Marine Invertebrates & Marine Plants

Marine invertebrates include a wide variety of animals without a backbone, for example hard and soft corals, echinoderms such as sea urchins, sea stars, and sea cucumbers, crustaceans such as prawns and crabs, molluscs such as mussels and oysters, and a wide variety of other, often small-sized, animals such as worms.

Marine plants include algae, seagrasses, and mangroves. Algae have a variety of growth forms ranging form single celled plankton algae to large seaweeds. They play a very important role in the marine ecosystem as the primary producers that form the basis of most marine food chains. Phytoplankton is particularly important in this regard, and is a considerable sink for carbon dioxide. On coral reefs, calcareous algae have a significant role in cementing the reef together. Large algae may also provide homes for a wide variety of small organisms.

In contrast, seagrasses are true flowering plants like many land plants. Seagrasses are important in coastal marine areas. They are the main diet of dugong and green turtles and provide a habitat for many, much smaller marine animals, some of which, like prawns and fish, are commercially important. They also stabilise sediment, helping to keep water clear. Australia has the highest number of seagrass species of any continent.

Mangroves are also flowering plant, which play a vital role in the biological diversity of Barrier Reef waters. Like other marine plants mangrove trees are an important part of the marine food chain. Many commercial and non-commercial fish and prawn species live in mangroves, feeding on small organisms in their juvenile stages. The coastal mangrove forests are linked to seagrass beds and reefs by animals, nutrients, and organic matter moving between these environments.

More information about GBR marine invertebrates and plants:

• CRC brochure COTS, coral bleaching, introduced species
• Bleaching page
• CRC Reef Coral Reef pages
• Great Barrier Reef Marine Park Authority’s State of the Reef Report (corals)
• Great Barrier Reef Marine Park Authority’s State of the Reef Report (Inter-reefal and lagoonal benthos)

The largest biological monitoring program in the Great Barrier Reef World Heritage Area (GBRWHA) is the Long-term Monitoring Program of the Australian Institute of Marine Science (AIMS), which has assessed benthic (sea floor animals and plants) and fish communities on coral reefs since 1993 . This monitoring program in its current form annually surveys 48 reefs along the length of the GBR, and located across the continental shelf (inshore, midshelf, and offshore reefs). Additional reefs are surveyed if time permits. The data has been extensively used for the reporting on the status of the GBRWHA, as required by the World Heritage Commission of the UNESCO. This program is informs on outbreaks of the coral eating crown-of-thorns starfish and the occurrence and impacts of coral bleaching.

There are several coral reef community monitoring programs that primarily rely on volunteers, including the Eye on the Reef and Reef Check initiatives.

A number of research studies of coral reef benthic communities have an important monitoring component , . Benthic monitoring data have also been collected as part of a number of environmental impact assessment programs of activities in the Marine Park .

Community groups play a major role in monitoring seagrass through the Seagrass-Watch program link to 44, which is managed by the Queensland Department of Primary Industries (QDPI). This program has been very successful in documenting status and trends of intertidal seagrasses (in shallow waters close to the shore and usually exposed at low tides) along the Great Barrier Reef coast. However, a regular assessment of subtidal (deeper water) seagrasses currently does not occur. It is currently unknown if subtidal seagrass status can be inferred from intertidal seagrass status.

Monitoring of intertidal and subtidal seagrass in certain regions or individual locations is part of fisheries habitat monitoring programs link to , , research projects , and some environmental impact monitoring programs.

Monitoring of mangrove forests is part of some fisheries habitat monitoring programs and some community monitoring programs . A program assessing mangrove health and associated water quality has been carried out in the Mackay region . There is currently now large-scale monitoring of mangrove status and health in the Great Barrier Reef World Heritage Area.

While monitoring of status and trends of midshelf and offshore coral reefs and of intertidal seagrass beds in the Great Barrier Reef World Heritage Area is relatively comprehensive, researchers and managers perceive there is paucity of large scale and long-term monitoring of biological communities in the nearshore environments of the GBRWHA, which are the areas most affected by land run-off and other human activities, such as boating and fishing.

A program monitoring the status and dynamics of nearshore fringing coral reefs in the Cairns section of the Great Barrier Reef Marine Park is underway since 1985 . Of the 48 core reefs that are regularly monitored by the AIMS Long-Term Monitoring Program 12 are nearshore reefs .

Marine invertebrates and plants, as well as fish, are also monitored in ports and harbours to document biological communities and to detect the presence of introduced marine species link to , .