LIFE IN THE MARINE ENVIRONMENT SOME BASICS OF BIOLOGY

Impact of Humans on the Marine Environment

1Anthropogenic impacts effects of human activities on the marine environment.Modification/Destruction of Habitats and Pollution can lead to:Loss of estuaries, mangrove forests and coral reefsDecrease in biodiversityLoss of habitat

Impact of Humans on the Marine Environment2Modification & Destruction includes activities such as dredging, dumping silt or mud, land filling, or the use of explosives.The effects of such disturbances are direct and immediate.Most destruction takes place along the coast.Modification and Destruction of Habitats3

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5Dredging results in the short term degradation of animals, vegetation and microbial communities that live in the dredged sediment. This reduces the estuary's capacity for nutrient cycling, primary production and habitat provision and can have effects up the food web. Though these effects tend to be short lived, in some cases they may trigger long-term changes. (Larkum and West, 1990; Lewis et al, 2001; Thrush and Dayton, 2002; Lohrer and Wertz, 2003; da Silva et al, 2004; Waycott et al, 2004; Ohimain et al; 2005) Changes in channel profile caused by dredging can increase tidal area, wave height and water velocity, resulting in bank erosion. Eroding banks threaten mangroves and other mudbank communitites and can lead to increased turbidity. Suspended sediment in the water column blocks light, reducing benthic primary productivity and inhibits the ability of benthic plants to recover from impacts of dredging. (Pringle, 1989; Larkum and West, 1990; Lewis et al, 2001; Rasheed and Balchand; 2001; Lohrer and Wertz, 2003; Sampson et al, 2005)

6Dredging exposes anaerobic layers of sediment, potentially disturbing and remobilizing toxic sediments, releasing contaminants. This has implications for water quality. (Linkov et al, 2001; Thibodeaux and Duckworth, 2001; Van Den Berg, 2001; Nayar et al, 2004) Dredge spoil needs to be deposited somewhere, though this could be deemed habitat creation, it can smother existing habitats and frequently contains contaminants which often move and bioaccumulate through the food web. The impacts of dredge spoil disposal can range from short term to long term (Linkov et al, 2001; Smith and Rule, 2001; National Ocean Disposal Guidelines for Dredged Material, 2002; Fredette and French, 2004)

7Estuaries and Salt MarshesOne of the most productive and biodiverse ecosystems on earthMany species that reproduce in these ecosystems are economically importantServe as breeding and resting grounds for many migratory speciesProvide natural water purification systemsProvide protection from the damaging wind and rain of hurricanesModification and Destruction of Habitats8Estuaries and Salt MarshesIncreasing pressures from human-induced activities are causing habitat loss and degradation, fisheries declines, and overall reductions in estuarine health and productivity. Associated physical alterations, such as dredging, damming, and bulkheading, change the natural flow of fresh water to estuaries, dramatically affecting water quality. Toxic substances and excess nutrients contribute to fish diseases, algal blooms, and low dissolved oxygen and can pose a threat to the health of humans and estuarine wildlifeModification and Destruction of Habitats9

Modification and Destruction of Habitats10Modification and Destruction of Habitats

11Mangrove ForestsAlso an ecosystem that is very productiveProvide food and shelter to many speciesHelp reduce coastal erosionShrimp mariculture is very destructiveForests are destroyed to build shrimp pondsWater from ponds, which contains large amounts of waste and excess nutrients is flushed into mangrove forest

Modification and Destruction of Habitats12Mangrove ForestsHave been cleared away for crops and urban developmentUsed as fuel and timberApproximately half have been destroyed

Modification and Destruction of Habitats13Modification and Destruction of Habitats

Shrimp Mariculture14Modification and Destruction of Habitats

Mangrove forest destruction for aquaculture in Indonesia15Coral ReefsHigh productivity and biodiversityProvides potentially life saving drugsThreatened byAgricultural runoffOvergrowth of seaweedsOver fishingMining of coral for construction materialClearing of rainforests causes increase sediment buildup on coral reefs. Higher sediment levels cause a decrease in photosynthesis which is detrimental to reefs

Modification and Destruction of Habitats16Coral ReefsBleaching of corals occurs when zooxnthellae (symbioses) are expelled and white patches form.Bleaching is a result of stress to corals which may be caused by in increase in water temperatures

Modification and Destruction of Habitats17Modification and Destruction of Habitats

18Modification and Destruction of Habitats

19Trawling nets are dragged across the bottom for shrimp and fish

Modification and Destruction of Habitats

20Pollution - The presence in or introduction into the environment of a substance or thing that has harmful or poisonous effects.Naturally occurring pollutants include:Natural oil seepshttp://video.nytimes.com/video/2011/03/21/science/100000000737132/22conversation.html (natural oil seep)Volcanic eruptionsSynthetic pollutants include:DDTPCB (polychlorinated biphenols)Metals released from mining operationsOil from human operations

Pollution21Pollution

22Pollution

23Eutrophication excessive algal growth as a result of excessive amounts of nutrients present in waterUsually occurs along coastsIncreases phytoplankton abundance sometimes causing blooms which decreases dissolved O2Reduces penetration of sunlightSome sources of nutrients includeAgricultural runoffFossil fuel combustionSewage runoff

Pollution24

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26Pollution

27Sewage - human domestic and industrial waste matter from buildings that is carried away through sewersMost sewage is dumped in oceans and riversPoses serious health hazardsDiseases such as hepatitis and brain infectionsBeaches and rivers may be closed because of risks to healthSewage may be treated in different ways to reduce health risksSludge waste that remains after sewage is treated is much more concentrated than the original sewage and can be more toxic to environment

Pollution28Oil (crude oil or petroleum) a mixture of hydrocarbons and certain chemicals; used as fuel and raw material for plastics, synthetic fibers, rubber, fertilizersSourcesAbout 210,056 gallons enter world oceans from pollutionAbout 179,872 gallons enter world oceans from natural seepage (not a pollutant)85% of polluting oil in North America comes from river runoff, coastal cities, fuel from small boats/jet skis, and fuel jettisoned by planes.15% comes from tanker and pipeline spills

Pollution29

1979 oil spill in the Gulf of Mexico (Blowout of an exploration well)30Oil is insoluble in water and therefore floatsSome oil evaporatesSome is broken down by bacteriahttp://video.nationalgeographic.com/video/player/environment/habitats-environment/habitats-oceans-env/declining-fish.html (oil eating bacteria)Some sinks to the bottom and accumulates in sediments, some remains at the surfaceOil that is not biodegraded may persist in the environment for decades

Pollution31

32http://www.youtube.com/watch?v=YkzB1ZYcTwM (Exxon Valdez oil spill 1989)http://www.youtube.com/watch?v=bXtsB4Go0hg&feature=related (Exxon Valdez oil spill 1 of 10)http://www.youtube.com/watch?v=MG6O92XIvFw&feature=related (Exxon Valdez oil spill 2 of 10)http://www.youtube.com/watch?v=rgEi7kxGXeo&feature=related (Exxon Valdez oil spill 3 of 10)http://www.youtube.com/watch?v=78bw1RdAh30&feature=related (Exxon Valdez oil spill 4 of 10)http://www.youtube.com/watch?v=CmczMUB07kw&feature=related (Exxon Valdez oil spill 5 of 10)

33http://www.youtube.com/watch?v=vB6m-CUqg2w&feature=related (Exxon Valdez oil spill 6 of 10)http://www.youtube.com/watch?v=eDTnfypbl0g&feature=related (Exxon Valdez oil spill 7 of 10)http://www.youtube.com/watch?v=s3L-WTmlXB8&feature=related (Exxon Valdez oil spill 8 of 10)http://www.youtube.com/watch?v=5LVv5EMwQ4M&feature=related (Exxon Valdez oil spill 9 of 10)http://www.youtube.com/watch?v=xj4mre_9boo&feature=related (Exxon Valdez oil spill 10 of 10)

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35Effects of oil pollution on marine life includeInterference with reproduction, development, growth and behavior of organismsIncreases susceptibility to diseases in fishesInhibits growth of phytoplanktonMany seabirds and marine mammals die of exposure when feathers of hair become coated with oil Many organisms starve to death

Pollution36

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38Containing an oil spill and clean up efforts can be as harmful to organisms as the oil itselfChemical dispersants used to break down oil are toxicPowerful streams of hot water used to clean oil off of rocks can damage marine lifeLocal economies suffer from oil spills

Pollution39http://news.discovery.com/videos/earth-gulf-coast-expert-oil-spill-threatens-seafood.html (gulf oil spill)

http://www.youtube.com/watch?v=mCWW5xt3Hc8 (satellite view growing gulf oil spill)http://video.nationalgeographic.com/video/player/environment/habitats-environment/habitats-oceans-env/declining-fish.html (stop oil from sticking to bird feathers)

http://www.nasa.gov/topics/earth/features/oilspill/

http://www.education.noaa.gov/Ocean_and_Coasts/Oil_Spill.html (use this site for educational materials)

http://oceanexplorer.noaa.gov/edu/guide/gomdse_edguide.pdf (another site for oil education make copy using color printer)

Pollution40Many pollutants never biodegrade and remain in the environment for decadesMajor group of synthetic chemical pollutants is the chlorinated hydrocarbons, these includePesticides such as DDTPCBs (polychlorinated biphenyls)Chlorinated dioxins and furansHeavy Metals

Persistent Substances41Chlorinated hydrocarbons dissolve in fats and are not excreted because the body can not metabolize themAt each level of the food chain the chlorinated hydrocarbons are more concentrated.This is known as biological magnification

Persistent Substances42Biological Magnification

43DDT levels were so high in fish that they had to be destroyed (too high for human consumtion)DDT caused a decrease in the deposition of calcium in bird eggs. The shells became so thin that they broke during incubation.DDT was banned in 1972 in the USPCBs were widely used in electrical transformers and in the manufacturing of plastics and paintsPCBs caused cancer and birth defectsPCBs banned in the US in 1979

Persistent Substances44Ibis Eggs that failed to hatch as a result of DDT

45Incinerating PCBs (See fig. 18-10)

46Dioxins and Furans enter the environment from pulp mills and waste incineratorsThey are carcinogenic and cause birth defects and damage to the immune system in many vertebratesHave been implicated in abnormal sexual behavior and reproductive ability in seabirds, marine mammals, and fishes. (PCBs form chemicals that are similar in structure to sex hormones and seem to disrupt reproduction)

Persistent Substances47Heavy MetalsRelationship to living organismsLiving organisms require varying amounts of "heavy metals." Iron, cobalt, copper, manganese, molybdenum, and zinc are required by humans.Excessive levels can be damaging to the organism. Other heavy metals such as mercury, plutonium, and lead are toxic metals that have no known vital or beneficial effect on organisms, and their accumulation over time in the bodies of animals can cause serious illness.

Persistent Substances48Heavy metal pollutionHeavy metal pollution can arise from many sources but most commonly arises from the purification of metals, e.g., the smelting of copper and the preparation of nuclear fuels.Through precipitation of their compounds or by ion exchange into soils and muds, heavy metal pollutants can localize and lay dormant.Unlike organic pollutants, heavy metals do not decay and thus pose a different kind of challenge for remediation.

Persistent Substances49Heavy MetalsOne of the largest problems associated with the persistence of heavy metals is the potential for bioaccumulation and biomagnification causing heavier exposure for some organisms than is present in the environment alone.

Persistent Substances50Solid Waste

51Solid Waste

52Seawater is often used in as a coolant in industriesThis heated water is then pumped back into the environment which causes thermal pollutionHigher water temperatures can adversely affect marine life

Thermal Pollution53

54Species are categorized as rare, threatened, or endangered when they face the possibility of extinction, or extermination.Causes of extermination (human induced extinction)Overexploitation for food and hidesDiscarded as fisheries by-catchHabitat destructionIntroduction of pest species

Threatened and Endangered Species55By-catch from shrimp trawling

http://www.youtube.com/watch?v=xwOlG8iu7DI&feature=BFa&list=PLDCB132D9DA2AD325&index=2 (whaling graphic images)http://videos.howstuffworks.com/animal-planet/28281-caught-in-the-moment-sea-turtle-conservation-video.htm (harvesting turtle eggs)

Threatened and Endangered Species57