COSEE Summer 2008 April Graves, Teacher Harriet Perry, Scientist
Human Impacts on the Marine Environment A day in the life of SpongeBob
Importance of Oceans • 97% of the Earth’s surface water is contained in the ocean. • Oceans moderate temperature and influence weather. • Oceans provide food and recreational resources. • Oceans are a source of fuel. • Nearly 3 billion humans live within 150 km of a coastline.
Connectivity Oceans connect the human world because their waters touch all shores. Thinking about the ocean must be done in a global context, recognizing the fluidity of water… Carl Safina, Audubon Oceans are changing at an unprecedented rate. Global warming, alteration of habitat, eutrophication, contaminated food webs, overharvesting, and the spread of exotic species are some of the factors affecting our marine ecosystems.
A New Ocean • A scientist, Dr. Jeremy Jackson, has predicted that due to human interaction with our oceans, ecosystems will be dominated by microbes and jellyfish.
Jackson predicts that over-fishing combined with nutrient enrichment will lead to the… Rise of Slime
Fishing Down the Food Web • Apex predators over harvested. • Fishing at lower trophic levels. • Landings from global fisheries have shifted from large carnivorous fishes to planktivorous fishes. http://kingfish.coastal.edu
Destruction of Benthic Habitats: Shallow Reefs SpongeBob’s quest to find stable ground.
SpongeBob’s Ecosystem Water must be • Warm • Clear/clean • Shallow
Excess nutrients Sewage and agricultural runoff. Overgrowth of algae can smother the reef.
Mining Corals are, in some regions, mined for commercial use.
Sedimentation • When vegetation is removed, erosion occurs. • Sediment is moved downstream to the oceans.
Larval sponges can not attach and grow…No more SpongeBabies!
Deep water Coral Reefs • The outer continental shelf off Mississippi, Alabama, and west Florida is dotted with ancient coral reef structures that have eroded over many thousands of years to steep sided pinnacles and plateaus. • These areas are covered with lush forests of soft corals, black corals, sponges, sea-lilies, and deep sea stony corals.
Destructive Fishery Practices Along the continental slope at around 600 feet and deeper lie Lopheliareefs that scientists have only recently begun to study. In 2002, scientists discovered extensive Lopheliareefs off the Mississippi coast at about 1,500 feet. Trawls, long-lines, anchors, and other fishing gear have visibly damaged many of these reefs.
Marine Pollution Pollution
Eutrophication The accelerated production of organic matter, particularly algae, in a water body. It is usually caused by an increase in the amount of nutrients being discharged to the water body. http://www.marietta.edu
Eutrophication Nutrient over enrichment can lead to areas of oxygen deprived waters known as Dead Zones. There are nearly 150 dead zones in the world’s oceans. The Dead Zone off of Louisiana is as large as the state of Massachusetts.
Good News and Bad News • Dead Zones are a soup of jellyfish and bacteria. • So there will be a lot of jellyfish for SpongeBob to chase, but he will have to wear scuba gear to breathe.
Toxic Substances • Enter into the Gulf of Mexico through the Mississippi watershed. • Accumulate in marine food webs. • Can cause serious health problems in humans consuming seafood • Detrimental to marine organisms.
DDT in Brown Pelicans • DDT, once found in pesticides, reached oceans from agricultural runoff. • The DDT made the pelican’s egg shells soft. • When the pelicans incubated their eggs, the shells broke.
Plastics • About 80% of marine debris come from the land via urban runoff and storm drains. http://www.helixcharter.net
Plastics in the Ocean • Plastics do not biodegrade. • Their polymer bonds can not be broken down by organisms. • Plastics will photodegrade into smaller and smaller pieces until only dust is left. • Plastic debris can remain in the ocean for centuries.
Plastic “Sponges” • Plastics are “sponges” for the accumulation of oily organic pollutants. • Jellyfish may consume the plastic pieces and introduce toxic substances into the food web.
North Pacific Garbage Patch http://usera.imagecave.com
Top 5 Types of Marine Debris Activity List what you think the top 5 types of marine debris are. http://library.thinkquest.org
Ocean Warming • Coral bleaching is a natural process. What is not natural is the rate at which it is occurring. • Coral bleaching results from high sea surface temperatures.
Invasive Species • Colonize pipes constricting flow, can reach densities as high as 700,000/m2 • Highly efficient filter feeders • Populations in lower Mississippi River; single specimen found in Mississippi Sound • Becoming more salinity tolerant;can reproduce in salinities of7 ppt; have the potential toestablish populations in estuaries. USGS
Ocean Acidification • The ocean is becoming more acidic due to an increase in atmospheric CO2. • Decreasing ocean pH will negatively affect organisms that have calcium in their shell or exoskeleton. • As pH falls, structures made of calcium carbonate are vulnerable to dissolution.