摘要:

Abstract.Dissolved nitrate, nitrite, ammonium and phosphate were monitored for 2.5 years along a coastal eutrophication gradient originating at the St. Andrews sewer outfall. Linear growth rates and tissue composition (phosphorus, various nitrogen fractions and storage carbohydrates) were monitored at the same stations in lamina tissue ofLaminaria digitataandL. saccharina.Growth rates were considerably enhanced at the eutrophicated stations both in spring, when exogenous nutrients were at peak values at all stations, and during the summer when exogenous nutrients were very low at all stations. Enhanced summer growth rates were correlated with the increased reserves of N and P accumulated during winter and spring, and particularly with soluble organic nitrogen reserves. Accumulation of storage carbohydrates was inversely correlated with growth rate and tissue N and P reserves, presumably because fixed carbon could be incorporated into new protein and thence new tissue only if internal non‐protein N reserves were availabl

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1985.tb00321.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract..The so‐called “band” diseases of reef corals, the White Band Disease (WBD) and the Black Band Disease (BBD), were observed in the Red Sea and in the Philippines. Since they were previously known only from the western Atlantic, this is the first record for the Indo‐Pacific region. WBD is neither infectious nor contagious and the pathogen is unknown. BBD is highly infectious and contagious and is caused by the cyanophytePhormidium corallyticum.Susceptibility to WBD occurs throughout the orderScleractinia,but the effects of the disease are most severe amongAcroporidae.Susceptibility to BBD seems to be restricted toFaviidae,withPlatygyraandGoniastreaspecies the most heavily afflicted. WBD cannot be influenced by any parameter tested so far. BBD can be enhanced by light and by water eutrophication, and its advance can be stopped by antibiotics. An active WBD seems to be a precondition for the origin

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1985.tb00322.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract.A bionomic study and cartography of the benthos of Medes Islands (NE Spanish coast, Catalan Costa Brava) is presented. From 1977 to 1980 the fauna and flora of the meso‐ and macrobenthos were sampled by a triple sampling procedure: standard, visual and photographic samples were simultaneously taken along underwater transects, yielding 124 punctual inventories, 176 visual inventories and some 1000 photographic “samples”. These, together with the floristic and faunistic study of each algal and invertebrate group, served as the basis for the bionomic survey of the islands' bottoms. In a first approach, the hard substrata of the infra‐ and circalittoral Stages were studied, along with thePosidoniameadows, and their communities diagrammatically sketched along representative transects. Further work focused on the submarine caves and tunnels of the area, the supra‐ and mediolittoral communities and the coastal detritic soft bottoms. The bionomic survey of the Medes Islands has emphasized, with minor differences, the basic similarity between the archipelago's benthic communities and those described elsewhere in the Northwestern Mediterranean. The identified communities or groups of communities are the trottoir, the photophilic algae, the sciaphilic algae (precoralligenous), the coralligenous and cave communities on hard substrata, as well as thePosidoniameadow and the coastal detritic community on soft substrata. These have been used as the basic macro‐units in the bionomic cartography of the islands, which has been plotted on a 1:2000 map. Their distribution, over a surface area of some 2 km2and to a depth of up to 60–70 m, follows that of the heterogeneous substrate, its slope and the hydrodynamical and illumination condition

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1985.tb00323.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract.The secondary production ofSpisula subtruncata(somatic production) is calculated in the framework of a benthic monitoring study in a coastal area. The temporal trends of density, biomass and growth increments are examined in the three year‐classes present. These are compared to certain physical and chemical parameter

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1985.tb00324.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract.Alkaline phosphatase activity (APA) was found in a nearshore, natural population of the red‐tide dinoflagellatePtychodiscus brevis.Initial hydrolysis rates were enhanced by two orders of magnitude within 24 h upon addition of ammonium. Other nutrient (additions) or no additions also lead to a higher, although less pronounced increase in activity. Enhanced growth after nutrient additions combined with specific APA indicated that the bloom was both N and P limited. Since the natural population was a mixture of diatoms and the dinoflagellate, APA was also measured in unialgal cultures ofP. brevis.APA was not reduced but enhanced by the addition of low concentrations of orthophosphate (0.5 and 1 μM). Higher orthophosphate concentrations (5 to 20 μM) reduced APA, although activity returned to control levels within 2 to 6h. Repression occurred within 30 sec after a 20 μM orthophosphate addition. Cells which had APA repressed by an orthophosphate addition regained their initial activity within 2 h after washing with phosphate‐free media. Phosphorus‐deficient cells ofP. brevispossess an alkaline phosphatase system which is capable of continued activity at lowin situorthophosphat

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1985.tb00325.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract.Deltaic populations ofConopeum seuratifrom diverse environmental settings have variable phenotypes related to strong competitive regimes and to dissolved oxygen minima. Under extremely stressful conditions, the poorly canalized phenotype of C.seuratidisplays new additional features such as kleistozooids (kleistós= closed) and chaotic celleporoid layers. Kleistozooids are clearly distinguishable polymorphs characterized by the presence of a compact, imperforate frontal membrane and by a strongly reduced lumen of the “opesium”. They commonly aggregate in clusters of regularly‐arranged individuals that store a large quantity of proteic material. The inferred function of these cell‐like structures is to supply nutrients for basic colony activities. Celleporoid layers are, possibly, a developmental relaxation of the colony ofC. seuratifor a more efficient use of space in competitive interactions.Both celleporoid layers and kleistozooids reveal the magnitude of intracolony variability of a widespread opportunistic bryozoan

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1985.tb00326.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY