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Abstract. An investigation was conducted on transplantation in the Mediterranean seagrass, Posidonia oceanica. The effects of rhizome length and season of transplantation were investigated over the first year of growth in relation to survival and development in orthotropic shoots. Twelve batches, each composed of 36 transplants bearing one leaf bundle, were detached and planted at the same site and depth. They were fixed horizontally to mesh supports. These twelve batches, comprising three classes of rhizome length (10, 15, and 20 cm), were transplanted at four times of year. Mortality was highest for transplants made in early summer, when temperatures exceeded 20°C, and lowest for those made in autumn. Although initial rhizome length had no discernible effect on subsequent mortality, it was positively related to the length of the necrosed portion one year later. The most successful transplants, made in autumn with 10 to 15 cm long rhizomes, gave survival rates of 92 to 97%. These results should help to develop transplantation techniques for restoring damaged sites. 相似文献
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Ruitton S Javel F Culioli JM Meinesz A Pergent G Verlaque M 《Marine pollution bulletin》2005,50(10):1061-1068
The introduced green alga Caulerpa racemosa var. cylindracea has been rapidly spreading in the Mediterranean Sea since 1990. It was first observed in France in 1997 (Marseilles). In early 2004, the stretch of the French Mediterranean coastline and the surface area affected by the invasion were estimated at about 83 km and 4014 ha, respectively. The depth range of colonized areas was usually 10-35 m depth. Shallow (0-10 m) and deep (down to 40 m) dense meadows were rarely observed. In contrast to the dead matte of Posidonia oceanica, which constituted the most widely colonized substratum, dense P. oceanica meadows and fine sand with large ripple-marks were not invaded. Few rocky areas were colonized and coarse sand bottoms were usually colonized below 20 m depth. All the colonized areas were exposed to human activities and more than 40% were fishing areas. Mild climate, suitable substrata, presence of vectors of dispersal and absence of efficient biological control make the French Mediterranean coast particularly vulnerable to the further spread of the alga. 相似文献
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Thomas Belsher Alexandre Meinesz Jean Robert Lefevre Charles-François Boudouresque 《Marine Ecology》1988,9(2):157-165
Abstract. In order to simulate SPOT-typc satellite imagery, remote sensing of the Bay of San Cyprianu (Corsica) was carried out using a radiation sensor mounted in an aircraft. The resulting simulated image was calibrated using a chart of the benthos produced by SCUBA diving. We show that remote sensing by satellite should be able to resolve certain bottom types and benthic communities in water down to a depth of 12 m. 相似文献
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Gérard Pergent Charles-François Boudouresque Alain Crouzet Alexandre Meinesz 《Marine Ecology》1989,10(3):221-230
Abstract. Leaf sheaths in the seagrass Posidonia oceanica can persist for millcnia and they show, according to their insertion rank, cyclic variations in parameters such as thickness and tissue structure. The principal cycles are always annual, but pluriannual cycles can also be detected. Annual cycles may be changed by environmental parameters such as light, temperature, or water movement. In a fashion analogous to the study of annual tree rings (dendrochronology), the study of cyclic changes in Posidonia oceanica sheaths is thus a technique allowing the study of past yearly changes in the near-shore environment. 相似文献
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Abstract. A large-scale map of the Posidonia oceanica seagrass beds as well as other benthic substrata and communities was compiled for a cove of a marine reserve free from pollution and man-made disturbance. An extensive diving survey of the cove and the interpretation of aerial colour photographs were used. The greater part of the cove is occupied by the P. oceanica meadow. Patches of dead "matte" were observed at a depth of between 7 and 14 m. They may be the result of a natural hydrodynamic equilibrium between building and erosion. 相似文献
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