Spratly Islands

The Spratly Islands are a disputed archipelago in the South China Sea. Composed of islands, islets, cays, and more than 100 reefs, sometimes grouped in submerged old atolls, the archipelago lies off the coasts of the Philippines, Malaysia, and southern Vietnam. Named after the 19th-century British whaling captain Richard Spratly who sighted Spratly Island in 1843, the islands contain less than of naturally occurring land area that is spread over hundreds of square km of the South China Sea.
The Spratly Islands are one of the major archipelagos in the South China Sea which complicate governance and economics in this part of Southeast Asia due to their location in strategic shipping lanes. The islands are largely uninhabited, but offer rich fishing grounds and may contain significant oil and natural gas reserves, and as such are important to the claimants in their attempts to establish international boundaries. Some of the islands have civilian settlements, but of the approximately 45 islands, cays, reefs and shoals that are occupied, all contain structures that are occupied by military forces from Malaysia, China, Taiwan, the Philippines, and Vietnam. Additionally, Brunei has claimed an exclusive economic zone in the southeastern part of the Spratly Islands, which includes the uninhabited Louisa Reef.

Geographic and economic overview

In 1939, the Spratly Islands were coral islets mostly inhabited by seabirds. Despite the Spratly Islands naturally consisting of 19 islands , according to a Chinese 1986 source, the Spratly Islands consist of 14 islands or islets, 6 banks, 113 submerged reefs, 35 underwater banks and 21 underwater shoals.
The islands are all of similar nature; they are cays : sand islands formed on old degraded and submerged coral reefs. The northeast part of the Spratly Islands is known as Dangerous Ground and is characterised by many low islands, sunken reefs, and degraded, sunken atolls with coral often rising abruptly from ocean depths greater than — all of which makes the area dangerous for navigation.
The Spratly Islands contain almost no arable land, are largely uninhabited, and very few of the islands have a permanent drinkable water supply.
Natural resources include fish, guano, oil and natural gas. Economic activity has included commercial fishing, shipping, guano mining, oil and gas exploitation, and more recently, tourism. The Spratly Islands are located near several primary shipping lanes.
The islands and cays, listed in descending order of naturally occurring area, are:

#	Island name	in Atoll	Area	Location	Currently occupied by	Reclaimed area
1	Itu Aba Island	Tizard Bank	46.00		Taiwan	~6 ha
2	Thitu Island	Thitu Reefs	37.20		Philippines
3	West York Island	West York Island	18.60		Philippines
4	Spratly Island	Spratly Island	13.00		Vietnam
5	Northeast Cay	North Danger Reef	12.70		Philippines
6	Southwest Cay	North Danger Reef	12.00		Vietnam	~8 ha
7	Sin Cowe Island	Union Banks	08.00		Vietnam	~1 ha
8	Nanshan Island	Nanshan Group	07.93		Philippines
9	Sand Cay	Tizard Bank	07.00		Vietnam	~2.1 ha
10	Loaita Island	Loaita Bank	06.45		Philippines
11	Swallow Reef	Swallow Reef	06.20		Malaysia
12	Namyit Island	Tizard Bank	05.30		Vietnam
13	Amboyna Cay	Amboyna Cay	01.60		Vietnam
14	Grierson Reef	Union Banks	01.60		Vietnam
15	West London Reef	London Reefs	01.10		Vietnam
16	Central London Reef	London Reefs	00.88		Vietnam
17	Flat Island	Nanshan Group	00.57		Philippines
18	Lankiam Cay	Loaita Bank	00.44		Philippines

The total area of the archipelago's naturally occurring islands is and with reclaimed land.
Confusingly, the Spratly Islands at times were also referred to as the Paracels.

Geology

The Spratly Islands consist of islands, reefs, banks and shoals made up of biogenic carbonate. These accumulations of biogenic carbonate lie upon the higher crests of major submarine ridges that are uplifted fault blocks known by geologists as horsts. These horsts are part of a series of half-grabens and rotated fault-blocks which lie parallel and en echelon. The long axes of the horsts, rotated fault blocks and half-grabens form well-defined linear trends that lie parallel to magnetic anomalies exhibited by the oceanic crust of the adjacent South China Sea. The horsts, rotated fault blocks, and the rock forming the bottoms of associated grabens consist of stretched and subsided continental crust that is composed of Triassic, Jurassic, and Cretaceous strata that include calc-alkalic extrusive igneous rocks, intermediate to acid intrusive igneous rocks, sandstones, siltstones, dark-green claystones, and metamorphic rocks that include biotite–muscovite–feldspar–quartz migmatites and garnet–mica schists.
The dismemberment and subsidence of continental crust into horsts, rotated fault blocks and half-grabens that underlie the Spratly Islands and surrounding sea bottom occurred in two distinct periods. They occurred as the result of the tectonic stretching of continental crust along underlying deeply rooted detachment faults. During the Late Cretaceous and Early Oligocene, the earliest period of tectonic stretching of continental crust and formation of horsts, half-grabens, and rotated fault-blocks occurred in association with the rifting and later sea-floor spreading that created the South China Sea. During the Late Oligocene-Early Miocene additional stretching and block faulting of continental crust occurred within the Spratly Islands and adjacent Dangerous Ground. During and after this period of tectonic activity, corals and other marine life colonised the crests of the horsts and other ridges that lay in shallow water. The remains of these organisms accumulated over time as biogenic carbonates that comprise the current day reefs, shoals and cays of the Spratly Islands. Starting with their formation in Late Cretaceous, fine-grained organic-rich marine sediments accumulated within the numerous submarine half-grabens that underlie sea bottom within the Dangerous Ground region.
The geological surveys show localised areas within the Spratly Islands region are favourable for the accumulation of economic oil and gas reserves. They include thick sequences of Cenozoic sediments east of the Spratly Islands. Southeast and west of them, there also exist thick accumulations of sediments that possibly might contain economic oil and gas reserves, which lie closer to the Spratly Islands.

Ecology

In some cays in the Spratly Islands, the sand and pebble sediments form the beaches and spits around the island. Under the influence of the dominant wind direction, which changes seasonally, these sediments move around the island to change the shape and size of the island. For example, Spratly Island is larger during the northeast monsoon, and smaller during the southwest monsoon.
Some islands may contain fresh groundwater fed by rain. Groundwater levels fluctuate during the day with the rhythm of the tides.
Phosphates guano are mainly concentrated in the beach rocks by the way of exchange-endosmosis. The principal minerals bearing phosphate are podolite, lewistonite and dehonite.

Coral reefs

are the predominant structures of these islands; the Spratly group contains over 600 coral reefs in total. In April 2015 The New York Times reported that China were using "scores of dredgers" to convert Fiery Cross Reef and several other reefs into military facilities.

Vegetation

Little vegetation grows on these islands, which are subject to intense monsoons. Larger islands are capable of supporting tropical forest, scrub forest, coastal scrub and grasses. It is difficult to determine which species have been introduced or cultivated by humans. Taiping Island was reportedly covered with shrubs, coconut, and mangroves in 1938; pineapple was also cultivated there when it was profitable. Other accounts mention papaya, banana, palm, and even white peach trees growing on one island. A few islands that have been developed as small tourist resorts had soil and trees brought in and planted where there was none.

Wildlife

A total of 2,927 marine species have been recorded in the Spratly Sea, including 776 benthic species, 382 species of hard coral, 524 species of marine fish, 262 species of algae and sea grass, 35 species of seabirds, and 20 species of marine mammals and sea turtles. Terrestrial vegetation in the islands includes 103 species of vascular plants of magnolia branches of 39 families and 79 genera. The islands that do have vegetation provide important habitats for many seabirds and sea turtles. Both the green turtle and the hawksbill turtle formerly occurred in numbers sufficient to support commercial exploitation. These species reportedly continue to nest even on islands inhabited by military personnel to some extent, though it is believed that their numbers have declined.
Seabirds use the islands as resting, breeding, and wintering sites. Species found here include streaked shearwater, brown booby, red-footed booby, great crested tern, and white tern. Little information is available regarding the current status of the islands' seabird populations, though it is likely that birds may divert nesting sites to smaller, less disturbed islands. Bird eggs cover the majority of Southwest Cay, a small island in the eastern Danger Zone. A variety of cetaceans such as dolphins, orcas, pilot whales, and sperm whales are also present around the islands.
This ecoregion is still largely a mystery. Scientists have focused their research on the marine environment, while the ecology of the terrestrial environment remains relatively unknown.