Marine biodiversity is a collection of highly interconnected ecosystem components or features that span all levels of biological organisation, from genes to species to populations to ecosystems, and each level’s diversity has structural and functional attributes. Furthermore, marine biodiversity, or any of its components, can be measured at a variety of time and spatial scales. The questions asked, which components are highlighted, and the information and understanding available, particularly about the system’s connectivity and feedback, all have an impact on the conceptual model of marine biodiversity and its interpretation. By definition, this implies an implicit understanding that the components are all part of a larger, interconnected system, and that changes in one element will inevitably have an impact on others.
Bottom-up processes can be considered, causing changes from the cell to the ecosystem and from the physicochemical system to the landscape system. They can also be viewed as responses in a top-down system focusing on the upper level (seascape and ecosystem), which is frequently the end-point of marine management and the subject of the current review. As a result, the genetic, molecular, physiological, biochemical, population, and size-biomass-spectrum aspects of biodiversity are not specifically addressed in this review, as these are both intrinsic and implicit aspects of biodiversity, depending on which viewpoint is emphasised.
Significance:
Marine biodiversity, or the diversity of life in the oceans and seas, is an essential component of all three pillars of sustainable development—economic, social, and environmental—supporting the planet’s healthy functioning and providing services critical to humanity’s health, well-being, and prosperity.
The ocean is one of the world’s most important biodiversity hotspots. It encompasses more than 90 percent of the planet’s habitable space and is home to over 250,000 known species, with many more yet to be discovered—at least two-thirds of the world’s marine species are unidentified.
The ocean and the life that lives in it are critical to the planet’s health, providing half of the oxygen we breathe and absorbing roughly 26% of the anthropogenic carbon dioxide emitted into the atmosphere each year.
Evidence of marine biodiversity’s critical role in sustaining a healthy planet and social well-being continues to emerge. Hundreds of millions of people, mostly low-income families, rely on the fishery and aquaculture sectors for a living, and they contribute both directly and indirectly to food security. Marine ecosystems provide a variety of services to coastal communities all over the world. Mangrove ecosystems, for example, feed over 210 million people while also providing a variety of other services such as livelihoods, clean water, forest products, and erosion and extreme weather protection.
Human settlements have sprung up along the coast due to the abundance of resources provided by the ocean: 38 percent of the world’s population lives within 100 kilometres of the coast, 44 percent within 150 kilometres, 50 percent within 200 kilometres, and 67 percent within 400 kilometres.
The ocean and coastal areas within 100 kilometres of the coastline account for approximately 61 percent of the world’s total GDP.
Coastal population densities are 2.6 times higher than inland population densities, and they benefit both directly and indirectly from the goods and services provided by coastal and marine ecosystems, which contribute to poverty eradication, sustained economic growth, food security, sustainable livelihoods, and inclusive work, while also hosting significant biodiversity and mitigating the effects of climate change.
As a result, pressures that negatively impact marine biodiversity also jeopardise the planet’s ability to provide the services we need to survive and thrive. Furthermore, as the demand for ocean services grows, so will the provisioning of these services. The poor suffer the most severe consequences of biodiversity loss because they rely heavily on local ecosystem services for their livelihoods and are particularly vulnerable to impacts on those services.
Marine biodiversity and ecosystems are inextricably linked to a wide range of services required for long-term development. These relationships, which are frequently complex and dynamic, are influenced by feedback loops and synergistic effects. These emphasise the importance of an integrated and holistic approach to marine biodiversity conservation and sustainable use that is based on ecosystem and precautionary approaches, inclusiveness and equity principles, and the need to provide multiple benefits to ecosystems and communities.
Example:
The number of fish species in the North Sea is an example of marine biodiversity; genetic diversity refers to genetic differences between different populations of the same fish species, and ecosystem diversity refers to the number of communities living in different habitats/ecosystems.
Threats:
- Excessive commercial and recreational exploitation
- Air pollution
- Habitat fragmentation and deforestation
- Non-native species invasion
Threats to marine biodiversity have a wide range of social, economic, and biological consequences, all of which have the potential to endanger our survival, including:
- Economic losses due to lower productivity
- Significant population declines in much popular edible fish and shellfish.
- Extinction of species that could be useful in the development of new medicines
- The ability of ecosystems to respond to natural (floods) and man-made disasters is harmed (pollution)
Conclusion:
Because there is a greater diversity of habitats near the coast, marine biodiversity is higher in benthic systems rather than pelagic systems, and along coasts rather than in the open ocean. The Indonesian archipelago has the greatest diversity of species, which decreases radially from there. The terrestrial pattern of increasing diversity from the poles to the tropics is visible from the Arctic to the tropics, but not in the southern hemisphere, where diversity is highest at high latitudes. Because of competing uses of coastal habitats, the loss of marine diversity is greatest in coastal areas. Protecting coastal habitat and landscape diversity is the most effective way to protect marine diversity. Marine protected areas are just one part of a larger conservation strategy. The sustainable use of coastal biodiversity is one of the primary goals of integrated coastal area management, which is proposed as a framework for coastal conservation.