Marine processes in physical geography refer to the various physical, chemical, and biological processes that occur in the ocean and coastal areas. These processes include coastal erosion, ocean currents, tides, and wave patterns. They also include the movement of sediment, nutrients, and other materials through the ocean, as well as the formation and distribution of marine organisms. Understanding marine processes is important for understanding the Earth’s climate, weather patterns, and the overall health of the ocean ecosystem. It also plays a key role in coastal zone management and human uses of the ocean, such as fishing, shipping, and coastal development.
There are 3 types of Marine processes which occur all the time throughout the entire planet. These three marine processes are:
- Erosion
- Transportation
- Deposition
What is Erosion in Marine Processes?
Coastal erosion refers to the wearing away of land and the reshaping of the coastline by the action of waves, currents, tides, wind-driven water, and other natural forces. Coastal erosion can occur through a variety of processes, including:
- Wave action: Waves can erode the coastline by breaking against it, causing the sediment and rock to wear away over time. The power of the waves increases with the height and frequency of the waves and the energy they carry.
- Longshore drift: This is the process by which waves approaching the shore at an angle (obliquely) can cause sediment to move along the coastline. This can lead to erosion on one side of the beach and deposition on the other.
- Tidal action: Tides can cause erosion by exposing the coastline to the erosive power of waves for longer periods of time. Tidal action can also cause erosion through processes such as tidal scouring, in which the force of the tide can carve out channels and caves in the coastline.
- Human activities: Coastal development, such as building seawalls and other structures, can disrupt natural processes and lead to erosion.
Coastal erosion can have significant impacts on coastal communities and ecosystems, and can also contribute to sea level rise. To mitigate the impacts of coastal erosion, various coastal management strategies have been developed, such as beach nourishment and shoreline armoring.
There are two methods for mass wasting:
- Mechanical, like breaking a stone with a sledgehammer.
- Chemical, like pouring corrosive on a stone to break down it.
Mechanical mass wasting refers to the movement of rock, soil, or sediment down a slope due to the force of gravity. In marine processes, mass wasting can occur along coastal cliffs and steep slopes, and can take various forms such as rockfalls, landslides, and mudflows.
- Rockfalls: Rockfalls occur when large chunks of rock break away from cliffs or steep slopes and fall into the ocean. This can happen due to natural weathering or erosion, or due to human activities such as construction or mining.
- Landslides: Landslides occur when a large mass of rock, soil, or sediment moves down a slope as a unit. This can happen due to a variety of factors such as earthquakes, volcanic activity, or heavy rainfall.
- Mudflows: Mudflows occur when a mixture of water and sediment (typically clay, silt, and sand) moves down a slope. This can happen due to heavy rainfall, snowmelt, or changes in the water table.
These processes are known to be natural coastal hazard, and can cause damage to coastal infrastructure, disrupt shipping lanes, and change the shape of the coastline. Human activities such as deforestation, urbanization, and mining can also increase the risk of mass wasting. To mitigate the risks associated with mass wasting, various strategies such as monitoring, early warning systems, and land-use planning have been developed.
Then there is chemical erosion. Chemical erosion, also known as chemical weathering, refers to the process by which rock, soil, or sediment is broken down or dissolved by chemical reactions. In mass wasting, chemical erosion can occur along coastal cliffs and steep slopes, and can take various forms:
- Solution: This occurs when certain types of rock, such as limestone, are dissolved by acidic water, either from the atmosphere or from groundwater.
- Hydration: This occurs when certain types of rock, such as basalt, are altered by the addition of water, which can cause the rock to expand and crack.
- Oxidation: This occurs when certain types of rock, such as iron-bearing minerals, are exposed to oxygen and water, which can cause the rock to rust and weaken.
Chemical erosion can be a slow process, but it can cause significant changes to the shape and stability of coastal cliffs and steep slopes over time. This can increase the risk of mass wasting and landslides.
Chemical erosion can also be accelerated by human activities such as mining and acid rain. To mitigate the risks associated with chemical erosion, various strategies such as monitoring, land-use planning, and reducing pollution have been developed.
Is it possible to build things up by erosion?
Processes of Erosion
- Hydraulic Action
- Abrasion
- Corrasion
- Attrition
Hydraulic action
Hydraulic action refers to the erosive power of moving water, which can cause erosion of the coastline and cliffs. This process occurs when the force of the water’s movement is strong enough to cause physical abrasion of the rock and sediment.
When waves crash against the coast, the force of the water can cause the rock and sediment to be broken down and worn away. The force of the water can also create cracks and fissures in the rock, making it more susceptible to erosion. This process is more effective in areas with cliffs, cliffs with a lot of cracks, or cliffs with a lot of loose rock or sediment. The water pushes into these cracks, and as the water withdraws, it can pull out pieces of the cliff or rock.
This process is also known as wave scouring, as the water scours and erodes the rock.
Hydraulic action is particularly effective in areas with high wave energy, such as in areas with large swells, strong winds, or a steep slope. It can also be affected by the shape and composition of the rock or sediment, as well as the presence of natural or human-made structures such as groins and breakwaters.
It is an important process in coastal erosion and can cause significant changes to the shape and stability of the coastline over time. It’s also a process that can be very destructive, and can cause damage to coastal infrastructure and can have a negative impact on coastal ecosystems.
Abrasion
Abrasion refers to the process of erosion caused by the friction and impact of rock, sediment, or other materials being moved by water, wind, or ice. In coastal areas, abrasion is caused by the movement of sediment, such as sand and pebbles, being transported by waves and currents.
Abrasion can happen when waves crash against the coast, and the sediment in the water is propelled against the rock or cliffs, causing the rock or cliffs to be worn away. The sediment acts like a sandpaper, scraping away at the rock or cliffs. This process is more effective when the sediment is harder than the rock or cliffs and when the waves are more powerful.
Abrasion is particularly effective in areas with high wave energy and in areas with a lot of sediment. It can also be affected by the shape and composition of the rock or sediment, as well as the presence of natural or human-made structures such as groins and breakwaters.
It is an important process in coastal erosion and can cause significant changes to the shape and stability of the coastline over time. It’s also a process that can be very destructive, and can cause damage to coastal infrastructure and can have a negative impact on coastal ecosystems. Coastal management strategies such as beach nourishment and shoreline armoring can be used to mitigate the impacts of abrasion.
Corrosion
Corrosion refers to the process of erosion caused by chemical reactions between a material and its environment. In coastal areas, corrosion can occur when rock, sediment, or other materials are exposed to acidic or saline water, or to other chemicals that can cause the material to break down or dissolve over time.
For example, in coastal areas, saltwater can cause corrosion of metal structures such as seawalls, piers, and other coastal infrastructure. Saltwater is an electrolyte and can cause an electrochemical reaction between the metal and the water, which can result in the metal rusting and weakening over time.
Similarly, acidic water can cause corrosion of limestone cliffs and other types of carbonate rock. Acid rain, which is caused by the emissions of sulfur dioxide and nitrogen oxides, can fall into the ocean, where it can dissolve the carbonate rock and cause erosion.
Corrosion is a slow process, but it can cause significant changes to the shape and stability of coastal cliffs and infrastructure over time. It can also be accelerated by human activities such as mining and pollution. To mitigate the risks associated with corrosion, various strategies such as monitoring, land-use planning, and reducing pollution have been developed.
Attrition
Attrition refers to the process of erosion caused by the grinding and wearing away of rock, sediment, or other materials by friction and collision. In coastal areas, attrition is caused by the movement of sediment, such as sand and pebbles, being transported by waves and currents.
Attrition occurs when the sediment in the water is propelled against each other, causing them to break down into smaller pieces. This process happens when the sediment is in suspension, meaning it’s being carried by the water and not in contact with the bottom. As the sediment collides with each other, they break down into smaller pieces, losing the sharp edges and becoming more rounded.
Attrition is particularly effective in areas with high wave energy and in areas with a lot of sediment. The size of the sediment and the amount of energy the waves carry play an important role in this process, as well as the composition of the sediment.
Attrition is an important process in coastal erosion and can cause significant changes to the shape and stability of the coastline over time. It’s also a process that can be very destructive, and can cause damage to coastal infrastructure and can have a negative impact on coastal ecosystems. Coastal management strategies such as beach nourishment and shoreline armoring can be used to mitigate the impacts of attrition.
What is Transportation?
Transportation in marine processes refers to the movement of sediment, water, and other materials through the ocean and coastal areas. The main agents of transportation are currents, waves, and tides.
- Currents: ocean currents are the horizontal movement of water in the ocean. There are two types of ocean currents: surface currents and deep-water currents. Surface currents are driven by winds and are responsible for the large-scale circulation of water in the ocean. Deep-water currents are driven by differences in water density and temperature, and are responsible for the vertical movement of water in the ocean. Both types of currents can transport sediment, nutrients, and other materials through the ocean.
- Waves: Waves are the vertical movement of water caused by wind or other forces. Waves can transport sediment, nutrients, and other materials along the coast and offshore. Waves can also erode the coastline and reshape the coastline.
- Tides: Tides are the rhythmic rise and fall of water levels caused by the gravitational pull of the Moon and the Sun on the Earth. Tides can transport sediment, nutrients, and other materials along the coast and offshore. Tides can also erode the coastline and reshape the coastline.
There are four process of transportation which are:
- Traction
- Saltation
- Suspension
- Solution
Traction
Traction refers to the process of transportation of sediment, rock, and other materials by the movement of water, typically in a nearshore or coastal environment. In traction, sediment and materials are rolled, bounced, or dragged along the bottom of the ocean or a riverbed by the force of the water.
Traction is a dominant process in the transportation of coarse-grained sediment such as gravel and cobbles, and it occurs when the velocity of the water is high enough to overcome the friction between the sediment and the bottom. The velocity of the water is determined by the wave energy and the slope of the bottom. The larger and heavier the sediment, the more energy is required to move it.
Traction can occur along the beach, in the surf zone and in the nearshore zone. It is responsible for the movement of material from the beach to the offshore, and also for the formation of bars and spits.
This is when little rocks are bobbed along the ocean bed.
Suspension
In suspension, sediment and materials are carried by the water in a suspended state, typically in the form of a mixture of water and sediment known as a suspension.
Suspension is a dominant process in the transportation of fine-grained sediment such as silt and clay, and it occurs when the velocity of the water is not high enough to move the sediment by traction, but is still strong enough to keep the sediment suspended in the water. The velocity of the water is determined by the wave energy and the slope of the bottom. The smaller and lighter the sediment, the less energy is required to keep it suspended.
Suspension can occur along the beach, in the surf zone and in the nearshore zone. It is responsible for the movement of material from the beach to the offshore, and also for the formation of bars and spits. It also happens in rivers, where sediment is carried in suspension by the flowing water.
It is an important process in shaping the coastal zone, and in the formation and distribution of marine organisms. It also plays a key role in coastal zone management and human uses of the ocean such as fishing, shipping and coastal development.
Solution
Solution refers to the process of transportation of dissolved minerals and other materials by the movement of water, typically in a nearshore or coastal environment. In solution, dissolved minerals and other materials are carried by the water in a dissolved state, rather than in a suspended or solid state.
Solution is a dominant process in the transportation of dissolved minerals and other materials, such as salt or dissolved carbonate. It occurs when the water is in contact with minerals that can dissolve in it, for example, when water comes in contact with rock that is composed of soluble minerals such as limestone or dolomite.
Solution can occur along the coast, in the nearshore zone and in the ocean. It is responsible for the movement of dissolved minerals and other materials from the coast to the offshore, and also for the formation of certain types of coastal landforms.
What is Deposition?
Deposition refers to the process by which sediment, rock, or other materials are laid down or deposited by natural forces such as water, wind, or ice. Deposition can occur in a variety of settings, including on land and in the ocean.
In the ocean and coastal areas, deposition is a process that occurs as a result of the movement of sediment and materials by currents, waves, and tides. When the energy of the water decreases, or when the water reaches a sheltered area or a place where the slope is less steep, sediment and materials will be laid down, rather than being transported. Deposition can occur in a variety of forms such as sandbars, dunes, and deltas.
Deposition can also occur in a river, where sediment is carried by the flowing water, and when the velocity of the water decreases the sediment is laid down. This process can create a variety of landforms such as meanders, bars, and floodplains.
Summary of Marine Processes
Marine processes of erosion and deposition refer to the natural processes by which the Earth’s surface is shaped and reshaped by the movement of water, wind, and ice. Erosion is the process by which natural forces wear away at the surface of the Earth, while deposition is the process by which sediment, rock, or other materials are laid down or deposited.
Erosion can occur through a variety of processes such as wave action, longshore drift, tidal action, and hydraulic action, which can cause the coastline to be worn away and reshaped. Coastal erosion can have significant impacts on coastal communities and ecosystems, and can also contribute to sea level rise.
Deposition is the process of sediment, rock, or other materials being laid down or deposited by natural forces such as water, wind, or ice. In the ocean and coastal areas, deposition is a process that occurs as a result of the movement of sediment and materials by currents, waves, and tides. Deposition can occur in a variety of forms such as sandbars, dunes, and deltas.
Both erosion and deposition are important processes in shaping the coastal zone, and in the formation and distribution of marine organisms. They also play a key role in coastal zone management and human uses of the ocean such as fishing, shipping, and coastal development. Understanding the patterns and processes of erosion and deposition is important for understanding the Earth’s climate, weather patterns, and the overall health of the ocean ecosystem.
Read more about Coastal Systems and Processes
Frequently Asked Questions
What are marine processes?
Marine processes refer to the various natural activities that shape and change coastal and oceanic environments, including erosion, sediment transport, and deposition.
How does wave action contribute to marine processes?
Waves erode coastlines through abrasion and transport sediments, leading to the formation of coastal landforms like beaches, spits, and sand dunes.
What role do tides play in marine processes?
Tides result from gravitational forces between the Earth, Moon, and Sun, influencing water levels, currents, and sediment movement along coastlines.
How do marine processes impact coastal ecosystems?
Marine processes shape habitats and influence the distribution of marine life, including coral reefs, mangroves, and intertidal zones.
How are human activities affecting marine processes?
Coastal development, pollution, and overfishing can disrupt natural marine processes, leading to habitat degradation and loss of biodiversity.
References
- (n.d.). Retrieved from National Geographic: https://www.nationalgeographic.org/encyclopedia/erosion/
- EllaTheBella2000. (n.d.). Coastal Landforms from erosion. Retrieved from quizlet: https://quizlet.com/247475906/coastal-landforms-from-erosion-flash-cards/
- Marine Life Facts. (n.d.). Retrieved from morefundiving: https://morefundiving.com/20-incredible-marine-life-facts/Marine Processes. (n.d.). Retrieved from ALevelGeography: https://www.alevelgeography.com/marine-processes/