Search results for "Atoll"

Vulnerability of Posidonia oceanica meadow inside a coastal lagoon (Stagnone di Marsala – Western Sicily)

2010

The use of very high resolution images for studying Posidonia oceanica reefs

2020

Posidonia oceanica is an endemic Mediterranean seagrass that forms wide and dense meadows from the surface up to about 40 m depth. This species can develop a biogenic structure called matte, a typical terraced formation built up by itself, consisting of intertwined rhizomes, roots and sediment, which may allow shoots to reach the sea surface forming reefs (récif barrière), considered natural monuments. Posidonia oceanica reefs are particularly exposed to the ongoing increase in temperature and in storm frequency and intensity due to climate change, with negative repercussions on their conservation. Much more attention must be paid to the implementation of monitoring tools able to detect ear…

A Preliminary BeppoSAX Study of the (Bright) Atoll Source GX 9+1

2003

We report the preliminary results of a 350 ks BeppoSAX observation of the bright atoll source GX 9+1. In the field of view of the MECS instrument we discovered a X-ray pulsar, designated SAX J1802.7 - 2017, at an angular distance from GX 9+1 of ∼ 22 ′ . Since the X-ray emission of SAX J1802.7 - 2017 contaminates the energy spectrum above 10 keV we studied the energy spectrum of GX 9+1 in the energy band 0.1 - 10keV. We selected four regions in the color-color diagram and extracted one spectrum from each region. A bump below 1keV is present in the spectra using a model composed by a Comptonized component absorbed by neutral matter having an equivalent hydrogen column of 1.5 x 10 22 cm -2 . T…

Sclerochronology - a highly versatile tool for mariculture and reconstruction of life history traits of the queen conch, Strombus gigas (Gastropoda)

2009

International audience; The queen conch, Strombus gigas, is an important fisheries resource in the Western Tropical Atlantic. In order to maintain harvesting success, improve fisheries management and contribute to mariculture pursuits, a detailed understanding of the life history traits of this species is required. Traditionally, this has been achieved by tedious and time-consuming long-term field observations. This study presents a highly versatile and rapid technique to estimate the timing and rate of shell growth based on sclerochronology. The Belizean S. gigas specimens (N = 2) from the offshore atoll, Glovers Reef, reached their final shell size (maximum shell height: 22.7 and 23.5 cm,…

Seagrass meadows at the extreme of environmental tolerance: the case ofPosidonia oceanicain a semi-enclosed coastal lagoon

2009

Atoll-like structures of the endemic Mediterranean seagrass Posidonia oceanica were encountered in the innermost area of the Stagnone di Marsala, a semi-enclosed coastal lagoon along the western coasts of Sicily. The area is characterized by limited water exchange with the open sea and by a marked seasonal variation of water salinity and temperature, reaching beyond the theoretical tolerance limits of the species. In the present study we determined the genetic composition of the atoll-like structures, as well as the growth performance and flowering rate of these stands. We also assessed whether and to what extent the atoll-like structures are genetically isolated from plants growing in mead…

Cat on a queer tin roof : a descriptive study of the process of character analysis and directing

2001

Maldivian Tourist Resorts and their Environmental Impact

1993

In the past two decades, the Maldivians have built up a flourishing tourist industry. Tourist resorts have been established on hitherto uninhabited small islands and by 1990 the number of tourists has increased to nearly 200 000. The Maldivian tourist resorts represent a special type of tropical beach resorts catering only to the tourists’ needs for accommodation, board, leisure and recreation. They are distinctly separate from the islands inhabited by the Maldivians and intercultural communication does not take place. These resorts are in effect ‘tourist enclaves’. Holiday facilities in the resorts are clearly geared to the coastal environment - the beach, lagoon and reef. The impact of to…

Recent evolution of the multi-isotopic radioactive content in ice of Livingston Island, Antarctica.

1999

The temporal arrangement of the ice layers that are produced in ecosystems with perpetual snows form situations that greatly favour the study of the temporal evolution of the radioactive fallout that occurs in the said zones, whether this fallout is natural or artificial in origin. This allows one to investigate the causes of the fallout and the mechanisms transporting the radionuclides involved from their source point to the study zone, as well as their subsequent behaviour in that zone. There are special difficulties involved in this type of study in Antarctica. Some are of a general character deriving from the conditions of extreme climate and isolation which complicate the processes of …