Taxa-area relationship of aquatic fungi on deciduous leaves

One of the fundamental patterns in macroecology is the increase in the number of observed taxa with size of sampled area. For microbes, the shape of this relationship remains less clear. The current study assessed the diversity of aquatic fungi, by the traditional approach based on conidial morphology (captures reproducing aquatic hyphomycetes) and next generation sequencing (NGS; captures other fungi as well), on graded sizes of alder leaves (0.6 to 13.6 cm2). Leaves were submerged in two streams in geographically distant locations: the Oliveira Stream in Portugal and the Boss Brook in Canada. Decay rates of alder leaves and fungal sporulation rates did not differ between streams. Fungal biomass was higher in Boss Brook than in Oliveira Stream, and in both streams almost 100% of the reads belonged to active fungal taxa. In general, larger leaf areas tended to harbour more fungi, but these findings were not consistent between techniques. Morphospecies-based diversity increased with leaf area in Boss Brook, but not in Oliveira Stream; metabarcoding data showed an opposite trend. The higher resolution of metabarcoding resulted in steeper taxa-accumulation curves than morphospecies-based assessments (fungal conidia morphology). Fungal communities assessed by metabarcoding were spatially structured by leaf area in both streams. Metabarcoding promises greater resolution to assess biodiversity patterns in aquatic fungi and may be more accurate for assessing taxa-area relationships and local to global diversity ratios.This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569), funded by national funds through the Portuguese Foundation for Science and Technology (FCT) I.P. (http://www.fct.pt/) and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI) and by the project PTDC/AAC-AMB/117068/2010, funded by national funds through FCT I.P. and the European Regional Development Funds through the Operational Competitiveness Program (FEDER-COMPETE). Support from FCT to SD (SFRH/BPD/47574/2008 and SFRH/BPD/109842/2015) and from NSERC Discovery grant program (http://www.nserc-crsng.gc.ca/index_eng.asp) to FB is also acknowledged. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.info:eu-repo/semantics/publishedVersio

Concept of scale in marine ecology: linking the words or the worlds?

The concept of scale (in sensu lato) is considered to be very promising as the integrative basis for modern ecology. Nowadays it is not a full-blown theory but rather a flexible and progressively developing methodology to outline future unifying theories. It provides a powerful conceptual framework for generating testable hypotheses and studying a wide range of ecological phenomena related with such themes as heterogeneity, hierarchy and size. Spatio-temporal heterogeneity, organizational hierarchies and body size are the main scaling factors for ecological patterns and processes. Broad comparison of patterns for these three different but interrelated dimensions can reveal some new regularities ("scaling laws") of ecological systems. It also allows us to look at the worlds of different organisms "through their own eyes". Some examples of applying the cross-scaling approach in marine ecology are considered: — Patterns and scales of spatial heterogeneity; — Species-area curves and body size; — Co-occurrence of congeners as scale-dependent phenomenon; — Spatio-temporal ranges of ecological hierarchies

Body size determines the strength of the latitudinal diversity gradient

In most groups of organisms, the species richness decreases from the tropics to the poles. The mechanisms causing this latitudinal diversity gradient are still controversial. We present data from a comprehensive weighted meta-analysis on the strength of the latitudinal gradient in relation to body size. We sampled literature data on the correlation between species richness and latitude for a variety of organisms, ranging from trees to protozoa. In addition, own data on the presence of large-scale diversity patterns for diatoms were included, both for local and regional species richness. The strength of the latitudinal gradient was positively correlated to the size of the organisms. Strongest decreases of species richness to the poles was found for large organisms like trees and vertebrates, whereas meiofauna, protozoa and diatoms showed weak or no correlations between species richness and latitude. These results imply that latitudinal gradients are shaped by non-equilibrium (regional) processes and are persistent under conditions of dispersal limitation

Compositionı characteristics and long-term variability of the freshwater microcrustacean fauna of the Faroe Islands

Chertoprud, Anna A. Novichkova ı Elena S., Azovsky, Andrey I. (2019): Compositionı characteristics and long-term variability of the freshwater microcrustacean fauna of the Faroe Islands. Journal of Natural History 53 (39): 2449-2465, DOI: 10.1080/00222933.2019.170458

The study of meiobenthos size structure with the sieving method (case study of the Arctic Basin free-living nematodes)

Body lengths and widths were measured and body volumes were calculated for 1556 Arctic nema-todes sampled from depths of 8003000 m. The samples were filtered through standard sieves with mesh sizesof 500, 250, 125, 63, and 32 µm. Due to the random orientation of the animal bodies with respect to the sieveplane and the presence of detrital and sediment particles, one can only assess the probabilities of the animalretention over the sieves. The distributions of the logarithms of the body volume and length values of nematodeswere close to the normal distribution on the three finer sieves. A simple mathematical filtration model describ-ing size distribution of nematodes on the sieves is proposed. The limitations for the appli-cation of this relation are discussed