Preface: Biogeography and spatial patterns of biodiversity of freshwater phytoplankton

Observations on mucus aggregates along Sicilian coasts during 1991–1992

Abstract The results of some observations on gelatinous material accumulating on the sea ground and free floating in the water column along Sicilian coasts are reported. The phenomenon showed different development patterns moving from the Tyrrherian to the Jonian coast and to the Sicilian Channel. Moreover, in 1991, mucus aggregates in the Tyrrhenian sea showed a similar structure, behaviour and origin to those observed in the Adriatic sea, whereas, in 1992, only a massive growth of metaphytic threadlike algae, more or less producing gelatinous sheaths, occurred.

Functional classifications in phytoplankton ecology: a comparative review of approaches and experiences

Empirical models of phytoplankton groups and their recurrence in water bodies have traditionally made use of taxonomic classifications, implicitly or explicitly assuming that species classified together could share similar ecological properties. Nevertheless, the use of taxonomy in ecology has many drawbacks. From one side, many broader groups include species with very different ecological properties. From the other side, convergent evolution, the independent evolution of similar characters in different lineages, can explain why distantly phylogenetically related species can be linked together by close analogous ecological affinities. With the aim to obtain a better understanding of the fun…

Studies on Italian reservoirs

The main morphometric and water quality characteristics of the 221 Italian reservoirs covering an area of at least 0.2 km2 is given. Most of the reservoirs are used for drinking water purposes, especially on the islands of Sicily and Sardinia, where the more important cases of eutrophication have been found. These situations are examined in greater detail, with regard to algal population dynamics, the phosphorus budget and the comparison between theoretical and experimental nutrients loads. -from Authors

Effects of ultraviolet radiation on productivity and nitrogen fixation in the Cyanobacterium, Anabaena sp. (Newton's strain)

The predatory role of white shrimp (Litopenaeus setiferus) in seasonal declines of subtidal macrobenthos

The overall purpose of this study was to develop a quantitative model to assess the influence of L. setiferus predation on subtidal macrobenthic abundance cycles in an estuarine creek system. Subtidal macrobenthic populations in temperate marine soft-bottom environments are known to undergo seasonal abundance cycles. Although the factors responsible for driving these seasonal shifts in abundance are difficult to identify, both environmental and biological factors have received credit. Juvenile white shrimp (Litopenaeus setiferus) are seasonally abundant epibenthic predators in the North Inlet estuary that have significant influence upon estuarine macrobenthic densities. Data generated from …

Spatial and seasonal changes of dissolved and particulate organic C in the North Sea

Sampling of the central region of the North Sea was carried out to study the spatial and seasonal changes of dissolved and particulate organic C (DOC and POC, respectively). The surface waters were collected during four cruises over a year (Autumn 2004–Summer 2005). DOC and POC concentrations were measured using high temperature catalytic oxidation methods. The surface water concentrations of DOC and POC were spatially and temporally variable. There were significantly different concentrations of DOC and POC between the inshore and offshore waters in winter and summer only, with no clear trend in autumn and spring. Highest mean concentrations of DOC were measured in spring with lower and sim…

The importance of nutrient source in determining the influence of retention time on phytoplankton: an explorative modelling study of a naturally well-flushed lake

Two models were used to examine the relationship between hydraulic retention time, nutrient source and total chlorophyll in a shallow lake (Bassenthwaite Lake, UK). The first model was a derivation of the Vollenweider model and the second was the phytoplankton community model, PROTECH. The adapted Vollenweider model produced two different responses to changing the retention time that were phosphorus source dependent. If the phosphorus was totally from a point source, then annual mean chlorophyll steadily declined with increasing flushing rate. However, when a diffuse source was used, the chlorophyll changed little and even increased with short retention times (retention time \40 days). The …