摘要:

Abstract.The changes in the concentrations of silicate, phosphate, and inorganic nitrogen in Eiefsis Bay. an intermittently anoxic basin, arc described and related to the changes in the physical properties of the water. Winter convection resulted in a very small vertical gradient of temperature, salinity, oxygen, and nutrients. Stratification started to develop in May and persisted for about 6 months. High values of silicate, phosphate, and ammonia occurred during the anoxic conditions prevailing in summer. The vertical transport of particulate organic matter and decomposition of abundant pelagic and benthic organic matter during the summer produced a low oxygen level in the bottom layer below the pycnoclinc. A high sea water temperature and vertical stability contributed to the development of anoxic conditions during the summer in the near bottom layer and to mass mortality of benthic macrofauna. Also the Eiefsis Bay anoxia appears to have had significant ecological effects on many other marine species, including several of economic importance.

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1988.tb00208.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract.Seven species belonging to three genera of folioseDictyoceratidaare described placing emphasis on field recognition characteristics. These sponges are dominant elements of the Great Barrier Reef fauna.One new genus,Strepsichordaia,and two new species,Strepsichordaia lendenfeldiandCarterio‐spongia contorta,are described and full redescriptions of poorly known older species are given.Features of skeletal morphology and terpene chemistry which make this group of genera distinct within theDictyoceratidaare discussed and a new familial allocation is suggeste

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1988.tb00209.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract.Populations of foliose dictyoccratid sponges were surveyed on the forc‐rccf (windward) slopes of reefs across the central and northern sections of the Great Barrier Reef. Foliose sponges constitute more than 50 % of invidual abundance on clean water reefs and more than 80 % on some of these reefs. These sponges arc generally small and occur in greatest abundance on the slopes between 10 and 30 m depth, forming more than 20% of the total sponge biomass. Species of the generaPhyllospongiaandCarteriospongiawere most prevalent, particularly the speciesP. lamel‐losa, C. flabellifera, C.foliascens,and an unidentified thorcctid. The majority of these foliose sponges have a predominantly phototrophic nutrition with more than 50% of carbon energy being derived from the photosynthetic activities of cyanobactcrial symbionts. The foliose dictyoccratids were absent from inner‐shelf reefs, which feature higher sediment loads and concentrations of organic nutr

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1988.tb00210.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract.The utilization of the spatial resources of two syntopic blenniid species ‐Blennius cunevueandBlennius incognitas ‐has been investigatedin siluand under laboratory conditions. Both species occupy bore holes of the musselLithophuguin the sublittoral zone.B. cunevuedominates the more shallow zone (x̄= 0.68 m) and prefers smaller (x̄= 12.76 mm diameter) and horizontal bore holes.B. incognitusinhabits the same depth range asB. cunevuebut occupies larger bore holes (x̄= 14.57 mm) in a deeper zone (x̄= 0.86 m). Individuals ofB. incognitusdo not prefer a special inclination angle. The two blenniid species defend territories with different intraspecific sizes: the mean territory radius ofB. cunevueis 6.87 mm, ofB. incognitusx̄= 10.95. Mechanisms to reduce competition include different activity rhythm, interspecific social dominance, and differences in territoriality.B. cunevueis the dominant species; its territories arc defended against conspecifics and againstB. in

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1988.tb00211.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract.A complex and highly unusual eukaryotic microorganism was discovered to be penetrating and removing the periostracum of deep‐sea mussels from the Florida Escarpment brine seeps at a depth of 3266 m. These brine seeps support a chemolithoautotrophic redox community similar to those known from Pacific hydrotherma! vents. This microorganism of unknown taxonomic affinity is filamentous and coenocytic, with a simple plasma membrane and no cell wall. It forms prostrate, radiating systems of branched tunnels, 8–15 u.m in diameter. The surface of the tunnels is sculptured by helically organized, scale‐like depressions, which are left as scars in the process of periostracum removal by the organism. Periostracum is removed in discrete pieces (scallops) at the ends of the tunnels. This organism has been found at three Atlantic deep‐sea redox communities, but not in similar communities of the

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1988.tb00212.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY