Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.Peer reviewe

A new ichnotaxon of tetrapod from Botucatu Formation, Early Cretaceous (Neocomian) from Brazil: locomotorial, preservational, and paleoecological aspects

Trace fossils (e.g. tracks and trackways), objects of Paleoichnology studys, represent behavioral responses of biota. They are vestiges produced by biological activity of past organisms and can be used for paleobiologicaL, paleoecological and paleoenvironmental reconstructions. The Botucatu Formation (Neocomian) was an immense paleoerg and is know worldwide for its ichnofossiliferous record, comprising traces of vertebrates (dinosaurs and mammal-like tracks) and invertebrates (coleoptera and arachnids). Among vertebrates, are of great importance tracks and trackways from the ichnogenus Brasilichnium Leonardi 1981, endemic of aeolian deposits and assign to mammal-like trackmakers. In the present study is described a new ichnotaxon, Brasilichnium saltatorium isp. nov., with saltatorial progression in phases, distinct and rare in fossil record, attempting to understanding locomotorial aspects and the paleoecology of the geologic unit. The new ichnotaxon show biological variation in behavioural level, and not in preservatonal level, when compared to brasilichnium elusivum, reflecting a great difference in autopodial configuration on trackways. In total, were analyzed 12 trackways, with upward and downard direction relative to the inclined plane of the paleodune. Neoichnological experiment were conducted with Meriones unguiculatus. In the experiment and in fossil trackways, autopodial dimensions are larger in downard direction due to the higher displacement of sediment, and may skew interpretations of the possible trackmaker for change the length/width ratio. Another parameter with the same observation among experiment and fossil trackways is the distance between sets of foot/hand, being greater in the downward direction due to the 4 movement dynamics. Compared to others ichnotaxa presenting the saltatorial locomotion, Brasilichnium saltatorium isp. nov. differs both in morphology of tracks and in the autopodium configuration in trackway, reiterating the new description. Regardless of the direction, the quadruped locomotion appears to be the rule, even when the marks of the hands are not printed, possibly because of the overlap of autopodia and/or production of footprints in the subsurface. Heteropody is most evident in the downward direction, however, it has a higher degree in the upward direction. Based on the study of current desserts, Brasilichnium trackmakers probably were opportunistic omnivores consumers, adopting asymmetrical locomotion to get speed. Near the São Bento Quarry, Araraquara, there must have been ephemeral ponds as a result of pluvial episodes recorded as impact craters in sandstone and the abundant ichnofauna. Such environments could support the biota of the region, enhancing the ecological relationships in these areas and forming locally productive communities.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Os icnofósseis (e.g. pegadas e pistas), objetos de estudo da Paleoicnologia, representam respostas comportamentais da biota. São vestígios produzidos pela atividade de organismos pretéritos e podem ser utilizados para reconstruções paleobiológicas, paleoecológicas e paleoambientais. A Formação Botucatu (Neocomiano) representa um imenso paleoerg e é mundialmente conhecida pelo seu registro icnofossilífero, composto por traços de vertebrados (dinossauros e mamaliformes) e invertebrados (coleópteros e aracnídeos). Dentre os vertebrados, destaca-se as pegadas e pistas atribuídas ao icnogênero Brasilichnium Leonardi 1981, endêmico de depósitos eólicos e associado a produtores mamaliformes. No presente estudo é descrito um novo icnotáxon, Brasilichnium saltatorium isp. nov., com progressão saltatorial em fases, distinta e rara no registro fossilífero, buscando-se entender os aspectos locomotoriais e a paleoecologia da unidade geológica. O novo icnotáxon apresenta variação biológica a nível comportamental, e não preservacional, quando comparado a Brasilichium elusivum, refletindo em uma grande diferença na configuração autopodial das pistas Foram analisadas no total 12 pistas, com direções ascendente e descendente em relação ao plano inclinado da paleoduna. Foi realizado experimento neoicnológico com a espécie Meriones unguiculatus. Nas pistas fósseis, assim como no experimento, as dimensões dos autopódios em direção descendente possuem maiores dimensões, devido 2 ao maior deslocamento do sedimento, podendo enviesar interpretações sobre o possível produtor por alterar a razão comprimento/largura. Outro parâmetro de mesmo comportamento entre as pistas fósseis e as pistas produzidas em experimento foi a distância entre os conjuntos pé/mão, sendo maior na direção descendente por conta da dinâmica do movimento. Comparativamente a outros icnotáxons que apresentam o movimento saltatorial, Brasilichnium saltatorium isp. nov. diferencia-se tanto na morfologia das pegadas quanto na configuração dos autopódios na pista, reiterando a nova descrição aqui realizada. Independente da direção, a locomoção quadrúpede parece ser a regra, mesmo quando as marcas das mãos não estão impressas, possivelmente em virtude da sobreposição dos autopódios e/ou produção das pegadas em subsuperfície. A heteropodia é mais evidente na direção descendente, porém, possui maior grau na direção ascendente. Com base no estudo de desertos atuais, os produtores de Brasilichnium provavelmente foram consumidores onívoros oportunistas, adotando a locomoção assimétrica para adquirir velocidade, visando escapar de predadores, perseguir presas, e/ou facilitar a locomoção em planos inclinados. Próximo a Pedreira São Bento, Araraquara, devem ter existido lagoas efêmeras, inferidas em decorrência de episódios pluviais registrados como crateras de impacto no arenito e a abundante icnofauna. Tais ambientes poderiam sustentar a biota da região, intensificando as relações ecológicas nessas áreas e formando comunidades localmente produtivas

Paleometry: a brand new area in brazilian science

Paleometry is a promising research field that brings together different areas, such as physics and chemistry, applied to paleobiological issues. In spite of being recognized abroad, it is a new research field in Brazil. The most important characteristic is the application of mostly non-destructive techniques to the study of fossils. This work compiles some paleometrical applications to different geological contexts, such as the synthesis of hard skeleton in Corumbella werneri, geochemical aspects about fresh water bivalves from the Bauru Group and the exceptional preservation of arthropods from the Crato Member. Diffuse Reflectance Infrared (DRIFT) and Energy Dispersive X-ray Spectroscopy (EDX) were complementary to elucidate the types of skeletogenesys in Corumbella. In the case of the bivalves, DRIFT revealed to be important to elucidate aspects about death and fossilization. Among arthropods, morphological analysis with Scanning Electron Microscopy (SEM) associated with EDX was more profitable to understand fossilization process and paleoenvironmental implications

Paleometry: a brand new area in brazilian science

Paleometry is a promising research field that brings together different areas, such as physics and chemistry, applied to paleobiological issues. In spite of being recognized abroad, it is a new research field in Brazil. The most important characteristic is the application of mostly non-destructive techniques to the study of fossils. This work compiles some paleometrical applications to different geological contexts, such as the synthesis of hard skeleton in Corumbella werneri, geochemical aspects about fresh water bivalves from the Bauru Group and the exceptional preservation of arthropods from the Crato Member. Diffuse Reflectance Infrared (DRIFT) and Energy Dispersive X-ray Spectroscopy (EDX) were complementary to elucidate the types of skeletogenesys in Corumbella. In the case of the bivalves, DRIFT revealed to be important to elucidate aspects about death and fossilization. Among arthropods, morphological analysis with Scanning Electron Microscopy (SEM) associated with EDX was more profitable to understand fossilization process and paleoenvironmental implications.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Geobiological and diagenetic insights from Malvinokaffric devonian biota (Chapada Group, Paran? Basin, Brazil) : paleobiological and paleoenvironmental implications.

This study tests the presence of differential preservation in the Devonian Malvinokaffric fauna from the Chapada Group (Parana? Basin, Brazil). Results of EDXRF, EDS, Raman Spectroscopy, and petrographic analyses show differential preservation of shells that were originally calcite as hematite and goethite fossils, while organisms with original calcium phosphate shells tend to be preserved inside phosphatic concretions. Both preservation types are commonly associated with pseudoframboids, while calcium sulfate minerals are commonly associated with hematized fossils. From this evidence, a diagenetic model for these fossils is proposed. The model includes an early diagenetic phase (characterized by anaerobic sulfate reduction and precipitation of pyrite and carbonate-fluorapatite) and a second, near-surface chemical weathering phase (characterized by the oxidation of pyrite and precipitation of iron oxyhydroxides and calcium sulfates). Acidic conditions in both phases may account for the dissolution of less stable minerals compared to calcium phosphate. It is considered that this model may assist in understanding other similarly preserved biotas, as well as enhancing understanding of the taphonomic overprint that may occur within this important and endemic Devonian biota

Stratification strength and light climate explain variation in chlorophyll a at the continental scale in a European multilake survey in a heatwave summer

To determine the drivers of phytoplankton biomass, we collected standardized morphometric, physical, and biological data in 230 lakes across the Mediterranean, Continental, and Boreal climatic zones of the European continent. Multilinear regression models tested on this snapshot of mostly eutrophic lakes (median total phosphorus [TP] = 0.06 and total nitrogen [TN] = 0.7 mg L-1), and its subsets (2 depth types and 3 climatic zones), show that light climate and stratification strength were the most significant explanatory variables for chlorophyll a (Chl a) variance. TN was a significant predictor for phytoplankton biomass for shallow and continental lakes, while TP never appeared as an explanatory variable, suggesting that under high TP, light, which partially controls stratification strength, becomes limiting for phytoplankton development. Mediterranean lakes were the warmest yet most weakly stratified and had significantly less Chl a than Boreal lakes, where the temperature anomaly from the long-term average, during a summer heatwave was the highest (+4 degrees C) and showed a significant, exponential relationship with stratification strength. This European survey represents a summer snapshot of phytoplankton biomass and its drivers, and lends support that light and stratification metrics, which are both affected by climate change, are better predictors for phytoplankton biomass in nutrient-rich lakes than nutrient concentrations and surface temperature.Peer reviewe