Marine geology
Marine geology or geological oceanography is the study of the history and structure of the ocean floor. It involves geophysical, geochemical, sedimentological and paleontological investigations of the ocean floor and coastal zone. Marine geology has strong ties to geophysics and to physical oceanography.
"Marine Geology" redirects here. For the scientific journal, see Marine Geology (journal).Marine geological studies were of extreme importance in providing the critical evidence for sea floor spreading and plate tectonics in the years following World War II. The deep ocean floor is the last essentially unexplored frontier and detailed mapping in support of economic (petroleum and metal mining), natural disaster mitigation, and academic objectives.
Economic benefits[edit]
Resource exploration[edit]
Marine geology has several methods of detecting geological features below the sea.[2][13][14][15] One of the economic benefits of geological surveying of the seafloor is determining valuable resources that can be extracted.[42] The two major resources mined at sea include oil and minerals. Over the last 30 years, deep-sea mining has generated between $9 -$11 billion USD in the United States of America.[43][44] Although this sector seems profitable, it is a high risk, high reward industry with many harmful environmental impacts.[45]
Some of the major minerals extracted from the sea include nickel, copper, cobalt, manganese, zinc, gold, and other metals.[46] These minerals are commonly formed around volcanic activity, more specifically hydrothermal vents and polymetallic nodules.[47][48] These vents emit large volumes of super-heated, metal infused fluids that rise and rapidly cool when mixed with the cold seawater. The chemical reaction causes sulfur and minerals to precipitate and from chimneys, towers, and mineral-rich deposits on the sea floor.[49] Polymetallic nodules, also known as manganese nodules, are rounded ores formed over millions of years from precipitating metals from seawater and sediment pore water.[50] They are typically found unattached, spread across the abyssal seafloor and contain metals crucial for building batteries and touch screens, including cobalt, nickel, copper, and manganese.[50]
Environmental impacts and mitigation[edit]
Habitat mapping and conservation[edit]
Marine geology has a key role in habitat mapping and conservation. With global events causing potentially irreversible damage to the sea habitats, such as deep-sea mining and bottom trawling, marine geology can help us study and mitigate the effects of these activity.[63]
The CCZ has been surveyed and mapped to designate specific areas for mining and for conservation. The International Seabed Authority has set aside approximately 160,000 square kilometers of seabed within the CCZ as the area is rich with biodiversity and habitats.[51] The zone houses over 5,000 species, including sea cucumbers, corals, crabs, shrimps, glass sponges, and members of the spider family and, has been an area where new species of sea worms have been discovered.[53] Furthermore, 90% of the species have yet to be identified.[64] Proper marine survey techniques have protected thousands of habitats and species by dedicating it to conservation.
Bottom trawling also poses a detrimental effects to the sea and using marine geology techniques can be helpful at mitigating them.[65] Bottom trawling, generally a commercial fishing technique, involves dragging a large net that herds and captures a target species, such as fish or crabs.[66] During this process, the net damages the seafloor by scraping and removing animals and vegetation living on the seabed, including coral reefs, sharks, and sea turtles.[67] It can tear up root systems and animal burrows, which can directly affect the sediment distribution.[68] This can lead to the change in chemistry and nutriment levels in the sea water.[69] Marine geology can determine areas which have been damaged to employ habitat restoration techniques. It can also help determine areas that have not been affecting by bottom trawling and employ conservation protection.
Sediment transportation and coastal erosion[edit]
Sediment transportation and coastal erosion is a complex subject that is necessary to understand to protect infrastructure and the environment.[70] Coastal erosion is the process of sediment and materials breaking down and transported due to the effects of the sea.[71] This can lead to destruction animal habitats, fishing industries, and infrastructure.[72] In the United States, damages to properties and infrastructure has caused approximately $500 million per year, and an additional $150 million a year is dedicated to mitigation from the U.S. federal government.[73] Marine geology supports the study of sediment types, current patterns, and ocean topography to predict erosional trends which can protect these environments.[74]
Future research[edit]
Seafloor mapping and bathymetry[edit]
Many section of the oceans are permanently dark, low temperatures, and are under extreme pressure, making them difficult to observe.[81] According to the National Oceanic and Atmospheric Administration (NOAA), only 23% of the seafloor has been mapped in detail and one of the leading projects in exploration is developing high-resolution maps of the seafloor. The Okeanos Explorer, a vessel owned by NOAA, has already mapped over 2 million km2 of the seafloor using multibeam sonar since 2008, but this technique has proved to be too time-consuming.[82]
The importance of mapping the seafloor has been recognized by governments and scientists alike. Because of this, an international collaboration effort to create a high-definition map of the entire seafloor was developed, called the Nippon Foundation-GEBCO Seabed 2030 Project. This committee has a set goal to have the project finished by 2030. To reach their goal, they are equipping old, new, and autonomous vehicles with sonar, sensors, and other GIS based technology to reach their goal.[82]