Presentation on theme: "Coastal and Marine Resources. Main Lecture Topics Economically important living and non-living resources International legal framework that governs utilization."— Presentation transcript:
Petroleum, oil, and gas are hydrocarbons derived from sedimentary rocks which were deposited in productive regions with anoxic (low-oxygen) bottom waters 1. Deep burial resulting in high temperature and pressure converted the organic remains into hydrocarbons. - Initially get oil, but at higher temperatures and pressures, methane (CH 4 ) natural gas is generated. Oil and Gas Production
2. Pressure forces the oil and gas from the source rock into water- filled porous and permeable strata above. 3. Because oil and gas are less dense than water, they migrate upwards until their path was blocked by an impermeable layer. 4. Oil and gas accumulate, forming a large deposit within the pores of the rock, usually sandstone.
5. Only in the last 40 years has technology been able to efficiently extract petroleum from beneath the seas 6. Location of possible accumulations of oil and gas can be determined using seismic reflection and refraction methods to determine the configuration of rock layers. 6. Advances in drilling technology have allowed oil companies to explore in deeper offshore environments
Problems with Oil and Gas Production Petroleum Resources are NOT unlimited-- reliance of global economy on petroleum production is short-sighted Pollution: 1.Frequent Oil spills from tankers and platforms cause harm for to marine and coastal ecosystems
Gas hydrates refer to the unusual hydrocarbon deposits that consist of frozen water molecules entrapping molecules of methane (natural gas). Gas Hydrate Production
Gas hydrates occur in sediments of the polar regions of the ocean or on the continental slope between the depths of 300 -500 m where cold water is in contact with the sea floor.
Gas hydrate deposits contain incredibly large amounts of gas, but currently there is no economical method for its recovery.
Sand, Gravel, & Limestone Mining Sand and gravel is an important resource used for: 1. Replenishing sand on beaches undergoing coastal erosion and to restore and/or create salt-marsh wetlands 2.Constructing commercial or residential buildings
Problems with Sand and Gravel Mining Serious problems for bottom-dwelling communities that rely on stable sediments Disrupts fauna and flora Creates plumes of mud that interfere with phytoplankton photosynthesis and clog the filter-feeding appendages of organisms
Phosphorus is required for growth by all organisms; commercial fertilizers add significantly to this pool Phosphate deposits generally form on submarine terraces where coastal upwelling zones generates high productivity. Organic matter decomposition releases phosphorus compounds which precipitate as slow-growing phosphate nodules (1–10mm/1000 years) World phosphate consumption = 150 million tons per year and known supplies should last until 2050. Marine Phosphorus Mining
Rebuilding coral takes time because colonies of tiny coral animals grow slowly. Mined or dredged areas take a very long time to recover. Problems with Limestone Reef Mining Removes habitat of local marine species Weakens coastal storm defenses