Ecological succession of a Jurassic shallow-water ichthyosaur fall.

After the discovery of whale fall communities in modern oceans, it has been hypothesized that during the Mesozoic the carcasses of marine reptiles created similar habitats supporting long-lived and specialized animal communities. Here, we report a fully documented ichthyosaur fall community, from a Late Jurassic shelf setting, and reconstruct the ecological succession of its micro- and macrofauna. The early 'mobile-scavenger' and 'enrichment-opportunist' stages were not succeeded by a 'sulphophilic stage' characterized by chemosynthetic molluscs, but instead the bones were colonized by microbial mats that attracted echinoids and other mat-grazing invertebrates. Abundant cemented suspension feeders indicate a well-developed 'reef stage' with prolonged exposure and colonization of the bones prior to final burial, unlike in modern whale falls where organisms such as the ubiquitous bone-eating worm Osedax rapidly destroy the skeleton. Shallow-water ichthyosaur falls thus fulfilled similar ecological roles to shallow whale falls, and did not support specialized chemosynthetic communities

The Impact of Global Warming and Anoxia on Marine Benthic Community Dynamics: an Example from the Toarcian (Early Jurassic)

The Pliensbachian-Toarcian (Early Jurassic) fossil record is an archive of natural data of benthic community response to global warming and marine long-term hypoxia and anoxia. In the early Toarcian mean temperatures increased by the same order of magnitude as that predicted for the near future; laminated, organic-rich, black shales were deposited in many shallow water epicontinental basins; and a biotic crisis occurred in the marine realm, with the extinction of approximately 5% of families and 26% of genera. High-resolution quantitative abundance data of benthic invertebrates were collected from the Cleveland Basin (North Yorkshire, UK), and analysed with multivariate statistical methods to detect how the fauna responded to environmental changes during the early Toarcian. Twelve biofacies were identified. Their changes through time closely resemble the pattern of faunal degradation and recovery observed in modern habitats affected by anoxia. All four successional stages of community structure recorded in modern studies are recognised in the fossil data (i.e. Stage III: climax; II: transitional; I: pioneer; 0: highly disturbed). Two main faunal turnover events occurred: (i) at the onset of anoxia, with the extinction of most benthic species and the survival of a few adapted to thrive in low-oxygen conditions (Stages I to 0) and (ii) in the recovery, when newly evolved species colonized the re-oxygenated soft sediments and the path of recovery did not retrace of pattern of ecological degradation (Stages I to II). The ordination of samples coupled with sedimentological and palaeotemperature proxy data indicate that the onset of anoxia and the extinction horizon coincide with both a rise in temperature and sea level. Our study of how faunal associations co-vary with long and short term sea level and temperature changes has implications for predicting the long-term effects of “dead zones” in modern oceans

Effects of different doses of erythropoietin in patients with myelodysplastic syndromes: A propensity score-matched analysis

Erythropoiesis-stimulating agents effectively improve the hemoglobin levels in a fraction of anemic patients with myelodysplastic syndromes (MDS). Higher doses (HD) of recombinant human erythropoietin (rhEPO) have been proposed to overcome suboptimal response rates observed in MDS patients treated with lower "standard doses" (SD) of rhEPO. However, a direct comparison between the different doses of rhEPO is lacking

A silicified Early Triassic marine assemblage from Svalbard

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Spectrophotometric methods for lignin and cellulose in forest soils as predictors for humic substances

The origin and fate of humus, a soil organic matter fraction that is most resistant to decomposition, are not yet completely understood. Humus derives mainly from plant structural components; that is, lignin and cellulose, together with several other primary and secondary compounds. There are several methods to estimate lignin and cellulose in plant material; however, the applications to soil are limited and usually complicated and expensive. Conversely, humus can be estimated in soil by chemical titration methods, which estimate the carbon linked to humic and fulvic acids (HAC and FAC). Therefore, we carried out analyses that aimed to compare, within beech forest soils, spectrophotometric data for lignin and cellulose with those of HAC and FAC. We used soil samples from six different beech woods in Italy, sampling in four layers from 0–5 to 30–40 cm. The relations between spectrophotometric cellulose and lignin and HAC and FAC were tested by linear mixed models. Our results showed that both lignin and cellulose were significant predictors for HAC and FAC, even if cellulose had a larger conditional coefficient of determination (R2 c). The best fit was between cellulose and the sum of HAC and FAC (R2 c = 0.675). Our novel approach proved that spectrophotometric lignin and cellulose provide reliable results in both organic and mineral beech forest soils, even though lignin had a greater random variation than cellulose. Thus, spectrophotometric lignin and cellulose provide reliable and rapidly obtained predictors of humic substances in beech forest soils, with appropriate conversion factors to estimate HAC and FAC. Highlights: Humic substances are of pivotal importance in the global carbon cycle. There is a need for simple and rapid methods to estimate humic substances. Spectrophotometric methods provide fast results for cellulose and lignin in soils. Lignin and cellulose function as good predictors for humic substances in forest soil

Spectrophotometric methods for lignin and cellulose in forest soils as predictors for humic substances

Summary: The origin and fate of humus, a soil organic matter fraction that is most resistant to decomposition, are not yet completely understood. Humus derives mainly from plant structural components; that is, lignin and cellulose, together with several other primary and secondary compounds. There are several methods to estimate lignin and cellulose in plant material; however, the applications to soil are limited and usually complicated and expensive. Conversely, humus can be estimated in soil by chemical titration methods, which estimate the carbon linked to humic and fulvic acids (HAC and FAC). Therefore, we carried out analyses that aimed to compare, within beech forest soils, spectrophotometric data for lignin and cellulose with those of HAC and FAC. We used soil samples from six different beech woods in Italy, sampling in four layers from 0–5 to 30–40 cm. The relations between spectrophotometric cellulose and lignin and HAC and FAC were tested by linear mixed models. Our results showed that both lignin and cellulose were significant predictors for HAC and FAC, even if cellulose had a larger conditional coefficient of determination (R2c). The best fit was between cellulose and the sum of HAC and FAC (R2c= 0.675). Our novel approach proved that spectrophotometric lignin and cellulose provide reliable results in both organic and mineral beech forest soils, even though lignin had a greater random variation than cellulose. Thus, spectrophotometric lignin and cellulose provide reliable and rapidly obtained predictors of humic substances in beech forest soils, with appropriate conversion factors to estimate HAC and FAC. Highlights: Humic substances are of pivotal importance in the global carbon cycle. There is a need for simple and rapid methods to estimate humic substances. Spectrophotometric methods provide fast results for cellulose and lignin in soils. Lignin and cellulose function as good predictors for humic substances in forest soils