Marotiri

Marotiri, other name: Bass Rocks, is not an isolated island, but a group of ten small and tiny, uninhabited rock in the Pacific Ocean. It belongs geographically to the archipelago of the Austral Islands and politically to French Polynesia and is administered by the municipality of Rapa.

Geography

Marotiri located in the extreme southeast of the Austral Islands, approximately 80 km southeast of the nearest inhabited island of Rapa Iti and forms with it geographically the subgroup of "Bass Islands ".

Marotiri rises from a lying in 100 feet of water, about 5 km through measured, submarine plateau. The four larger rock islands reach heights of up to 105 meters above sea level, the smaller ones are so low that they are constantly washed by the surf. The islets are between 1.5 and 3 kilometers apart. The land area of ​​the four larger combined is 43,100 m² (0.043 km ²):

The Bass Islands are located in the subtropical climate zone, the climate is humid and temperate.

Geology

Marotiri is of volcanic origin. The Austral Islands form a chain that extends from southeast to northwest in the South Pacific. They are the product of a hot spot under the still active McDonald Seamount, the Austral Islands is below sea southeast today. The geologically oldest, more eroded and rugged islands are in the northwest, the younger to the southeast of the chain. The most recent of which is Marotiri. The age of the basaltic rocks that make up the rock islands, is 5.5 to 3.2 million years.

Flora

Although the bare rocks without vegetation appear at first glance, a closer examination revealed by the botanist Francis Raymond Fosberg in 1934 that they still bear traces of plant growth. A sparse, low-growing and constantly exposed to salt fog flora is found only in the higher ranges of the four major islands. Composed of: Bidens saint- johniana, a Digitaria species, grasses of the genus Cyperus, Portulaca lutea, Solanum nigrum and Solanum carolinense as well as an unspecified milkweed plant (Euphorbia ). In sheltered rock crevices grow three different ferns: Strip ferns ( Asplenium ), lip ferns ( Cheilanthes ) and sword fern ( Nephrolepis ). On the lower slopes comes before a Bocksdornart ( Lycium ) and some rocks are sparsely covered with lichens.

Fauna

Compared with the low biodiversity of the flora, the fauna of the country - only small creatures such as insects, spiders, millipedes and woodlice - surprisingly varied and numerous.

A group of researchers, who also belonged to the American entomologist Elwood Curtin Zimmerman, landed on Marotiri on 22 July 1934. A survey revealed that lived on the rock ticks, mites, silverfish, rockhopper, springtails, crickets, ants and chinch bugs. The researchers also saw flies and moths unspecified identifiable species.

Six species of spiders were discovered: Ariadna lebronneci, Theridion Adamsonite, Ostearius melanopygius, Lycosa tanna, Australaena hystricina and Pseudomaevia insulana

Zimmerman collected from the not hitherto described species of beetle Microcryptorhynchus superstes (synonym: Rhyncogonus zimmermani ) a single copy of a bush of Bidens saint- johniana, of which he seems to feed themselves. Another, somewhat smaller species of the genus, Rhyncogonus variabilis, attracts as food plant Portulaca lutea probably before.

The higher islands are important resting and breeding areas for several species of seabirds, especially for shearwaters and White-tailed Tropicbird. The shearwaters nest on ledges and between the tussocks. Since predators are missing, the unprotected eggs and hatchlings themselves in the open areas are safe.

History

It hardly seems possible that Marotiri was ever inhabited, because the islands do not offer any resources for human life. In particular, there is no fresh water sources. Nevertheless, the "Norwegian Archaeological Expedition to Easter Island and the East Pacific " by Thor Heyerdahl was on a visit to Southern Rock on June 17, 1956 six stone structures that originate from Polynesian natives.

Whether the buildings were built of permanent residents or temporary visitors, who began birds, bird eggs collected and fishing in the surrounding waters, is not known. The most prominent feature is a rectangular, made ​​of raw bricks and mortar without an attached tower on the saddle between the highest point of the island and the south-western tip. The tower measures 2.1 x 1.4 m and 2.2 m high. There are other, rectangular, circular and semi-circular stone structures whose function and age is unknown. They are not more than 1.4 m high and measure only one to two meters in diameter.

The Frenchman Jean Guilin, author of a travel guide about the Austral Islands, concludes on the Southern rock had once been a stronghold of the Polynesian indigenous people who had been created by the tribes of the neighboring island of Rapa for the protection of fishing areas as a refuge.

There was speculation the four larger, visible even when passing islands of Bass Rocks are with the mentioned by Pedro Fernández de Quirós group " Las Cuatro Coronadas " identical. This assumption has not been assigned.

Marotiri was discovered in 1800 by the British ship's doctor and researcher George Bass for Europe.