Monday, 12 May 2008

A biologic and geologic survey of Saint Kitt Islands.

Krogstad A, Nicholas K.
A biologic and geologic survey of Saint Kitt Islands.
Proc Royal Soc 1898 ; 5.

The Royal Society for the Advancement of Knowledge in the Natural Sciences, Tamrannoch, Caledon.

Saint Kitt Islands is a newly-discovered crown colony of the Independent State of Caledon. The area is composed of a volcanic crater and surrounding atoll, and comprises approximately 65,000 square metres (16 acres, or 0.025 square miles) of land and surrounding sea. Despite its relatively close geographic proximity to Caledon proper, its climate and indigenous plant life is quite distinct from that of the Independent State. In this paper we present the initial descriptions of the island and its biology.

The islands were surveyed by the authors on 11 and 12 May, 1898, funded by an unrestricted grant from the Royal Society for the Advancement of Knowledge in the Natural Sciences. One of the authors (AK) obtained oceanographic information to include sea bed depth, water temperature, currents, and a biologic survey. The other author (KN) was responsible for the geophysical data collection (AK performed the volcanic crater survey). Both authors participated in cataloguing the land-based biodiversity

The atoll itself is 146 metres in maximum north-south dimension, and 100m east-west. The topology is irregular, however, and gives a maximum contiguous straight-line distance (“widest point”) of 142m north-south and 56m east-west. The mean elevation is 2m above sea level at the beachfront. The mountain range running north-south in the atoll is at 11m for the southern-most plateau. Three peaks make up the mountain range proper: 30m at the southern peak, 28m at the centre, and 30m at the northern peak. The peaks are of igneous rock, with lower elevations (i.e. within 5m of sea level) covered in sandy soil and vegetation.

The volcano lies across the atoll to the east, and measures approximately 65 metres in diameter. Maximum elevations are as follows: 32m north rim, 31m southern rim, and 47-50m eastern rim. The rim measures approximately 55m in diameter north-south, and 36m east-west. The crater floor is 20m below sea level, and the cauldron is flooded to sea level. The crater itself is devoid of contents. No lava tunnels or other structures were identified.

The sea depth is -11m in the atoll, near the boat mooring, and -13m elsewhere. The sea bed appears to be uniformly sand, with little ejecta field, lava flows, or other evidence of recent volcanic activity.

In general, the surface conditions are those expected for a volcanic island. The exposed rock is igneous, and the soil is sandy, though rich enough to support vegetation. Sand is the typical pumice-based variety, and is uniformly fine, without larger elements of lava fragments.
Despite the relatively close geographic proximity to Caledon, the climate is an oceanic climate in the Köppen climate classification scheme. Winds appear to move west-to-east, though there is considerable surface-level variability. The day-night cycle is the same as in Caledon. Seismic activity was monitored; those data will be published at a later date.

For a young island, plant biodiversity is greatly important in establishing the biome. On Saint Kitt, two species of palm trees (Arecaceae spp.) and plumeria (Plumeria rubra) are found on the flat coastal regions, facing the atoll. No grasses or flowers were found. The usual ground cover was evident up to 5m or so above sea level, then giving way to igneous rock.

No terrestrial or aquatic animal species were noted despite extensive observations. No bird life was sighted.

Saint Kitt Islands were formed from volcanic activity resulting in an island and atoll. The weathering patterns on the volcano itself suggest a young age, perhaps under 50 years. Seismic activity predicts potential surrounding activity, consistent with known patterns of island-building volcanic activity. Seawater temperatures surrounding the island (unpublished data) point towards other submarine volcanic activity in the area. Further geophysical studies will be required to determine the amount and extent of landmass building that has occurred in the region.

Despite a tropical climate and the amount of plant biodiversity, there is a lack of animal species. This corroborates the geologic weathering-based age of the island, favouring a young landmass. Care must be taken not to introduce foreign plant or animal species if the original species are to be conserved. Caution is also advised regarding wide-scale tourist activity, as the native biome has a potential for serious disruption if faced with unchecked human intervention.

Saint Kitt Islands represent a major find for biologists, geophysicists, vulcanologists, and conservationists. Ongoing investigations would be expected to provide a wealth of information in those fields.

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