Effects of urbanization on streams of the Melbourne region, Victoria, Australia. I. Benthic macroinvertebrate communities

1. Macroinvertebrate community composition was assessed in small streams of the Melbourne region to test the effects of (a) urban density (catchment imperviousness 0–51%) and (b) stormwater drainage intensity (comparing the intensively drained metropolitan area with urban areas of the hinterland, which had open drains and some localized stormwater drainage).
2. Hinterland communities separated into two groups of sites correlating strongly with patterns of electrical conductivity (EC), basalt geology and annual rainfall. Community composition varied little in the high-EC, western group (imperviousness 0.2–1.2%), but in the eastern group it was strongly correlated with catchment imperviousness (0–12%), with lower taxon richness in more impervious catchments.
3. Metropolitan communities (imperviousness 1–51%) were all severely degraded, with high abundances of a few tolerant taxa. Community composition was poorly correlated with patterns of geology, rainfall or imperviousness. Differences between metropolitan and hinterland communities were well explained by patterns of biochemical oxygen demand and electrical conductivity, which were postulated to indicate the more efficient transport of pollutants to receiving streams by the metropolitan stormwater drainage system.
4. Degradation of macroinvertebrate community composition was well explained by urban density but intensive urban drainage increased degradation severely at even low urban densities. Quantification of relationships between imperviousness, drainage intensity and stream degradation can better inform the assessment, conservation and restoration of urban streams.     

Distribution patterns of some subterranean Crustacea in the territory of the former Yugoslavia

A selection of the most representative distribution patterns of stygobiont animals is presented. The range of a genus may extend beyond the Dinaride karst, while some species exhibit a holo-Dinaric distribution. The mero-Dinaric distribution is organised in two vicarious centres (in the NW and SE) as well as an epilittoral and a paralittoral belt. The paralittoral distribution is a result of paleogeographic rather than present-day ecological conditions. Important differences between the interstitial faunas of Slovenia (and NE Italy) and Macedonia are probably the result of their different sources. Some other distribution patterns are discussed or summarized from the existing literature. The distribution patterns of this stygobiont fauna are extremely diverse, and are influenced by the geological complexity of the territory as well as by the richness of the fauna concerned. New distribution data for some Copepoda, Thermosbaenacea, and Amphipoda are appended.     

Nest site choice by the three-spined stickleback, Gasterosteus aculeatus (form leiurus), in spring-fed waters

The nest site characteristics of the freshwater three-spined stickleback, Gasterosteus aculeatus (form leiurus ), were quantitatively investigated in springs and the main stream of the Yamayoke and the Tsuya River system, central Japan. Most nests (93·4%) were on a muddy or sandy substratum, at depths of 10–40 cm (84·3%), in water velocities less than 15 cm s⁻¹ (76·2%) and in the temperature range of 14 to 16° C (82·7%), Spring-fed localities provided more of these conditions than the main stream channel and hence contained more potential nesting areas. Thus, they were utilized by male sticklebacks both temporally (prolonged breeding season) and spatially (more nest sites).     

Distribution of the phytoplankton from the Guri Reservoir (Venezuela)

The distribution of phytoplankton species of a tropical blackwater reservoir is discussed on the basis of spatial differences in water composition and of species abundance and diversity. Spatial heterogeneity in water composition identified three different environments within the reservoir itself: (1) strongly colored waters, high turbidity and iron concentrations at the inflow; (2) calcium enriched, nearly uncolored waters at El Pao Bay; (3) lightly colored water, higher transparency and a higher ratio monovalent to divalent cations in the main body of the reservoir. Three corresponding phytoplankton associations were found. Principal Component Analysis helped to explore the relationship of particular species with the abiotic factors. Among them, water color, turbidity, and mineralization proved to be determinant in habitat diversification.     

The impact of the Scheldt input on the trace metal distribution in the Belgian coastal area (results of 1981–1983 and 1995–1996)

Offshore fluxes of Cu, Zn, Cd, Pb and Hg were calculated based onresidual flow patterns and salinity gradients along the Belgian coast. Theresidual flow lines along the Belgian coast are more or less parallel to thecoast except in the area where the north-easterly flowing watermass comingfrom the Channel encounters the south-westerly-oriented Scheldt outflow,forming a residual hydrodynamical front. From the steady-state salinitypattern, diffusion coefficients perpendicular to the residual flow werededuced; they ranged from 21 to 108 m² s^-1. Offshore fluxes of dissolved and particulate trace metals based on diffusiveand mixing processes are calculated. The steady state profiles of dissolvedmetals show a dilution effect in the coastal waters, reaching an almostconstant concentration in the marine watermass in the 1981–1983dataset. The ratios of the Scheldt input of trace metals to the totaldissolved offshore flux vary from 38 to 55% (1981–1983),depending on the kind of metal, and from 55 to 91% (1995–1996).The ratio of the Scheldt input to the dissolved metal flow parallel to thecoast, is in both periods (1981–1983 and 1995–1996), smallerthan 1%. The steady-state concentration profiles of particular metalsversus salinity are fairly constant in the coastal-estuarine and marinewatermasses, but decrease very abruptly from the first to the secondwatermass. Assuming a conservative behaviour of the particular metals,offshore fluxes and the resulting concentration increases agree fairly wellwith the observed values. The ratios of the Scheldt input to the particulatetrace metal offshore flux vary between 30 to 46% (1981–1983)and 13 to 37% (1995–1996). The contribution of the Scheldtestuary to the flows parallel to the coast ranges from 1.6 to 2.9%(1981–1983) and from 0.6 to 1.6% (1995). This revised version was published online in July 2006 with corrections to the Cover Date.     

Occurrence of Cladocera (Crustacea) in subterranean waters in Yugoslavia

Contrary to some localities in France and Spain, Cladocera occur in hypogean waters in Yugoslavia very sporadically. Beside the stygobitic species, Alona hercegovinae from caves and Alona smirnovi from interstitial waters, particularly some other Chydoridae seem to be suited for hypogean life. Chydorus sphaericus, reputed as one of the most euryoecious cladocerans, occurs also the deepest in interstitial waters as well as in caves. Other species, found in hypogean waters are Simocephalus vetulus, Ilyocryptus sordidus, Eurycercus lamellatus, Chydorus ovalis, Leydigia leydigi, Acroperus harpae and Biapertura affnis.     

Biogeography of dinoflagellate cysts in northwest Atlantic estuaries

Few biogeographic studies of dinoflagellate cysts include the near‐shore estuarine environment. We determine the effect of estuary type, biogeography, and water quality on the spatial distribution of organic‐walled dinoflagellate cysts from the Northeast USA (Maine to Delaware) and Canada (Prince Edward Island). A total of 69 surface sediment samples were collected from 27 estuaries, from sites with surface salinities >20. Dinoflagellate cysts were examined microscopically and compared to environmental parameters using multivariate ordination techniques. The spatial distribution of cyst taxa reflects biogeographic provinces established by other marine organisms, with Cape Cod separating the northern Acadian Province from the southern Virginian Province. Species such as Lingulodinium machaerophorum and Polysphaeridinium zoharyi were found almost exclusively in the Virginian Province, while others such as Dubridinium spp. and Islandinium? cezare were more abundant in the Acadian Province. Tidal range, sea surface temperature (SST), and sea surface salinity (SSS) are statistically significant parameters influencing cyst assemblages. Samples from the same type of estuary cluster together in canonical correspondence analysis when the estuaries are within the same biogeographic province. The large geographic extent of this study, encompassing four main estuary types (riverine, lagoon, coastal embayment, and fjord), allowed us to determine that the type of estuary has an important influence on cyst assemblages. Due to greater seasonal variations in SSTs and SSSs in estuaries compared to the open ocean, cyst assemblages show distinct latitudinal trends. The estuarine context is important for understanding present‐day species distribution, the factors controlling them, and to better predict how they may change in the future.     

Nature and occurrence of sulfoxidizing bacteria in Barégine developing in sulfurated thermal waters at Barèges (France)

An Attempt is made to define the nature of the barégine, a whitish mucilaginous complex found in the thermal waters of the village of Barèges, Hautes-Pyrénées, France, and the organisms responsible for its formation. In sulfurated waters, a Thiobacterium-like micro-organism produces this substance. It uses reduced sulfur as a source of energy. Filamentous species of Thiothrix, often indicated as the main element of barégine, are only part of an accompanying flora in this medium.     

Potential of the luminol reaction in the sensitive detection of pesticide residues by flow injection analysis.

This study presents the first analytical application of the luminol chemiluminescence (CL) reaction for the sensitive detection of carbamate residues. Some experiments have been carried out to check the influence of the presence of traces of a N-methylcarbamate (carbaryl) on the CL emission produced from the oxidation of luminol using different oxidants, showing a significant enhancing effect on the CL emission when the oxidation of luminol is produced by potassium permanganate in alkaline medium, this enhancement being proportional to the carbaryl concentration. This fact has permitted the establishment of a sensitive chemiluminescence flow-injection (CL-FIA) method for the direct determination of carbaryl. The optimization of instrumental and chemical variables influencing the CL response has been carried out by applying experimental designs. Under the optimal conditions, the CL intensity was linear for a carbaryl concentration over the range 5-100 ng/mL with a detection limit of 4.9 ng/mL. This luminol-KMnO4-based FIA-CL system in basic medium shows an easy, fast and cheap alternative detection mode for the analysis of carbaryl residues in environmental water samples.