Marine ecosystem

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Coral reefs form complex marine ecosystems with tremendous biodiversity. Maldivesfish2.jpg
Coral reefs form complex marine ecosystems with tremendous biodiversity.

Marine ecosystems are the largest of Earth's aquatic ecosystems and exist in waters that have a high salt content. These systems contrast with freshwater ecosystems, which have a lower salt content. Marine waters cover more than 70% of the surface of the Earth and account for more than 97% of Earth's water supply [1] [2] and 90% of habitable space on Earth. [3] Seawater has an average salinity of 35 parts per thousand of water. Actual salinity varies among different marine ecosystems. [4] Marine ecosystems can be divided into many zones depending upon water depth and shoreline features. The oceanic zone is the vast open part of the ocean where animals such as whales, sharks, and tuna live. The benthic zone consists of substrates below water where many invertebrates live. The intertidal zone is the area between high and low tides. Other near-shore (neritic) zones can include mudflats, seagrass meadows, mangroves, rocky intertidal systems, salt marshes, coral reefs, lagoons. In the deep water, hydrothermal vents may occur where chemosynthetic sulfur bacteria form the base of the food web.

Contents

Marine ecosystems are characterized by the biological community of organisms that they are associated with and their physical environment. Classes of organisms found in marine ecosystems include brown algae, dinoflagellates, corals, cephalopods, echinoderms, and sharks.

Marine ecosystems are important sources of ecosystem services and food and jobs for significant portions of the global population. Human uses of marine ecosystems and pollution in marine ecosystems are significantly threats to the stability of these ecosystems. Environmental problems concerning marine ecosystems include unsustainable exploitation of marine resources (for example overfishing of certain species), marine pollution, climate change, and building on coastal areas. Moreover, much of the carbon dioxide causing global warming and heat captured by global warming are absorbed by the ocean, ocean chemistry is changing through processes like ocean acidification which in turn threatens marine ecosystems.

Because of the opportunities in marine ecosystems for humans and the threats created by humans, the international community has prioritized "Life below water" as Sustainable Development Goal 14. [5] The goal is to "Conserve and sustainably use the oceans, seas and marine resources for sustainable development". [6]

Types or locations

Marine coastal ecosystems

Global distribution of coral, mangrove, and seagrass diversity Global distribution of coral, mangrove, and seagrass diversity.png
Global distribution of coral, mangrove, and seagrass diversity

Coral reefs

Coral reef The Coral Reef at the Andaman Islands.jpg
Coral reef

Coral reefs are one of the most well-known marine ecosystems in the world, with the largest being the Great Barrier Reef. These reefs are composed of large coral colonies of a variety of species living together. The corals form multiple symbiotic relationships with the organisms around them. [7]

Mangroves

Mangrove forests Mangrove swamp, Iriomote Island, Okinawa, Japan.jpg
Mangrove forests

Mangroves are trees or shrubs that grow in low-oxygen soil near coastlines in tropical or subtropical latitudes. [8] They are an extremely productive and complex ecosystem that connects the land and sea. Mangroves consist of species that are not necessarily related to each other and are often grouped for the characteristics they share rather than genetic similarity. [9] Because of their proximity to the coast, they have all developed adaptions such as salt excretion and root aeration to live in salty, oxygen-depleted water. [9] Mangroves can often be recognized by their dense tangle of roots that act to protect the coast by reducing erosion from storm surges, currents, wave, and tides. [8] The mangrove ecosystem is also an important source of food for many species as well as excellent at sequestering carbon dioxide from the atmosphere with global mangrove carbon storage is estimated at 34 million metric tons per year. [9]

Seagrass meadows

Seagrass meadow Fan mussel (Pinna nobilis).jpg
Seagrass meadow

Seagrasses form dense underwater meadows which are among the most productive ecosystems in the world. They provide habitats and food for a diversity of marine life comparable to coral reefs. This includes invertebrates like shrimp and crabs, cod and flatfish, marine mammals and birds. They provide refuges for endangered species such as seahorses, turtles, and dugongs. They function as nursery habitats for shrimps, scallops and many commercial fish species. Seagrass meadows provide coastal storm protection by the way their leaves absorb energy from waves as they hit the coast. They keep coastal waters healthy by absorbing bacteria and nutrients, and slow the speed of climate change by sequestering carbon dioxide into the sediment of the ocean floor.

Seagrasses evolved from marine algae which colonized land and became land plants, and then returned to the ocean about 100 million years ago. However, today seagrass meadows are being damaged by human activities such as pollution from land runoff, fishing boats that drag dredges or trawls across the meadows uprooting the grass, and overfishing which unbalances the ecosystem. Seagrass meadows are currently being destroyed at a rate of about two football fields every hour.

Kelp forests

Kelp forest Diver in kelp forest.jpg
Kelp forest

Kelp forests occur worldwide throughout temperate and polar coastal oceans. [10] In 2007, kelp forests were also discovered in tropical waters near Ecuador. [11]

Physically formed by brown macroalgae, kelp forests provide a unique habitat for marine organisms [12] and are a source for understanding many ecological processes. Over the last century, they have been the focus of extensive research, particularly in trophic ecology, and continue to provoke important ideas that are relevant beyond this unique ecosystem. For example, kelp forests can influence coastal oceanographic patterns [13] and provide many ecosystem services. [14]

However, the influence of humans has often contributed to kelp forest degradation. Of particular concern are the effects of overfishing nearshore ecosystems, which can release herbivores from their normal population regulation and result in the overgrazing of kelp and other algae. [15] This can rapidly result in transitions to barren landscapes where relatively few species persist. [16] [17] Already due to the combined effects of overfishing and climate change, kelp forests have all but disappeared in many especially vulnerable places, such as Tasmania's east coast and the coast of Northern California. [18] [19] The implementation of marine protected areas is one management strategy useful for addressing such issues, since it may limit the impacts of fishing and buffer the ecosystem from additive effects of other environmental stressors.

Estuaries

Estuaries Nerr0791 - Flickr - NOAA Photo Library.jpg
Estuaries

Estuaries occur where there is a noticeable change in salinity between saltwater and freshwater sources. This is typically found where rivers meet the ocean or sea. The wildlife found within estuaries is unique as the water in these areas is brackish - a mix of freshwater flowing to the ocean and salty seawater. [20] Other types of estuaries also exist and have similar characteristics as traditional brackish estuaries. The Great Lakes are a prime example. There, river water mixes with lake water and creates freshwater estuaries. [20] Estuaries are extremely productive ecosystems that many humans and animal species rely on for various activities. [21] This can be seen as, of the 32 largest cities in the world, 22 are located on estuaries as they provide many environmental and economic benefits such as crucial habitat for many species, and being economic hubs for many coastal communities. [21] Estuaries also provide essential ecosystem services such as water filtration, habitat protection, erosion control, gas regulation nutrient cycling, and it even gives education, recreation and tourism opportunities to people. [22]

Lagoons

Lagoon Kara-Bogaz Gol from space, September 1995.jpg
Lagoon

Lagoons are areas that are separated from larger water by natural barriers such as coral reefs or sandbars. There are two types of lagoons, coastal and oceanic/atoll lagoons. [23] A coastal lagoon is, as the definition above, simply a body of water that is separated from the ocean by a barrier. An atoll lagoon is a circular coral reef or several coral islands that surround a lagoon. Atoll lagoons are often much deeper than coastal lagoons. [24] Most lagoons are very shallow meaning that they are greatly affected by changed in precipitation, evaporation and wind. This means that salinity and temperature are widely varied in lagoons and that they can have water that ranges from fresh to hypersaline. [24] Lagoons can be found in on coasts all over the world, on every continent except Antarctica and is an extremely diverse habitat being home to a wide array of species including birds, fish, crabs, plankton and more. [24] Lagoons are also important to the economy as they provide a wide array of ecosystem services in addition to being the home of so many different species. Some of these services include fisheries, nutrient cycling, flood protection, water filtration, and even human tradition. [24]

Salt marsh

Salt marshes Marismas del Oka 03.jpg
Salt marshes

Salt marshes are a transition from the ocean to the land, where fresh and saltwater mix. [25] The soil in these marshes is often made up of mud and a layer of organic material called peat. Peat is characterized as waterlogged and root-filled decomposing plant matter that often causes low oxygen levels (hypoxia). These hypoxic conditions causes growth of the bacteria that also gives salt marshes the sulfurous smell they are often known for. [26] Salt marshes exist around the world and are needed for healthy ecosystems and a healthy economy. They are extremely productive ecosystems and they provide essential services for more than 75 percent of fishery species and protect shorelines from erosion and flooding. [26] Salt marshes can be generally divided into the high marsh, low marsh, and the upland border. The low marsh is closer to the ocean, with it being flooded at nearly every tide except low tide. [25] The high marsh is located between the low marsh and the upland border and it usually only flooded when higher than usual tides are present. [25] The upland border is the freshwater edge of the marsh and is usually located at elevations slightly higher than the high marsh. This region is usually only flooded under extreme weather conditions and experiences much less waterlogged conditions and salt stress than other areas of the marsh. [25]

Intertidal zones

Intertidal zones Intertidal greenalgae.jpg
Intertidal zones

Intertidal zones are the areas that are visible and exposed to air during low tide and covered up by saltwater during high tide. [27] There are four physical divisions of the intertidal zone with each one having its distinct characteristics and wildlife. These divisions are the Spray zone, High intertidal zone, Middle Intertidal zone, and Low intertidal zone. The Spray zone is a damp area that is usually only reached by the ocean and submerged only under high tides or storms. The high intertidal zone is submerged at high tide but remains dry for long periods between high tides. [27] Due to the large variance of conditions possible in this region, it is inhabited by resilient wildlife that can withstand these changes such as barnacles, marine snails, mussels and hermit crabs. [27] Tides flow over the middle intertidal zone two times a day and this zone has a larger variety of wildlife. [27] The low intertidal zone is submerged nearly all the time except during the lowest tides and life is more abundant here due to the protection that the water gives. [27]

Ocean surface

Sea spray containing marine microorganisms can be swept high into the atmosphere, where it becomes part of the aeroplankton and may travel the globe before falling back to earth. Ocean mist and spray 2.jpg
Sea spray containing marine microorganisms can be swept high into the atmosphere, where it becomes part of the aeroplankton and may travel the globe before falling back to earth.

Organisms that live freely at the surface, termed neuston, include keystone organisms like the golden seaweed Sargassum that makes up the Sargasso Sea, floating barnacles, marine snails, nudibranchs, and cnidarians. Many ecologically and economically important fish species live as or rely upon neuston. Species at the surface are not distributed uniformly; the ocean's surface harbours unique neustonic communities and ecoregions found at only certain latitudes and only in specific ocean basins. But the surface is also on the front line of climate change and pollution. Life on the ocean's surface connects worlds. From shallow waters to the deep sea, the open ocean to rivers and lakes, numerous terrestrial and marine species depend on the surface ecosystem and the organisms found there. [28]

The ocean's surface acts like a skin between the atmosphere above and the water below, and harbours an ecosystem unique to this environment. This sun-drenched habitat can be defined as roughly one metre in depth, as nearly half of UV-B is attenuated within this first meter. [29] Organisms here must contend with wave action and unique chemical [30] [31] [32] and physical properties. [33] The surface is utilised by a wide range of species, from various fish and cetaceans, to species that ride on ocean debris (termed rafters). [34] [35] [36] Most prominently, the surface is home to a unique community of free-living organisms, termed neuston (from the Greek word, υεω, which means both to swim and to float. Floating organisms are also sometimes referred to as pleuston, though neuston is more commonly used). Despite the diversity and importance of the ocean's surface in connecting disparate habitats, and the risks it faces, not a lot is known about neustonic life. [28]

A stream of airborne microorganisms circles the planet above weather systems but below commercial air lanes. [37] Some peripatetic microorganisms are swept up from terrestrial dust storms, but most originate from marine microorganisms in sea spray. In 2018, scientists reported that hundreds of millions of viruses and tens of millions of bacteria are deposited daily on every square meter around the planet. [38] [39]

Deep sea and sea floor

The deep sea contains up to 95% of the space occupied by living organisms. [40] Combined with the sea floor (or benthic zone), these two areas have yet to be fully explored and have their organisms documented. [40] [41]

Large marine ecosystems

General characteristics of a large marine ecosystem (Gulf of Alaska) General characteristics of a large marine ecosystem.jpg
General characteristics of a large marine ecosystem (Gulf of Alaska)
Global map of large marine ecosystems. Oceanographers and biologists have identified 66 LMEs worldwide. Global map of large marine ecosystems.jpg
Global map of large marine ecosystems. Oceanographers and biologists have identified 66 LMEs worldwide.

In 1984, National Oceanic and Atmospheric Administration (NOAA) of the United States developed the concept of large marine ecosystems (sometimes abbreviated to LMEs), to identify areas of the oceans for environmental conservation purposes and to enable collaborative ecosystem-based management in transnational areas, in a way consistent with the 1982 UN Convention on the Law of the Sea. This name refers to relatively large regions on the order of 200,000 km2 (77,000 sq mi) or greater, characterized by their distinct bathymetry, hydrography, productivity, and trophically dependent populations. Such LMEs encompass coastal areas from river basins and estuaries to the seaward boundaries of continental shelves and the outer margins of the major ocean current systems. [42]

Altogether, there are 66 LMEs, which contribute an estimated $3 trillion annually. This includes being responsible for 90% of global annual marine fishery biomass. [43] LME-based conservation is based on recognition that the world's coastal ocean waters are degraded by unsustainable fishing practices, habitat degradation, eutrophication, toxic pollution, aerosol contamination, and emerging diseases, and that positive actions to mitigate these threats require coordinated actions by governments and civil society to recover depleted fish populations, restore degraded habitats and reduce coastal pollution. Five modules are considered when assessing LMEs: productivity, fish and fisheries, pollution and ecosystem health, socioeconomics, and governance. [44] Periodically assessing the state of each module within a marine LME is encouraged to ensure maintained health of the ecosystem and future benefit to managing governments. [45] The Global Environment Facility (GEF) aids in managing LMEs off the coasts of Africa and Asia by creating resource management agreements between environmental, fisheries, energy and tourism ministers of bordering countries. This means participating countries share knowledge and resources pertaining to local LMEs to promote longevity and recovery of fisheries and other industries dependent upon LMEs. [46]

Large marine ecosystems include:

Role in ecosystem services

Ecosystem services delivered by epibenthic bivalve reefs. Reefs provide coastal protection through erosion control and shoreline stabilization, and modify the physical landscape by ecosystem engineering, thereby providing habitat for species by facilitative interactions with other habitats such as tidal flat benthic communities, seagrasses and marshes. Ecosystem services delivered by epibenthic bivalve reefs.png
Ecosystem services delivered by epibenthic bivalve reefs. Reefs provide coastal protection through erosion control and shoreline stabilization, and modify the physical landscape by ecosystem engineering, thereby providing habitat for species by facilitative interactions with other habitats such as tidal flat benthic communities, seagrasses and marshes.

In addition to providing many benefits to the natural world, marine ecosystems also provide social, economic, and biological ecosystem services to humans. Pelagic marine systems regulate the global climate, contribute to the water cycle, maintain biodiversity, provide food and energy resources, and create opportunities for recreation and tourism. [48] Economically, marine systems support billions of dollars worth of capture fisheries, aquaculture, offshore oil and gas, and trade and shipping.

Ecosystem services fall into multiple categories, including supporting services, provisioning services, regulating services, and cultural services. [49]

The productivity of a marine ecosystem can be measured in several ways. Measurements pertaining to zooplankton biodiversity and species composition, zooplankton biomass, water-column structure, photosynthetically active radiation, transparency, chlorophyll-a, nitrate, and primary production are used to assess changes in LME productivity and potential fisheries yield. [50] Sensors attached to the bottom of ships or deployed on floats can measure these metrics and be used to quantitatively describe changes in productivity alongside physical changes in the water column such as temperature and salinity. [51] [52] [53] This data can be used in conjunction with satellite measurements of chlorophyll and sea surface temperatures to validate measurements and observe trends on greater spatial and temporal scales.

Bottom-trawl surveys and pelagic-species acoustic surveys are used to assess changes in fish biodiversity and abundance in LMEs. Fish populations can be surveyed for stock identification, length, stomach content, age-growth relationships, fecundity, coastal pollution and associated pathological conditions, as well as multispecies trophic relationships. Fish trawls can also collect sediment and inform us about ocean-bottom conditions such as anoxia. [54]

Threats

Drivers of change in marine ecosystems Drivers of change in marine ecosystems.png
Drivers of change in marine ecosystems
Global cumulative human impact on the ocean Global cumulative human impact on the ocean.png
Global cumulative human impact on the ocean

Human activities affect marine life and marine habitats through overfishing, habitat loss, the introduction of invasive species, ocean pollution, ocean acidification and ocean warming. These impact marine ecosystems and food webs and may result in consequences as yet unrecognised for the biodiversity and continuation of marine life forms. [58]

The ocean can be described as the world's largest ecosystem and it is home for many species of marine life. Different activities carried out and caused by human beings such as global warming, ocean acidification, and pollution affect marine life and its habitats. For the past 50 years, more than 90 percent of global warming resulting from human activity has been absorbed into the ocean. This results in the rise of ocean temperatures and ocean acidification which is harmful to many fish species and causes damage to habitats such as coral. [59] With coral producing materials such as carbonate rock and calcareous sediment, this creates a very unique and valuable ecosystem not only providing food/homes for marine creatures but also having many benefits for humans too. Ocean acidification caused by rising levels of carbon dioxide leads to coral bleaching where the rates of calcification is lowered affecting coral growth. [60] Additionally, another issue caused by humans which impacts marine life is marine plastic pollution, which poses a threat to marine life. [61] According to the IPCC (2019), since 1950 "many marine species across various groups have undergone shifts in geographical range and seasonal activities in response to ocean warming, sea ice change and biogeochemical changes, such as oxygen loss, to their habitats." [62]

It has been estimated only 13% of the ocean area remains as wilderness, mostly in open ocean areas rather than along the coast. [63]

Human exploitation and development

Coastal marine ecosystems experience growing population pressures with nearly 40% of people in the world living within 100 km of the coast. [64] Humans often aggregate near coastal habitats to take advantage of ecosystem services. For example, coastal capture fisheries from mangroves and coral reef habitats are estimated to be worth a minimum of $34 billion per year. [64] Yet, many of these habitats are either marginally protected or not protected. Mangrove area has declined worldwide by more than one-third since 1950, [65] and 60% of the world's coral reefs are now immediately or directly threatened. [66] [67] Human development, aquaculture, and industrialization often lead to the destruction, replacement, or degradation of coastal habitats. [64]

Moving offshore, pelagic marine systems are directly threatened by overfishing. [68] [69] Global fisheries landings peaked in the late 1980s, but are now declining, despite increasing fishing effort. [48] Fish biomass and average trophic level of fisheries landing are decreasing, leading to declines in marine biodiversity. In particular, local extinctions have led to declines in large, long-lived, slow-growing species, and those that have narrow geographic ranges. [48] Biodiversity declines can lead to associated declines in ecosystem services. A long-term study reports the decline of 74–92% of catch per unit effort of sharks in Australian coastline from the 1960s to 2010s. [70] Such biodiversity losses impact not just species themselves, but humans as well, and can contribute to climate change across the globe. The National Oceanic and Atmospheric Administration (NOAA) states that managing and protecting marine ecosystems is crucial in attempting to conserve biodiversity in the face of Earth’s rapidly changing climate. [71]

Pollution

Marine pollution occurs when substances used or spread by humans, such as industrial, agricultural and residential waste, particles, noise, excess carbon dioxide or invasive organisms enter the ocean and cause harmful effects there. The majority of this waste (80%) comes from land-based activity, although marine transportation significantly contributes as well. [72] It is a combination of chemicals and trash, most of which comes from land sources and is washed or blown into the ocean. This pollution results in damage to the environment, to the health of all organisms, and to economic structures worldwide. [73] Since most inputs come from land, either via the rivers, sewage or the atmosphere, it means that continental shelves are more vulnerable to pollution. Air pollution is also a contributing factor by carrying off iron, carbonic acid, nitrogen, silicon, sulfur, pesticides or dust particles into the ocean. [74] The pollution often comes from nonpoint sources such as agricultural runoff, wind-blown debris, and dust. These nonpoint sources are largely due to runoff that enters the ocean through rivers, but wind-blown debris and dust can also play a role, as these pollutants can settle into waterways and oceans. [75] Pathways of pollution include direct discharge, land runoff, ship pollution, bilge pollution, atmospheric pollution and, potentially, deep sea mining.

The types of marine pollution can be grouped as pollution from marine debris, plastic pollution, including microplastics, ocean acidification, nutrient pollution, toxins and underwater noise. Plastic pollution in the ocean is a type of marine pollution by plastics, ranging in size from large original material such as bottles and bags, down to microplastics formed from the fragmentation of plastic material. Marine debris is mainly discarded human rubbish which floats on, or is suspended in the ocean. Plastic pollution is harmful to marine life.

Invasive species

Climate change

Society and culture

Global goals

By integrating socioeconomic metrics with ecosystem management solutions, scientific findings can be utilized to benefit both the environment and economy of local regions. Management efforts must be practical and cost-effective. In 2000, the Department of Natural Resource Economics at the University of Rhode Island has created a method for measuring and understanding the human dimensions of LMEs and for taking into consideration both socioeconomic and environmental costs and benefits of managing Large Marine Ecosystems. [76] [77] [78]

International attention to address the threats of coasts has been captured in Sustainable Development Goal 14 "Life Below Water" which sets goals for international policy focused on preserving coastal ecosystems and supporting more sustainable economic practices for coastal communities. [79] [5] Furthermore, the United Nations has declared 2021-2030 the UN Decade on Ecosystem Restoration, but restoration of coastal ecosystems has received insufficient attention. [80]

See also

Related Research Articles

<span class="mw-page-title-main">Coast</span> Area where land meets the sea or ocean

The coast, also known as the coastline, shoreline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. Shores are influenced by the topography of the surrounding landscape, as well as by water induced erosion, such as waves. The geological composition of rock and soil dictates the type of shore which is created. The Earth has around 620,000 kilometres (390,000 mi) of coastline. Coasts are important zones in natural ecosystems, often home to a wide range of biodiversity. On land, they harbor important ecosystems such as freshwater or estuarine wetlands, which are important for bird populations and other terrestrial animals. In wave-protected areas they harbor saltmarshes, mangroves or seagrasses, all of which can provide nursery habitat for finfish, shellfish, and other aquatic species. Rocky shores are usually found along exposed coasts and provide habitat for a wide range of sessile animals and various kinds of seaweeds. In physical oceanography, a shore is the wider fringe that is geologically modified by the action of the body of water past and present, while the beach is at the edge of the shore, representing the intertidal zone where there is one. Along tropical coasts with clear, nutrient-poor water, coral reefs can often be found between depths of 1–50 meters.

<span class="mw-page-title-main">Marine biology</span> Scientific study of organisms that live in the ocean

Marine biology is the scientific study of the biology of marine life, organisms in the sea. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies species based on the environment rather than on taxonomy.

<span class="mw-page-title-main">Estuary</span> Partially enclosed coastal body of brackish water

An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environments and are an example of an ecotone. Estuaries are subject both to marine influences such as tides, waves, and the influx of saline water, and to fluvial influences such as flows of freshwater and sediment. The mixing of seawater and freshwater provides high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world.

<span class="mw-page-title-main">Coral reef</span> Outcrop of rock in the sea formed by the growth and deposit of stony coral skeletons

A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups.

<span class="mw-page-title-main">Littoral zone</span> Part of a sea, lake, or river that is close to the shore

The littoral zone, also called litoral or nearshore, is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark, to coastal areas that are permanently submerged — known as the foreshore — and the terms are often used interchangeably. However, the geographical meaning of littoral zone extends well beyond the intertidal zone to include all neritic waters within the bounds of continental shelves.

<span class="mw-page-title-main">Dead zone (ecology)</span> Low-oxygen areas in coastal zones and lakes caused by eutrophication

Dead zones are hypoxic (low-oxygen) areas in the world's oceans and large lakes. Hypoxia occurs when dissolved oxygen (DO) concentration falls to or below 2 mg of O2/liter. When a body of water experiences hypoxic conditions, aquatic flora and fauna begin to change behavior in order to reach sections of water with higher oxygen levels. Once DO declines below 0.5 ml O2/liter in a body of water, mass mortality occurs. With such a low concentration of DO, these bodies of water fail to support the aquatic life living there. Historically, many of these sites were naturally occurring. However, in the 1970s, oceanographers began noting increased instances and expanses of dead zones. These occur near inhabited coastlines, where aquatic life is most concentrated.

<span class="mw-page-title-main">Benthic zone</span> Ecological region at the lowest level of a body of water

The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "the depths." Organisms living in this zone are called benthos and include microorganisms as well as larger invertebrates, such as crustaceans and polychaetes. Organisms here generally live in close relationship with the substrate and many are permanently attached to the bottom. The benthic boundary layer, which includes the bottom layer of water and the uppermost layer of sediment directly influenced by the overlying water, is an integral part of the benthic zone, as it greatly influences the biological activity that takes place there. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, and bay mud.

<span class="mw-page-title-main">Kelp forest</span> Underwater areas with a high density of kelp

Kelp forests are underwater areas with a high density of kelp, which covers a large part of the world's coastlines. Smaller areas of anchored kelp are called kelp beds. They are recognized as one of the most productive and dynamic ecosystems on Earth. Although algal kelp forest combined with coral reefs only cover 0.1% of Earth's total surface, they account for 0.9% of global primary productivity. Kelp forests occur worldwide throughout temperate and polar coastal oceans. In 2007, kelp forests were also discovered in tropical waters near Ecuador.

<span class="mw-page-title-main">Aquatic ecosystem</span> Ecosystem in a body of water

An aquatic ecosystem is an ecosystem found in and around a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms—aquatic life—that are dependent on each other and on their environment. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems. Freshwater ecosystems may be lentic ; lotic ; and wetlands.

<span class="mw-page-title-main">Intertidal zone</span> Area of coast exposed only at low tide

The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide: in other words, the part of the littoral zone within the tidal range. This area can include several types of habitats with various species of life, such as seastars, sea urchins, and many species of coral with regional differences in biodiversity. Sometimes it is referred to as the littoral zone or seashore, although those can be defined as a wider region.

<span class="mw-page-title-main">Wild fisheries</span> Area containing fish that are harvested commercially

A wild fishery is a natural body of water with a sizeable free-ranging fish or other aquatic animal population that can be harvested for its commercial value. Wild fisheries can be marine (saltwater) or lacustrine/riverine (freshwater), and rely heavily on the carrying capacity of the local aquatic ecosystem.

<span class="mw-page-title-main">Coastal fish</span> Fish that inhabit the sea between the shoreline and the edge of the continental shelf

Coastal fish, also called inshore fish or neritic fish, inhabit the sea between the shoreline and the edge of the continental shelf. Since the continental shelf is usually less than 200 metres (660 ft) deep, it follows that pelagic coastal fish are generally epipelagic fish, inhabiting the sunlit epipelagic zone. Coastal fish can be contrasted with oceanic fish or offshore fish, which inhabit the deep seas beyond the continental shelves.

<span class="mw-page-title-main">Ecological values of mangroves</span>

Mangrove ecosystems represent natural capital capable of producing a wide range of goods and services for coastal environments and communities and society as a whole. Some of these outputs, such as timber, are freely exchanged in formal markets. Value is determined in these markets through exchange and quantified in terms of price. Mangroves are important for aquatic life and home for many species of fish.

<span class="mw-page-title-main">Marine habitat</span> Habitat that supports marine life

A marine habitat is a habitat that supports marine life. Marine life depends in some way on the saltwater that is in the sea. A habitat is an ecological or environmental area inhabited by one or more living species. The marine environment supports many kinds of these habitats.

<span class="mw-page-title-main">Marine botany</span> Science of ocean plant life

Marine botany is the study of flowering vascular plant species and marine algae that live in shallow seawater of the open ocean and the littoral zone, along shorelines of the intertidal zone and coastal wetlands, even in low-salinity brackish water of estuaries.

Cape Byron Marine Park is one of four marine parks in New South Wales, Australia, and is the most recently sanctioned. The Cape Byron Marine Park is located in Northern NSW and extends 37 kilometres (23 mi) from the Brunswick River to Lennox Head. The marine park extends out to 3 nautical miles which dictates the border between state and federal jurisdiction. The marine park covers an area of 220 square kilometres (85 sq mi) and includes a variety of marine terrain including beaches, rocky shores, open ocean and the tidal waters of the Brunswick River and its tributaries, the Belongil Creek and Tallow Creek. The Cape Byron Marine Park was declared in 2002 and the zoning plan was implemented in April 2006. Of the 15 distinct marine ecosystems identified within the Tweed-Moreton bioregion, the Cape Byron Marine Park supports 10 of these.

The Hluleka Marine Protected Area is an inshore conservation region in the territorial waters of the Eastern Cape province of South Africa.

<span class="mw-page-title-main">Human impact on marine life</span>

Human activities affect marine life and marine habitats through overfishing, habitat loss, the introduction of invasive species, ocean pollution, ocean acidification and ocean warming. These impact marine ecosystems and food webs and may result in consequences as yet unrecognised for the biodiversity and continuation of marine life forms.

<span class="mw-page-title-main">Marine coastal ecosystem</span> Wildland-ocean interface

A marine coastal ecosystem is a marine ecosystem which occurs where the land meets the ocean. Marine coastal ecosystems include many very different types of marine habitats, each with their own characteristics and species composition. They are characterized by high levels of biodiversity and productivity.

Sri Lanka exhibits a remarkable biological diversity and is considered to be the richest country in Asia in terms of species concentration.

References

  1. "Oceanic Institute". www.oceanicinstitute.org. Archived from the original on 2019-01-03. Retrieved 2018-12-01.
  2. "Ocean Habitats and Information". 2017-01-05. Archived from the original on April 1, 2017. Retrieved 2018-12-01.
  3. "Facts and figures on marine biodiversity | United Nations Educational, Scientific and Cultural Organization". www.unesco.org. Retrieved 2018-12-01.
  4. United States Environmental Protection Agency (2 March 2006). "Marine Ecosystems" . Retrieved 2006-08-25.
  5. 1 2 Ritchie, Roser, Mispy, Ortiz-Ospina. "Measuring progress towards the Sustainable Development Goals. SDG 14" SDG-Tracker.org, website (2018).
  6. United Nations (2017) Resolution adopted by the General Assembly on 6 July 2017, Work of the Statistical Commission pertaining to the 2030 Agenda for Sustainable Development (A/RES/71/313)
  7. "Corals and Coral Reefs". Ocean Portal | Smithsonian. 2012-09-12. Retrieved 2018-03-27.
  8. 1 2 US Department of Commerce, National Oceanic and Atmospheric Administration. "What is a mangrove forest?". oceanservice.noaa.gov. Retrieved 2019-03-21.
  9. 1 2 3 "Mangroves". Smithsonian Ocean. 30 April 2018. Retrieved 2019-03-21.
  10. Mann, K.H. 1973. Seaweeds: their productivity and strategy for growth. Science 182: 975-981.
  11. Graham, M.H., B.P. Kinlan, L.D. Druehl, L.E. Garske, and S. Banks. 2007. Deep-water kelp refugia as potential hotspots of tropical marine diversity and productivity. Proceedings of the National Academy of Sciences 104: 16576-16580.
  12. Christie, H., Jørgensen, N.M., Norderhaug, K.M., Waage-Nielsen, E., 2003. Species distribution and habitat exploitation of fauna associated with kelp (Laminaria hyperborea) along the Norwegian coast. Journal of the Marine Biological Association of the UK 83, 687-699.
  13. Jackson, G.A. and C.D. Winant. 1983. Effect of a kelp forest on coastal currents. Continental Shelf Report 2: 75-80.
  14. Steneck, R.S., M.H. Graham, B.J. Bourque, D. Corbett, J.M. Erlandson, J.A. Estes and M.J. Tegner. 2002. Kelp forest ecosystems: biodiversity, stability, resilience and future. Environmental Conservation 29: 436-459.
  15. Sala, E., C.F. Bourdouresque and M. Harmelin-Vivien. 1998. Fishing, trophic cascades, and the structure of algal assemblages: evaluation of an old but untested paradigm. Oikos 82: 425-439.
  16. Dayton, P.K. 1985a. Ecology of kelp communities. Annual Review of Ecology and Systematics 16: 215-245.
  17. Norderhaug, K.M., Christie, H., 2009. Sea urchin grazing and kelp re-vegetation in the NE Atlantic. Marine Biology Research 5, 515-528
  18. Morton, Adam; Cordell, Marni; Fanner, David; Ball, Andy; Evershed, Nick. "The dead sea: Tasmania's underwater forests disappearing in our lifetime". the Guardian. Retrieved 2020-10-22.
  19. Steinbauer, James. "What Will It Take to Bring Back the Kelp Forest? - Bay Nature Magazine". Bay Nature. Retrieved 2020-10-22.
  20. 1 2 US Department of Commerce, National Oceanic and Atmospheric Administration. "What is an estuary?". oceanservice.noaa.gov. Retrieved 2019-03-22.
  21. 1 2 US Department of Commerce, National Oceanic and Atmospheric Administration. "Estuaries, NOS Education Offering". oceanservice.noaa.gov. Retrieved 2019-03-22.
  22. "Estuaries". www.crd.bc.ca. 2013-11-14. Retrieved 2019-03-24.
  23. US Department of Commerce, National Oceanic and Atmospheric Administration. "What is a lagoon?". oceanservice.noaa.gov. Retrieved 2019-03-24.
  24. 1 2 3 4 Miththapala, Sriyanie (2013). "Lagoons and Estuaries" (PDF). IUCN, International Union for Conservation of Nature. Archived from the original (PDF) on 2016-11-23. Retrieved 2019-03-24.
  25. 1 2 3 4 "What is a Salt Marsh?" (PDF). New Hampshire Department of Environmental Services. 2004. Archived from the original (PDF) on 2020-10-21. Retrieved 2019-03-24.
  26. 1 2 US Department of Commerce, National Oceanic and Atmospheric Administration. "What is a salt marsh?". oceanservice.noaa.gov. Retrieved 2019-03-20.
  27. 1 2 3 4 5 US Department of Commerce, National Oceanic and Atmospheric Administration. "What is the intertidal zone?". oceanservice.noaa.gov. Retrieved 2019-03-21.
  28. 1 2 Helm, Rebecca R. (28 April 2021). "The mysterious ecosystem at the ocean's surface". PLOS Biology. Public Library of Science (PLoS). 19 (4): e3001046. doi: 10.1371/journal.pbio.3001046 . ISSN   1545-7885. PMC   8081451 . PMID   33909611. CC-BY icon.svg Material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.
  29. Fleischmann, Esther M. (1989). "The measurement and penetration of ultraviolet radiation into tropical marine water". Limnology and Oceanography. 34 (8): 1623–1629. Bibcode:1989LimOc..34.1623F. doi: 10.4319/lo.1989.34.8.1623 . S2CID   86478743.
  30. Hardy, J.T. (1982). "The sea surface microlayer: Biology, chemistry and anthropogenic enrichment". Progress in Oceanography. 11 (4): 307–328. Bibcode:1982PrOce..11..307H. doi:10.1016/0079-6611(82)90001-5.
  31. Wurl, Oliver; Holmes, Michael (2008). "The gelatinous nature of the sea-surface microlayer". Marine Chemistry. 110 (1–2): 89–97. Bibcode:2008MarCh.110...89W. doi:10.1016/j.marchem.2008.02.009.
  32. Cunliffe, Michael; Murrell, J Colin (2009). "The sea-surface microlayer is a gelatinous biofilm". The ISME Journal. 3 (9): 1001–1003. doi: 10.1038/ismej.2009.69 . PMID   19554040. S2CID   32923256.
  33. Wurl, Oliver; Ekau, Werner; Landing, William M.; Zappa, Christopher J. (2017). "Sea surface microlayer in a changing ocean – A perspective". Elementa: Science of the Anthropocene. 5. doi: 10.1525/elementa.228 .
  34. Thiel, M.; Gutow, L. (2005). "I. The floating substrata". In Gibson, Robin (ed.). Oceanography and marine biology : an annual review. Boca Raton, Fla: CRC Press. ISBN   978-0-203-50781-0.
  35. Thiel, M.; Gutow, L. (2005). "II. The rafting organisms and community". In Gibson, Robin (ed.). Oceanography and marine biology : an annual review. Boca Raton, Fla: CRC Press. ISBN   978-0-203-50781-0.
  36. Thiel, M.; Gutow, L. (2005). "III. Biogeographical and evolutionary consequences". In Gibson, Robin (ed.). Oceanography and marine biology : an annual review. Boca Raton, Fla: CRC Press. ISBN   978-0-203-50781-0.
  37. Living Bacteria Are Riding Earth’s Air Currents Smithsonian Magazine, 11 January 2016.
  38. Robbins, Jim (13 April 2018). "Trillions Upon Trillions of Viruses Fall From the Sky Each Day". The New York Times . Retrieved 14 April 2018.
  39. Reche, Isabel; D’Orta, Gaetano; Mladenov, Natalie; Winget, Danielle M; Suttle, Curtis A (29 January 2018). "Deposition rates of viruses and bacteria above the atmospheric boundary layer". ISME Journal. 12 (4): 1154–1162. doi:10.1038/s41396-017-0042-4. PMC   5864199 . PMID   29379178.
  40. 1 2 "The Deep Sea". Ocean Portal | Smithsonian. 2012-07-24. Retrieved 2018-03-27.
  41. "The Benthic Zone". Ecosystems. Retrieved 2018-03-27.
  42. "Large Marine Ecosystems (LME)". NOAA. 1 January 2005. Retrieved 31 July 2023.
  43. "Large Marine Ecosystems Hub - A Regional Perspective on the World's Ocean" . Retrieved 31 July 2023.
  44. Olsen SB, Sutinen JG, Juda L, Hennessey TM, Grigalunas TA. 2006. A Handbook on Governance and Socioeconomics of Large Marine Ecosystems. Kingston, RI: Coastal Resources Center, University of Rhode Island. 94 p.
  45. Wang H. 2004. An evaluation of the modular approach to the assessment and management of large marine ecosystems. Ocean Development and International Law 35:267-286.
  46. Juda L, Hennessey T. 2001. Governance profiles and the management of the uses of large marine ecosystems. Ocean Development and International Law 32:41-67.
  47. Ysebaert T., Walles B., Haner J., Hancock B. (2019) "Habitat Modification and Coastal Protection by Ecosystem-Engineering Reef-Building Bivalves". In: Smaal A., Ferreira J., Grant J., Petersen J., Strand Ø. (eds.) Goods and Services of Marine Bivalves. Springer. doi : 10.1007/978-3-319-96776-9_13.
  48. 1 2 3 "Millennium Ecosystem Assessment, Marine Systems" (PDF).
  49. "Ecosystem Services | Mapping Ocean Wealth". oceanwealth.org. Retrieved 2018-03-27.
  50. Pauly D, Christensen V. 1995. Primary production required to sustain global fisheries. Nature 374:255-257.
  51. Aiken J, Pollard R, Williams R, Griffiths G, Bellan I. 1999. Measurements of the upper ocean structure using towed profiling systems. In: Sherman K, Tang Q, editors. Large marine ecosystems of the Pacific Rim: Assessment, sustainability, and management. Malden, MA: Blackwell Science, Inc. p 346-362.
  52. Berman MS, Sherman K. 2001. A towed body sampler for monitoring marine ecosystems. Sea Technology 42(9):48-52.
  53. SAHFOS. 2008. Annual Report 2007. Plymouth, UK: The Sir Alister Hardy Foundation for Ocean Science.
  54. Sea Around Us Project at www.seaaroundus.org/
  55. Österblom, H., Crona, B.I., Folke, C., Nyström, M. and Troell, M. (2017) "Marine ecosystem science on an intertwined planet". Ecosystems, 20(1): 54–61. doi : 10.1007/s10021-016-9998-6.
  56. Halpern, B. S., Frazier, M., Afflerbach, J. et al. (2019) "Recent pace of change in human impact on the world’s ocean." Scientific Reports, 9: 11609. doi:10.1038/s41598-019-47201-9.
  57. Halpern, B. S., Walbridge, S., Selkoe, K. A., Kappel, C. V., Micheli, F., D'agrosa, C., Bruno, J. F., Casey, K. S., Ebert, C., Fox, H. E. and Fujita, R. (2008) "A global map of human impact on marine ecosystems". Science, 319(5865): 948–952. doi:10.1126/science.1149345.
  58. Human impacts on marine ecosystems Archived 22 October 2019 at the Wayback Machine . GEOMAR Helmholtz Centre for Ocean Research. Retrieved 22 October 2019.
  59. "5 ways that climate change affects the ocean". www.conservation.org. Retrieved 2022-12-09.
  60. Kawahata, Hodaka; Fujita, Kazuhiko; Iguchi, Akira; Inoue, Mayuri; Iwasaki, Shinya; Kuroyanagi, Azumi; Maeda, Ayumi; Manaka, Takuya; Moriya, Kazuyoshi; Takagi, Haruka; Toyofuku, Takashi; Yoshimura, Toshihiro; Suzuki, Atsushi (2019-01-17). "Perspective on the response of marine calcifiers to global warming and ocean acidification—Behavior of corals and foraminifera in a high CO2 world "hot house"". Progress in Earth and Planetary Science. 6 (1): 5. doi: 10.1186/s40645-018-0239-9 . ISSN   2197-4284.
  61. Villarrubia-Gómez, Patricia; Cornell, Sarah E.; Fabres, Joan (2018-10-01). "Marine plastic pollution as a planetary boundary threat – The drifting piece in the sustainability puzzle". Marine Policy. 96: 213–220. doi: 10.1016/j.marpol.2017.11.035 . ISSN   0308-597X.
  62. Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC). IPCC (Report). 25 September 2019. p. 2. Retrieved 25 March 2020.
  63. Jones, K. R., Klein, C. J., Halpern, B. S., Venter, O., Grantham, H., Kuempel, C. D., Shumway, N., Friedlander, A. M., Possingham, H. P. and Watson, J. E. (2018) "The location and protection status of Earth’s diminishing marine wilderness". Current Biology, 28(15): 2506–2512. doi:10.1016/j.cub.2018.06.010.
  64. 1 2 3 "Millennium Ecosystem Assessment, Coastal Systems" (PDF).
  65. Alongi, Daniel M. (September 2002). "Present state and future of the world's mangrove forests". Environmental Conservation. 29 (3): 331–349. doi:10.1017/S0376892902000231. ISSN   1469-4387. S2CID   1886523.
  66. "Coral Reefs". Ocean Health Index. Retrieved 2018-12-01.
  67. Burke, Lauretta Marie (2011). Reefs at Risk Revisited | World Resources Institute. World Resources Institute. ISBN   9781569737620 . Retrieved 2018-12-01.{{cite book}}: |website= ignored (help)
  68. Coll, Marta; Libralato, Simone; Tudela, Sergi; Palomera, Isabel; Pranovi, Fabio (2008-12-10). "Ecosystem Overfishing in the Ocean". PLOS ONE. 3 (12): e3881. Bibcode:2008PLoSO...3.3881C. doi: 10.1371/journal.pone.0003881 . ISSN   1932-6203. PMC   2587707 . PMID   19066624.
  69. Urbina, Ian (June 19, 2020). "The Bane of Unsustainable Fishing". The Safina Center.
  70. Mumby, Peter J.; Mark A. Priest; Brown, Christopher J.; Roff, George (2018-12-13). "Decline of coastal apex shark populations over the past half century". Communications Biology. 1 (1): 223. doi:10.1038/s42003-018-0233-1. ISSN   2399-3642. PMC   6292889 . PMID   30564744.
  71. Information, NOAA National Centers for Environmental (2021-09-27). "In Hot Water: Ocean Heat and Our Warming World". ArcGIS StoryMaps. Retrieved 2022-03-01.
  72. Sheppard, Charles, ed. (2019). World seas: an Environmental Evaluation. Vol. III, Ecological Issues and Environmental Impacts (Second ed.). London: Academic Press. ISBN   978-0-12-805204-4. OCLC   1052566532.
  73. "Marine Pollution". education.nationalgeographic.org. Retrieved 2023-06-19.
  74. Duce, Robert; Galloway, J.; Liss, P. (2009). "The Impacts of Atmospheric Deposition to the Ocean on Marine Ecosystems and Climate WMO Bulletin Vol 58 (1)". Archived from the original on 18 December 2023. Retrieved 22 September 2020.
  75. "What is the biggest source of pollution in the ocean?". National Ocean Service (US). Silver Spring, MD: National Oceanic and Atmospheric Administration. Retrieved 2022-09-21.
  76. Sutinen J, ed. 2000. A framework for monitoring and assessing socioeconomics and governance of large marine ecosystems. NOAA Technical Memorandum NMFS-NE-158:32p.
  77. Sutinen, J.G. , P. Clay, C.L. Dyer, S.F. Edwards, J. Gates, T. Grigalunas, T. Hennesey, L. Juda, A.W. Kitts, P. Thunberg, H.R. Upton, and J.B. Walden. 2005. A framework for monitoring and assessing socioeconomics and governance of large marine ecosystems. 27-81 In, Hennessey, T.M. and J.G. Sutinen (Editors), Sustaining Large Marine Ecosystems: The human dimension. Elsevier.368p.
  78. Duda, A.M.. 2005.Targeting development assistance to meet WSSD goals for large marine ecosystems and small island developing states. Ocean & Coastal Management 48:1014
  79. United Nations (2017) Resolution adopted by the General Assembly on 6 July 2017, Work of the Statistical Commission pertaining to the 2030 Agenda for Sustainable Development (A/RES/71/313)
  80. Waltham, Nathan J.; Elliott, Michael; Lee, Shing Yip; Lovelock, Catherine; Duarte, Carlos M.; Buelow, Christina; Simenstad, Charles; Nagelkerken, Ivan; Claassens, Louw; Wen, Colin K-C; Barletta, Mario (2020). "UN Decade on Ecosystem Restoration 2021–2030—What Chance for Success in Restoring Coastal Ecosystems?". Frontiers in Marine Science. 7: 71. doi: 10.3389/fmars.2020.00071 . hdl: 2440/123896 . ISSN   2296-7745.