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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

hydrauic pumping


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


what is the precautionary principle

a replacement for the maximum sustainable yeild to avoid anything that may potentially damage or negatively effect a fishery