Oceanologica Acta最新文献

{"title":"Variations of zooplankton metabolism and feeding in the frontal area of the Alboran Sea (western Mediterranean) in winter","authors":"Raymond Gaudy,&nbsp;Faiçal Youssara","doi":"10.1016/S0399-1784(02)00005-1","DOIUrl":"10.1016/S0399-1784(02)00005-1","url":null,"abstract":"<div><p>Respiration, excretion (NH₄ and PO₄) and feeding of zooplankton from the upper 200 m of the Almeria–Oran frontal region (western Mediterranean), were studied during winter 1997. Eight sites belonging to the three main hydrodynamic structures of the area (Mediterranean water, geostrophic Atlantic jet and associated anticyclonic gyre) were considered. Lowest values of respiration, PO₄<span><span> excretion, O/P atomic ratio and particle ingestion were found in Mediterranean waters. At the frontal limit, respiration and ammonium excretion were enhanced compared to the adjacent structures (Mediterranean water and Atlantic jet). In the gyre water, lowest O/N and highest N/P values were observed and maximum faecal pellet<span> production and reproduction activity (inferred from the proportion of nauplii in plankton) were recorded. </span></span>Selectivity<span> was observed for feeding with respect to particular spectra. At the front and in the jet, large particles (&gt; 20 μm), were preferred, while medium- and small-sized particles were mainly used for food at the gyre and in Mediterranean water. As the bulk of zooplankton components was the same at all the stations, physiological variations were interpreted as adaptive processes to qualitative and quantitative changes in the food resource, i.e. Mediterranean scarcity and Atlantic water richness, “new production” of diatoms at the front limit, enhancement of the microbial food chain at the gyre and in Mediterranean waters. The maximum proportion of copepod nauplii observed at the gyre could result, either from an isopycnal transport from the front, of larvae issued from eggs produced at the frontal limit, or from a local enhancement of copepod reproductive activity induced by the favourable food conditions prevailing at the gyre, as suggested by the increase of faecal production.</span></span></p></div>","PeriodicalId":100980,"journal":{"name":"Oceanologica Acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0399-1784(02)00005-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80761804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flow variability near the Cape Verde frontal zone (subtropical Atlantic Ocean)","authors":"Annick Vangriesheim ,&nbsp;Claudie Bournot-Marec ,&nbsp;Anne-Claire Fontan","doi":"10.1016/S0399-1784(02)00002-6","DOIUrl":"10.1016/S0399-1784(02)00002-6","url":null,"abstract":"<div><p><span>During the JGOFS-France/Eumeli programme, biogeochemical processes governing particle fluxes<span><span> throughout the water column were studied in the Eastern Subtropical North Atlantic Ocean. From February 1991 to December 1992, three consecutive sets of sediment trap moorings were installed at two sites: the mesotrophic site: ~18° 30 N, 21° 00 W, and the oligotrophic site: ~21° 00 N, 31° 00 W. Currents were measured at each sediment trap level (250, 1000 and 2500 m) in order to understand better the dynamics in this area and its influence on the particle fluxes through the water column and to monitor the current speed conditions during the particle trapping. The results of these current measurements are presented here, including statistics, </span>spectral analysis, horizontal and vertical correlations and the time variability which is studied by comparisons with previous studies and models. The main feature of the dynamics in this area is the presence of the Cape Verde frontal zone at the southeastern part of the North Atlantic subtropical gyre, which is an unstable boundary between the North Atlantic Central Water and the South Atlantic Central Water. At 250 m, highest mean current speeds (~8–14 cm s</span></span>^–1) and highest variability are encountered at the mesotrophic site which is the closest to this frontal zone, whereas they are ~8 cm s^–1 at the oligotrophic site. At 1000 and 2500 m, they are of the same order for the two sites (~5 and 3 cm s^–1<span>, respectively). In addition to the short time scale variability at the inertial periods (33.4 and 38 h) and semi-diurnal tidal period, long time scale variability at ~100 d is very high at 250 and 1000 m, particularly on the meridional component. Comparisons show that this result fits and expands previous eulerian and lagrangian observations and is consistent with Rossby waves predicted by models, in spite of small discrepancies.</span></p></div>","PeriodicalId":100980,"journal":{"name":"Oceanologica Acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0399-1784(02)00002-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"56208743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The decomposition of hydrogen peroxide by marine phytoplankton","authors":"George T.F. Wong,&nbsp;William M. Dunstan,&nbsp;Dong-Beom Kim","doi":"10.1016/S0399-1784(02)00006-3","DOIUrl":"10.1016/S0399-1784(02)00006-3","url":null,"abstract":"<div><p><span><span>All nine species of marine phytoplankton tested (a </span>cyanobacterium: </span><span><em>Synechococcus</em></span> sp., three diatoms: <span><em>Chaetoceros</em><em> simplex</em></span>, <span><em>Thalassiosira</em><em> oceanica</em></span> and <span><em>Skeletonema costatum</em></span>, two prymnesiophytes: <span><em>Pleurochrysis carterae</em></span> and <span><em>Isochrysis galbana</em></span>, a prasinophyte: <span><em>Tetraselmis</em></span><span> sp., a green alga: </span><span><em>Dunaliella</em><em> tertiolecta</em></span><span>, and a dinoflagellate: </span><span><em>Amphidinium</em><em> carterae</em></span>) were able to decompose hydrogen peroxide in the dark. Since these phytoplankton species can be found widely in a variety of marine sub-environments, this indicates that the dark decomposition of hydrogen peroxide by phytoplankton is a general phenomenon in the oceans. The decomposition rates were first order with respect to the concentration of hydrogen peroxide and biomass. The second-order rate constants for these nine species of phytoplankton ranged between 2 × 10^–4 and 2.7 × 10^–2 μg Chl-<em>a</em>^–1 1 h^–1. <em>Synechococcus</em> sp. and <em>S. costatum</em> were the most efficient, while <em>P. carterae</em> and <em>D. tertiolecta</em> were the least efficient decomposers. While the magnitudes and patterns in the changes were species-dependent, in general, increasing salinity, temperature, the presence of light and the depletion of nutrients enhanced the decomposition of hydrogen peroxide. The effect of growth phase was small.</p></div>","PeriodicalId":100980,"journal":{"name":"Oceanologica Acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0399-1784(02)00006-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79927836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Séquences d'évolution morphodynamique des barres intertidales d'une plage macrotidale : l'exemple d'Omaha beach (Normandie, France)","authors":"Alexis Stépanian,&nbsp;Franck Levoy","doi":"10.1016/S0399-1784(02)00004-X","DOIUrl":"10.1016/S0399-1784(02)00004-X","url":null,"abstract":"<div><p>The present paper deals with the morphodynamics of intertidal bars on <em>Omaha beach</em>, a macrotidal beach located along the Normandy coastline. During two years (defined here as medium-term time-scale), a monthly topographic monitoring has been conducted on this beach. An analysis of the morphological evolution of the ridge and runnel systems is performed and correlated to the forcing conditions (waves and tide) recorded on the lower foreshore. Our results allow to distinguish some morphodynamical evolution sequences with one stage of accretion and one stage of destruction of the bars. In order to discriminate these two stages, an energetic criterion is used. Accretion stages correspond to long periods of fair weather conditions (significant wave height, H_s &lt; 1m), when bars build up and migrate onshore with a rate under 0.4 m per day. On the opposite, destruction stages result from wave height increases during storms (H_s &gt; 1m). The destructive processes are modulated by tide level and pre-existing morphology. Our results show also a medium-term morphodynamic variability along the beach profile. Indeed, the upper beach bars are much more mobile than the lower beach ones. The drainage channel dynamic is also highlighted as a destabilizing factor which weakens the bar resistance to storm activity. Moreover, the construction and the evolution of intertidal bars correspond to short-term reorganisations of an intertidal sand volume which seems to be quite stable over a medium-term period.</p></div>","PeriodicalId":100980,"journal":{"name":"Oceanologica Acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0399-1784(02)00004-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88284939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vertical distribution of pico- and nano-sized Dapi yellow particles at Dyfamed time-series station, NW Mediterranean","authors":"Tsuneo Tanaka ,&nbsp;Fereidoun Rassoulzadegan","doi":"10.1016/S0399-1784(03)00011-2","DOIUrl":"10.1016/S0399-1784(03)00011-2","url":null,"abstract":"<div><p>We measured abundance and surface area of pico- and nano-sized organic particles that are stained by 4’6-diamidino-2-phenylindole (Dapi), namely Dapi yellow particles. This study was done monthly from April 1999 to March 2000 from surface down to 2000 m at the French-JGOFS time-series station Dyfamed in the NW Mediterranean. Dapi yellow particles were always observed throughout the water column and the total surface area of Dapi yellow particles 0.2–10 μm ranged from 0.5 to 51.5 mm² l^–1. Dapi yellow particles were generally less abundant in the surface layer, greater between 70 and 500 m and decreased toward 2000 m. During the mixing period, Dapi yellow particles were homogeneous throughout the upper 200 m, suggesting that distribution of Dapi yellow particles was influenced by the hydrological structure. Dapi yellow particles correlated positively with inorganic nutrients (NO₃, PO₄ and Si) and negatively with dissolved oxygen concentration (<em>P</em> &lt; 0.05). These results suggest that abundant Dapi yellow particles from the bottom of the euphotic layer to the intermediate layer reflect the process of particle degradation in the ocean.</p></div>","PeriodicalId":100980,"journal":{"name":"Oceanologica Acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0399-1784(03)00011-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"56209276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acquisition de données sur l'expansion de Caulerpa taxifolia et Caulerpa racemosa en rade d'Hyères et en rade de Toulon (France)","authors":"Thomas Belsher ,&nbsp;Michel Lunven ,&nbsp;Erwann Le Gall ,&nbsp;Xavier Caisey ,&nbsp;Olivier Dugornay ,&nbsp;Christian Mingant","doi":"10.1016/S0399-1784(02)00003-8","DOIUrl":"10.1016/S0399-1784(02)00003-8","url":null,"abstract":"<div><p>The oceanographic cruise Califa 2000, as the previous cruise, which concerned the “Parc National de Port-Cros”, had for its principal objective to furnish some elements susceptible to help in the control of <em>Caulerpa taxifolia</em> expansion and in the protection of particularly sensitive areas (national parks, patrimonial sectors, regions of socio-economic importance). The cruise lasted from the 4th to the 21st of September 2000 in the rade d'Hyères, Porquerolles island included, and the rade of Toulon. This detailed prospection gives a location of <em>C. taxifolia</em> and <em>C. racemosa</em>, a new invasive seaweed.</p></div>","PeriodicalId":100980,"journal":{"name":"Oceanologica Acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0399-1784(02)00003-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81413207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variations à différentes échelles spatiales de l'herbier à Posidonia oceanica (L.) Delile ; effets sur les paramètres physico-chimiques du sédiment","authors":"S Gobert ,&nbsp;M Kyramarios ,&nbsp;G Lepoint ,&nbsp;C Pergent-Martini ,&nbsp;J.-M Bouquegneau","doi":"10.1016/S0399-1784(02)00009-9","DOIUrl":"10.1016/S0399-1784(02)00009-9","url":null,"abstract":"<div><p>The biometric parameters (shoot density, length and width of leaves, leaf and epiphyte biomasses, leaf surface) of the <em>P. oceanica</em> meadow present a significant spatial variability at the mesoscale level (100m²). All the parameters studied, excepting the number of leaves, decrease according to the depth. The horizontal spatial variations (centrifuge and centripetal distributions) reach a maximum in the shallower areas. The analysis of the microstructures (m²) of the meadow has not allowed a relationship to be established between the spatial variations of the biometric parameters and the environmental factors in the sediment (pH, water and organic matter content, red-ox potential, nutrient content). The heterogeneity of the meadow in the Revellata Bay quite probably results from the internal shoot and rhyzome growth dynamics. On the other hand, it appears that the presence of the prairie modifies the physical-chemical characteristics of the sediment. In fact, the sandy patches present different physical-chemical characteristics: lower organic matter, different granulometric and much higher interstitial water nutrient levels, as well as a higher pH and oxydo-reduction potential.</p></div>","PeriodicalId":100980,"journal":{"name":"Oceanologica Acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0399-1784(02)00009-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88465194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Life cycles in brackish habitats: adaptive strategies of some polychaetes from the Venice lagoon","authors":"D. Prevedelli, R. Simonini","doi":"10.1016/S0399-1784(02)01232-X","DOIUrl":"https://doi.org/10.1016/S0399-1784(02)01232-X","url":null,"abstract":"","PeriodicalId":100980,"journal":{"name":"Oceanologica Acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84118334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fish as bioindicators of brackish ecosystem health: integrating biomarker responses and target pollutant concentrations","authors":"Ilaria Corsi,&nbsp;Michela Mariottini,&nbsp;Cristiana Sensini,&nbsp;Lucia Lancini,&nbsp;Silvano Focardi","doi":"10.1016/S0399-1784(02)01237-9","DOIUrl":"https://doi.org/10.1016/S0399-1784(02)01237-9","url":null,"abstract":"<div><p>Biological responses and contaminant levels in biological tissues were investigated in fish specimens of grass goby (<span><em>Zosterisessor ophiocephalus</em></span><span><span>) collected in spring 2000 in a moderately polluted brackish ecosystem, the Orbetello lagoon (southern coast of Tuscany, Italy). The complexity of harmful effects that contaminants may cause in fish over time was assessed. General condition indices (somatic liver index, and gonadal somatic index), cytochrome P450 enzymes, </span>acetylcholinesterase<span> activity and ovarian morphology were integrated with the content of organochlorines (OCs—hexachlorobenzene, DDTs and polychlorinated biphenyls) in liver and ovaries and </span></span><em>p</em>-nonylphenol (NP) and lower ethoxylate (NPE_1–2<span><span>) content in muscle and ovaries as well. Samples collected from the western basin of the lagoon near the Orbetello sewage treatment plant had somatic liver index values and two P450 activities significantly higher than those collected from the same basin at the Albegna </span>river delta and in the Ansedonia canal in the eastern basin (</span><em>P</em> &lt; 0.05). On the other hand, while muscle content of <em>p</em>-NP and NPE_1–2<span> was significantly higher in samples from the Orbetello and Albegna river sites than in samples from the Ansedonia canal site, OC levels in liver (DDTs &gt; PCBs &gt; HCB) were particularly lower in samples from STP compared to levels detected in sites AC and AR. Light microscopy<span> of ovaries revealed that although the gonads<span> were sexually mature, the diameter of the oocytes and eggs was smaller than that commonly reported. High levels of OCs and NPs were, in fact, observed in grass goby ovaries, and the differences observed between acetylcholinesterase activities among investigated sites suggest exposure to insecticides as well. The integration of biological responses and contaminant tissue content reveals that certain areas of the lagoon are selectively impacted by various human activities and helps in distinguishing relationships between biological responses and contaminant load in the lagoon environment.</span></span></span></p></div>","PeriodicalId":100980,"journal":{"name":"Oceanologica Acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0399-1784(02)01237-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91726553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial heterogeneity in the distribution of plants and benthic invertebrates in the lagoon of Orbetello (Italy)","authors":"Anna Maria De Biasi ,&nbsp;Lisandro Benedetti-Cecchi ,&nbsp;Lorenzo Pacciardi ,&nbsp;Elena Maggi ,&nbsp;Stefano Vaselli ,&nbsp;Iacopo Bertocci","doi":"10.1016/S0399-1784(02)01226-4","DOIUrl":"10.1016/S0399-1784(02)01226-4","url":null,"abstract":"<div><p>Many studies in marine coastal lagoons have focused on the marine-to-terrestrial gradient as a main source of variation for the structure of assemblages. In this paper, the magnitude of differences among locations arranged along the marine-to-terrestrial gradient of the western lagoon of Orbetello (Grosseto, Italy) was contrasted with the amount of spatial variability occurring among sets of locations that were not positioned along this axis. We propose that if the most important processes influencing assemblages were those associated with the external–internal gradient of the lagoon, as usually supposed, then assemblages should differ more among these locations than among any other locations. To test the above proposition, four locations arranged along the two major axes of the lagoon were established in November 2000. Each location was sampled three times (November 2000, April 2001, August 2001) to test for temporal consistency in spatial patterns. At each time of sampling, three replicate sites were established in each location. This design enabled estimates of spatial variability to be obtained at three scales: among locations hundreds of meters apart, among sites tens of meters apart and among quadrats hundreds of centimeters apart. Non-metric multidimensional scaling (nMDS) ordination plots on abundance data revealed differences among assemblages hundreds of meters apart. Assemblages in the inner part of the lagoon were separated from those closer to the sea inlet, depending on the marine-to-terrestrial gradient. In addition to this pattern, differences also occurred among assemblages hundreds of meters apart, but positioned at a similar distance from the sea. Multifactorial Anovas on abundance of the most common taxa showed significant differences in mean values at the scales of location and site, with patterns changing over time. These results indicated that spatial structure in assemblages was not a distinctive feature of locations arranged along the marine-to-terrestrial gradient in the lagoon of Orbetello. Similar differences also occurred among other sets of locations at the scale of hundreds of meters, regardless of their position in the lagoon.</p></div>","PeriodicalId":100980,"journal":{"name":"Oceanologica Acta","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0399-1784(02)01226-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88231864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}