6.5 Ocean Resources and Human Impacts
6 min read•august 14, 2024
The oceans are a vital source of food, minerals, and energy for humans. From fish and shellfish to offshore oil and wind farms, we rely on these resources. But our use of the seas comes at a cost, impacting marine ecosystems through , , and habitat destruction.
Climate change is also taking a toll on our oceans. Rising temperatures cause , while increased CO2 leads to acidification. These changes, along with sea level rise, threaten marine life and coastal communities. Sustainable management practices are crucial to protect our oceans for future generations.
Ocean Resources
Food Sources
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- The oceans provide a wide range of food resources, including fish (tuna, cod, salmon), shellfish (shrimp, crabs, oysters), and seaweed (kelp, nori), which are important sources of protein for many people around the world
- , the farming of , is increasingly being used to supplement wild-caught seafood and meet growing global demand for fish and shellfish
- Seaweed is not only used as a food source but also has applications in the production of food additives (carrageenan, agar) and biofuels
Mineral Extraction
- Minerals such as salt, magnesium, and bromine are extracted from seawater through various processes, including solar evaporation and electrolysis
- Salt is the most commonly extracted mineral from seawater and is used for a variety of purposes, including food preservation, de-icing roads, and chemical production
- Magnesium and bromine are used in the production of various industrial and consumer products, such as fire retardants, pharmaceuticals, and batteries
Energy Resources
- Oil and natural gas are extracted from offshore reserves using drilling platforms and pipelines, providing a significant portion of the world's energy supply
- Offshore oil and gas production occurs in many regions around the world, including the Gulf of Mexico, the North Sea, and the Persian Gulf
- Renewable energy sources, such as offshore wind farms, , and , are increasingly being developed to harness the power of the oceans
- Offshore wind farms, such as the Hornsea Wind Farm in the United Kingdom, can generate significant amounts of electricity while reducing
Biotechnology and Pharmaceuticals
- Marine organisms, such as algae and bacteria, are being researched for their potential use in biotechnology and pharmaceutical applications
- Compounds derived from marine organisms have been used to develop drugs for treating cancer (bryostatin), pain (ziconotide), and viral infections (vidarabine)
- Marine microalgae, such as Spirulina and Chlorella, are used as dietary supplements and have potential applications in biofuel production and wastewater treatment
Human Impacts on Marine Ecosystems
Overfishing and Bycatch
- Overfishing occurs when fish are caught at a rate faster than they can reproduce, leading to the depletion of fish populations and the disruption of marine food webs
- Examples of overfished species include Atlantic cod, bluefin tuna, and several species of sharks
- , the unintentional capture of non-target species during fishing, can result in the death of many marine animals, including dolphins, sea turtles (loggerhead, leatherback), and seabirds (albatrosses, petrels)
- Fishing methods such as bottom trawling and longline fishing are particularly prone to high levels of bycatch
Pollution and Marine Debris
- Pollution from land-based sources, such as agricultural runoff (pesticides, fertilizers), industrial waste (heavy metals, chemicals), and sewage, can introduce harmful chemicals and excess nutrients into marine ecosystems, leading to and the creation of
- The Gulf of Mexico dead zone, caused by nutrient runoff from the Mississippi River, is one of the largest in the world and can reach sizes of over 6,000 square miles
- , particularly plastic waste, can entangle or be ingested by marine animals, causing injury, starvation, and death
- The , a large accumulation of plastic debris in the North Pacific Ocean, is estimated to cover an area twice the size of Texas
Habitat Destruction
- The destruction of coastal habitats, such as and , through development (coastal construction, aquaculture), pollution, and climate change, can reduce biodiversity and the ecosystem services these habitats provide
- Mangrove forests, which serve as nurseries for many fish species and protect coastlines from erosion and storms, have declined by over 35% worldwide in the past 50 years
- Coral reefs, which support an estimated 25% of all marine life, are threatened by a combination of factors, including , warming temperatures, and pollution
- The Great Barrier Reef, the world's largest coral reef system, has experienced several mass bleaching events in recent years, leading to widespread coral mortality
Climate Change Effects on Oceans
Ocean Warming and Coral Bleaching
- Rising atmospheric carbon dioxide levels, primarily due to human activities (fossil fuel combustion, deforestation), are causing an increase in global ocean temperatures, a process known as ocean warming
- The average global sea surface temperature has increased by approximately 0.13°C per decade since 1901
- Warmer ocean temperatures can lead to coral bleaching, where coral polyps expel their symbiotic algae (zooxanthellae), often resulting in the death of the coral and the loss of reef habitats
- The 2016 global coral bleaching event, the longest and most severe on record, affected over 70% of the world's coral reefs
Ocean Acidification
- The absorption of atmospheric carbon dioxide by the oceans is causing ocean acidification, as the dissolved carbon dioxide reacts with water to form carbonic acid, lowering the pH of the ocean
- The average pH of the ocean surface has decreased by approximately 0.1 units since the start of the industrial era, representing a 30% increase in acidity
- Ocean acidification can impair the ability of calcifying organisms, such as corals and some plankton (coccolithophores, foraminifera), to build their calcium carbonate shells and skeletons, potentially disrupting marine food webs
- Experimental studies have shown that ocean acidification can also affect the behavior and survival of some marine species, such as fish and mollusks
Sea Level Rise
- Melting land-based ice, such as glaciers and ice sheets (Greenland, Antarctica), and thermal expansion of seawater due to rising temperatures are causing global sea levels to rise, threatening low-lying coastal areas and islands
- Global average sea level has risen by approximately 21-24 centimeters since 1880, with about a third of that occurring in the last 25 years
- Sea level rise can lead to increased coastal flooding, erosion, and saltwater intrusion into freshwater aquifers and wetlands
- Low-lying island nations, such as the Maldives and Tuvalu, are particularly vulnerable to sea level rise and may become uninhabitable by the end of the century
Sustainable Ocean Management
Fisheries Management and Marine Protected Areas
- Sustainable practices, such as setting catch limits, implementing , and reducing bycatch, can help maintain fish populations and ensure the long-term viability of the fishing industry
- , a management approach that allocates a portion of the total allowable catch to individual fishers or communities, have been shown to reduce overfishing and improve the economic performance of fisheries
- (MPAs) are designated regions where human activities are restricted or prohibited to protect marine ecosystems, biodiversity, and ecosystem services
- The Ross Sea MPA in Antarctica, established in 2016, is the world's largest MPA and covers an area of 1.55 million square kilometers
International Agreements and Regulations
- International agreements and regulations, such as the (UNCLOS) and the (IWC), aim to promote the sustainable use and conservation of marine resources
- UNCLOS, adopted in 1982, establishes a legal framework for the use and protection of the world's oceans, including provisions for the conservation of living marine resources and the prevention of pollution
- The IWC, established in 1946, aims to conserve whale populations and regulate whaling activities, and has implemented a moratorium on commercial whaling since 1986
Reducing Pollution and Promoting Awareness
- Reducing land-based pollution through better waste management (recycling, proper disposal), improved agricultural practices (reduced pesticide and fertilizer use), and stricter industrial regulations (wastewater treatment, emission controls) can help protect marine ecosystems and maintain water quality
- The International Convention for the Prevention of Pollution from Ships (MARPOL), adopted in 1973, sets standards for the prevention of pollution by oil, chemicals, sewage, and garbage from ships
- Promoting public awareness and education about the importance of and the impacts of human activities on the oceans can encourage more sustainable practices and support for conservation efforts
- The annual World Oceans Day, celebrated on June 8, aims to raise global awareness of the importance of the oceans and encourage action to protect marine environments
Key Terms to Review (34)
Aquaculture: Aquaculture is the practice of farming aquatic organisms, including fish, crustaceans, mollusks, and aquatic plants, in controlled environments. This method provides a sustainable alternative to wild fishing, aiming to meet the increasing global demand for seafood while addressing overfishing and habitat destruction.
Aquatic organisms: Aquatic organisms are living creatures that primarily inhabit water environments, including oceans, rivers, lakes, and wetlands. These organisms can range from microscopic plankton to large marine mammals and play a vital role in maintaining ecological balance, supporting food webs, and influencing global biogeochemical cycles. Their survival is intricately linked to the health of aquatic ecosystems, which are increasingly impacted by human activities.
Biomonitoring: Biomonitoring is the process of assessing the health of ecosystems by measuring the presence and effects of pollutants or environmental changes on living organisms. It serves as an important tool for understanding how human activities impact natural systems, especially in relation to ocean resources and their sustainability. By studying indicators within biological communities, scientists can identify trends in environmental health and make informed decisions regarding conservation efforts.
Blue economy: The blue economy refers to the sustainable use of ocean resources for economic growth, improved livelihoods, and jobs while preserving the health of ocean ecosystems. This concept emphasizes balancing economic development with environmental conservation, recognizing the vital role oceans play in supporting human life and biodiversity.
Bycatch: Bycatch refers to the unintended capture of non-target species during fishing operations. This includes fish, marine mammals, sea turtles, and seabirds that are caught unintentionally while fishermen aim for specific species. The issue of bycatch highlights the ecological impacts of fishing practices and raises concerns about sustainability and biodiversity in marine ecosystems.
Catch Shares: Catch shares are a fishery management tool that allocates a specific portion of the total allowable catch to individual fishermen or fishing groups. This system aims to promote sustainable fishing practices by giving fishers a vested interest in the health of fish stocks. By ensuring that fishermen can plan their activities based on secure allocations, catch shares can reduce overfishing and support marine ecosystems.
Coral bleaching: Coral bleaching is a phenomenon where coral polyps expel the symbiotic algae (zooxanthellae) living within their tissues, leading to a loss of color and vital energy sources. This process can occur due to various stressors such as increased water temperature, pollution, and ocean acidification, and it has significant implications for marine ecosystems and human activities reliant on healthy coral reefs.
Coral reefs: Coral reefs are underwater structures formed by the accumulation of coral polyps, tiny marine animals that secrete calcium carbonate to create a hard skeleton. These vibrant ecosystems are among the most diverse habitats on Earth, providing essential services to marine life and coastal communities while also being highly sensitive to environmental changes.
Dead zones: Dead zones are areas in aquatic environments, especially oceans and large lakes, where oxygen levels are so low that marine life cannot survive. This phenomenon is primarily caused by nutrient pollution from human activities, leading to algal blooms that deplete oxygen in the water when they die and decompose. The presence of dead zones has significant implications for ocean resources, biodiversity, and human impacts on marine ecosystems.
Eutrophication: Eutrophication is the process by which a body of water becomes overly enriched with nutrients, leading to excessive growth of algae and other aquatic plants. This phenomenon can cause significant ecological impacts, including oxygen depletion and disruption of aquatic ecosystems. As nutrient inputs from sources like fertilizers, sewage, and runoff increase, they stimulate algal blooms that can harm water quality and marine life.
Fish stocks: Fish stocks refer to populations of fish that are grouped together based on shared characteristics such as species, location, and reproductive patterns. Understanding fish stocks is crucial for sustainable fishing practices, as it helps manage and conserve fish populations, ensuring they remain healthy and viable for future generations. The dynamics of fish stocks can be significantly influenced by human activities, particularly overfishing, which can lead to depletion and ecological imbalances in marine environments.
Fisheries management: Fisheries management refers to the science and practice of regulating fish populations and their habitats to ensure sustainable fishing practices and maintain the health of aquatic ecosystems. This approach encompasses various strategies, including setting catch limits, implementing fishing quotas, and protecting critical habitats, all aimed at balancing ecological integrity with human demand for fishery resources.
Great Pacific Garbage Patch: The Great Pacific Garbage Patch is a vast area of marine debris concentration located in the North Pacific Ocean, primarily made up of plastic waste and other human-made materials. It represents a significant environmental issue, highlighting the impact of pollution on ocean ecosystems and the challenges posed by waste management practices in modern society.
Greenhouse gas emissions: Greenhouse gas emissions refer to the release of gases such as carbon dioxide, methane, and nitrous oxide into the atmosphere, which trap heat and contribute to global warming and climate change. These emissions arise from various human activities, particularly in the burning of fossil fuels, deforestation, and agricultural practices. Understanding the sources and impacts of these emissions is crucial in addressing environmental challenges and developing sustainable energy solutions.
Hypoxia: Hypoxia refers to a condition where there is a deficiency of oxygen in the water, affecting marine life and ecosystems. This phenomenon can lead to significant environmental impacts, particularly in ocean regions where human activities contribute to nutrient over-enrichment, often resulting in harmful algal blooms. These blooms can consume the oxygen in the water as they decompose, creating 'dead zones' where aquatic life struggles to survive.
International Whaling Commission: The International Whaling Commission (IWC) is an international body established in 1946 to regulate whaling and ensure the conservation of whale populations. It plays a crucial role in balancing the interests of whaling nations with conservation efforts, aiming to protect marine biodiversity and promote sustainable practices.
Mangrove forests: Mangrove forests are coastal ecosystems characterized by salt-tolerant trees and shrubs that thrive in intertidal zones where saltwater and freshwater meet. These unique ecosystems provide vital habitats for a variety of marine and terrestrial species, playing a crucial role in biodiversity and coastal protection.
Marine conservation: Marine conservation refers to the protection and preservation of marine environments and their resources to maintain biodiversity, restore ecosystems, and ensure sustainable use. This concept emphasizes the need to address human impacts such as overfishing, pollution, and habitat destruction, while promoting practices that support the health of ocean ecosystems. Effective marine conservation strategies often involve a combination of policy-making, scientific research, and community engagement to achieve long-term sustainability in ocean resource management.
Marine debris: Marine debris refers to any human-created waste that ends up in oceans, seas, and other large bodies of water. This waste can take various forms, including plastics, metal, glass, and organic materials, and poses significant risks to marine life and ecosystems. The accumulation of marine debris highlights the broader impact of human activities on ocean resources and the importance of addressing pollution for environmental sustainability.
Marine minerals: Marine minerals refer to the naturally occurring inorganic substances found in the ocean that can be extracted and utilized for various purposes, such as construction, electronics, and even pharmaceuticals. These minerals include a range of elements like magnesium, potassium, and various salts that play a crucial role in both ecological systems and human industries. Their extraction and utilization have significant implications for environmental health and resource management.
Marine protected areas: Marine protected areas (MPAs) are designated regions of the ocean where human activities are restricted or managed to conserve marine ecosystems and biodiversity. These areas are critical for protecting vulnerable species, habitats, and the overall health of marine environments, while also serving as a tool for sustainable resource management and ecological restoration.
No-take zones: No-take zones are designated areas within marine environments where all forms of extraction, such as fishing or mining, are prohibited. These zones are established to protect marine biodiversity, allow ecosystems to recover, and ensure sustainable use of ocean resources. By limiting human impact, no-take zones play a crucial role in mitigating the adverse effects of overfishing, habitat destruction, and pollution on marine life.
NOAA: NOAA, or the National Oceanic and Atmospheric Administration, is a scientific agency within the U.S. Department of Commerce that focuses on understanding and predicting changes in climate, weather, oceans, and coasts. This agency plays a crucial role in managing ocean resources and addressing human impacts on marine environments through research, data collection, and public policy.
Ocean acidification: Ocean acidification is the process by which the ocean becomes more acidic due to increased carbon dioxide (CO2) absorption from the atmosphere. This change in pH levels disrupts marine ecosystems and has significant implications for biodiversity, marine resources, and the global carbon cycle.
Oil spills: Oil spills refer to the accidental or deliberate release of liquid petroleum hydrocarbons into the environment, particularly marine areas, due to human activity. These incidents can have devastating impacts on marine life, ecosystems, and coastal communities, highlighting the fragile balance between resource extraction and environmental preservation.
Overfishing: Overfishing refers to the practice of catching fish from the ocean at rates faster than they can reproduce, leading to a depletion of fish stocks and threatening marine biodiversity. This practice disrupts the balance of marine ecosystems and can result in the collapse of fish populations, which impacts not only the environment but also the livelihoods of communities that rely on fishing for food and income.
Plastic pollution: Plastic pollution refers to the accumulation of plastic products and materials in the environment, particularly in oceans, where they can cause significant harm to marine life and ecosystems. This pollution is primarily the result of human activities, such as improper disposal, overuse of single-use plastics, and industrial waste. The pervasive nature of plastic waste not only threatens biodiversity but also impacts human health and the overall health of ocean resources.
Pollution: Pollution refers to the introduction of harmful substances or contaminants into the environment, leading to adverse effects on ecosystems, human health, and the overall quality of natural resources. It can occur in various forms such as air, water, soil, and noise pollution, impacting different ecosystems and resource systems. Understanding pollution is crucial for assessing human impacts on nature and finding ways to mitigate these effects for a sustainable future.
Remote sensing: Remote sensing is the process of acquiring information about an object or phenomenon without making physical contact, typically through satellite or aerial imagery. This technology allows for the collection of data on various Earth systems, facilitating the monitoring and analysis of environmental changes, resource management, and natural disasters.
Sustainable fishing: Sustainable fishing refers to practices that allow fish populations to be harvested at a rate that does not compromise their ability to reproduce and thrive over time. This concept is closely linked to the management of ocean resources and emphasizes the balance between human consumption and the health of marine ecosystems, ensuring that fishing activities do not lead to overfishing, habitat destruction, or depletion of marine biodiversity.
Tidal power: Tidal power is a form of renewable energy that harnesses the gravitational pull of the moon and the sun to generate electricity from the movement of tides. This energy source is considered sustainable because it relies on natural tidal cycles, which are predictable and consistent, making it a reliable option for energy generation in various coastal regions.
United Nations Convention on the Law of the Sea: The United Nations Convention on the Law of the Sea (UNCLOS) is an international treaty that establishes a comprehensive legal framework governing the use and conservation of the world's oceans and their resources. It covers various aspects such as territorial waters, exclusive economic zones, continental shelves, and marine environmental protection, making it crucial in managing ocean resources and addressing human impacts.
Wave energy: Wave energy is the energy harnessed from the surface motion of ocean waves. This renewable energy source is generated by the gravitational pull of the moon and sun, as well as the wind's interaction with the water surface, creating waves that can be converted into usable energy through various technologies. Wave energy is considered a significant resource for sustainable power generation and has implications for both energy production and environmental management.
World Wildlife Fund: The World Wildlife Fund (WWF) is an international non-governmental organization dedicated to environmental conservation and reducing the human impact on the natural world. It plays a crucial role in protecting endangered species and their habitats, advocating for sustainable practices, and addressing climate change, particularly in relation to ocean resources and human activities that threaten marine ecosystems.