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In this paper, we review observational and modelling results on the upwelling in the tropical Atlantic between 10 ∘ N and 20 ∘ S. We focus on the physical processes that drive the seasonal variability of surface cooling and the upward nutrient flux required to explain the seasonality of biological productivity. We separately consider the equatorial upwelling system, the coastal upwelling system of the Gulf of Guinea and the tropical Angolan upwelling system. All three tropical Atlantic upwelling systems have in common a strong seasonal cycle, with peak biological productivity during boreal summer. However, the physical processes driving the upwelling vary between the three systems. For the equatorial regime, we discuss the wind forcing of upwelling velocity and turbulent mixing, as well as the underlying dynamics responsible for thermocline movements and current structure. The coastal upwelling system in the Gulf of Guinea is located along its northern boundary and is driven by both local and remote forcing. Particular emphasis is placed on the Guinea Current, its separation from the coast and the shape of the coastline. For the tropical Angolan upwelling, we show that this system is not driven by local winds but instead results from the combined effect of coastally trapped waves, surface heat and freshwater fluxes, and turbulent mixing. Finally, we review recent changes in the upwelling systems associated with climate variability and global warming and address possible responses of upwelling systems in future scenarios. [ABSTRACT FROM AUTHOR]

Several moons in the outer solar system host liquid water oceans. A key next step in assessing the habitability of these ocean worlds is to determine whether life's elemental and energy requirements are also met. Phosphorus is required by all known life and is often limited to biological productivity in Earth's oceans. This raises the possibility that its availability may limit the abundance or productivity of Earth-like life on ocean worlds. To address this potential problem, here we calculate the equilibrium dissolved phosphate concentrations associated with the reaction of water and rocks—a key driver of ocean chemical evolution—across a broad range of compositional inputs and reaction conditions. Equilibrium dissolved phosphate concentrations range from 10−11 to 10−1 mol/kg across the full range of carbonaceous chondrite compositions and reaction conditions considered, but are generally > 10−5 mol/kg for most plausible scenarios. Relative to the phosphate requirements and uptake kinetics of microorganisms in Earth's oceans, such concentrations would be sufficient to support initially rapid cell growth and construction of global ocean cell populations larger than those observed in Earth's deep oceans. Is phosphorous a limiting factor for life on ocean worlds (e.g. Europa and Enceladus)? Calculated dissolved phosphate concentrations from a wide range of possible water-rock reactions suggest cell populations larger than those observed in Earth's deep oceans could be supported. [ABSTRACT FROM AUTHOR]

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In the southwestern Sea of Okhotsk, a large spring phytoplankton bloom occurs after the sea ice melts. A suggested scenario is that sea ice with materials such as iron-containing sediment or ice algae is transported from the north and melted with release of them, inducing a prominent bloom. We hypothesize that sea ice containing materials that could enhance spring bloom originates from active coastal polynyas in the upstream region. To verify this hypothesis and identify which coastal areas generate sea ice that is further transported to the bloom area, we simulated the transport of sea ice produced in the coastal polynyas by a particle-tracking method. Sea ice production and drift velocity were derived from satellite microwave data. For regions near the coast, where ice drift data derived from the satellite are inaccurate, we combined ice drift data derived from the wind using the wind factor and the turning angle obtained from mooring data. Further, we used the apparent wind factor that expresses enhancement of the alongshore component of ice drift by the ocean current. The simulations suggest that most of the sea ice that melts in the western Kuril Basin originates from the Terpenia Bay and Sakhalin polynyas. The area where high net community production occurs after the sea ice melts corresponds well to the area where sea ice originating from these polynyas melts. The simulation of frazil ice suggests the importance of melt ice originating from the Terpenia Bay polynya with a higher rate of frazil ice production. [ABSTRACT FROM AUTHOR]

Among the land-dominated natural formations, like forests and grasslands, the attention of humanity is drawn at present primarily to the former. It is the forests of temperate and tropical zones that are supposed to play an important role in the regulation of biosphere processes on Earth, including the current climate. This almost completely ignores the importance of herbaceous systems widely represented by steppes and meadows. The overwhelming superiority of forests over grass ecosystems in productivity and phytomass stock is recognized. A comparative analysis of production estimates (t/ha/year) and of organic material stocks (t/ha) in the underground and aboveground parts of herbaceous and forest ecosystems accumulated in the scientific literature has shown that meadows and steppes are not inferior (and often even superior) to forests both in the mass of accumulated organic matter and in annual growth of phytomass. The only difference is that organic production is localized in forest communities mainly in the aboveground part as considerable wood (trunk) mass while it is equally or more shifted underground in herbaceous communities in the form of soil organic matter. The leaf (photosynthesizing) masses of herbaceous and forest communities are close in quantity, respectively, and their synthesis of organic products and carbon exchange with the atmosphere are also similar. The author argues that the steppe and meadow ecosystems do not lag behind forests in organic mass and participation in biosphere processes, thus deserving no less effort for their preservation. [ABSTRACT FROM AUTHOR]

This study examines the impact of two very severe tropical cyclonic events, Phailin (over the Bay of Bengal) and Ockhi (over the Arabian Sea), on surface ocean pCO2 and the associated changes in the upper ocean structure using a coupled biogeochemical ROMS model. The primary productivity averaged over the mixed layer is increased from 6.9 to 12.0 (7.2–45.6) mgCm−3d−1 in response to Phailin (Ockhi). A decomposition analysis reveals that the mean contribution of temperature‐driven changes in inducing pCO2 variability in response to pre‐ and post‐cyclonic conditions, in case of Phailin (Ockhi), are 5.4 (−8.8) and −7.6 (−58.8) μatm whereas dissolved inorganic carbon (DIC) driven changes are 23.6 (19.5) and 27.8 (78.0) μatm. Although salinity and total alkalinity have a relatively lesser control in inducing pCO2 variability, salinity's response to the post‐Phailin conditions is significant owing to strong salinity stratification in the Bay of Bengal. The enhancement of DIC is more in the near‐surface waters than its removal by net biological processes resulting in the dominance of cyclone‐induced upwelling and associated vertical mixing driven changes over the enhanced biology‐driven changes in controlling pCO2 variability during both cyclones. Despite comparable magnitudes of environmental forcing during both cyclones, the oceanic response to Phailin is comparatively short‐lived and subdued due to stronger stratification in the Bay of Bengal. A relatively large ratio of DIC to total alkalinity in the upper layers of Arabian Sea facilitates a higher pCO2 response to Ockhi. This makes Ockhi a greater source of CO2 to the atmosphere. Plain Language Summary: Tropical cyclones dissipate large amounts of energy into the upper ocean, enhancing vertical mixing under the influence of strong winds. The enrichment of nutrients and carbon due to upwelling of deeper waters enhance pCO2 levels making a favorable environment for biological productivity eventually utilizing the CO2, and decreasing the net pCO2 level. This study examines the impact of two very severe cyclones on surface pCO2 variability in two contrasting basins of the northern Indian Ocean. In both the basins, physical processes like heat, water fluxes, air‐sea exchanges of inorganic carbon and mixing are largely controlling pCO2 variability during tropical cyclones. Biological processes like carbonate production/dissociation and organic matter cycling have a considerable control on pCO2 variability but not comparable with pCO2 variability driven by the physical processes. The strong upper ocean stratification in the Bay of Bengal and the vertical distribution of the inorganic carbon inventory inherent to both basins result in differential oceanic response to tropical cyclones. The Arabian Sea (Ockhi) acts as a greater source of CO2 to the atmosphere in comparison to the Bay of Bengal (Phailin) during tropical cyclones. Key Points: Cyclone‐induced upwelling and associated vertical mixing driven pCO2 variability dominate over the enhanced biology‐driven variabilityRelatively large ratio of DIC to total alkalinity in the upper layers of Arabian Sea facilitates a higher pCO2 response during cyclonesProportion of variance explained by ocean pCO2 on air‐sea CO2 flux is 53% (69%) whereas wind speed explained 57% (62%) for Phailin (Ockhi) [ABSTRACT FROM AUTHOR]

Introduction: Conservation agriculture is a sustainable system of farming that safeguard and conserves natural resources besides enhancing crop production. The biological properties of soil are the most sensitive indicator to assess the short term impact of management practices such as tillage and residue incorporation. Methods: Nine treatments of tillage and residue management practices [Reduced till direct seeded rice-zero till barley (RTDSR–ZTB); RTDSR–ZTB–green gram residue (Gg); Zero till direct seeded rice–zero till barley–zero till green gram (ZTDSR–ZTB–ZTGg); RTDSR–ZTB + rice residue at 4 t ha 1 (RTDSR–ZTBRR4); RTDSR–ZTBRR6; un-puddled transplanted rice (UPTR)–ZTB–Gg; UPTR–ZTBRR4; UPTR–ZTBRR6, and puddled transplanted rice (PTR)–RTB] executed under fixed plot for five years on crop productivity and soil biological properties under rice-barley production system. Results: The shifting in either RTDSR or ZTDSR resulted in yield penalty in rice compared to PTR. The PTR recorded highest pooled grain yield of 3.61 ha−1. The rice grain yield reduced about 10.6% under DSR as compared to PTR. The ZTB along with residue treatments exhibited significantly higher grain yield over ZTB, and the RTDSR-ZTBRR6 registered highest pooled grain yield of barley. The system productivity (12.45 t ha−1) and sustainable yield index (0.87) were highest under UPTR-ZTBRR6. Biological parameters including microbial biomass carbon, soil respiration, microbial enzymes (Alkaline phosphatase, nitrate reductase and peroxidase), fluorescein diacetate hydrolysis, ergosterol, glomalin related soil proteins, microbial population (bacteria, fungi and actinobacteria) were found to be significantly (p< 0.05) effected by different nutrient management practices. Based on the PCA analysis, Fluorescein diacetate hydrolysis, microbial biomass carbon, soil respiration, nitrate reductase and fungi population were the important soil biological parameters indicating soil quality and productivity in present experiment. The results concluded that UPTR-ZTBRR6 was a more suitable practice for maintaining system productivity and soil biological health. Discussion: The understanding of the impact of different tillage and residue management practices on productivity, soil biological properties and soil quality index under rice-barley cropping system will help in determining the combination of best conservation agriculture practices for improved soil quality and sustainable production. [ABSTRACT FROM AUTHOR]

Pigeon pea hairy root cultures (PPHRCs) have been proven to be a promising alternative for the production of health-beneficial phenolic compounds, such as the most important health-promoting compound, i.e., cajaninstilbene acid (CSA). In this study, PPHRCs were cocultured with live Aspergillus fungi for further improving phenolic productivity via biological elicitation. Aspergillus oryzae CGMCC 3.951 (AO 3.951) was found to be the optimal fungus that could achieve the maximum increment of CSA (10.73-fold increase) in 42-day-old PPHRCs under the inoculum size of mycelia 0.50% and cocultivation time 36 h. More precisely, the contents of CSA in hairy roots and culture media after fungal elicitation increased by 9.87- and 62.18-fold over control, respectively. Meanwhile, the contents of flavonoid glycosides decreased, while aglycone yields increased upon AO 3.951 elicitation. Moreover, AO 3.951 could trigger the oxidative stress and pathogen defense response thus activating the expression of biosynthesis- and ABC transporter-related genes, which contributed to the intracellular accumulation and extracellular secretion of phenolic compounds (especially CSA) in PPHRCs. And PAL2, 4CL2, STS1, and I3′H were likely to be the potential key enzyme genes regulating the biosynthesis of CSA, and ABCB11X1-1, ABCB11, and ABCG24X2 were closely related to the transmembrane transport of CSA. Overall, the cocultivation approach could make PPHRCs more commercially attractive for the production of high-value phenolic compounds such as CSA and flavonoid aglycones in nutraceutical/medicinal fields. And the elucidation of crucial biosynthesis and transport genes was important for systematic metabolic engineering aimed at increasing CSA productivity. Key points: • Cocultivation of PPHRCs and live fungi was to enhance CSA production and secretion. • PPHRCs augmented CSA productivity 10.73-fold when cocultured with AO 3.951 mycelia. • Several biosynthesis and transport genes related to CSA production were clarified. [ABSTRACT FROM AUTHOR]

The water mass assembly of Nares Strait is variable, owing to fluctuating wind forcings over the central Arctic Basin, and irregular northward flows from the West Greenland Current (WGC) in Baffin Bay. Here we characterize the physico‐chemical properties of the water masses entering Nares Strait in August 2014. We employ an extended optimum multi‐parameter (OMP) analysis to estimate the mixing fractions of predefined source water masses, and to distinguish the role of physical and biological processes in governing the distribution of dissolved inorganic carbon (DIC) in Nares Strait. We show the first documented evidence of Siberian shelf waters arriving in Nares Strait, along with a diluted upper halocline layer of partial Pacific‐origin. These mixed‐origin water masses appear to play an important role in driving a modest phytoplankton bloom in Kane Basin, leading to decreased surface pCO2 concentrations in Nares Strait. Although inorganic nitrogen was already limited near the surface in northern Nares Strait, the rather shallow upper halocline layer and the shoaling bathymetry in Kane Basin facilitated upwelling of nutrients to the surface. Our observations suggest that the positioning of the Transpolar Drift, and hence the balance of Atlantic and Pacific water delivered to Nares Strait, may play an important role in regional biological productivity and carbon uptake from the atmosphere. We also observed water masses from the WGC transported as far north as Kane Basin, contributing to relatively high pCO2 and low pH in the intermediate and deep water column of southern Nares Strait and northern Baffin Bay. Plain Language Summary: Nares Strait is the northernmost outflow channel from the Arctic Ocean, located between Ellesmere Island and northern Greenland. The physical and chemical properties of the waters exiting the Arctic Ocean through Nares Strait play an important role in freshwater transport, carbon dynamics, and in supplying nutrients to marine ecosystems downstream, including delivery to the historically productive North Water polynya region, and eventually the North Atlantic. The water masses transported through Nares Strait are known to change depending on the predominant wind patterns over the Arctic Ocean. Here we document the export of surface waters that originated from the Siberian shelf seas, on the other side of the Arctic Ocean, carrying with them a strong river water signal. This study demonstrates that the carbon dynamics in Nares Strait are largely dictated by mixing of water masses from the north and south, with local biology playing an important role in facilitating atmospheric CO2 drawdown in Nares Strait and further downstream. Key Points: Siberian shelf waters are identifiable in Nares Strait, in the high Canadian Arctic ArchipelagoThe position of the Transpolar Drift determines surface water properties in Nares Strait, affecting regional productivity and CO2 uptakePrimary production is limited in Nares Strait due to nutrient‐limited surface waters, but plays an important role in lowering surface pCO2 [ABSTRACT FROM AUTHOR]

We extend the ecological component ('ECOGEM') of the carbon-centric Grid Enabled Integrated Earth system model ('cGEnIE') to include a diatom functional group. ECOGEM represents plankton community dynamics via a spectrum of ecophysiological traits originally based on size and plankton food web (phyto- and zooplankton; EcoGEnIE 1.0), which we developed here to account for a diatom functional group (EcoGEnIE 1.1). We tuned EcoGEnIE 1.1, exploring a range of ecophysiological parameter values specific to phytoplankton, including diatom growth and survival (18 parameters over 250 runs) to fit best the model behaviour akin to observations of diatom biogeography, size class distribution, and global ocean biogeochemistry. This, in conjunction with a previously developed representation in the water column of opal dissolution and an updated iron cycle, produced an improved distribution of dissolved oxygen in the water column relative to the previous EcoGEnIE 1.0 as well as a value for global export production (7.5 Pg C yr−1) closer to previous estimates. Simulated diatom biogeography is characterised by larger size classes dominating at high latitudes, notably in the Southern Ocean, and smaller size classes dominating at lower latitudes. Overall, diatom biological productivity accounts for ~ 20 % of global carbon biomass in the model, with diatoms out-competing other phytoplankton functional groups when dissolved silica is available due to their faster maximum photosynthetic rates and reduced palatability to grazers. Adding a diatom functional group provides the cGEnIE Earth system model with an extended capability to explore ecological dynamics and their influence on ocean biogeochemistry through the late Mesozoic and Cenozoic, as well as enabling a broader range of palaeoceanographic proxies to be interpreted. [ABSTRACT FROM AUTHOR]

Anthropogenic‐induced variations of the Atlantic Meridional Overturning Circulation (AMOC) and the associated Deep‐Water Formation (DWF) are a major concern. Using measurements of triple oxygen isotopes in the deep North Atlantic, we present novel evidence for a dramatic decadal to centennial shift in ocean conditions at the source region of DWF. These measurements suggest a recent decrease in the percentage of photosynthetic O2 derived from the source regions of AMOC in the Nordic Seas compared to the Little Ice Age. 1‐D model simulations suggest that a reduction in photosynthetic O2 production can explain the observed decrease. Alternatively, it may indicate a substantial decrease in sea‐ice cover and thus increased air‐sea gas exchange, bringing the isotopic composition of O2 closer to equilibrium with the atmosphere. Our novel data can serve as a benchmark for climate models. Plain Language Summary: In this study, we use the isotopic signature of dissolved oxygen gas in the deep North Atlantic Ocean to demonstrate a recent dramatic change in the Nordic Seas. Water in the deep Atlantic at present was at the surface of the Nordic Seas several hundred years ago, during the Little Ice Age (LIA). The isotopic signature shows that the percentage of oxygen sourced from photosynthesis was greater during the LIA. This may indicate a greater rate of photosynthesis than at present. However, we know that when sea ice covers the ocean surface, it prevents the influx of atmospheric oxygen, while sunlight penetration through the ice keeps a high rate of photosynthesis and production of biological oxygen. Therefore, it is also possible that during the LIA, sea‐ice cover was much more extensive than today. Key Points: Oxygen isotopic evidence for a recent dramatic shift in the North Atlantic source region of deep water‐massesThe isotopic measurements suggest high extent of ice cover and/or higher primary production rates during the Little Ice AgeThese new observations can serve as a benchmark for climate models [ABSTRACT FROM AUTHOR]

Climate changes on the Southwest coast of India have essential impacts on social and economic development, and the ecosystem of Southern India. Here, we present the last 2000 cal yr AD rare earth elemental records of the sediment core from the Cherai, Kerala coast, southwest India. The light rare earth elements (LREE) were the most abundant fraction in the core sediment, followed by medium rare earth elements (MREE) and heavy rare earth elements (HREE). Total REE (ΣREE) showed a significant correlation with fine fractions and Y, Al, Ti, Fe and total organic carbon content of the sediments, suggesting an intrinsic relationship between REE, total organic carbon and fine grain-size fraction. The LREE and MREE were enriched over the MREE due to their high adsorption with the fine fraction. The lack of correlation between terrigenous elements and low Y/Ho elemental ratio suggests a minor shift in the source materials. High ΣREE values during warm (Medieval Warm Period/ Medieval Climate Anomaly (MWP/MCA) and cold Little Ice Age (LIA) periods indicate a high influx of lithogenous materials during these intervals. The negative δCe values except MCA suggest a suboxic condition and the δEu values suggest feldspar-rich source rock material derived from moderately weathered sediments. It also indicates that the REE variations are controlled by factors like river supply, biological productivity and redox condition. A close link between monsoonal precipitation and REE records existed on the southwest coast of India. During the Dark Age Cold Period (DACP)/MWP transition, a sudden increase in monsoon is documented and the monsoon precipitation was further decreased during LIA and Current Warming Period. The Cherai core REE records synchronize with the episodes of centennial-scale warm/cool events and essentially follow the northern hemispheric climate cycles. [ABSTRACT FROM AUTHOR]

The carbon cycle is an important process that regulates Earth's evolution. We compare two typical periods, in the Paleoproterozoic and Neoproterozoic, in which many geological events occurred. It remains an open question when modern plate tectonics started on Earth and how it has influenced the carbon cycle through time. In the Paleoproterozoic, intense weathering in a highly CO2 and CH4 rich atmosphere caused more nutritional elements to be carried into the ocean. Terrestrial input boosted high biological productivity, deposition of sediments and the formation of an altered oceanic crust, which may have promoted an increase in the oxygen content. Sediment lubrication and a decrease in mantle potential temperature made cold and deep subduction possible, which carried more carbon into the deep mantle. Carbon can be stored in the mantle as diamond and carbonated mantle rocks, being released by arc and mid‐ocean ridge outgassing at widely different times. From the Paleoproterozoic through the Neoproterozoic to the Phanerozoic, the carbon cycle has promoted the evolution of a habitable Earth. [ABSTRACT FROM AUTHOR]

The causes of CO2 variations over the past million years remain poorly understood. Imbalances between the input of elements from rock weathering and their removal from the atmosphere‐ocean‐biosphere system to the lithosphere likely contributed to reconstructed changes. We employ the Bern3D model to investigate carbon‐climate responses to step‐changes in the weathering input of phosphorus, alkalinity, carbon, and carbon isotope ratio (δ13C) in simulations extending up to 600,000 years. CO2 and climate approach a new equilibrium within a few ten thousand years, whereas equilibrium is established after several hundred thousand years for δ13C. These timescales represent a challenge for the initialization of sediment‐enabled models and unintended drifts may be larger than forced signals in simulations of the last glacial–interglacial cycle. Changes in dissolved CO2 change isotopic fractionation during marine photosynthesis. This causes distinct spatio‐temporal perturbations in δ13C and affects the burial flux of 13C. We force a cost‐efficient emulator, based on the Bern3D results, with contrasting literature‐based weathering histories over the last 800 thousand years. Glacial–interglacial amplitudes of up to 30 ppm in CO2, 0.05‰ in δ13C, and ∼15 mmol m−3 in deep ocean CO32− ${\text{CO}}_{3}^{2-}$ are emulated for changes in carbonate rock weathering. Plausible input from the decomposition of organic matter on shelves causes variations of up to 10 ppm in CO2, 0.09‰ in δ13C, and 5 mmol m−3 in CO32− ${\text{CO}}_{3}^{2-}$, highlighting the non‐negligible effect of weathering‐burial imbalances. Plain Language Summary: Data from ice cores and marine sediments document large changes in atmospheric carbon dioxide (CO2) and climate during the past million years. Carbon isotopes and other proxies can help to understand underlying processes. In this study, we investigate Earth's response to plausible changes in the input of carbon and other elements from the weathering of rocks or the decomposition of previously accumulated organic matter with the help of a computer model. Results show significant variations in CO2, carbon isotopes, marine chemistry, marine biological productivity, and burial fluxes of biogenic particles to the lithosphere. The adjustment time to changes in input flux is several ten thousand years for CO2 and climate, and several hundred thousand years for carbon isotopes. As it is computationally challenging to simulate such long time periods with complex models, we used our results to build an emulator. Such emulators, representing the responses of spatially resolved and process‐based models, are useful for studies addressing Earth's history over many millions of years. Simulating a million years with the emulator takes seconds, whereas it takes about 4 months with the complex model. In conclusion, our work highlights the role of weathering fluxes and their possible contribution to past climate‐carbon cycle swings. Key Points: Earth system's response to weathering changes is probed in 600,000 year‐long simulations with the Bern3D model and a cost‐efficient emulatorEquilibration timescales are on the order 10,000 years for CO2 and 100,000 years for δ13C, requiring careful model initializationLiterature‐based weathering scenarios for the past 800,000 years reveal significant responses in CO2, carbonate ion, and δ13C [ABSTRACT FROM AUTHOR]

[Display omitted] • Fertilization of mushroom substrate with anaerobic digestate was evaluated. • A high concentration of anaerobic digestate impeded mushroom growth. • Productivity was similar to that on standard mushroom substrate. • Protein content in fruiting bodies was similar to that on standard substrate. • Ammonia volatilization from the digestate during substrate preparation was low. Anaerobic digestion of organic waste results in production of biogas and a nutrient-rich digestate that has an established use as fertilizer in plant production. This study evaluated use of anaerobic digestate based on a high concentration of organic household waste as a fertilizer in sawdust-based production of oyster mushrooms (Pleurotus ostreatus). Inclusion of 0.5 L of anaerobic digestate (AD) per kg sawdust gave similar productivity in terms of biological efficiency (79.5 ± 5.4 %), and protein concentration (24.7 ± 2.4 % of dry weight (dw)) as standard mushroom substrate (78.1 ± 5.3 %, and 21.9 ± 3.0 % of dw, respectively). However, mushroom growth was impaired at the highest concentration of anaerobic digestate tested, 1 L digestate per kg dw sawdust. Comparison of the AD-fertilized substrate with a mushroom substrate with standard components (sawdust, wheat bran, calcium sulfate) and with similar C/ N -ratio revealed some differences in elemental composition of the fruiting bodies, with an major increase in sodium concentration for the AD-fertilized substrate compared with the standard substrate (413.3 ± 28.9 and 226.7 ± 30.6 mg kg−1 dw, respectively). This difference can be explained by high sodium concentration in the anaerobic digestate, most likely due to inclusion of food scraps from households and restaurants in the biodigester feedstock. Screening of both substrates for a total of 133 micropollutants revealed that total sum of micropollutants was significantly higher in the AD-fertilized substrate (258 ± 12 ng/g dw substrate) than in the standard substrate (191 ± 35 ng/g dw substrate). Nitrogen losses during preparation of the AD-fertilized substrate were negligible. [ABSTRACT FROM AUTHOR]

Pelagic clay that contains rare‐earth elements and yttrium (REY) at over 2000 ppm (termed "highly REY‐rich mud") has been reported from a few areas in the western North Pacific Ocean through focused geochemical analyses. Those REY are carried by biogenic calcium phosphate, suggesting that the formation of highly REY‐rich mud involves enhanced biological productivity. However, detecting REY enrichment in sediment is time‐consuming, and the global significance of the formation of REY‐rich mud is still under debate. Here we perform x‐ray computed tomography (CT) analyses on cores recovered around Minamitorishima Island and demonstrate the positive correlation with highly REY‐rich mud and high CT numbers of the sediment. The variation of the CT number matches the wet bulk density. Further quantitative analyses using direct measurements of density and geochemistry suggest that a grain density increase and a porosity decrease due to the REY‐carrying biogenic apatite are essential to explain the high CT numbers in the REY‐enriched layer. While the chemical composition itself is of minor importance to elevate the CT numbers, our results suggest that x‐ray CT can be a proxy for highly REY‐rich mud. [ABSTRACT FROM AUTHOR]

Geological processes influence water chemistry and biological productivity along the Suwannee River and divide the mainstem of the river into 6 distinct ecological reaches (ERs) in Florida. Because of these distinctions, we hypothesized that the Macrochelys suwanniensis (Suwannee Alligator Snapping Turtle) population varies among ERs. During 2011–2013, we sampled two 5-km sites in each ER to investigate spatial variation in relative abundance, sex ratio, size-class distribution, and body size of M. suwanniensis. Capture rates and male body sizes were greater in the middle ERs than in the upstream and downstream ERs. Sex ratios were male-skewed only in the middle ERs. Additional research is needed to understand the ecological drivers of M. suwanniensis population dynamics in this river. [ABSTRACT FROM AUTHOR]

The western North Pacific and its marginal seas are known for having the highest biological productivity in the world's oceans. Although vertical turbulent mixing is considered important in transporting nutrients to maintain primary production, no research into vertical turbulent nutrient flux based on microstructure measurements has been conducted in this area. Observational and numerical studies over the continental slope in the southeastern Bering Sea indicate the relevance of vertical nitrate and iron flux induced by tidal mixing for maintaining high summer primary production. This research also suggests that the abrupt topography in the path of the Kuroshio and Tsugaru Warm Current act as a hotspot for vertical turbulent nitrate transport from the lower layer. Finally, this article discusses the future direction of nutrient flux observations. [ABSTRACT FROM AUTHOR]

Upwelling brings deep, cold, and nutrient-rich water to the euphotic zone, enhancing biological primary productivity. Coastal upwelling is affected by various factors, such as winds, topography, and tides. However, it remains unclear how the upwelling is affected by surface waves, particularly the Stokes drift and its related forces, that is, conservative wave effects. Here using a coupled wave–circulation model, we examined how conservative wave effects impact the wind-driven coastal upwelling system over an idealized continental shelf. We showed that conservative wave effects reduce upwelling but enhance downwelling; consequently, the amount of deep cold water brought up to the surface by upwelling is reduced with waves, leading to a weaker upwelling front than that without waves. Conservative wave effects also change the potential vorticity (PV) fluxes across the sea surface/bottom and alter the thickness of surface/bottom negative-PV layers. In addition, conservative wave effects modify the turbulent thermal wind (TTW) associated with the upwelling front, forming a Stokes–TTW balance. Further, we studied sensitivities of the upwelling and downwelling magnitudes to four parameters: wave height, wind stress, shelf slope, and wave incident angle. We combined these parameters into a single nondimensional number that can indicate when conservative wave effects need to be included in the upwelling and downwelling. Significance Statement: Upwelling is important to the marine ecosystem because it enhances biological primary productivity by bringing nutrient-rich water to the euphotic zone from depths. However, it remains unclear how the upwelling is affected by ubiquitous surface waves. Here using numerical simulations, we showed that Stokes drift and its related forces due to surface waves reduce upwelling but enhance downwelling. It implies that there could be a substantial bias in the estimation of upwelling and downwelling if surface waves are not considered. Further, we proposed a nondimensional number to indicate when surface waves need to be considered in the upwelling and downwelling. [ABSTRACT FROM AUTHOR]

Cowpea bean [Vigna unguiculata (L.) Walp.] is an important grain legume with agronomic and productive potential under edaphoclimatic conditions in Cuba, but little known and studied in agroecosystems of Pinar del Río. In “San Juan y Martínez” municipality, four cowpea cultivars were established ('INIFAT 93', 'INIFAT 94', 'IPA 206' and 'TITÁN') with the aim of evaluating their growth and yield. The sowing was carried out in spring (04/02/2019), at a frame of 0.60 x 0.15-0.20 m, in a leached Yellowish Ferrallitic soil dedicated to the cultivation of tobacco (Nicotiana tabacum L.). A randomized block experimental design with four treatments (cultivars) and four replicates was used. Higher biological productivity and agricultural yield were obtained in the cultivars 'TITÁN' and 'INIFAT 94', which exceeded more than 32 % the production of 'INIFAT 93', although this reached a harvest index higher than 50 % and all expressed indices of vain pods less than 30 %. The increase in the number of pods with shorter length and greater mass of grains per pod enhanced crop yield. The results suggest the use of 'INIFAT 94' and 'TITÁN' in the production of grains in tobacco agroecosystems of Pinar del Río, but different spatial and temporal arrangements must be studied, the contribution of biomass to the soil, the incidence of pests, among other aspects with influence on the productivity and sustainability of the crop. [ABSTRACT FROM AUTHOR]

Hereby, we report the new experimental data of plant biomass and biological productivity (net primary production, NPP) of wetland/peatland plant communities of oligotrophic bogs located on the same latitude, but at a distance of 1300 km west-east in the forest–steppe region of Western Siberia. The data were collected by implementing direct in situ measurements based on a unique methodology developed by authors. The study revealed that the values of net primary production (NPP) are basically constrained by the live fraction of plant biomass (or phytomass). It also revealed that the dead fraction of plant biomass (mortmass), along with the live fraction of biomass (phytomass) and net primary production (NPP), all major components of the carbon cycle, differ significantly at the two study sites. The values of dead biomass (mortmass), live biomass (phytomass) and net primary production (NPP) were found at significantly higher values in bog ecosystems studied in western regions than in those of the eastern regions.

The distribution of species among spatially isolated habitat patches supports regional biodiversity and stability, so understanding the underlying processes and structure is a key target of conservation. Although multivariate statistics can infer the connectivity processes driving species distribution, such as dispersal and habitat suitability, they rarely explore the structure. Methods from graph theory, applied to distribution data, give insights into both connectivity pathways and processes by intuitively formatting the data as a network of habitat patches. We apply these methods to empirical data from the hydrothermal vent habitats of the Northwest Pacific. Hydrothermal vents are "oases" of biological productivity and endemicity on the seafloor that are imminently threatened by anthropogenic disturbances with unknown consequences to biodiversity. Here, we describe the structure of species assemblage networks at hydrothermal vents, how local and regional parameters affect their structure, and the implications for conservation. Two complementary networks were formed from an extensive species assemblage dataset: a similarity network of vent site nodes linked by weighted edges based on their pairwise assemblage similarity and a bipartite network of species nodes linked to vent site nodes at which they are present. Using these networks, we assessed the role of individual vent sites in maintaining network connectivity and identified biogeographic sub‐regions. The three sub‐regions and two outlying sites are separated by their spatial arrangement and local environmental filters. Both networks detected vent sites that play a disproportionately important role in regional pathways, while the bipartite network also identified key vent sites maintaining the distinct species assemblages of their sub‐regions. These regional connectivity pathways provide insights into historical colonization routes, while sub‐regional connectivity pathways are of value when selecting sites for conservation and/or estimating the multivent impacts from proposed deep‐sea mining. [ABSTRACT FROM AUTHOR]

Frazil ice in the coastal polynyas has been increasingly recognized as important for efficient sea ice production, associated dense water formation, transport of particulate matter and consequent biological production. However, it has not been well understood where and to what degree active‐frazil areas occur in the Northern Hemisphere polynyas. We presented the first mapping of active frazil in the Northern Hemisphere, using sea ice data during September–May for 2002/2003–2010/2011, created from an Advanced Microwave Scanning Radiometer for the Earth Observing System thin ice algorithm that can detect active frazil areas. The North Water, Northeast Water, Anadyr, and St. Lawrence Island polynyas were found to have a relatively high occurrence rate of active frazil compared with other polynyas. We improved the estimation of sea ice production by discriminating between active frazil and thin solid ice and found that previous algorithms tended to overestimate sea ice production, particularly for polynyas dominated by thin solid ice such as the Okhotsk Northwestern polynya. We also made the first global comparison of polynya characteristics for all the major coastal polynyas. The annual ice production rate is 3–4 m yr−1 in the Northern Hemisphere polynyas and 6–9 m yr−1 in the Antarctic coastal polynyas. This large difference is mainly explained by the less frequent occurrence of active frazil and thin ice areas in the Northern Hemisphere polynyas owing to a lower occurrence of strong wind events. Plain Language Summary: Coastal polynyas, which are high‐latitude coastal regions of thin ice or open water surrounded by thick sea ice, are important components of the global climate system. High production of sea ice in coastal polynyas generates dense water, which then influences physical and biological processes in the surrounding regions. Thin ice areas in a polynya are roughly classified into two ice types: active frazil, a mixture of grease/frazil ice and open water formed under turbulent conditions, and thin solid ice, a relatively uniform thin ice region formed under calm conditions. In this study, we focused on measuring the active frazil, which indicates areas of efficient ice production. Frazil ice also incorporates and transports sediments or micro‐nutrients, possibly leading high biological productivity. We presented the first mapping of active‐frazil areas in the Northern Hemisphere, and improved estimates of total ice production taking account of the ice type. We also discussed the characteristics of major coastal polynyas in the world. The rates of ice production and active frazil occurrence are generally lower in the Northern Hemisphere than in the Antarctic coastal polynyas because of lower wind speeds in the Northern Hemisphere high‐latitude coastal regions. Key Points: The active frazil area in the Northern Hemisphere is mapped for the first time, with improved estimation of sea ice productionSeveral coastal polynyas with a high occurrence rate of active frazil and high ice production rate are extractedThe ice production rate in Northern Hemisphere polynyas is generally lower than in Antarctic polynyas owing to fewer strong wind events [ABSTRACT FROM AUTHOR]

Recycling waste, such as rice straw and water treatment residuals, is important to reduce harmful effects on the environment and to improve canola yield and soil quality in degraded soils. Nanotechnology for the production of nanomaterials from biochar and water treatment residues will be a future revolution for improving soil quality and increasing canola yield in degraded soil. Therefore, this study aims to identify the properties of some recycled nanomaterials, such as nanobiochar (nB) and nanowater treatment residue (nWTR), and their effect on the biological activity and productivity of canola in degraded soils. The results showed that the nWTR and nB contain many functional groups and minerals, and they also have high negative zeta potential. The addition of the studied soil amendments significantly improved microbial biomass carbon (MBC) and biological activity, which played a major role in increasing canola yield. The highest dehydrogenase (DHA) and catalase (CLA) activity was found in nWTR-treated soil at 50 mg kg−1, with increases of 32.8% and 566.7% compared to the control, respectively. The addition of nB greatly improved the growth of canola plants in the soil. This was evident from the increase in the weight of seeds, the weight of 1000 grains, the number of pods per plant, and the highest increase was for nB added at the rate of 250 mg per kg−1 soil. The addition of 50 mg kg−1 of nWTR gave the best results in seed yield by 150.64% compared to the control. These results indicate that recycled nWTR and nB are some of the best waste recycling treatments, in addition to good soil health, in increasing soil biology and canola yield in degraded soils. In the future, research on recycled nanomaterials should examine the residual effect they have on yield, soil quality, and soil fauna in the long term. [ABSTRACT FROM AUTHOR]

Phosphorus is an essential macronutrient that plays a crucial role in the regulation of the biological productivity and biogeochemical cycling of other biogenic elements. As a large tidal wetland dominated by reeds in Liaoning province, China, the Shuangtai estuary wetland is a unique ecosystem class. To better understand the spatial and temporal distributions of total phosphorus (TP) in the sediments of the Shuangtai estuary wetland during the period of reed growth, eight sampling sites were established within the wetland, approximately 11 to 24 km from Liaohe River. These sites were sampled once a month at multiple sediment depth intervals between April and October in 2018 and 2019, periods of time that corresponded with the reed growth period. An alkali fusion method was used to determine TP in the sediment samples. The results show that sediment TP content of wetland sediments ranged from 0.001 to 0.781 mg/kg, and decreases from southwest to northeast with the increase in sediment depth. The TP content reaches the maximum corresponding to the fastest growth stage of the reeds (June and July), while the minimum occurs in October (i.e., the maturity stage of reeds). The variation law of TP in cross-sectional sediment in the wetland is that the deeper the sediments are, the lower the content; its maximum content occurs in surface soil. The TP content of each site tends to be stable with increasing depth and has a regularly dynamic seasonal variation with the growth of reeds. [ABSTRACT FROM AUTHOR]

Nitrogen (N) plays a central role in marine biogeochemistry by limiting biological productivity in the surface ocean, influencing the cycles of other nutrients, carbon, and oxygen, and controlling oceanic emissions of nitrous oxide (N2O) to atmosphere. Multiple chemical forms of N are linked together in a dynamic N cycle that is especially active in oxygen minimum zones (OMZs), where high organic matter remineralization and low oxygen concentrations fuel aerobic and anaerobic transformations. Biogeochemical models used to understand the oceanic N cycle and project its change often employ simple parameterizations of the network of N transformations and omit key intermediary tracers such as nitrite (NO-2) and N2O. Here present a new model of the oceanic N cycle (Nitrogen cycling in Oxygen Minimum Zones, or NitrOMZ) that resolves transformation occurring within OMZs, and their sensitivity to environmental drivers. The model is designed to be easily coupled to current ocean biogeochemical models by representing the major forms of N as prognostic tracers, and parameterizing their transformations as a function of seawater chemistry and organic matter remineralization, with minimal interference with other elemental cycles. We describe the model rationale, formulation, and numerical implementation in a one-dimensional representation of the water column that reproduces typical OMZ conditions. We further detail the optimization of uncertain model parameters against observations from the Eastern Tropical South Pacific OMZ, and evaluate the model ability to repro15 duce observed profiles of N tracers and transformation rates in this region. We conclude by describing the model sensitivity parameter choices and environmental factors, and discussing the model suitability for ocean biogeochemical studies. [ABSTRACT FROM AUTHOR]

Lakes are key ecosystems within the global biogeosphere. However, the environmental controls on the biological productivity of lakes – including surface temperature, ice phenology, nutrient loads, and mixing regime – are increasingly altered by climate warming and land-use changes. To better characterize global trends in lake productivity, we assembled a dataset on chlorophyll- a concentrations as well as associated water quality parameters and surface solar radiation for temperate and cold-temperate lakes experiencing seasonal ice cover. We developed a method to identify periods of rapid net increase of in situ chlorophyll- a concentrations from time series data and applied it to data collected between 1964 and 2019 across 343 lakes located north of 40 ∘. The data show that the spring chlorophyll- a increase periods have been occurring earlier in the year, potentially extending the growing season and increasing the annual productivity of northern lakes. The dataset on chlorophyll- a increase rates and timing can be used to analyze trends and patterns in lake productivity across the northern hemisphere or at smaller, regional scales. We illustrate some trends extracted from the dataset and encourage other researchers to use the open dataset for their own research questions. The PCI dataset and additional data files can be openly accessed at the Federated Research Data Repository at 10.20383/102.0488 (Adams et al., 2021). [ABSTRACT FROM AUTHOR]

Anthropogenic pressures have been increasing on shark and ray populations globally, and their conservation and management can be compromised by lack of information on their diversity and status of species. This study presents a desktop review of the sharks and rays of the Republic of Palau, drawing on citizen science, fisheries data and other scientific literature to document their diversity, economic and cultural values, and pressures affecting their populations. This account of Palau's sharks and rays includes a preliminary assessment of risks based-on existing risk assessments, and their biological productivity. Records were found documenting 56 sharks and rays in Palau: 31 species are considered here as 'confirmed and verified', 10 species as 'requires verification', and 11 species listed as 'plausible'. An additional two species are listed as 'unlikely', and two species is 'unknown' due to the taxonomy being unclear. The biological productivity analysis showed that the basking shark (Cetorhinus maximus) had the lowest productivity of Palau's sharks and rays, while the blue shark (Prionace glauca) showed the highest productivity of species examined. Historically, fishing mortality presented the most significant threat to Palau's sharks and rays, but recent conservation initiatives have the potential to significantly reduce this threat as large areas are closed to fishing following the full implementation of the Palau National Marine Sanctuary in 2020. Palau's sharks have a wide range of social and cultural values and are important to tourism. This study presents a new synthesis and overview of available information including citizen science, but also highlights the need for further local taxonomic work and research. Sharks and rays are important parts of marine ecosystems in the Pacific, and are significant to livelihoods and communities. However, relatively little is known about shark and ray diversity, status and values in the Pacific. This paper presents a species checklist and overview of the sharks and rays of Palau. [ABSTRACT FROM AUTHOR]

The alpine-subalpine Loch Vale watershed (LVW) of Colorado, USA, has relatively high natural lithogenic P5+ fluxes to surface waters. For 1992-2018, the largest number of stream samples with P5+ concentrations ([P5+]) above detection limits occurred in 2008, corresponding with the highest frost-cracking intensity (FCI). Therefore, relatively cold winters and warm summers with a comparatively low mean annual temperature partly influence stream [P5+]. Sediment cores were collected from The Loch, an outlet lake of the LVW. Iron-, Al-, and Mnoxide-bound phosphorus (adsorbed and authigenic phosphates; NP) serves as a proxy measurement for paleolake [P5+]. The highest NP in the core occurred during the cold and dry Allerød interstade. The lowest NP concentrations in the core occurred during climatically very wet periods in the Late Pleistocene and Early Holocene. Therefore, [P5+] are highest with relatively cold winters followed by relatively warm summers, relatively low mean annual temperatures, and relatively little rainfall and/or cryospheric melting. Currently the LVW is experiencing warming and melting of the permanent cryosphere with a rapidly declining FCI since 2008. This has the potential to dramatically decrease [P5+] in surface water ecosystems of the LVW, reducing biological productivity, enhancing P-limitation, and increasing ecosystem reliance on aeolian P5+. [ABSTRACT FROM AUTHOR]

Modern anoxic marine sediments release phosphorus (P) to seawater, driving feedbacks at multiple timescales. On sub‐Myr timescales, anoxic P regeneration amplifies ocean deoxygenation; on multi‐Myr timescales, it stabilizes atmospheric O2. Some authors have extended this thinking to the Precambrian: by analogy, widespread ocean anoxia would imply extensive P regeneration from sediments. However, this neglects the role of sulfate in P regeneration. While abundant in seawater today, sulfate was scarce in the Precambrian. Here a simple model is used to isolate the role of sulfate in anoxic P cycling. The model reproduces known feedbacks driven by anoxic P regeneration in a high‐sulfate world, but shows muted P regeneration in low‐sulfate, anoxic sediments. The transition between "limited" and "enhanced" P regeneration is thus controlled by sulfate. As a result, sulfate is a double‐edged sword wielded by the anoxic P cycle: it can amplify oxygenation or deoxygenation depending on environmental context. Plain Language Summary: Phosphorus is a critical nutrient and its availability controls the rate of biological productivity in the ocean. Constraining phosphorus availability in seawater through time is thus of great interest to paleoceanographers. A key observation in recent years has been that ancient marine sediments from the Precambrian Era (prior to 541 million years ago) contain less phosphorus than younger sediments. Researchers disagree as to why this is, with proposed ideas falling into two main camps. One camp maintains that phosphorus burial was efficient in the Precambrian, meaning that phosphorus was quickly removed from seawater, creating a small ocean inventory and keeping sedimentary phosphorus levels low. Another camp suggests that Precambrian phosphorus burial was inefficient, causing sediments to have low phosphorus content, instead allowing phosphorus to accumulate to high levels in seawater. Here a simple model is used to reconcile these contrasting hypotheses. The model examines the effect of sulfate on phosphorus burial efficiency in anoxic sediments, finding that lower sulfate levels imply higher burial efficiency, and vice‐versa. The contrasting hypotheses for Precambrian phosphorus burial can thus both potentially be accurate, and this exercise highlights the importance of constraining marine sulfate levels to know more about the ancient phosphorus cycle. Key Points: Sulfur cycling drives phosphorus (P) release from modern anoxic sediments to overlying seawaterIn a high‐sulfate, high‐O2 world, P regeneration stabilizes atmospheric O2 on long timescales, but amplifies transient ocean anoxic eventsIn a low‐sulfate, low‐O2 world, P regeneration amplifies transient atmosphere oxygenation events [ABSTRACT FROM AUTHOR]

After evaluating the ecological and economic aspects, it is predicted that the use of urease inhibitors and biological preparations should reduce the risk of nutrient leaching by using fertilizers containing amide, ammonium, and nitrate forms of nitrogen and would increase nitrogen use efficiency. Moreover, with lower nitrogen fertilizer rates, it would be possible to achieve or even increase planned maize biomass yield. The field experiment was performed in 2019–2021 at the Experimental Station of Vytautas Magnus University Agriculture Academy. The soil of the experimental field was Endohipogleyic-Eutric Planasol. The aim of this study was to investigate the effect of urease inhibitors and biological preparations in combination with nitrogen fertilizers on the productivity of aboveground maize (Zea mays L.) biomass. A two-factor experiment was carried out: factor A included nitrogen fertilizer rates of (1) 100 kg N ha−1, (2) 140 kg N ha−1, and (3) 180 kg N ha−1; and factor B included the use of preparations of (1) no use of urease inhibitors (UIs) and biological preparations (BPs) (control), (2) the urease inhibitor ammonium thiosulphate (UI ATS), (3) the urease inhibitor (UI URN)—N-Butyl-thiophosphorus triamide (NBPT), (4) the biological preparation of suspension of humic and fulvic acids (BP HUM); and (5) the biological preparation (BP FIT) of suspension of Ascophyllum nodosum The studies showed that the dry matter yield of maize was significantly increased not only by increasing nitrogen fertilizer rates but also by the use of UIs and BPs. The highest dry matter yield of maize (24.1 t ha−1) was obtained with N180 fertilizer and UI ATS. UI ATS significantly increased the dry matter yield of the aboveground maize in all nitrogen fertilization backgrounds. The UIs and BPs tested had a greater and significant (p < 0.05) effect on the dry matter yield of maize at lower rates of N100 and N140 nitrogen fertilizer. Increasing nitrogen fertilizer rates up to N180 had a positive significant effect on dry matter yields of the aboveground part of maize, its cobs, leaves, and stems. Positive, moderate, strong, and very strong correlations were found in most cases between the latter variables. These correlations were statistically significant (r2 = 0.62–0.98). The UIs and BPs increased the efficiency of nitrogen fertilizer; therefore, the lower rates of nitrogen fertilizer (N100 and N140) could be used to produce maize productivity the same as that obtained with a high rate of nitrogen fertilizer (N180). [ABSTRACT FROM AUTHOR]

Exploited abalone (genus Haliotis) populations are prone to serial depletion and stock collapse. Spatial management units (MUs) aim to separate monitoring and management of meta‐populations with varying productivity. In the South Australian Southern Zone blacklip abalone (Haliotis rubra rubra, Leach) fishery, spatial terms at scales of kilometres (reporting areas, RAs) and tens of kilometres (MUs) explained a greater proportion of variability in daily catches than effort in linear mixed models. Temporal patterns in spatial structures of catches among RAs were consistent with those among MUs based on similar productivity. Results of this study support the hypothesis that changes in the spatial distribution of catches differs among management regimes based on minimum legal lengths (MLLs) and annual total allowable commercial catches (TACCs). Stable distribution of catches during 1992–2012 occurred contemporaneously with zonal TACCs combined with catch caps (sub‐TACCs) and MLLs applied to areas of low productivity providing a reference for future management. The number of MUs fished annually by each licence increased during this period. Results of this study suggest that successful spatial management of abalone fisheries requires MUs at scales based on biological productivity combined with MLLs and mandatory, conservative catch caps applied to each MU. [ABSTRACT FROM AUTHOR]

Closure of the Central American Seaway (CAS) and hydrology of the Caribbean Sea triggered Northern Hemisphere Glaciation and played an important role in the Pliocene to modern‐day climate re‐establishing the deep and surface ocean currents. New data on Mn/Ca obtained with femtosecond laser ablation inductively coupled plasma mass spectrometry on well‐preserved tests of the epibenthic foraminifer Cibicidoides wuellerstorfi and infaunal C. mundulus contribute to the interpretation of paleoenvironmental conditions of the Caribbean Sea between 5.2 and 2.2 Ma (million years) across the closure of the CAS. Hydrothermal activity at the Lesser Antilles may be a primary source of Mn in the well‐oxygenated Plio‐Pleistocene Caribbean Sea. Incorporation of Mn in the benthic foraminifer shell carbonate is assumed to be affected by surface ocean nutrient cycling, and may hence be an indicator of paleoproductivity. Plain Language Summary: The closure of the Panama Isthmus caused the expansion of ice sheets in the Northern Hemisphere and changed the water current dynamics and climate in the Caribbean Sea since the Pliocene (∼5.3 million years ago). New Mn/Ca data measured using femtosecond laser ablation inductively coupled plasma mass spectrometry on the deep‐sea benthic foraminifer species Cibicidoides wuellerstorfi and Cibicidoides mundulus help us understand past environmental conditions of the Caribbean Sea prevailed between 5.2 and 2.2 million years ago. While manganese might be sourced from the surrounding hydrothermal vents, its incorporation in the foraminifer shell carbonate might be related to nutrient cycling and may indicate past biological productivity in the ocean. Key Points: Femtosecond‐laser ablation inductively coupled plasma mass spectrometry provides a new approach on distinguishing Mn of the ontogenetic shell calcite from Mn of the authigenic coatingsOntogenetic Mn within the foraminifer shell calcite may result from the regional nutrient cycleMn in the deep eastern Caribbean Sea may mainly derive from hydrothermal sources along the Antilles Island Arc [ABSTRACT FROM AUTHOR]

Coastal marine settings are important in terms of geochemical cycles and biological productivity. Climate change is predicted to affect coastal environment via hypoxia and Submarine Groundwater Discharge (SGD). Appropriate proxies could help to better understand oxygenation history and the role of SGD in regulating hypoxia. This would also benefit prediction of potential outcomes of future environmental changes. The sensitivity of benthic foraminiferal shell chemistry to environmental conditions opens the possibility to use them as proxies of coastal hypoxia and SGD. We report here that the average Mn/Ca ratios in tests of living benthic foraminiferal shells in the Changjiang River Estuary (CJE) is 2.3 times higher during hypoxia periods than under well-mixed conditions. In addition, Ba/Ca ratios in living benthic foraminiferal shells co-varied well with radon-inferred SGD signals. Fluctuations of Mn/Ca and Ba/Ca ratios in tests of a single foraminiferal shell along successive chambers corresponds well with seasonal-scale variations of hypoxia and SGD. We suggest that Mn/Ca and Ba/Ca ratios within intra-tests of benthic foraminifer can provide a reliable proxy for past hypoxia and SGD trends. • This work investigated proxies to record hypoxia and SGD on shells of same foraminiferal chambers. • Synchronous tendency of Mn/Ca and Ba/Ca ratios in tests of a single foraminiferal shell along successive chambers reflects seasonal-scale variations of hypoxia and SGD. • This work will provide a novel proxy for reconstructing the contribution of SGD to hypoxia over a long-term history. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a potent neurotoxin that enters the food web and may contaminate commercial, recreational, subsistence, and ceremonial fish stocks. Understanding the pathways by which this contamination occurs in marine systems is thus an essential component of minimizing consumer health risk. Our knowledge of the biogeochemical cycling of mercury, however, is relatively limited. Temporal changes in sinking particulate mercury (PHg) fluxes throughout the upper 400 m were examined at Station ALOHA (22°N, 158°W) in the North Pacific Subtropical Gyre (NPSG) and spatially along a north-south transect to the Equator (17.5°N to 5°N x 155°W) using a combination of in situ pumps and Uranium-238/Thorium-234 disequilibria as a tracer of particle export. Our results indicate that Station ALOHA is characterized by seasonally variable export fluxes of PHg, with highest fluxes occurring in May (175 m, 346 pmol m−2 day−1), with the advent of summer zooplankton growth, and in September (400 m, 356 pmol m−2 day−1), coinciding with a diazotroph mediated summer export pulse. PHg fluxes in May and September were higher than those previously measured in the equatorial Pacific at 150 m and continued to be high (> 100 pmol Hg m−2 d−1) down to 400 m, thereby providing a significant source of Hg to the mesopelagic food web. In contrast to Station ALOHA, at 8 and 5°N, PHg fluxes attenuated rapidly with depth, and fluxes were generally lower, with a maximum flux of 86 pmol m−2 d−1 (5°N). Depth profiles at 8 and 5°N were significantly different from one another, with PHg fluxes higher throughout the water column at 5°N and characterized by a subsurface peak in Hg flux 3 times higher than at 8°N (86 vs. 29 pmol Hg m−2 d−1). Monomethylmercury (MeHg) fluxes (max = 1.09 ± 0.57 pmol m−2 d−1) and concentrations (max = 0.14 fmol L−1) comprised only a small percentage of the total PHg pool. These results suggest that PHg cycling significantly differed between the NPSG and near the equator at least during an El Niño year. At Station ALOHA, microbial reworking of small particles below the deep chlorophyll maximum coupled with changes in zooplankton grazing drive seasonal export variability. In contrast near the equator, low fluxes associated with low biological productivity result in significantly lower PHg transport to depth during an El Niño year. • Summer and spring particulate mercury (PHg) fluxes are higher than those in winter at Station ALOHA. • Seasonal changes in zooplankton grazing and diazotroph mediated summer export pulse influence PHg fluxes at Station ALOHA. • Low particulate mercury (PHg) fluxes in the equatorial Pacific are associated with El Nino. • At Station ALOHA, microbial reworking of small particles below the deep chlorophyll maximum enhances PHg accumulation. [ABSTRACT FROM AUTHOR]

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. • Pisco Basin phosphorites concentrate at stratigraphic unconformities. • Phosphogenesis occurred just below the sediment-water interface during early transgression. • Sedimentary condensation by dynamic bypassing determined the formation of phosphorite beds. • Rare Earth Element patterns in phosphorite indicate early diagenesis and suboxic conditions. [ABSTRACT FROM AUTHOR]

Multispecies uneven-aged forests have received increasing scientific attention due to the assumption that tree biological and structural diversity enhance biomass production. However, assessments have yielded inconsistent results. The objective of this study was therefore to evaluate this assumption using a dataset of 394 permanent plots (2500 m2) located in temperate multispecies forests in Durango, Mexico. We assessed the effects of tree biological (based on species richness and evenness) and structural (based on stem density and size heterogeneity) diversity on biomass production (ton · ha−1· yr−1) through a generalized additive model. The developed model explained 46 percent of the total variance of biomass production, and the effects of tree biological and structural diversity were statistically significant. The effect of tree biological diversity on productivity showed that multispecies stands dominated by a few species exhibited higher productivity than stands with evenly distributed species. On the other hand, tree size heterogeneity improved the influence of stem density on woody biomass production. In conclusion, tree biological and structural diversity play an essential role in developing strategies for temperate multispecies stand management, where dominant trees have a major effect on biomass production. • Evenness influences the richness-productivity relationship. • Tree-size heterogeneity improves biomass production. • Biomass production is higher in stands dominated by a few tree species. [ABSTRACT FROM AUTHOR]

• Coccolith PIC export, coccolith δ13C, and foraminifer Cd/Ca are analyzed at two cores in the tropical western pacific. • Enhanced coccolith PIC export correlates with low phosphate concentration in the precessional band over the past 250 kyr. • Low phosphate concentration or high degree of phosphorus utilization is coupled with enhanced nitrogen fixation. • The precession-driven hydrological changes control the biogeochemical and nutrient cycling. Unravelling the biogenic material export production and its relationship to surface ocean nutrient conditions, along with their external forcing, will provide insights into the ocean carbon biogeochemical cycle. In this study, we present data on coccolith particulate inorganic carbon (PIC) export production, coccolith carbon isotopic vital effects, and planktonic foraminifer cadmium to calcium ratio in the tropical western Pacific over the past 250 kiloyears (kyr). These proxies indicate the strength of the coccolith-based carbonate counter pump or coccolithophore productivity, and phosphate concentration in the surface ocean. Our results show that low phosphate concentration correlates with enhanced coccolith-based carbonate counter pump in the precessional band (a cyclicity of 19–23 kyr). Additionally, low phosphate concentration, which indicates high degree of phosphorus utilization, is coupled with enhanced nitrogen fixation, as shown by a nitrogen isotope record in the tropical western Pacific. Greater precipitation in Papua New Guinea (PNG) can occur during local insolation maxima, suggesting a dominant control of precession. This will in turn drive the biogeochemical and nutrient cycling in the tropical western Pacific. We propose that higher amounts of the PNG riverine input caused by greater precipitation can provide additional nutrients and trace element iron (Fe) for phytoplankton. An increased bioavailable Fe in the surface ocean can promote the growth of nitrogen-fixing diazotrophs, which results in a high degree of phosphorus utilization and relieves a potential nitrogen limitation. This may ultimately lead to increased biological productivity, e.g., the coccolith PIC. [ABSTRACT FROM AUTHOR]

Background. Symphytum officinale L. is a valuable forage and medicinal plant. The roots and leaves of the species are used in folk medicine as an antimicrobial and antiinflammatory agent; preparations from the roots of the plant have pronounced immunostimulating properties. The basis of introduction is the passage of the species through all stages of the life cycle in the conditions of culture, the ability to form fruits and seeds. Materials and methods. Ontogenetic studies were carried out according to the methodology of T.A. Rabinova, with additions by A.A. Uranov and E.L. Nukhimovsky. Results. S. officinale in the conditions of the Angara region there are 3 periods of ontogenesis: latent, virginal, generative. Seedlings appear on the 14th-15th day. A rosette of leaves begins to form in juvenile plants. In immature individuals, branching of shoots begins, while the number of leaves in the rosette increases by 2 times. Young generative individuals bloom for the first time for 1-2 years of life. Individuals enter the middle-aged generative state for 3 years, two generations of shoots are observed in plants. At the 4th year of life, the plants pass into the old generative state. At the end of August-September, individuals have a partial rhizome. The following year, a large number of new reproductive shoots begin to grow from the renewal buds on the rhizome. Conclusions. In the conditions of the Angara culture, S. officinale successfully passes all stages of development, blooms, forms fruits and seeds. The plant is a promising species for cultivation in the conditions of culture of the Angara region. It has a number of advantages for feed production: with rapid growth and development, during the growing season, the species has two generations of shoots, the plant has good otavnost and the ability to form a large number of adventitious buds and shoots, the absence of characteristic signs of rapid biological aging, self-rejuvenation, vegetative and seed reproduction, high productivity of stems, leaves and roots.

Cruise 89 of the R/V Akademik Mstislav Keldysh was organized by the Shirshov Institute of Oceanology in the framework of the Program "Marine Ecosystems of the Siberian Arctic" and was conducted from September 19 to October 10, 2022. Sixty scientists from institutes of the Russian Academy of Sciences, Moscow State University, Moscow Institute of Physics and Technology, VNIRO, and MES participated in the cruise. Coordinated hydrophysical, hydrochemical, biooceanological, and geochemical research and assessments of greenhouse gas concentrations in the near-surface atmosphere were carried out over the shelf and continental slope of the poorly studied eastern Kara Sea. The ecosystem of Blagopoluchiya Bay (Novaya Zemlya) and the conditions of radioactive waste disposal there were also objectives of the research. [ABSTRACT FROM AUTHOR]

Although the southeast region of the Gulf of California has a high fish diversity, due to the high biological productivity, the coastal area of Nayarit has few studies in this regard. The main objective of this work is to describe the variability of the structure of the ichthyofauna in the coastal zone of Nayarit during an annual cycle. Biological samples were collected at 10 stations during February, May, July, and December 2014. The temperature, depth, salinity, and organic material and carbonates in sediments were also recorded. The analysis of diversity includes three facets: ecological, taxonomic, and functional. A total of 82 species belonging to 56 genera, 31 families, 11 orders, and two classes were identified. The most abundant species included Selene peruviana, Stellifer wintersteenorum, Cathorops sp., and Larimus argenteus. Of the total of identified species, 62% were considered as rare according to their abundance and frequency. Although the environmental variables analyzed were variable, all diversity indices did not reveal an evident spatio-seasonal pattern. Likewise, most values of average taxonomic distinctness presented the expected values. However, some values showed a low taxonomic diversity. The indices of functional diversity showed a stable functional richness and redundancy in the attributes of the species. [ABSTRACT FROM AUTHOR]

Marine and lacustrine carbonate minerals preserve carbon cycle information, and their stable carbon isotope values (δ13C) are frequently used to infer and reconstruct paleoenvironmental changes. However, multiple processes can influence the δ13C values of bulk carbonates, confounding the interpretation of these values in terms of conditions at the time of mineral precipitation. Co‐existing carbonate forms may represent different environmental conditions, yet few studies have analyzed δ13C values of syndepositional carbonate grains of varying morphologies to investigate their origins. Here, we combine stable isotope analyses, metagenomics, and geochemical modeling to interpret δ13C values of syndepositional carbonate spherules (>500 μm) and fine‐grained micrite (<63 μm) from a ~1600‐year‐long sediment record of a hypersaline lake located on the coral atoll of Kiritimati, Republic of Kiribati (1.9°N, 157.4°W). Petrographic, mineralogic, and stable isotope results suggest that both carbonate fractions precipitate in situ with minor diagenetic alterations. The δ13C values of spherules are high compared to the syndepositional micrite and cannot be explained by mineral differences or external perturbations, suggesting a role for local biological processes. We use geochemical modeling to test the hypothesis that the spherules form in the surface microbial mat during peak diurnal photosynthesis when the δ13C value of dissolved inorganic carbon is elevated. In contrast, we hypothesize that the micrite may precipitate more continuously in the water as well as in sub‐surface, heterotrophic layers of the microbial mat. Both metagenome and geochemical model results support a critical role for photosynthesis in influencing carbonate δ13C values. The down‐core spherule–micrite offset in δ13C values also aligns with total organic carbon values, suggesting that the difference in the δ13C values of spherules and micrite may be a more robust, inorganic indicator of variability in productivity and local biological processes through time than the δ13C values of individual carbonate forms. [ABSTRACT FROM AUTHOR]

The carbonate chemistry of sea ice is known to play a role in global carbon cycles, but its importance is uncertain in part due to disparities in reported results. Variability in physical and biological drivers is usually invoked to explain differences between studies. In the Canadian Arctic Archipelago, "invisible polynyas" – areas of strong currents, thin ice, and potentially high biological productivity – are examples of extreme spatial variability. We used an invisible polynya as a natural laboratory to study the effects of inferred initial ice formation conditions, ice growth rate, and algal biomass on the distribution of carbonate species by collecting enough cores to perform a statistical comparison between sites located within, and just outside of, a polynya near Iqaluktuttiaq (Cambridge Bay, Nunavut, Canada). At both sites, the uppermost 10 cm ice horizon showed evidence of CO 2 off-gassing, while carbonate distributions in the middle and bottommost 10 cm horizons largely followed the salinity distribution. In the polynya, the upper ice horizon had significantly higher bulk total inorganic carbon (TIC), total alkalinity (TA), and salinity potentially due to freeze-up conditions that favoured frazil ice production. The middle ice horizons were statistically indistinguishable between sites, suggesting that ice growth rate is not an important factor for the carbonate distribution under mid-winter conditions. The thicker (non-polynya) site experienced higher algal biomass, TIC, and TA in the bottom horizon. Carbonate chemistry in the bottom horizon could largely be explained by the salinity distribution, with the strong currents at the polynya site potentially playing a role in desalinization; biology appeared to exert only a minor control, with some evidence that the ice algae community was net heterotrophic. We did see evidence of calcium carbonate precipitation but with little impact on the TIC:TA ratio and little difference between sites. Because differences were constrained to relatively thin layers at the top and bottom, vertically averaged values of TIC, TA, and especially the TIC:TA ratio were not meaningfully different between sites. This provides some justification for using a single bulk value for each parameter when modelling sea ice effects on ocean chemistry at coarse resolution. Exactly what value to use (particularly for the TIC:TA ratio) likely varies by region but could potentially be approximated from knowledge of the source seawater and sea ice salinity. Further insights await a rigorous intercomparison of existing data. [ABSTRACT FROM AUTHOR]

As an intermediary connection between primary producers and higher trophic levels, zooplankton are an important component of the aquatic food chain, contributing significantly to aquatic biological productivity. This study describes the zooplankton diversity and community structure, as well as their relationships with ecological factors, in homestead ponds of a coastal district along the northern Bay of Bengal region. Significant differences (p < 0.05) were detected in the mean values of temperature, pH, DO, TDS, transparency, and phosphates from the ponds during December 2020, but no significant differences were found in the nitrate levels. However, no significant variances in the ecological parameters between months were found due to the study taking place in the same season. Sixteen zooplankton species, representing four groups, were found in the study area, with the highest mean abundance of 301.19 ± 40.55 ind./L recorded in February 2021 and the lowest of 293.02 ± 21.13 ind./L recorded in December 2020. The diversity (H'), evenness (e), richness (J), and dominance (D) ranged from 2.49 to 2.12, from 0.93 to 0.84, from 2.05 to 1.56, and from 0.13 to 0.09, respectively. Based on the SIMPER analysis, Diaptomus gracilis and Brachionus calyciflorus were found to be significant contributors (>10%) to the zooplankton community structure in different months. The ANOSIM results revealed that 10 species of zooplankton were significant contributors based on their average dissimilarity. The canonical correspondence analysis (CCA) identified that pH, transparency, nitrates, and phosphates have a significant impact on the abundance of zooplankton species in the homestead ponds in the study area. [ABSTRACT FROM AUTHOR]

In the last 60 years, chemical fertilizer has played a significant role in world food production. It provides around half of the total amount of N that crops need. Nitrates (NO3) leaching, ammonia (NH3) volatilization and nitrous oxide (N2O) emissions contribute to low crop production efficiency (10 to 50 percent) principally due to the loss of N through these processes. Furthermore, nitrogen fertilizer production costs are extremely high. Technology like nitrogen inhibitors and slow-releasing nitrogen fertilizers are used to boost nutrient uptake, fertilizer use efficiency, and crop yields as a result of these situations. Typical Haplustept soils were studied to see how changing fertilizers affected growth, yield, and soil genetic indicators. Fertilizer doses and sources affect soil biological characteristics, which in turn affects enzymatic activity. In the right circumstances, enzymes alter the nitrogen supply in the soil and the plant's expansion and limestone structure. The Lovely Professional University School of Agriculture, Phagwara, Punjab, conducted two years of fertilizer studies in a rice-wheat cropping system on typical Haplustept soils from 2018 to 2020. Neem coated urea + PK + S + Zn-EDTA performed significantly better than the other treatments for almost all crop growth and agronomic yield attributing characteristics (plant height, number of tillers, effective tillers, panicle/spikelet length and grain per spik, test weight, grain and straw yields). At various stages of rice-wheat growth, enzyme activity in the soil (dehydrogenase and aryl sulfatase) was also measured in the current study. Enzyme activity peaked at the heading stage in surface soil in all treatments, and then steadily declined thereafter. For both stages of crop growth in surface soil, the highest dehydrogenase and aryl sulfatase activity was found in urea + PK + S + Zn -EDTA covered with Neem. Anhydrous ammonia was shown to have the lowest enzymatic activity. [ABSTRACT FROM AUTHOR]

Realistic prediction of the near‐future response of Arctic Ocean primary productivity to ongoing warming and sea ice loss requires a mechanistic understanding of the processes controlling nutrient bioavailability. To evaluate continental nutrient inputs, biological utilization, and the influence of mixing and winter processes in the Laptev Sea, the major source region of the Transpolar Drift (TPD), we compare observed with preformed concentrations of dissolved inorganic nitrogen (DIN) and phosphorus (DIP), silicic acid (DSi), and silicon isotope compositions of DSi (δ30SiDSi) obtained for two summers (2013 and 2014) and one winter (2012). In summer, preformed nutrient concentrations persisted in the surface layer of the southeastern Laptev Sea, while diatom‐dominated utilization caused intense northward drawdown and a pronounced shift in δ30SiDSi from +0.91 to +3.82‰. The modeled Si isotope fractionation suggests that DSi in the northern Laptev Sea originated from the Lena River and was supplied during the spring freshet, while riverine DSi in the southeastern Laptev Sea was continuously supplied during the summer. Primary productivity fueled by river‐borne nutrients was enhanced by admixture of DIN‐ and DIP‐rich Atlantic‐sourced waters to the surface, either by convective mixing during the previous winter or by occasional storm‐induced stratification breakdowns in late summer. Substantial enrichments of DSi (+240%) and DIP (+90%) beneath the Lena River plume were caused by sea ice‐driven redistribution and remineralization. Predicted weaker stratification on the outer Laptev Shelf will enhance DSi utilization and removal through greater vertical DIN supply, which will limit DSi export and reduce diatom‐dominated primary productivity in the TPD. Plain Language Summary: Ongoing warming and sea ice loss in the Arctic Ocean may significantly impact biological productivity, which is mainly controlled by light and nutrient availability. To investigate nutrient inputs from land, biological utilization, and the influence of water mass mixing and winter processes on the nutrient distributions, we measured nutrient concentrations and silicon isotopes in the Laptev Sea. We found high concentrations in the southeastern Laptev Sea in agreement with nutrient inputs from the Lena River. Toward the northern Laptev Sea, nutrient concentrations decreased in the surface layer and the silicon isotope signatures shifted to heavier values, consistent with nutrient utilization by phytoplankton. In contrast to the depleted surface layer, the bottom layer beneath the Lena River plume was strongly enriched in some nutrients, which we attribute to different physical and biogeochemical processes. These observations are important for our understanding of nutrient bioavailability in the Laptev Sea and the Transpolar Drift (TPD), which is a surface current that connects the Laptev Sea with the central Arctic Ocean and the Fram Strait. The changing hydrography of the Laptev Sea will likely cause a decrease in silicic acid concentrations and thus a reduction in nutrient export and diatom‐dominated primary productivity in the TPD. Key Points: Surface dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), silicic acid (DSi), and Si isotope dynamics are controlled by marine and riverine inputs and uptake by phytoplanktonStrong DIP and DSi enrichments beneath the Lena River plume are due to sea ice‐driven nutrient redistribution and remineralizationEnhanced DSi utilization in the Laptev Sea will lead to a reduced diatom‐dominated primary productivity in the Transpolar Drift [ABSTRACT FROM AUTHOR]

The research was carried out on the territory of the Russian Federation in the forest-steppe region of the south Western Siberia (Omsk state), in the long-term (43 years) stationary experiment. Sprinkling was used for irrigation in the experiment. The number of different physiological groups of microorganisms, the cellulolytic activity of the soil, and nitrification capacity were determined under the sowing of an eight-field grain-grass crop rotation (perennial grasses (Bunias orientalis L. + Bromopsis inermis L. + Galega orientalis Lam. 6–8 years old), spring barley Hordeum vulgare Leyss.—variety Sasha). Immobilization processes predominated in the soil under the sowed crops, it contributes to the preservation of soil organic matter (mineralization coefficient SAA/MPA < 1). The highest transformation ratio of soil organic matter, i.e. increased conversion of plant residues into organic matter, was noted with applying nitrogen-phosphorus fertilizers (N60P60) under the barley. The combination of irrigation factors and the use of mineral fertilizers (N30-60P60) were contributed to the growth of the microorganisms' population, the amplification of decomposition of cellulose, and improvement of nitrification capacity in the soil. The perennial irrigation of the meadow-chernozem soil and the application of intensive technology of cultivation of crops in crop rotation stimulated the growth of the microorganisms' population and didn't detriment the ecological state of the soil. [ABSTRACT FROM AUTHOR]