Time filter

Source Type

Sede distaccata di Pisa, Italy

Silva-Benavides A.M.,University of Costa Rica | Torzillo G.,CNR Institute of Ecosystem Study
Journal of Applied Phycology | Year: 2012

Batch cultures of the green microalga Chlorella vulgaris and cyanobacterium Planktothrix isothrix and their corresponding co-cultures were grown in municipal wastewater in order to study their growth as well as the nitrogen (NH 4-N) and phosphorus (PO 4 3--P) removal. The cultures were grown under two irradiances of 20 and 60 μmol photons m -2 s -1 in shaken and unshaken conditions. The co-culture of unshaken Chlorella and Planktothrix showed the greatest growth under both irradiances. The monoalgal Planktotrix cultures showed better growth when unshaken than when shaken, whereas Chlorella cultures grew better when mixed, but only at the higher irradiance. The highest percentage of nitrogen removal (up to 80%) was attained by the unshaken co-cultures of Chlorella and Planktothrix. The amount of nitrogen recycled in the biomass reached up to 85% of that removed. Shaken monoalgal cultures of Chlorella showed phosphorus removal under both irradiances. They completely removed the initial phosphorus concentration (7.47 ± 0.17 mg L -1) within 96 and 48 h under 20 and 60 μmol photons m -2 s -1, respectively. © 2011 Springer Science+Business Media B.V.

Callieri C.,CNR Institute of Ecosystem Study
Journal of Limnology | Year: 2010

Picocyanobacteria (Pcy) single-cells and microcolonies are common in lakes throughout the world, and abundant across a wide spectrum of trophic conditions. The single-celled Pcy populations tend to be predominant in large, deep oligo-mesotrophic lakes, while the microcolonies find optimal conditions in warmer, shallower and more nutrient rich lakes. Microcolonies of different size (from 5 to 50 cells) constitute a gradient without a net separation from single-celled types. Considering microcolonies as transitional forms from single-cells to colonial morphotypes it is conceivable to propose a common ecology where local communities are not isolated but linked by dispersal of multiple, potentially interactive, species. In this review abiotic forcing and biotic regulation of Pcy community structure and dynamics are examined to offer an updated view of Pcy ecology.

Fontaneto D.,CNR Institute of Ecosystem Study | Hortal J.,CSIC - National Museum of Natural Sciences
Molecular Ecology | Year: 2013

Body size is one of the main regulators of the ecological characteristics of living organisms, including their biogeography. The 'ubiquity hypothesis' for microorganisms states that they are widely distributed, if not cosmopolitan, due to their small size that allows passive dispersal, in contrast to large organisms that are limited by geographical barriers in their active dispersal. Such idea, summarized in the tenet 'Everything is everywhere, but the environment selects', has driven most of the research in biogeography for microscopic organisms in the last decades, spurring a debate on whether there are fundamental differences in the biogeography of small and large organisms or not (Fenchel & Finlay 2004; Foissner 2008; Hortal 2011). The strong focus on the ubiquity hypothesis may have been often abused to provide a rationale for otherwise descriptive work on the spatial distribution of microscopic organisms; nevertheless, such focus also provides a framework to understand the mechanisms originating and maintaining biodiversity in space. The reliability of the analyses on unknown and understudied organisms is improving, and Heger et al. (2013) is a splendid example on small unicellular eukaryotes of what should be done to overcome the major problems and ambiguities that heated the debate on the ubiquity hypothesis. © 2013 John Wiley & Sons Ltd.

Taiti S.,CNR Institute of Ecosystem Study
Tropical Zoology | Year: 2014

Twenty-seven species of terrestrial isopods are recorded from the Maldive Islands (North Kaafu Atoll and Vaavu Atoll). One genus (Eubelinum) in the family Eubelidae and three species (Styloniscusmaldivensis, Eubelinumincertum, and Pseudodiploexochusindicus) are described as new, and 26 species are newly recorded from the archipelago. Ligia dentipes Budde-Lund, 1885 is also recorded from Sri Lanka and Seychelles. The poorly known species Tylosalbidus Budde-Lund, 1885 and Platyarthrus acropyga Chopra, 1924 are also illustrated. The composition and origin of the oniscidean fauna of the Maldives are briefly discussed.http://zoobank.org/urn:lsid:zoobank.org:pub:ABD0E6EA-83FE-4F61-8B81- D3C8A0B23848 © 2014 Istituto per lo Studio degli Ecosistemi of the Consiglio Nazionale delle Ricerche, Firenze .

Carlozzi P.,CNR Institute of Ecosystem Study
Journal of Biomedicine and Biotechnology | Year: 2012

The main goal of this study was to increase the hydrogen production rate improving the culture technique and the photobioreactor performances. Experiments were carried out at a constant culture temperature of 30°C and at an average irradiance of 480Wm -2 using a cylindrical photobioreactor (4.0cm, internal diameter). The culture technique, namely, the semicontinuous regime for growing Rhodopseudomonas palustris 42OL made it possible to achieve a very high daily hydrogen production rate of 594 ± 61mL (H2) L -1d -1. This value, never reported for this strain, corresponds to about 25mL (H2) L -1h -1, and it was obtained when the hydraulic retention time (HRT) was of 225 hours. Under the same growth conditions, a very high biomass production rate (496 45mg (dw) L -1d -11) was also achieved. Higher or lower HRTs caused a reduction in both the hydrogen and the biomass production rates. The malic-acid removal efficiency (MAre) was always higher than 90. The maximal hydrogen yield was 3.03mol H2 mol MA -1 at the HRT of 360 hours. The highest total energy conversion efficiency was achieved at the HRT of 225 hours. © Copyright 2012 Pietro Carlozzi.

Discover hidden collaborations