Flashcards in L18 Deck (44):
what is the law of the seas
in a treaty that placed the control of the seabed, its resources, and the water of the continental shelf under the country that owns the nearest land.
in what year was the law o the sea created and where
1958 and 1960 at the Geneva convention
rule on territorial waters
Territorial waters that extend seaward for 12 nautical miles from the coast and are under the direct jurisdiction of the coastal nation
rule on exclusive economic zone (EEZ)
An Exclusive Economic Zone (EEZ) that extends for 200 nautical miles offshore or to the edge of the continental shelf (note geological/tectonic controls), if that is farther, giving coastal nations the right to regulate fishing, mineral resources, pollution, and research. The right of vessels to free and innocent passage outside the territorial waters and through international straits that lie within territorial waters.
what odes the UN international seabed authority do
The United Nations’ International Seabed Authority must approve all private exploitation of mineral resources beyond the exclusive economic zones. Furthermore, part of the revenue from the exploiting resources must be shared with the developing nations.
how much of the ocean is (EEZ) and what is the remaining called
40% and the other 60% is the high sees
where are petroleum, oil and gas derived from
Petroleum, oil, and gas are hydrocarbons derived from sedimentary rocks that were deposited in quiet, productive regions with anoxic bottom waters in which the remains of phytoplankton accumulated
describe the process of petroleum oil and gas being produced
Deep burial resulting in high temperature and pressure converted the organic remains into hydrocarbons. Initially, oil was generated, but as temperatures and pressures increased due to burial, methane (CH4) and natural gas were produced. Pressure forced the oil and gas from the source rock into water-filled porous and permeable strata above. Because oil and gas are less dense than water, they migrated upward until an impermeable layer blocked their path. Oil and gas accumulated, forming a large deposit in the pores of the reservoir rock, usually composed of porous sandstone.
how can the location of oil and gas be determined
seismic reflection and refraction, but only drilling can corroborate the presence of the hydrocarbons
what is a gas hydrates
Gas hydrates refer to the unusual hydrocarbon deposits composed of frozen water molecules entrapping a single molecule of methane (natural gas
where do gas hydrates occur
Gas hydrates occur in polar sediments and in deposits of the continental slope between the depths of 300 and 500 meters, where cold water is in contact with the seafloor.
why are gas hydrates not recovered if the source is so rich
there is no economical method to collect them
how could gas hydrates contribute to global warming
Methane, along with hydrogen sulfide and ammonia, can seep into the water, where they are taken up by microbes. These microbes provide food for filter feeders around these cold seeps. If global warming raises the temperature of bottom water sufficiently, deep-sea hydrate deposits may melt and release large amounts of methane—a greenhouse gas—into the atmosphere. This could dramatically affect the climate.
why are sand and gravel mined
These materials are used for construction of roads and buildings and to replenish eroded beaches
what threat does mining sand and gravel cause
Mining sand and gravel deposits from the shelf threaten both the benthic and pelagic communities and introduce large amounts of fine suspended sediment in the water column.
what are manganese nodules composed of
Manganese nodules are composed of about 20 to 30 percent manganese, 10 to 20 percent iron oxide, 1.5 percent nickel, and less than 1 percent cobalt, copper, zinc, and lead
why are the manganese nodules not mined
Currently, there is no economical method of recovering the nodules from the deep sea
where are ferromanganese crusts found and what are they enriched with
The sides of many seamounts and islands have ferromanganese crusts that are enriched in cobalt between the depths of 1 and 2.5 kilometers
where are large sulphide deposits found
Massive Sulphide deposits are formed by precipitation of metals leached by hydrothermal fluid as it interacts with the cooler ambient seawater at or beneath the seafloor at hydrothermal vent sites
how are the sulphide deposits made
These fluids may discharge at temperatures up to 350°C from “black smoker” chimneys (at depths in excess of 2,500 m), but also at lower temperature (200°C) from hydrothermal vents. These generate in some cases mineralization of considerable economic potential, with primary Cu and Zn sulphide ores and occasionally the inclusion of precious metals such as gold.
where are phosphorite deposits found
Phosphorite deposits generally form on submarine terraces, where coastal upwelling generates high productivity.
how do phosphorite deposits form
Organic wastes and remains accumulate in the sediment, and as they decay, they release phosphorus compounds that precipitate as phosphate nodules
how fast do phosphate nodules grow
Nodules grow at the rate of about 1–10 mm/103 years
how long could phosphate supplies last
World consumption of phosphate is about 150 million tons per year, and known supplies should last until 2050.
how could mining deep ocean deposits be accomplished
what will be the three issues with hydraulic pumping
. The majority of the organisms drawn into the system will be killed.
2. Each day, large areas of the seafloor will be disrupted and stripped of life.
3. Sediment released at the surface will create a massive sediment plume as it sinks to the bottom. If the plume sinks quickly, it will have little impact on photosynthesis. If it remains near the surface, it likely will inhibit biological productivity. Rapid settlement of large quantities of sediment will bury and smother organisms on the sea floor. Pollutants at depth could be introduced into the surface water and disrupt food webs.
what are the two types of marine finfish
pelagic and groundfish
why are most fish found near regions of upwelling
because the rest of the ocean has low nutrient
how does the fishing industry find schools of fish
The fishing industry uses sonar, scouting vessels, airplanes, and satellites to locate schools and then deploy the fishing fleets to those areas
why are drift nets contreversial
Drift nets are controversial because they capture everything that is too large to pass through the mesh of the net and thereby needlessly kill many organisms
what does the 1989 United Nations’ Convention for the Prohibition of Long Driftnets state
The 1989 United Nations’ Convention for the Prohibition of Long Driftnets prohibited the use of drift nets longer than 2.5 kilometers, but compliance is largely voluntary and impossible to enforce in the open sea.
what is the worlds annual fish production
World ocean fish production appears to have levelled off at between 80 and 90 million tons annually
is the fishing industry financially stable
Currently, the expense incurred in fishing exceeds the profit from the sale of fish, and fishing industries only survive through government subsidies.
what is mariculture
Mariculture is marine agriculture, which is “farming” of finfish, shellfish, and algae. Mariculture requires raising the organisms under favorable conditions until they are large enough to be harvested for food
what are the conditions for mariculture to be financially viable
For mariculture to be economically viable the species must be: Marketable. Inexpensive to grow. Trophically efficient. At marketable size within 1 to 2 years. Disease resistant.
what are the statistics for how many fish consumed have lived on a fish farm
Currently, about one out of every four fish consumed spent at least part of its life on a fish farm, and for some organisms, the percentage supplied by mariculture is larger than what is harvested by fishing
what is overfishing
Overfishing is removing a living resource from the sea faster than it can replace itself, and if continued for a sufficient amount of time, the fisheries will collapse
how is overfishing possible today
Technology has made it easier to locate large schools of fish and direct fishing fleets to those locations. Mismanagement of policies related to sustaining fish production. Fishermen resist quotas and misreport catches.
what is the maximum sustainable yield
Maximum sustainable yield is the theoretical maximum amount of fish that can be removed from a population without significantly interfering with the population’s ability to renew itself each year.
how is the maximum sustainable yield established (what do they use to get the number)
The maximum sustainable yield is based on biological factors such as population dynamics, food webs, and spawning success and the fishing effort required to produce a given catch.
what are some problems with determining a maximum sustainable yield
Underreporting the amount of fish caught. Natural fluctuations of populations due to predation and food supply. The inherent difficulty in determining the size of fish populations.
what is discard fish
those returned to the sea because they are too small to retain or are of poor quality
what impact do discard fish have on the population
it is unknown