Arafura Sea

Arafura Sea
source
Name	Arafura Sea
Caption	Map showing the location of the Arafura Sea.
Location	Australasia, between Northern Australia and Western New Guinea
Type	Sea
Part of	Pacific Ocean
Basin countries	Australia, Indonesia, Papua New Guinea
Max-depth	~3,680 m
Islands	Aru Islands, Croker Island, Goulburn Islands

Arafura Sea. The Arafura Sea is a marginal sea of the western Pacific Ocean, situated between the northern coast of Australia and the southern coast of Western New Guinea. It is bounded to the north by the Ceram Sea and the Banda Sea, to the east by the Torres Strait and the Coral Sea, and to the west by the Timor Sea. This body of water serves as a critical maritime corridor and supports rich marine ecosystems and significant economic activities.

Geography

The Arafura Sea spans approximately 650,000 square kilometers, lying primarily on the Sahul Shelf, a vast, shallow continental shelf. Its northern boundary is generally defined by a line from the Tanahmerah Bay in Papua to the southwestern tip of New Guinea, connecting to the islands of the Banda Arc. To the east, it connects with the Gulf of Carpentaria via the shallow Arafura Sill, and its eastern limit is marked by the entrance to the Torres Strait, near the Great Barrier Reef. Major island groups within or adjacent to the sea include the Aru Islands, part of Maluku Province, and several Australian islands such as the Goulburn Islands and Croker Island. Key coastal settlements include Daru in Papua New Guinea, Merauke in Indonesia, and Nhulunbuy in Australia's Northern Territory.

Geology

The seafloor geology is dominated by the extensive, stable Sahul Shelf, composed of ancient Precambrian and Mesozoic sedimentary rocks overlain by thick Cenozoic deposits. This shelf is part of the Australian Plate, which is moving northward and colliding with the Pacific Plate and the Banda Sea Plate, creating complex tectonic interactions along its northern margins. The Aru Trough, a significant depression in the central Arafura Sea, represents a failed rift zone. The region's geological history includes periods of glaciation during the Pleistocene, when lower sea levels exposed the shelf as a land bridge, facilitating the migration of ancient fauna and early human populations, such as the ancestors of Indigenous Australians, between Sundaland and Sahul.

Hydrology

The hydrology is characterized by warm, tropical waters with surface temperatures typically ranging from 26°C to 30°C. A major feature is the seasonally reversing Indonesian Throughflow, which transports water from the Pacific Ocean to the Indian Ocean through the archipelago, influencing regional currents and salinity. The shallow shelf areas experience significant tidal mixing, with tides being predominantly semidiurnal. Freshwater input from major rivers like the Digul River in Papua and the Liverpool River in Australia creates localized estuarine conditions and plumes that affect water clarity and nutrient distribution. The exchange with the deeper Banda Sea occurs over the Timor Trough.

Ecology

The sea supports diverse and productive marine ecosystems, particularly over the nutrient-rich Sahul Shelf. Extensive seagrass meadows and algal beds provide critical habitat for dugong populations, green sea turtles, and commercially important penaeid prawn species. The Arafura Sea is part of the Coral Triangle periphery, hosting biodiverse coral reef systems, especially around the Aru Islands. The waters are a vital feeding ground for migratory species, including the humpback whale and several seabirds like the lesser frigatebird. Fisheries target species such as the banana prawn, barramundi, and Spanish mackerel, while the ecosystem faces pressures from climate change, bottom trawling, and sedimentation from river runoff.

Human use

The sea has been used for millennia by indigenous peoples, including the Yolngu and Maring for trade and subsistence. Modern use is dominated by commercial fishing, with the Arafura Sea Fishery being one of Australia's most valuable, managed under agreements like the Torres Strait Treaty. Significant oil and gas exploration occurs on the shelf, with projects like the Bayu-Undan gas field. The sea is a major shipping route for vessels traveling between the Indian Ocean and East Asia, passing through the Lombok Strait and Torres Strait. Environmental management involves cross-border initiatives between Australia and Indonesia, addressing challenges such as illegal, unreported and unregulated fishing and marine conservation. Category:Marginal seas of the Pacific Ocean Category:Seas of Australia Category:Seas of Indonesia Category:Seas of Oceania