摘要:

AbstractAn annual organic matter budget for a 1700 m segment of Fort River (Massachusetts, USA) is presented. Primary production in this fourth order stream exceeds litter input annually, however ecosystemP/Ris 0.5. Respiration in excess of gross primary production is supported by allochthonous organic matter imported from upstream reaches. The relative contribution of organic matter size fractions to stream consumers depends upon biologic lability, rate of input, and residence time in the ecosystem. Particles of seston size (1 μm to 1 mm) are most heavily used by consumers, however dissolved organic matter represents the largest input component. Microorganisms are the predominant consumers in this soft‐water, nutrient‐poor stream ecosystem. A conceptual model for assessing the processing efficiency of stream ecosystems is presented and discussed in terms of several headwater to estuary gradi

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620601

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractFour natural lentic habitats on the Central Plains Experimental Range in Colorado were intensively studied physically, chemically, and biologically for 2 yr (1968–1970) and intermittently for 5 (1971–1975). Lynn Lake and Lake George were chosen as examples of ephemeral or temporary sites, while Cottonwood Pond and Spring Pond were chosen as permanent habitats. Chemically, the waters of each site were analytically separated into dissolved and suspended (sestonic) components. The temporary sites were characterized by their exceptionally high seston loads, the presence of Eubranchiopoda, the prevalence of Ca as the major dissolved cation, ana the high Fe content of their sediments. The two permanent sites, on the other hand, had high total dissolved salt content, rich and varied flora and fauna, Na as the prevalent cation in the dissolved fraction, and high Ca content in the sediments. All four of the sites were “seston digesters” with large amounts of wind‐blown organic material being entrapped, decomposed, and mineralized. By comparison with adjacent soils the sediments of all four basins were much richer in K, Zn, Fe, Cu, and Mn. Both temporary and permanent sites function as nutrient sinks. Rates of daily and annual phytoplankton primary productivity are reported for the two perman

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620602

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractTwo new species of Gnathostomulida from Bermuda and one from North Carolina are described. All belong to the higher Bursovaginoidae with two occurring in the genusAustrognathiaand one in the genusGnathostomula. Tables of major diagnostic characters showing morphological variability within species and between previously described species in the same genus are included. Clarification in recognition ofGnathostomula jenneriandGnathostomula brunidensis given under “Remarks on Known Species

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620603

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractMicrobial cellulolytic activity was determined by an indirect method (loss of tensile strength in cotton yarn). The activity values were high in late autumn, but low in spring and early summer. The factors responsible for the seasonal variation are discussed.

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620604

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractIntercalibrations of phytoplankton countings were made in the Baltic in 1974 and 1975, where seven laboratories participated, each using their routine method. A statistical evaluation was made on the results, and recommendations for routine countings with the Utermöhl technique are given

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620605

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractThe following parameters were measured during May 1976 along the coasts of the Gulf of Elat (or: Gulf of Aqaba): phytoplankton species composition, chlorophyll content and photosynthetic production; weight of suspended particles and nutrient concentration; chlorophyll content of the sediments. The study areas were coral reefs of the northern part of the Gulf and a mangrove pool south of it.Phytoplankton characteristics and nutrient levels are those of oligotrophic waters. However, the sediments harbour such an abundant plant biomass that in coastal waters per m2surface area, there is several hundred times more chlorophyll in the sand than in the plankton. Reasons why both the mangrove and the coral reef may exhibit the same trends are discussed.

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620606

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

摘要:

AbstractThere are good reasons to believe that in cold temperate regions the whole water masses of ponds with little or no through flow are anoxic during the winter. This feature, demonstrated for Scandinavian ponds of widely differing productivity, must be of great ecological significance for the pond fauna.

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620607

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620609

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620612

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.1977.3510620614

出版商:Akademie Verlag, Berlin    

年代:1977

数据来源: WILEY