摘要:

AbstractThe diatoms of plankton samples taken between 1916 and 1929 and in 1975 from shallow pools, which were originally oligotrophic, are compared. Data about the past and present distribution of macrophytes were gathered from the literature and by field studies. Eutrophication caused by agriculture and recreation, and acidification from precipitation led to important changes in the biocenoses of the moorland pools during the last fifty years.

ISSN:0020-9309    

DOI:10.1002/iroh.19780630502

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19780630504

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractThe following changes were observed in three lakes as a result of their heating and decrease of retention time (data for summer periods): increase of mixing rate, active bottom area, and nutrients (Pinorg., Ninorg.) concentrations; significant changes in gross primary production, phytoplankton biomass and production of filtering cladocerans. These changes seem to indicate the higher efficiency of utilization of autochthonous trophic resources and energy transfer in plankton.

ISSN:0020-9309    

DOI:10.1002/iroh.19780630505

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19780630507

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractThe distribution of phytoplankton was studied in Lake Lanao, Philippines. In calm weather, the species segregate vertically with motile species and buoyancy‐regulating species above other species in the water column. On a distance scale of 12.5 km, horizontal variability yields a coefficient of variation of 23.6% for total biomass, 30.2% for net primary production, and an average of 30.3% for individual species biomass after removal of error variances. Variabilities on a scale of 1 km are about half as large. Horizontal patchiness of individual species is not related to their abundance, surface to volume ratio, morphotype, or taxon, but is negatively related to their siz

ISSN:0020-9309    

DOI:10.1002/iroh.19780630508

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19780630510

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractAttachment of eight groups of estuarine benthic species was recorded on a 4000 ft. intertidal‐subtidal transect on Delaware Bay, Cape May, New Jersey. Asbestos‐board panels were spaced at 3‐foot vertical intervals and harvested at weekly intervals for two seasons. Intraspecies attachment patterns were very regular both spatially, and temporally indicating specific setting behavior interacting with a relatively stable environmental influence.Intertidal, on‐bottom patterns were associated withCrepidulasp. andBalanussp. whereasSabellaria vulgarispreferred subtidal, on‐bottom panels. Subtidal, off‐bottom panels were colonized byTubularia crocea, Conopeum tenuissimum, Caprellidae and Gammaridae.Crassostrea virginicashowed a variable pattern, predominantly on‐bottom and subtidal, but occasionally on‐bottom intertidal, inshore. Factors producing concentration of larvae and release of the setting response are important in the inshore recruitment of oysters. All information indicates that the mechanism of selective settlement is a dominant factor in producing bent

ISSN:0020-9309    

DOI:10.1002/iroh.19780630511

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

ISSN:0020-9309    

DOI:10.1002/iroh.19780630513

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractAmong numerous physical, chemical and biological parameters, the enumeration and identification of microplankton cells have been carried on at all stations and depths, by means of UTERMÖHL'S method (on board and on land). After dealing with space and time distribution of the data, they are compared with some features of environment and particulate organic matter. Abundance and composition of the populations depend on the supply of nutrients, which on its turn depends on the thermal stratification. More or less clear or sure other correlations are discussed: with density, light, bacterioplankton, varied seston parameters, etc

ISSN:0020-9309    

DOI:10.1002/iroh.19780630514

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY

摘要:

AbstractRegional and seasonal variations of some environmental characteristics in the 630 km stretch of the lower Tigris were studied and discussed. The lowest air and average water temperatures were recorded in January. The highest average pH values, generally found in October and July, are due mainly to the abundance of phytoplankton. The remarkably low average chlorosity values found in the periods of high water were correlated with the high discharge. The highest average values for dissolved oxygen concentration were generally recorded in January and April, and the lowest ones were observed in October and July.

ISSN:0020-9309    

DOI:10.1002/iroh.19780630515

出版商:Akademie Verlag, Berlin    

年代:1978

数据来源: WILEY