Biological Production Rates Research Articles

Bio-Valorization of Spent Coffee Grounds and Potato Peel as Substrates for Pleurotus ostreatus Growth

Pleurotus ostreatus, due to its saprophytic nature, can extract nutrients and bioactive compounds from the substrate on which it is grown. This study aimed to assess the effect of adding spent coffee grounds (SCG) and potato peel (PPW) in the wheat straw substrate formulation to grow over the production indicators, physicochemical, techno-functional, total chemical compounds, and antioxidant properties. Treatments were described as follows: T1, wheat straw at 100%; T2, wheat straw at 80% + 10% of SCG + 10% of PPW; T3, wheat straw at 70% + 15% of SCG + 15% of PPW; T4, wheat straw at 60% + 20% of SCG + 20% of PPW. After P. ostreatus growth, non-differences were found in production indicators for T1–T4, including biological efficiency, production rate, and yield. With respect to P. ostreatus dried powders, T1–T4 showed pH values near neutrality concerning soy protein (SP), and the color samples were beige. Also, T2 and T3 exert higher water-holding (WHC) values, while T1–T4 exert higher oil-holding (OHC) and emulsifying capacity (EC) values concerning SP, in dependence on the growth substrate. T1–T4 showed lower swelling (SC) and T1–T3 lower gelling capacity (GC) values. Regarding total chemical compounds and antioxidant properties of P. ostreatus extracts, growth substrate and solvent extraction have an effect on metabolite content and antiradical and reducing power properties. The multivariate analysis revealed that T2 water extracts exert the highest total tannin (TTC) and protocatechuic acid contents (PAC), as well as the highest antiradical (RCSA) and reducing power (RPA) values. In conclusion, this study demonstrated that using SCG and PPW as a partial substitute for substrate (what straw) enhances the physicochemical, techno-functional, and antioxidant activity of P. ostreatus.

Unraveling marine phosphogenesis along the Miocene coast of Peru: Origin and sedimentological significance of the Pisco Formation phosphorites

Phosphorite deposits form through phosphogenesis, a mechanism of diffusion and concentration of interstitial phosphate in sediments leading to Ca-phosphate mineral precipitation in a favorable sedimentary regime at the seafloor. Stretching along the Peruvian coast, the East Pisco Basin is known to host phosphorite beds of Miocene age. In this study, we investigate the petrographic, mineralogical and chemical composition of the Miocene phosphorite layers of the East Pisco Basin, and discuss the phosphogenetic mechanism(s) and sedimentary dynamics that led to the genesis and accumulation of P-rich deposits. Phosphorite samples were collected from layers overlaying stratigraphic unconformities within the Pisco Formation and subsequently analyzed through multiple methods: optical microscopy, XRD, XRF, SEM-EDS, EPMA, ICP-MS and LA-ICP-MS. Our results indicate that these layers consist of phosphatic clasts and nodules along with dolomite clasts, basement boulders, shark teeth, mollusk molds and vertebrate bone fragments. The P-rich clasts are mainly composed of phosphatic intraclasts and small phosphatic nodules. They occur associated with minor amounts of dolomite clasts coated by Fe-oxyhydroxides and laminites. Clasts and nodules are cemented by both early and late diagenetic cements, such as dolomite, calcite, silica, gypsum/anhydrite and baryte. Our observations suggest that the Pisco phosphorite deposits are transgressive lags laying on ravinement surfaces. They formed just below the sediment-water boundary during the early transgression phases, when the porewaters were enriched in phosphorus due to the abundance of organic-rich sediments and the microbial activity, as typical of upwelling settings. These deposits formed in shallow marine conditions, characterized by high biological productivity and low net sedimentation rates, with suboxic conditions at and beneath the sediment-water interface. The concentration of phosphate-coated clasts was then favored by a sedimentary condensation mechanism of dynamic bypassing. Overall, this study provides new insights into the genesis of phosphorite layers in the East Pisco Basin and highlights the importance of understanding the complex interplay between authigenic and sedimentological processes in the formation of these economically and geologically relevant sedimentary rocks.

Multivariate analysis for yield and yield-related traits of oat (Avena sativa L.) genotypes in Ethiopia

The study aimed to generate information on agro-morphological variability among the 120 oat genotypes in the central highlands of Ethiopia. The result showed that the hierarchical clustering grouped the genotypes into four clusters. The highest number of genotypes grouped into the first cluster (38) followed by the second cluster (35) and the fourth cluster (33) while the lowest genotypes (14) were recorded in the third cluster. High forage yield-producing genotypes were grouped into the second cluster while high grain-producing genotypes were grouped into the third cluster. The intra-cluster genetic distance values ranged from 4.3 (C3) to 2.3 (C1). The minimum inter-cluster genetic distance was recorded at 11.7 (between C1 and C2), while the maximum inter-cluster distance was 63.2 (between C3 and C4). Principal component analysis showed that the first four principal components with eigenvalues greater than one contributed 78.3% of the variability among genotypes. The highest contributing traits in the first component were forage yield production rate, biological yield production rate, panicle length at grain harvest, forage dry matter yield, and number of spikelets per panicle. The traits with the greatest weight on the second component were harvest index, grain yield, number of leaves at forage harvest, and plant height at grain harvest. Proper selection of best yield performing genotypes coupled with high yield contributing traits is very important to yield improvement and future oat breeding program. Therefore, selection based on the traits that had a high contribution to the first two principal components would be effective for yield improvement in oat genotypes.

Simulating of human physiological supersystems: interactions of cardiovascular, thermoregulatory and respiratory systems

Special quantitative model of the human thermoregulatory system (MTS) functioning with cardiovascular and lung systems is created. These systems form a human physiological supersystem (HPSS). MTS describes thermoregulatory responses to alterations of both external environmental physical characteristics and internal biological characteristics. Algorithms provide designing of scenarios including simulation of either short-time or long-time (hours or days) observations. Input data include different combinations of environmental variables (air or water temperature, air humidity, wind or water flow speed, light intensity, infrared radiation) for a naked or wear human, as well as for given dynamics of biological characteristics (rate of heat production including its components associated with metabolism and ATP molecules leasing during mental and physical activities). Human body is presented by a core, blood, and a skin compartments. Skin and lung evaporation are under hypothalamic control based on afferent impulse patterns from internal, and skin heat and cold receptors. Dynamic output data include blood, hypothalamic, and skin temperatures, hemodynamic parameters like heart rate, cardiac output, regional blood flows, vascular resistances, blood pressures, and regional blood volumes. Serotonin and melatonin concentrations modulating biological heat production rate are associated with a day/night light intensity. Currently, the PCbased simulator is autonomous software to be used both for educational purposes and for providing of special computer research. In a near future, this simulator has to be widened by models of kidneys, and a mechanism of liverpancreas interaction.

Different flavours of oxygen help quantify seasonal variations of the biological carbon pump in the Celtic Sea

Shelf seas represent only 10% of the World’s Ocean by area but support up to 30% of its primary production. There are few measurements of biological production at high spatial and temporal resolution in these physically and biologically dynamic systems. Here, we use dissolved oxygen to-argon (O2/Ar) ratios and oxygen triple isotopes in O2 (16O, 17O, 18O) to estimate net community production, N(O2/Ar), and gross O2 production, G(17O), in summer and autumn 2014 and spring and summer 2015 in the Celtic Sea, as part of the UK Shelf-Sea Biogeochemistry Programme. Surface O2/Ar concentration ratios were measured continuously using a shipboard membrane inlet mass spectrometer. Additional depth profiles of O2/Ar concentration ratios, δ(17O) and δ(18O) were measured in discrete water samples from hydrocasts. The data were combined with wind-speed based gas exchange parameterisations to calculate biological air-sea oxygen fluxes. These fluxes were corrected for diapycnal diffusion, entrainment, production below the mixed layer, and changes over time to derive N(O2/Ar) and G(17O). The Celtic Sea showed the highest G(17O) in summer 2014 (825 mmol m–2 d–1) and lowest during autumn 2014 (153 mmol m–2 d–1). N(O2/Ar) was highest in spring 2015 (43 mmol m–2 d–1), followed by summer 2014 (42 mmol m–2 d–1), with a minimum in autumn 2014 (–24 mmol m–2 d–1). Dividing the survey region into three hydrographically distinct areas (Celtic Deep, Central Celtic Sea and Shelf Edge), we found that Celtic Deep and Shelf Edge had higher N(O2/Ar) in summer (71 and 63 mmol m–2 d–1, respectively) than in spring (49 and 22 mmol m–2 d–1). This study shows regional differences in the metabolic balance within the same season, as well as higher net community production in summer than in spring in some areas and years. The seasonal patterns in biological production rates and the export efficiency (f-ratio) identified the importance of biology for supporting the Celtic Sea’s ability to act as a net CO2 sink. Our measurements thus help improve our understanding of the biological carbon pump in temperate shelf seas.

The Paleoenvironment and Mechanisms of Organic Matter Enrichment of Shale in the Permian Taiyuan and Shanxi Formations in the Southern North China Basin

The organic-rich shale of the Permian Taiyuan Formation (TYF) and Shanxi Formation (SXF) in the Southern North China Basin (SNCB) is considered a potential shale gas source. The shale was formed in a marine-continental transitional sedimentary environment, which has rarely been studied, with the enrichment mechanisms of organic matter (OM) remaining unclear. This study investigated the controlling factors and enrichment mechanisms of OM by analyzing the total organic carbon (TOC) content, paleoclimate, paleoproductivity, sedimentation rate, redox, and paleosalinity. The TOC of the TYF ranged from 0.92 to 7.43 wt.%, with an average of 2.48 wt.%, which was higher than that of the SXF (TOC = 0.36–5.1 wt.%, average of 1.68 wt.%). These geochemical indices suggest that both the TYF and SXF were deposited in warm and humid paleoclimates, with relatively high biological productivity and sedimentation rates. During the deposition process, the TYF experienced frequent transgression and regression events, leading to an enhancement of water reducibility, a relatively high sedimentation rate, reduced OM oxidation, and rapid deposition of OM, which were conducive to the preservation of OM. Moreover, a high biological productivity increased respiratory oxygen consumption in the water column, which could lead to OM accumulation. However, the regression event experienced by the SXF reduced the paleoproductivity and sedimentation rate and increased water oxidation, leading to a decrease in OM. The main controlling factors for the enrichment of OM in the TYF and SXF were the sedimentation rate, paleoproductivity, and redox conditions, thus establishing the enrichment models for OM in the TYF and SXF. This study is conducive to understanding shale enrichment mechanisms and guiding shale gas exploration.

Effects of Phytoplankton on the Production and Emission of Estuarine Dimethyl Sulfide Under Different Nutrient Inputs From Changjiang River

AbstractContinuous input from the Changjiang River significantly reshuffled the ecosystems in the Changjiang Estuary and adjacent East China Sea, impacting the production, distribution, and emission of marine dimethyl sulfide (DMS). However, the effect of phytoplankton biomass and composition on DMS under different nutrient inputs remains poorly understood. Two comprehensive cruises to characterize their effects were conducted in spring and summer 2015. The areas with high concentrations of DMS, dimethylsulfoniopropionate (precursor of DMS), and dimethyl sulfoxide (photo‐oxidation product of DMS) were largely consistent with high phytoplankton abundances along the front of Changjiang Diluted Water in both seasons. Both the higher conversion ratio of dissolved dimethylsulfoniopropionate to DMS and the higher DMS biological production rate in summer contributed to the higher DMS levels. Once produced in seawater, more than half of the DMS was directly consumed by microbes, resulting in a turnover time of 1–2 days, which was shorter than that driven by ventilation. A ship‐based incubation experiment revealed that, with increasing N/Si and N/P ratios from the Changjiang River, phytoplankton biomass increased and the community shifted from diatom‐dominated to dinoflagellate‐dominated, which was conducive to DMS production. It was noteworthy that strong DMS photo‐degradation induced by high nitrate concentrations may have masked DMS production to some extent, while urea only had a promoting effect and therefore led to a maximum increase in DMS yield. Our findings indicated that the increase in phytoplankton biomass and succession of phytoplankton community induced by changes in nutrient inputs will promote DMS emissions from the Changjiang Estuary.

Evaluación del bagazo de Agave salmiana como sustrato para el cultivo de Pleurotus djamor

The objective of this study is to evaluate the potential of agave bagasse supplemented with urea for use as an alternative substrate in the cultivation of a wild fungus isolated from Agave salmiana (A. salmiana), determining the biological efficiency, production rate, morphological characteristics and nutritional. The fungus was identified by molecular methods amplifying the ITS region and subsequently cultivated on A. salmiana bagasse supplemented with urea (0.77, 0.95, 1.14, 1.32 and 1.5% of total nitrogen (TN)). For the cultivation of the fungus, two types of inoculum were used: in the form of grain and in the form of granules. The fungus was identified as Pleurotus djamor. A biological efficiency (BE) of 70% was obtained in the sample inoculated with grain at 1.32% TN, at 1.5% it produced malformations in the fruiting bodies. Chemical analysis of the sporocarps shows a crude protein content of 15-26%. This is the first report of the isolation of P. djamor from A. salmiana as an atypical substrate, which represents an opportunity for its commercialization and the bagasse, due to its chemical composition and being supplemented with urea, allows the growth of the fungus without alter its nutritional composition of this genus.

Simultaneous assessment of oxygen- and nitrate-based net community production in a temperate shelf sea from a single ocean glider

Abstract. The continental shelf seas are important at a global scale for ecosystem services. These highly dynamic regions are under a wide range of stresses, and as such future management requires appropriate monitoring measures. A key metric to understanding and predicting future change are the rates of biological production. We present here the use of an autonomous underwater glider with an oxygen (O2) and a wet-chemical microfluidic total oxidised nitrogen (NOx-=NO3-+NO2-) sensor during a spring bloom as part of a 2019 pilot autonomous shelf sea monitoring study. We find exceptionally high rates of net community production using both O2 and NOx- water column inventory changes, corrected for air–sea gas exchange in case of O2. We compare these rates with 2007 and 2008 mooring observations finding similar rates of NOx- consumption. With these complementary methods we determine the O2:N amount ratio of the newly produced organic matter (7.8 ± 0.4) and the overall O2:N ratio for the total water column (5.7 ± 0.4). The former is close to the canonical Redfield O2:N ratio of 8.6 ± 1.0, whereas the latter may be explained by a combination of new organic matter production and preferential remineralisation of more reduced organic matter at a higher O2:N ratio below the euphotic zone.

A Pseudo‐Lagrangian Transformation to Study a Chlorophyll‐a Patch in the Ría de Vigo (NW Iberian Peninsula)

AbstractBecause of the difficulties in tracking a water mass over time and conducting synoptic surveys over large spatial scales, measurements of biological variables in the ocean are often restricted to isolated Eulerian observations. Here a proof‐of‐concept of a pseudo‐Lagrangian transformation was applied to a time series of chlorophyll‐a profiles acquired at a single fixed station to diagnose the shape of a phytoplankton patch, and its physical‐biological rates of transformation. During August 2013, a 27‐hr time series of observations of horizontal currents, hydrographic properties, turbulent mixing and chlorophyll‐a was acquired at a central station of the Ría de Vigo (NW Iberian Peninsula). A chlorophyll‐a patch, tilted upward toward the inner part of the Ría, was observed moving back and forth past the sampling station. Its shape and position during the sampling period were modulated by the semi‐diurnal (M2) tidal currents and the vertically sheared upwelling circulation. The pseudo‐Lagrangian transformation allowed estimation of chlorophyll‐a net rates of change. These rates were positive between 12 and 14 m depth, and negative elsewhere, with a mean value of −0.001 ± 0.449 days−1 within the patch maximum. After accounting for the effects of diffusion and sinking, the mean net biological production rate in the upper 15 m (0.53 ± 0.25 days−1) was comparable with in vitro estimates of the balance between phytoplankton growth and mortality obtained from dilution experiments carried out under similar conditions (0.2 ± 0.7 days−1). This pseudo‐Lagrangian transformation is complementary to traditional analyses for the quantification of ecological processes and biogeochemical budgets.

Yield, and phenolic content of shiitake mushrooms cultivated on alternative substrates

The productivity of four strains of shiitake (Lentinula edodes) on diverse lignocellulosic by-products used as substrates were evaluated. The objective was to determine the correlation between the composition of the substrate with the productivity of carpophores and their polyphenol content. The fungi were produced on vineyard prunings (VP), sorghum stubble (SS), sugarcane bagasse (SB), and oak shavings (OS). The productivity was evaluated based on the biological efficiency (BE), production rate (PR), and yield (Y). To evaluate the effect on shiitake growth on the chemical composition of the substrates, the content of fiber [neutral detergent fiber (NDF), hemicellulose, cellulose, lignin] was determined before and after inoculation. Total phenolic compounds were quantified by spectrophotometry. The highest BE was observed for the IE-256 strain on SS (145.11%), and the highest PR for the IE-245 strain on SS (1.69%). The highest Y was observed for the IE-256 strain on SS (41.96%). The fiber results were significantly affected by growth period, strain, substrate, and the selected combinations of strains and substrates. The phenolic compound content of the carpophores was also significantly affected by substrate and strain; the lowest and highest values were obtained for the IE-256 strain on OS (1.5983 mg GAE*g-1) and SS (2.7197 mg GAE*g-1), respectively. On average, the highest carpophores production per substrate and strain corresponded to SS and IE-245, respectively. The carpophores of the IE-256 strain cultivated on SS could potentially present greater antioxidant activity because of their high polyphenol content.

Experimental N and P additions relieve stoichiometric constraints on organic matter flows through five stream food webs.

Human activities have dramatically altered global patterns of nitrogen (N) and phosphorus (P) availability. This pervasive nutrient pollution is changing basal resource quality in food webs, thereby affecting rates of biological productivity and the pathways of energy and material flow to higher trophic levels. Here, we investigate how the stoichiometric quality of basal resources modulates patterns of material flow through food webs by characterizing the effects of experimental N and P enrichment on the trophic basis of macroinvertebrate production and flows of dominant food resources to consumers in five detritus-based stream food webs. After a pre-treatment year, each stream received N and P at different concentrations for 2years, resulting in a unique dissolved N:P ratio (target range from 128:1 to 2:1) for each stream. We combined estimates of secondary production and gut contents analysis to calculate rates of material flow from basal resources to macroinvertebrate consumers in all five streams, during all 3years of study. Nutrient enrichment resulted in a 1.5× increase in basal resource flows to primary consumers, with the greatest increases from biofilms and wood. Flows of most basal resources were negatively related to resource C:P, indicating widespread P limitation in these detritus-based food webs. Nutrient enrichment resulted in a greater proportion of leaf litter, the dominant resource flow-pathway, being consumed by macroinvertebrates, with that proportion increasing with decreasing leaf litter C:P. However, the increase in efficiency with which basal resources were channelled into metazoan food webs was not propagated to macroinvertebrate predators, as flows of prey did not systematically increase following enrichment and were unrelated to basal resource flows. This study suggests that ongoing global increases in N and P supply will increase organic matter flows to metazoan food webs in detritus-based ecosystems by reducing stoichiometric constraints at basal trophic levels. However, the extent to which those flows are propagated to the highest trophic levels likely depends on responses of individual prey taxa and their relative susceptibility to predation.

Producción y caracterización de cepas reconstituídas de Pleurotus spp. cultivadas en diferentes residuos agrícolas

Two reconstituted strains were produced by mating neohaplonts (monokaryons) obtained by chemical dedikaryotization of two parental strains i.e. Pleurotus ostreatus (OS) and Pleurotus djamor (DS). Five monokaryons were recovered employing homogenization time periods between 60 to 90 s, and incubation at 28oC in a peptone-glucose solution (PGS) for Pleurotus spp. Mycelial kinetics on MEA and wheat grain were determined using 4 math models, the parental strains on MEA showed μmax values between 8.11 and 10.73 mm day-1 and on wheat grain presented μmax values since 0.23 to 9.18 cm3 day-1, while the reconstituted strains on MEA exhibited μmax values ranged from 8.68 and 12.93 mm day-1 and on wheat grain showed μmax values between 0.25 and 9.30 cm3 day-1. The parental and reconstituted strains were cultivated using two agricultural wastes such as wheat straw (WS) and a mixture of oak sawdust, wheat straw, millet seed, cotton seed hull and CaCO3 (AP). The productivity and chemical composition of the mushrooms, and also the chemical composition of the substrates before and after harvest were determined. Reconstituted strain Pleurotus djamor (DS2xDS4) cultivated on WS showed the highest biological efficiency (125.84 %) and production rate (2.79 %), and also this strain produced on AP presented the highest productivity parameters: biological efficiency (98.43 %) and productivity rate (2.27 %). The reconstituted strain of Pleurotus ostreatus (OS4xOS5) produced on AP presented fruit bodies with highest protein content being of 24.03%, while the reconstituted strain of Pleurotus djamor (DS2xDS4) cultivated on WS exhibited the highest protein content of 32.94%. The substrate AP used in the cultivation of the reconstituted strain (DS2xDS4) presented the highest biodegradation value of lignin (33.60%).

Distribution Characteristics of Dimethylated Sulfur Compounds and Turnover of Dimethylsulfide in the Northern South China Sea During Summer

AbstractSpatial distributions of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP), and dimethyl sulfoxide (DMSO) in the northern South China Sea were determined in the summer of 2015. The mean concentrations of DMS, particulate DMSP (DMSPp), dissolved DMSP (DMSPd), dissolved DMSO (DMSOd), and particulate DMSO (DMSOp) in the surface seawater were 2.8 ± 1.0, 6.8 ± 1.5, 14.0 ± 3.1, 12.2 ± 3.2, and 9.2 ± 2.6 nmol L−1, respectively. The contributions of three principal removal pathways of DMS were investigated. The average biological production and consumption rates of DMS in the surface seawater were 6.15 ± 1.12 and 4.63 ± 1.32 nmol L−1 day−1. Deck incubation experiments showed that the photooxidation rates of DMS for different radiation bands followed the order: KUVB > KUVA > Kvisible light. The DMS photooxidation rates were higher in the coastal waters than in the open ocean, which might be associated with the higher concentrations of dissolved organic matter of terrigenous input. The sea‐to‐air fluxes of DMS ranged from 1.6 to 50.3 μmol m−2 day−1 with an average value of 15.6 ± 11.6 μmol m−2 day−1. Based on the respective turnover times of DMS, the contributions of biological consumption, photooxidation, and sea‐to‐air exchange to the sink of DMS were 32.6 ± 11.0%, 23.2 ± 8.9%, and 44.1 ± 19.2%, respectively, suggesting that the three removal pathways were all critical to the migration and transformation of DMS in the surface seawater during summer.

Production of acetaldehyde from ethanol in coastal waters

Interest in understanding the cycling of ethanol in the environment has grown as ethanol use as a gasoline additive has increased. The production of acetaldehyde from ethanol was measured in Southern California coastal seawater. The rate of increase of acetaldehyde was positively correlated with the rate constant for ethanol biodegradation and bacteria count and was consistent with two consecutive first-order reactions where acetaldehyde is first biologically produced from ethanol then consumed. Correlation with bacteria counts suggested that acetaldehyde degradation was also a biological process. The rate constants for acetaldehyde production from ethanol and acetaldehyde loss averaged 3.0 ± 3.4 × 10-3min-1 and 2.3 ± 4.5 × 10-2min-1 respectively. The branching ratio for acetaldehyde production from ethanol was 0.46 ± 0.26 and estimated acetaldehyde biological production rates ranged from 0.022 to 0.800nMmin-1. With high bacterial counts, biological production rates from ethanol exceeded photochemical production rates from chromophoric dissolved organic matter. Overall, acetaldehyde production rates were larger than biodegradation rates, suggesting these waters are a source of acetaldehyde to the atmosphere. Extrapolation to higher ethanol concentrations associated with spills suggests that the production rate of acetaldehyde will initially increase and then decrease as ethanol concentrations increase.

Chemical composition and biological properties of Pleurotus spp. cultivated on peat moss and wheat straw

The productivity parameters of 2 Pleurotus spp. cultivated with two mixtures of wheat straw (WS) and peat moss (MG) were evaluated, the chemical composition of the mushrooms and also the antioxidant, antibacterial activities of hexanic extracts of the fruit bodies were determined. Pleurotus strains were fructified using the mixture 1 (60% of WS + 40% of MG) obtained the highest biological efficiencies, production rates and yields. The strain of Pleurotus ostreatus (XC005) cultivated using the mixture 2 (80% WS + 20% of MG) presented fruit bodies with highest protein content being of 25.28%, and also the strain of Pleurotus djamor (XC007) fructified on the mixture 2 showed mushrooms with highest protein content being of 30.98%. The highest antioxidant effect resulted in the hexanic extract of the Pleurotus ostreatus cultivated on M2 was found using the TBARS inhibition assay (EC50 = 0.12 mg mL- 1), while the highest antioxidant activity showed the hexanic extract of the Pleurotus djamor produced on M1 was found using the TBARS inhibition assay (EC50 = 0.21 mg mL- 1). The bactericidal effect of the hexanic extracts of Pleurotus ostreatus was obtained between 21.09 to 27.90 mg mL−1, whereas the bacteriostatic activity of the hexanic extracts of Pleurotus djamor was achieved since 19.82 to 30.98 mg mL−1. The results evidenced that the Pleurotus spp. cultivated on the mixture 2 presented highest protein content and better biological properties, encouraging the production of edible fungi strains and their use in the industrial field.

Land-use intensity alters both the source and fate of CO2 within eight sub-tropical estuaries

Combined pressures from inland agricultural intensification and coastal development are dramatically altering estuaries’ structure and function. Despite the established global significance of estuarine carbon (C) cycling, the impact of growing anthropogenic stress on coastal C inputs and exports is unclear. To address this gap, we evaluated the magnitude and drivers of estuary C fluxes in eight sub-tropical estuaries at Low (n = 3), Moderate (n = 2), and High (n = 3) levels of nutrient enrichment. We measured changes in the concentration and isotopic composition (δ13C) of the major C pools (organic and inorganic) and gaseous product of C turnover (CO2) over wet and dry seasons. Over both sampling periods estuaries classified Moderate and High emitted far more CO2 (37 ± 10 mmol m−2 d−1) than those classified Low (6.3 ± 4 mmol m−2 d−1). However, estuaries with both high nutrients and high turbidity produced less CO2, and thus exported more DIC, than expected from hydrodynamics (freshwater flushing time). Differences in estuary phytoplankton biomass (Chla concentrations) corresponded with differences in the biological CO2 production (respiration) rates estimated from δ13C-DIC variations, although respiration rates were higher than predicted based on hydrodynamics (surface area/discharge) in high nutrient, low turbidity systems. Together these findings demonstrate that land-use intensification can alter both the source and the production of estuary CO2, and suggest that the direction of this shift can depend on ancillary factors like turbidity as well as nutrient enrichment. Evidence that human alterations to coastal ecosystems can shift the balance between DIC downstream export and CO2 emissions outside of the range predicted by hydrodynamic factors like residence time, surface area, and discharge has implications for global C models.

Culture of Pleurotus ostreatus in pine shavings: isolation of strains and evaluation of their productivity

In order to obtain strains of the edible mushroom Pleurotus ostreatus that can be cultivated in pine wood shavings, 36 monosporic cultures were isolated and propagated in vitro, selecting 6 cultures of rapid mycelial growth in order to obtain interspecimen crosses and dikaryon-monokaryon mating. Eleven of the crosses obtained and their 6 parental strains were cultured in vitro in order to determine their growth in pine shavings and barley straw (control), selecting 6 strains (3 crosses, 3 parental strains) for sporome production in the two growth substrates. At in vitro level, significant differences were found between the mycelial areas of monokaryons and dikaryons in the treatments (time, substrate) evaluated. In terms of sporome productivity, the cultures in barley straw presented higher biological efficiency (22.6%-46.4%) and production rate (0.31%-0.77%) values than those in the pine shavings (3.3%-12% and 0.03%-0.11%, respectively). Sporome pileus diameters of 5 cm to 9.9 cm were the most frequent in both substrates. In general, the crosses surpassed their parents in both mycelial growth and sporome production, although further study is required in order to facilitate increased productivity of the strains in this potentially useful agroforestry residue.

Variations in Rates of Biological Production in the Beaufort Gyre as the Arctic Changes: Rates From 2011 to 2016

AbstractThe Arctic Ocean is experiencing profound environmental changes as the climate warms. Understanding how these changes will affect Arctic biological productivity is key for predicting future Arctic ecosystems and the global CO2 balance. Here we use in situ gas measurements to quantify rates of gross oxygen production (GOP, total photosynthesis) and net community production (NCP, net CO2 drawdown by the biological pump) in the mixed layer in summer or fall from 2011 to 2016 in the Beaufort Gyre. NCP and GOP show spatial and temporal variations with higher values linked with lower concentrations of sea ice and increased upper ocean stratification. Mean rates of GOP range from 8 ± 1 to 54 ± 9 mmol O2·m−2·d−1 with the highest mean rates occurring in summer of 2012. Mean rates of NCP ranged from 1.3 ± 0.2 to 2.9 ± 0.5 mmol O2·m−2·d−1. The mean ratio of NCP/GOP, a measure of how efficiently the ecosystem is recycling its nutrients, ranged from 0.04 to 0.17, similar to ratios observed at lower latitudes. Additionally, a large increase in total photosynthesis that occurred in 2012, a year of historically low sea ice coverage, persisted for many years. Taken together, these data provide one of the most complete characterizations of interannual variations of biological productivity in this climatically important region, can serve as a baseline for future changes in rates of production, and give an intriguing glimpse of how this region of the Arctic may respond to future lack of sea ice.

Stomach content and stable isotope analyses reveal resource partitioning between juvenile bluefin tuna and Atlantic bonito in Alboran (SW Mediterranean)

The Alboran Sea holds one of the highest biological productivity rates in the Mediterranean, and thus represents an important nursing area for pelagic fishes including tunas. Trophic interactions between sympatric populations of age-0 bluefin tuna (ABFT) and Atlantic bonito (BON) were investigated in Alboran by integrating stomach content analysis (SCA) and stable isotope analysis of bulk muscle (BSIA) and individual amino acids (AA-CSIA). BON and ABFT individuals were collected in the Bay of Malaga; additionally, ABFT were caught off Carboneras. SCA showed that BON fed only on teleost fishes, whereas ABFT diet also comprised invertebrates. We found significant dietary differences between groups using SCA and BSIA data. Low values of niche width estimated from SCA and BSIA indicate poor dietary diversity in the two sampling sites. There was no isotopic niche overlap between groups, which may indicate resource partitioning. Trophic positions (TP) estimated from SCA, BSIA and AA-CSIA place BON at higher TP than ABFT.