate

DDT caused bird mortality

Seen in the artic and sub-artic 3

DDT increased from Ringed and Square flipper seals to Polar bears

Polar bear milk contained increased levels of DDT

Pesticides: DDTPesticides: DDT

This is not just affecting animals and plants

In Kibaha in Tanzania DDT was found in crops 4

The crops were eucalyptus, cashew, plums and casava which are eaten by humans

In Mato Grosso, Brazil the DDT in the soil is leaking into the underground water 5

In Turkey DDT has been found in 12 edible fish 6

These are concerns for public health


Some animals such as a few of the bird species that showed eggshell thinning are recovering since DDT was banned 1

In Grey Seals since the use of DDT has been stopped the gynaecological problems that the seal populations had have decreased and pregnancies have increased 7


These are the alternatives to the CHs 1

Have been seen to kill herbivorous birds 1

Affects birds that feed on sprayed insects 1

Rainbow trout that were exposed to methiocarb had lemmellar edema and the epidermis became separated from the lamellae 8

One of these is called Dioxin which causes cancer and birth defects in lab animals, this is still in use 1

Many of these substances have now been banned

Pesticides: Carbamates and Pesticides: Carbamates and OrganophosphatesOrganophosphates

The estimate of oil input into the environment is 3.2 million tons a year

Most of this is from land waste put into the ocean or into rivers

Evaporation and combustion allow petrol compounds into the air which are then cycled into the sea

More noticeable is the large media events of the ocean oil spills

Oil Pollution Oil Pollution 11

The worst spill was seen in the Persian gulf

This was during the war to liberate Kuwait in 1991

1,700,000 tons of oil was released into the sea

Not far off was the spill in 1979 from a Mexican platform

500,000 to 1,400,000 tons of oil was spilt

Better publicised are the oil tanker spills such as the Exxon Valdez in Alaska and Amoco Cadiz in France

Oil Pollution Oil Pollution 11

Spill occurred on March 24th 1989

The tanker hit a reef off the coast of Alaska

41,000 tons of crude oil was spilt

40-45% of the oil spilled ended up on the coast

Death Toll

350,000-500,000 sea birds

200 bald eagles

3,500-5,500 sea otters

350 Harbour seals

14 killer whales

Oil Pollution Case Study: Oil Pollution Case Study: The Exxon Valdez The Exxon Valdez 11

A misguided clean up operation was started

Activities lasted four years

Shores were washed with hot water and oil and tar was collected

Unfortunately the hot washing killed many of the shores invertebrates and pushed the oil onto unaffected beaches

The coast that had been cleaned was more damaged than the unclean part

Oil Pollution Case Study: Oil Pollution Case Study: The Exxon Valdez The Exxon Valdez 11

Long term affects

Fry of the pink salmon were sterile 1

Sockeye salmon could not be harvested, their numbers increased allowing many fry to starve to death 1

Mussels and clams are still poisoned 9

Sea otters have only managed to regain half of their numbers 9

People have had to move away from the coastline as they relied on the fish and seals for food 10

Oil Pollution Case Study: Oil Pollution Case Study: The Exxon ValdezThe Exxon Valdez

Differs from habitat to habitat

In open ocean oil slicks kill plankton and fish and effect sea mammals and sea birds

At the coast, sandy beaches can hide oil for months and rocky coasts become coated with the oil and kills almost all the organisms, this can last for years

In estuaries and salt marshes the effect of an oil spill are felt the hardest, here the oils can affect the environment for decades as it gets buried in the anoxic sediments to be exposed again at a later date

Oil Pollution: Impacts on the wildlife Oil Pollution: Impacts on the wildlife 11

Sea birds suffer the most when oil is spilled into the ocean

Many sea birds dive into the ocean to get food, every time they dive they pass through the oil slick

This causes their feathers to become oily which in turn inhibits their flight and buoyancy

Oil soaked feathers are not good insulators so the birds get cold

Trying to remove the oil by preening causes more problems like toxic effects on the liver, kidneys and pancreas

Oil Pollution: Impacts on the wildlife Oil Pollution: Impacts on the wildlife 11

Used as insulators and fire retardant

Have made way into aquatic systems

Long lived

High solubility in lipids

Food chain magnification

Impairs reproductive success in birds and seals and affects polar bears

Polychlorinated biphenyls Polychlorinated biphenyls 11

Found in petrol and cigarette smoke and given off after combustion of fossil fuels 1

Pollute aquatic environment 1

PAHs are activated by cytochrome P450 and form compounds that damage or mutate DNA, RNA or proteins 11

Some bond with the DNA, RNA or proteins and can cause cancer 11

Polynuclear aromatic hydrocarbons Polynuclear aromatic hydrocarbons

Heavy metal pollution has been going on for about 8000 years 12

Archaeologists have found evidence of copper extraction and smelting in the Faynan orefield in Jordan 12

Athenian civilisations managed to pollute the air with 2300 tons of copper every year, these figures were calculated from the ice sheets in Greenland 12

Other examples; mercury, lead and nickel 1

Many show food chain magnification 1

Affects fish, marine birds 1

For example gold mining uses mercury to separate the gold and the waste is poured into local water 1

An obscure example is the use of a paint on the hulls of ships that contains tin, it is toxic to marine organisms and is banned in some countries 1

Heavy MetalsHeavy Metals

Naturally occurs in soils

Where desert regions are farmed selenium leaches into the local water

An example of this was seen in California at the Kesterson National Wildlife Reserve

Caused reproductive failure in some birds and birds that did manage to breed hatched deformed chicks

Also caused death

Selenium Selenium 11

For example, caesium, strontium and

phosphorous

All show bioconcentration and biomagnification

A well known example of this kind of pollution

was seen at the disaster of Chernobyl

Radioisotopes Radioisotopes 11

The Chernobyl disaster occurred in the Ukraine in 1986

There had been a nuclear reactor at the site since 1977

The explosion occurred due to a safety test

The explosion exposed the core

Radioactive fission products and debris rose 1 km into the air

The pollution was carried north-west on the wind

The graphite fire lasted 9 days

Radioisotopes – Chernobyl Radioisotopes – Chernobyl 1313

The soviet government at the time did not admit that there was anything wrong

Only noticed by Swedish workers who saw the smoke

A tunnel was dug underneath the core to place a concrete slab and a cooling system

The core was placed in a 300,000 ton concrete and steel box

Before the box was in place six tonnes of uranium dioxide and fission products along with xenon, krypton, iodine, tellurium and caesium were released into the atmosphere


The effects of the radiation widespread

Caesium has a long half life and is absorbed into the body like potassium so it quickly got into the food chain 13

Radiation got in to the ground water 13

There was a rise in thyroid cancer 13

More than 20 species show genetic damage 14

Radiation reduces antioxidants and immune response in animals 15

Has increased levels of partial albinism

Has affected breeding successes of animals 15

Radioisotopes – Chernobyl Radioisotopes – Chernobyl

Now the concrete and steel box that is containing the radiation is breaking down

Work is being carried out to repair the box

A large arch is being constructed to contain the radiation and the concrete box

The three undamaged reactors need to be decommissioned

Need to dispose of the radioactive waste that was dug into the ground in 1986


Plastics pollute the land and sea

On the Sargaso sea surface there are about 3500 pieces of plastic making up 290 grams per km2 16

Animals are known to eat plastics

Sea turtles are notorious for eating plastic bags assuming they are jellyfish

Laysan albatrosses have been seen to feed plastic bags to their chicks 1

In a study by Moser and Lee (1992) 1033 birds were collected from 1975-1989 17

21 of the 38 bird species had plastic in their stomach

The amount of plastic in the birds stomach increased over time

Some birds selected for particular colours or shapes

Plastic Plastic

There is no easy answer

Man will continue to pollute and the environment will carry on suffering

Some governments regulate the use of pesticides

Oil tankers are now built with a double hull 1

An international dumping convention in 1972 agreed to by 64 countries states that deliberate dumping of CHs, PCBs, some heavy metals, plastics, petroleum and radioactive waste must be stopped 1

The answerThe answer

This pollution occurs when we switch lights on outside at night

Estimates show that two thirds of the population are living in areas above the accepted light pollution level 18

Light pollution affects many species in ways we are only just understanding

Trees increase their growing season in the presence of outdoor lighting and are then susceptible to winter frosts 19

The Hawk moth (Deilephilia elpenor) shows decreased ability to see colours in artificially lit environments 20

Artificial light at night increased tumour growth and decreased survival in female rats 21

Light PollutionLight Pollution

Large topic much talked about recently

Estimate that 18% of the species in Central America, Australia, South Africa and Europe will disappear 22

Earth warmer now than in the last 40 million years 23

Problems:

Change may occur so rapidly that plants and animals cannot adjust

Compounded by habitat fragmentation and degradation

The new conditions may be more suitable for invasive species

Has caused distribution shifts in species

Global Climate Change Global Climate Change 11

Species are moving pole-wards, global meta-analysis predicts that ranges will move north by 6.1km per decade and spring will become 2.3 days earlier

Shown by non-migratory butterfly species, 63% of 35 species have shifted their range northward by between 35-240km 24

Species are adjusting their breading seasons

Shown by native amphibian species in Britain 25

Species are moving higher in altitude

Species are becoming extinct

Shown by Bufo periglenes 26

Global Climate ChangeGlobal Climate Change

Study by Beebee (1995)

The time that five species entered a pond was recorded over 17 years

Bufo calamita and Rana esculenta spawned earlier each year

The three newt species arrived 5 weeks earlier in 1994 than in 1978

Pond arrival time of T. vulgaris and spawning of R. esculenta gets 9-10 days earlier every 1 °C increase in temperature

Global Climate Change – Global Climate Change – Species altering breeding season Species altering breeding season 2525

Study by Pounds et al. (1997)

The Golden toad (Bufo periglenes) lived in the Monteverde cloud forest

It is not conclusive but evidence suggests that the climate changed in the years preceding the disappearance of the Golden Toad

The toad relied on the cool, wet cloud forest and water bodies for breeding

Global Climate Change – Global Climate Change – Species becoming extinct Species becoming extinct 2626

This is an enormous topic and not everything is covered here

The human population is doing a lot to pollute the environment

The effects of this pollution are not fully understood

In conclusionIn conclusion

1. Cox, G. W. (1997) Conservation Biology (2nd ed) concepts and applications. Pp 223-232

2. Boykins (1967) The effects of DDT contaminated earthworms in the diet of birds. Bioscience 17:37-39

3. Bowes, G. W. and Jonkel, C. J. (1975). Presence and distribution of polychlorinated biphenols in artic and sub-artic marine food chains. Journal of Fish Research Board, Canada 32: 2111-2123

4. Marco, J. A. M. and Kishimba, M. A. (2006). Pesticides and metabolites in cassava, eucalyptus, plum and cashew leaves and roots in relation to a point source in Kibaha, Tanzania. Chemosphere 64: 542-548

5. Villa, R. D. et al. (2006). Dissipation of DDT in a heavily contaminated soil in Mato Gosso, Brazil. Chemosphere 64: 549-554

6. Coelhan et al. (2006). Organochlorine levels in edible fish from the Marmara sea, Turkey. Environmental International 32: 275-280

7. Bergman, A. (1999). Health condition of the Baltic grey seal (Halichoenis grypus) during two decades. APMIS 107: 270-282

8. Altinok, I. et al. (2006). Effects of water quality and fish size on toxicity of methocarb, a carbamate pesticide, to rainbow trout. Environmental Toxicology and Pharmacology 22: 20-26

9. BBC news at News.bbc.co.uk/1/hi/world/americas/3333369.stm (accessed July 2006)

10. BBC news at News.bbc.co.uk/1/hi/ programmes/from_our_own_correspondent/301097.stm (accessed July 2006)

11. Oh, E. et al. (2006). Comparison of immunological and genotoxilogical parameters in automobile emission inspectors exposed to PAHs. Environmental Toxicology and Pharmacology 21:108-117

12. Grattan et al. (2006). The local and global dimensions of metalliferous pollution derived from a reconstruction of an eight thousand year record of copper smelting and mining at a desert mountain frontier in Southern Jordan. Journal of Archaeological Science (in press)

ReferencesReferences

13. BBC news at Bbc.co.uk/dna/h2g2/A2922103 (accessed July 2006)

14. BBC news at News.bbc.co.uk/1/hi/in_depth/europe/2006/chernobyl/default.stm (accessed July 2006)

15. Moller, A. P. and Mousseau, T. A. (2006). Biological consequences of Chernobyl: 20 years on. Trends in Ecology and Evolution 21: 200-207

16. Carpenter, E. and Smith, K. L. (1972). Plastics on the Sargasso sea surface. Science 175: 1240-1241

17. Moser and Lee. (1992). A fourteen year survey of plastic ingestion by Western North Atlantic sea birds. Colonial Waterbirds 15: 83-94

18. Cinzano, P. et al. (2001). The first world atlas of the artificial night sky brightness. Monthly Notices of the Royal Astronomical Society 328:689-707

19. International dark sky association at www.darksky.org (accessed July 2006)

20. Johnsen et al. (2006). Crepuscular and nocturnal illumination and its affects on colour perception by the nocturnal hawk moth, Deilephilia elpenor. Journal of Experimental Biology 209: 789-800

21. Cos, et al. (2006) Exposure to light-at-night increases the growth of DMBA-induced mammary adenocarcinomas in rats. Cancer Letters 235: 266-271

22. Thomas, C. D. et al. (2004). Extinction risk from climate change. Nature 427: 145-148

23. Easterling, D. R. et al. (1997). Maximum and minimum temperature trends for the globe. Science 277: 364-367

24. Parmesan, et al. (1999). Poleward shifts in geographical ranges of butterfly species associated with regional warming. Nature 399: 579-583

25. Beebee, T. J. C. (1995) Amphibian breeding and climate. Nature 374: 219-220

26. Pounds, J. et al. (1999) Biological response to climate change on a tropical mountain. Nature 398: 611-614

ReferencesReferences

threats to biological diversity 4: environmental factors

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