AQUATIC biodiversity refers to the variety of life and the ecosystems that make up the freshwater, tidal, and marine regions of the world. Aquatic biodiversity includes freshwater ecosystems — lakes, ponds, reservoirs, rivers/streams, groundwater and wetlands — and marine ecosystems, such as oceans, estuaries, salt marshes, sea-grass beds, coral reefs, kelp beds, and mangrove forests. Aquatic ecosystems provide home to many species, including plankton (tiny plants which are the base of the food web in marine environments), zooplankton (tiny invertebrates that float freely throughout the waters), aquatic plants, insects, fish, birds, mammals, among others.  These are organized at many levels, from the smallest building blocks of life to complete ecosystems. In short, aquatic biodiversity includes unique species and habitats, and the interaction between them.

Why is Aquatic Biodiversity Important?
Marine ecosystems are very important to the overall health of both marine and terrestrial environments. According to the World Resources Center, coastal habitats alone account for approximately one-third of all marine biological productivity, and estuarine ecosystems — salt marshes, sea-grasses, mangrove forests — are among the most productive regions on the planet. In addition, other marine ecosystems, such as coral reefs, provide food and shelter to the highest levels of marine diversity in the world.
The diversity and productivity of marine ecosystems are also important to human survival and wellbeing. These habitats provide us with a rich source of food and income, and support species that serve as animal feed, fertilizers for crops, additives in foods (ice-cream) and cosmetics (creams and lotions).
Areas such as mangroves, reefs, and sea-grass beds also provide protection to coastlines by reducing wave action and helping to prevent erosion, while areas such as salt marshes and estuaries have acted as sediment sinks, filtering runoff from the land.
Aquatic biodiversity has enormous economic and aesthetic value, and is largely responsible for maintaining and supporting overall environmental health.
Humans have long depended on aquatic resources for food, medicines, and materials, as well as for recreational and commercial purposes such as fishing and tourism. Aquatic organisms also rely upon the great diversity of aquatic habitats and resources for food, materials, and breeding grounds.
Despite the importance of marine ecosystems, increased human activities such as overfishing, coastal development, pollution, and the introduction of exotic species have had significant negative impact on, and pose a serious threat to, marine biodiversity.
Factors including overexploitation of species, the introduction of exotic species, pollution from urban, industrial and agricultural areas, as well as habitat loss and alteration all contribute to the declining levels of aquatic biodiversity in both freshwater and marine environments.
As a result, valuable aquatic resources are becoming increasingly susceptible to both natural and artificial environmental changes. This has led to the need for conservation strategies to protect and conserve aquatic life to maintain the balance of nature and support the availability of resources for future generations.
Interconnectivity

The health of marine environments is directly related to each component of the ecosystem. Alterations in the upper watershed, for instance, can impact an entire lake or creek ecosystem. When a forest is cleared, not only is the physical structure of the terrestrial ecosystem altered, the tributary streams, coastal areas and the open lake can also be affected.

When vegetation is removed near a tributary, precipitation is allowed to run off directly into the river or stream, causing flows in these streams to increase much more quickly following rainfall. This run-off picks up more soil than it otherwise would and the load of sediment in the tributary will be increased. The increased sediments can destroy the habitat required by fish and insect species and can prevent the spawning of fish migrating from salt water to spawn in fresh water (anadromous fishes). These sediments can also accelerate the formation of sand bars and blockages at river-mouths and alter nearby coasts.

Protecting Aquatic Biodiversity
Increasing public awareness is one of the most important ways to conserve aquatic biodiversity. This can be accomplished through educational programmes, incentive programmes, volunteer monitoring programmes and media programmes.

In addition, harvesting or using aquatic resources wisely will help in conservation and preservation of this most valuable resource.

Getting involved in clean up campaigns such as coastal clean-ups along sea and river banks will help to prevent litter from getting into the water system. Proper waste disposal methods will also help to prevent litter finding its way into water systems.

Waste disposal at sea also needs to be closely monitored to prevent harmful substances being dumped in the marine environment.

Each individual can be an advocate for the environment and help to inform others of actions that are bad for the environment and on better alternatives.

You can share ideas and questions by sending your letters to: ‘Our Earth, Our Environment’, C/o EIT Division, Environmental Protection Agency, Ganges Street, Sophia, GEORGETOWN, or email eit.epaguyana@gmail.com