摘要:

Abstract.Thein situdiet of the copepodUndinula vulgariswas examined by comparing contents of fecal pellets produced on natural food with assemblages of available phytoplankton. Samples were collected in continental shelf waters of the northern Gulf of Mexico.U. vulgariswas an indiscrimi‐nant suspension feeder, ingesting a broad size, shape, and taxonomic array of phytoplankters. Contents of fecal pellets generally matched those of available phytoplankton assemblages. The presence within the same fecal pellets of remains of microplankters ranging over two orders of magnitude in longest dimension suggests that feeding is nonselective, and thatU. vulgarismay rapidly switch between several modes of feedin

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1986.tb00144.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Abstract.Reproductive parameters of the females ofPenaeus semisulcatusregarding the process of ovary maturation, the degree of synchronization of the ova maturation stage within an ovary, the correlation between female length and both maturity and fecundity, as well as the relationship between moulting, copulation and ovarian maturity stage were investigated.The seasonal and spatial pattern of the reproduction of the female population ofP. semisulcatusalong the southeastern coast of the Mediterranean was determined.Average ova diameter, morphological appearance of the ova, presence of sperm, characteristics of the spermatophore, and hardness of the cuticle were used in order to study the above parameters.

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1986.tb00145.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Abstract.Survival and behaviour of the hermatypic coralDiploria strigosawas studied during 6–24 h doses with water‐accomodated fractions of chemically dispersed crude oil, and for a subsequent recovery period of 1 month. Experiments utilized a flow‐through laboratory dosing procedure and incorporated petroleum hydrocarbon measurements in order to simulate a major but short‐term oil spill in shallow subtidal benthic reef environments. Chemically dispersed oil treatments consisted of Arabian Light Crude oil with Corexit 9527 or BP1100WD at 1–20 ppm concentrations of oil.In general, effects observed were sub‐lethal, temporary, and associated with the highest concentrations tested. Responses to the presence of dispersed oil at 20ppm for 24 h included mesenterial filament extrusion, extreme tissue contraction, tentacle retraction and localized tissue rupture. The nature and severity of reactions during the dosing phase varied between colonies and treatments, but colonies typically resumed normal behaviour within 2 h to 4 d of the recovery period. It therefore seems unlikely that observed biological effects would impair long‐t

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1986.tb00146.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Abstract.The nutrient cycling of Epidavros, a deep basin in the Saronikos Gulf, was studied in relation to various environmental factors during 1973–1976 at a station characterized by stagnant conditions. The regeneration of nutrients was related to the consumption of oxygen, and a seasonal nutrient cycle occurred with low nutrient concentrations in the spring and summer, followed by high nutrient levels in autumn and winter. In addition high values of nitrate and silicate were observed in the deeper waters, which tended to be anoxic, although the water masses were renewed during spring 1974. The distribution pattern of nutrients together with nutrient ratios were compared with previous studies of the same and neighbouring areas as well as of other isolated basins. A stoichiometric model indicates that plankton organisms in the Epidavros basin have approximate atomic ratios for C: N: P of 150: 14:1, while the ratio of change for nitrogen and phosphorus in the water is only 8.8:1 by atoms. This is probably because of the slow rate of regeneration of nitrogenous material and/or assimilation and regeneration in organic forms. The water/plankton relation in the Epidavros basin appears to be very similar to that in the Baltic Se

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1986.tb00147.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Abstract.Zooplankton stock as well as faecal pellet numbers were monitored over 2 weeks during May in the central Baltic. Considerable changes in concentrations of chlorophyll and its derivates in copepod faecal pellets as well as in surface sediments were found during this period. The maximum concentration of 1.05 ngchl.afaecal pellet‐1, measured on 12 May, decreased by the end of the month to 0.08 ngchl.afaecal pellet‐1. This decrease was positively correlated with the disappearance of intact diatoms inside faeces. A flux of 1.53mgchl.a‐m‐2‐day‐1via faecal pellets was calculated for the deep water layer (60–80 m) in mid May. This decreased to 0.005mgchl.am‐2day‐1by the end of May. Chi.aaccounted for up to 10 % of total pigments in samples from the top centimetre of the sediment surface. The means of transportation of faecal pellets as well as their function as a food supply to deeper ecosyst

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1986.tb00148.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Abstract.Recent publications on the coral community of the Tuamotu archipelago have dealt with the Mururoa and Taiaro atolls, with virtually no information available on Takapoto. Consequently the reefs of this atoll were studied using SCUBA to a depth of 70 m and in different biotopes such as patch reefs of the lagoon, and external or protected slopes. A description of the various coral communities is given; specific diversity, ecological valence, community composition, percent coverage, and constructive potential is discussed in relation to abiotic factors.SummaryIn June 1978 the coral associations of the atoll Takapoto, Tuamotu Archipelago, were studied down to 70m by SCUBA (D.Kühlmann) and the corals later determined by J.‐P. Chevalier(†) in Paris. Fifty‐eightScleractiniaand five hydrocorals were observed in the reefs.The highest diversity of species exists in clear, moderate moving waters on a moderately inclined substratum. An ecological valence was established as euryoecious forMontipora verrucosa, Porites lobata, Favia speciosaandMille‐pora platyphylla.Deep water species areLeptoseris porosaandFungiacf.granulosa.The coral associations show characteristic differences at the windward and leeward outer slopes as well as at the patch reefs of the lagoon; these differences are regulated by distinctive hydrodynamics, sedimentation processes, and substrate types as the most effective environmental factors in smaller habitats. The highest degree of coverage of hard corals is found at the windward slope between 10 and 20 m with 90%, the lowest with less than 10% at the slopes of the patch reefs in the lagoon because of the strong sedimentation. The most important reef constructors in the different habitats are listed.RemerciementsJ'exprime ma gratitude à B. Salvat, qui m'a fourni la possibilityé de travailler à 'Antenne de Moorea du Muséum national d'Histoire naturelle, et sur 'atoll de Takapoto. Mes remerciements s'adressent également au Ministére des Universités de la République Démocratique Allemande pour la prise en charge du voyage Berlin‐Tahiti‐Berlin. A.Hauti, Chef du Sérvice de la Pêche, Station de Recherche Nacre et Perliculture de Takapoto, a mis á ma disposition tous les moyens nécessaires á la plongée sur les récifs, embarcations comprises. 'aide de Cigi, Puhipuhi, Bernard, Ismail et Pari fut toujours éfficace. Je n'oublierai pas 'amitie profonde de mes compagnons, G. Richardet G. Vergonzanne. Aprés le décès de J.‐P. Chevalieren 1981, M. Pichon, B. Thomassinet H. et J. ZIBROWIUS ont aimablement

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1986.tb00149.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY