Dataset to assess the shadow effect of an outdoor microalgae culture

[EN] This data in brief (DIB) article is related to a Research article [1]. Microalgae biomass absorb the light photons that are supplied to the culture, reducing the light availability in the inner parts of the photobioreactors. This is known as self-shading or shadow effect. This effect has been widely studied in lab conditions, but information about self-shading in outdoor photobioreactors is scarce. How this shadow effect affects the light availability in an outdoor photobioreactor was evaluated. In addition, advantages and disadvantages of different artificial light sources which can overcome light limitation are described.This research work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO, Projects CTM2014-54980-C2-1-R and CTM2014-54980-C2-2-R) jointly with the European Regional Development Fund (ERDF), both of which are gratefully acknowledged. It was also supported by the Spanish Ministry of Education, Culture and Sport via a pre doctoral FPU fellowship to author J. Gonzalez-Camejo (FPU14/05082).Gonzalez-Camejo, J.; Viruela, A.; Ruano, MV.; Barat, R.; Seco, A.; Ferrer, J. (2019). Dataset to assess the shadow effect of an outdoor microalgae culture. Data in Brief. 25:1-4. https://doi.org/10.1016/j.dib.2019.104143S142

Short-term dynamics of submerged aquatic vegetation diversity and abundance in deep lakes.

Question: What are the short-term trends of submerged aquatic vegetation (SAV) in deep lakes? Is it possible to measure significant changes in SAV distribution in deep lakes characterized by different trophic states and stable water physico-chemical conditions using standard procedures over a 3-yr period (2010–2013), as defined by the Water Framework Directive?. Location: We collected data from four deep lakes belonging to the Italian volcanic lake system (central Italy), which is one of the most important reserves of freshwater in Mediterranean Italy as well as one of the main hotspots of stonewort diversity in the Mediterranean area. Methods: Macrophytes were sampled along five transects in each lake in 2010 and 2013. Data on aquatic plant diversity, composition and abundance were collected from each 1-m depth intervals down to the maximum colonization depth. Simultaneously, the water quality and climate were assessed by standard procedures. Data were analysed with PCA, ANOVA, PROTEST and rank abundance curves. Results: The sampling revealed a significant rearrangement of SAV. Increased species diversity in the first meters of depth (0–5 m) was due to the migration of mid-depth species to lower depths. A reduction in the maximum growing depth of macrophytes was observed within the deepest stonewort communities (below 5 m). No significant changes emerged in water quality or climate. Conclusions: Over 3 yr, SAV displayed significant changes that appear to be independent of summer nutrient conditions and climate drivers. In particular, vascular and stonewort species underwent a distinct spatial rearrangement according to specific behaviours. The present data point to the need for more rigorous analyses of the intra-annual dynamics of macrophytes in deep lakes. An influence of the significant increase in spring precipitation (which is in keeping with local climate variability) recorded in central Italy in the last decade cannot be ruled out a priori, nor can the possibility of stochastic fluctuations be excluded. All these considerations further highlight the critical role of aquatic plants as bioindicator

Role of abiotic and biotic factors in structuring the metazoan plankton community in a lowland river

Water and quantitative zooplankton samples were collected at approximately monthly intervals from June 2000 to June 2002 in the middle section of the Po River (Northern Italy). Highly variable hydrological conditions were observed in the 2 years, with river flow varying approximately between 400 and 9300m3 s-1. Dissolved inorganic nitrogen (DIN) usually decreased at higher river discharges. Autotrophic production was limited by phosphorus availability during the growing period (May-October); no significant adverse effect of zooplankton grazing upon algal biomass was detected. A total of 161 zooplankton taxa were found. The records of the rotifers Lecane incospicua, L. cornuta, Proales sigmoidea, Cephalodella limosa, and of the cladoceran Phrixura leei were new for Italy. Rotifers strikingly were the most abundant group over the entire sampling period. Zooplankton abundance was positively correlated to water temperature and chlorophyll-a concentration, and only in warmer months inversely correlated to river flow. Species of the genus Brachionus were responsible for the two density peaks (>1000 indL-1) of the rotifer taxocoenosis observed in July 2000 and August 2001, coinciding with chlorophyll-a peaks higher than 50 μg L-1 and minima of Shannon equitability index. Water temperature, chlorophyll-a, and soluble reactive phosphorus (SRP) were found to be the most important variables in explaining the observed rotifer assemblages by Canonical Correspondence Analysis. A simple descriptive model is proposed to represent the combined influence of abiotic constraints and biotic interactions on the zooplankton abundance and diversity in the middle reach of the Po River