Supply Of Organic Matter Research Articles

Microbial Communities of Interglacial and Interstadial Paleosols of the Late Pleistocene

The taxonomic structure of microbial communities in the Late Pleistocene paleosols of different ages in the Central Russian Upland formed under contrasting climatic conditions were analyzed. The humic horizons of paleosols in the interstadial periods of the Early Valdai (105–95 kyr ago), Middle Valdai (33–24 kyr ago), Mikulino interglacial (130–117 kyr ago), and of the modern (Holocene) chernozem were considered. Microbial DNA was analyzed using quantitative PCR and 16S rRNA gene amplicon sequencing (DNA metabarcoding). The numbers of copies of archaeal, bacterial, and fungal genes gradually decreased with an increase in the soil age. All considered paleosols significantly differed from one another in the structure of their microbial communities. The Verrucomicrobia-to-Nitrospirae ratio was used as a diagnostic parameter reflecting the organic matter supply and the changes in carbon and nitrogen cycles. The Verrucomicrobia-to-Nitrospirae ratio in the interstadial soils was 140–200 times lower as compared with that in the modern soil (typical chernozem) and in the paleosols of the Mikulino interglacial. The share of gram-negative Proteobacteria and Acidobacteria increased with the soil age, whereas the share of gram-positive Actinobacteria and Firmicutes decreased. The modern chernozems and interglacial paleosols were characterized by similar values of microbial diversity, while the paleosols of the Valdai interstadial had significantly lower microbial diversity and species richness. Analysis of β-diversity showed that the paleosols of different types and ages maintained the difference in the structure and diversity of their microbial communities depending on the conditions of their formation. Thus, the microbial communities can be used as potential stratigraphic markers and indicators of different climatic conditions, under which the given paleosols were formed.

Focus of mineralization-synthesis processes of the organic matter in the leached chernozem while cultivating potatoes on different fertilization backgrounds

Aim. To investigate the focus of the mineralization–synthesis processes in leached chernozem while cultivating potatoes in different fertilization systems, ensuring different supplies of raw organic matter into the soil. Methods. Field experiment, gas chromatography. Results. The study of emissions of nitrous oxide and carbon dioxide from the soil followed by the calculations of the specifi c losses of N-N2O (g/kg C-CO2), depending on fertilization system and in comparison with the indicators of the “reference” soil, provide an opportunity for rapid determination of the focus of the mineralization-synthesis processes in the organic matter in agrocenoses. The use of exclusively mineral fertilization systems results in the highest specifi c losses of N2O as the increase of the applied fertilizer doses initiates the mineralization processes in the soil. The combination of mineral fertilizers with raw organic products (5 t/ha straw and 13 t/ha of lupine cover crop) signifi cantly improves the situation. At the same time, in experiment with the lowest (N40P40K40 kg/ha) and medium (N80Р80К80 kg/ha) doses of mineral fertilizers the balance of mineralization-synthesis processes of organic matter was observed. The highest rate of mineral fertilizer dose in the experiment (N120P120K120 kg/ha), even in combination with the raw organic material, activates mineralization processes. With the use of manure, as well as upon its combination with the lupine cover crop and low doses of mineral fertilizers, the optimization of nitrous oxide and carbon dioxide emissions is observed. Conclusions. The use of solely mineral fertilizers in the technology of potato cultivation is inappropriate in terms of environmental reasons. The combination of mineral fertilizers (not exceeding N80Р80К80 kg/ha dose) with straw and lupine cover crop ensures optimization of the processes of mineralization-synthesis of organic matter. Moreover, the optimization of biological processes in the soil was observed in experiments with the use of manure, its combination with lupine cover crop and low doses of mineral fertilizers. The calculations of the indices of mineralization-synthesis of organic matter, considering the emission factors of N2O and CO2, obtained with the use of modern high-sensitivity gas chromatographic methods, allow to determine the focus of biological processes in the soil, depending on fertilization system, and to estimate ecologic sustainability of types and doses of fertilizers.

Intense summer floods may induce prolonged increases in benthic respiration rates of more than one year leading to low river dissolved oxygen

The supply of readily-degradable organic matter to river systems can cause stress to dissolved oxygen (DO) in slow-flowing waterbodies. To explore this threat, a multi-disciplinary study of the River Thames (UK) was undertaken over a six-year period (2009–14). Using a combination of observations at various time resolutions (monthly to hourly), physics-based river network water quality modelling (QUESTOR) and an analytical tool to estimate metabolic regime (Delta method), a decrease in 10th percentile DO concentration (10-DO, indicative of summer low levels) was identified during the study period. The assessment tools suggested this decrease in 10-DO was due to an increase in benthic heterotrophic respiration. Hydrological and dissolved organic carbon (DOC) data showed that the shift in 10-DO could be attributed to summer flooding in 2012 and consequent connection of pathways flushing degradable organic matter into the river. Comparing 2009–10 and 2013–14 periods, 10-DO decreased by 7.0% at the basin outlet (Windsor) whilst median DOC concentrations in a survey of upstream waterbodies increased by 5.5–48.1%. In this context, an anomalous opposing trend in 10-DO at one site on the river was also identified and discussed. Currently, a lack of process understanding of spatio-temporal variability in benthic respiration rates is hampering model predictions of river DO. The results presented here show how climatic-driven variation and urbanisation induce persistent medium-term changes in the vulnerability of water quality to multiple stressors across complex catchment systems.

Long-term analysis from a cropping system perspective: Yield stability, environmental adaptability, and production risk of winter barley

Abstract In the face of climate change, the potential impacts of adverse weather conditions on the productivity and vulnerability of cropping systems (CS) worldwide constitute a key agronomic issue upon which global food security depends. To date, little information regarding how the diversity of CS or agricultural practices affect the long-term yield responses of winter barley is available. The aim of this study was to investigate the impact of CS diversity in terms of cropping sequences, organic matter supplies, and nitrogen (N) fertilization on the yield vulnerability of winter barley. Yields were evaluated in terms of their stability, environmental adaptability, and production risk (probability of yield loss). Data from a 27-year experiment were statistically analyzed using three mixed models giving residual maximum likelihood estimates including the Shukla stability variance index, the Finlay-Wilkinson environmental regression, and the Eskridge risk assessment approach. The results showed that winter barley grown in cropping sequences dominated by cereals had lower yield stability and environmental adaptability and greater production risks compared with winter barley grown in CS with higher crop diversity and additional organic matter inputs. When barley yields were compared at three doses of mineral N, the highest yield stability was achieved with the medium N dose (70 kg N ha−1), followed by the higher level of N (140 kg N ha−1). The most unstable yields with the highest production risks were observed when barley was grown without any mineral N fertilization. Overall, a higher level of crop diversity with organic matter inputs and intermediate N fertilization resulted in lower yield vulnerability in winter barley.

Soil fertility characteristics and their influencing factors in tea plantations of Jiangxi Pro-vince, China

To investigate soil fertility status and characteristics of typical tea plantations, we selec-ted 372 typical tea plantations of 21 areas across Jiangxi Province and analyzed the soil nutrient, spatial data, and their correlations with topography, soil type, elevation and plantation age. The results showed that soil pH, organic matter, alkaline nitrogen, available phosphorus, available potassium, total nitrogen, total phosphorus and total potassium of tea plantation in Jiangxi reached 53.9%, 60.1%, 56.1%, 22.9%, 38.5%, 43.7%, 11.1% and 95.5% of indices of high fertility, high efficiency and high yield tea plantation, respectively, with the available phosphorus showing a strong variation. Soil available copper, zinc, iron, manganese and boron reached 76.3%, 74.2%, 96.8%, 73.1% and 0.0% of the first-class standards for soil trace elements, respectively. Tea plantations with highest soil fertility located in central Jiangxi, followed by northeastern and northwestern Jiangxi, and lowest in southern Jiangxi. Soil pH was significantly positively correlated with organic matter, alkaline nitrogen, available phosphorus, available potassium, total nitrogen and total phosphorus but not for total potassium. For different topography, soil fertility was highest in the flat land, followed by the high mountains, and lowest in the mountains and hills. Across different soil types, soil fertility was higher in paddy soil, sandy soil and mountain yellow brown soil, followed by yellow soil, red-yellow soil and purple soil, and lowest in red soil. Soil pH, organic matter and total potassium increased while available phosphorus decreased with altitude. The organic matter, alkaline nitrogen, available phosphorus, total nitrogen and total phosphorus increased, but soil pH decreased with time. In summary, soil fertility of tea plantations in Jiangxi Province was generally good, with high organic matter, total potassium, available copper, zinc, iron and manganese. However, soil was acidic, available phosphorus and total phosphorus content was low, available boron was seriously limited. We suggest increase soil pH and potassium supply in central Jiangxi, increase potassium and nitrogen fertilizer supply in northeastern Jiangxi, increase organic matter and phosphorus fertilizer supply in northwestern Jiangxi, and increase nitrogen, phosphorus and potassium supply combined with organic fertilizers in southern Jiangxi. High mountain tea plantations should enhance available phosphorus and potassium supply. Mountain tea plantations should enhance nitrogen and phosphate supply. Tea plantations with red and yellow soil should increase pH and total potassium supply. Tea plantations with red soil should apply nitrogen, phosphorus and potassium fertilizers combined with organic fertilizers. Tea plantations with yellow soil and mountain yellow brown soil required additional phosphorus supply, and tea plantations with purple soil should increase soil organic matter supply. Tea plantations need to increase dolomite powder, physiological alkaline fertilizers and organic fertilizers to prevent soil acidification.

Influence of Manila clam aquaculture on rates and partitioning of organic carbon oxidation in sediment of Keunso Bay, Yellow Sea

We investigated the effects of Manila clam aquaculture on the rates and pathways of anaerobic organic carbon (OC) oxidation in highly bioturbated (HB) and poorly bioturbated (PB) sediment in Keunso Bay, Yellow Sea. Due to the labile organic matter supply via sediment reworking by Manila clams, the anaerobic OC oxidation rate in HB sediment (38.8 mmol m-2 d-1) was ~1.5 times higher than that in PB sediment (26.8 mmol m-2 d-1). Microbial Fe(III) reduction (FeR) dominated OC oxidation pathways in HB sediment, comprising 55 to 76% of anaerobic OC oxidation, whereas sulfate reduction (SR) was the dominant oxidation pathway in PB sediment, accounting for up to 92% of anaerobic OC oxidation. Despite higher anaerobic respiration rates at the HB site, concentrations of NH4+, PO43-, oxalate-extractable iron (Fe(II)(oxal)), and total reduced inorganic sulfur were 2 to 3 times lower in HB than in PB sediment. Conversely, the concentration of reactive Fe(III)(oxal) at the HB site (2243 mmol m-2) exceeded that at the PB site (1127 mmol m-2) by a factor of 2. These results indicate that bioturbation by Manila clams enhances the re-oxidation processes of reduced metabolites in the sediment, thereby prohibiting SR and promoting FeR. Overall, the results suggest that aquaculture activities of Manila clams shift the dominant OC oxidation pathways in sediment from SR to FeR, which generates relatively oxidized and less sulfidic environments.

Impact of the Paleoclimate, Paleoenvironment, and Algae Bloom: Organic Matter Accumulation in the Lacustrine Lucaogou Formation of Jimsar Sag, Junggar Basin, NW China

Shale oil exploration has been a key area of onshore oil and gas exploration in China in recent years. In this study, organic geochemistry and element geochemistry are united to study the shale oil and source rock in the Lucaogou formation of Jimusar sag, in order to reveal the paleoclimate, paleoenvironment, source of organic matter, and factors affecting organic matter accumulation and shale oil generation. The shale oil in the study area is mainly accumulated in two strata with good reservoir properties and oiliness, known as the upper sweet spot and lower sweet spot. Indexes of biomarkers and sensitive elements revealed the warm and semi-arid paleoclimate during Lucaogou formation, and the water column was brackish to salty. Water stratification caused a suboxic to anoxic environment in the deep-water column and coincided with the anoxic photic zone phenomenon. Compared with the lower sweet spot, the more humid climate, deeper and fresher water, and stronger water stratification characterize the upper sweet spot during sedimentation. This made the photic zone with freshwater more suitable for the reproduction of algae in the upper sweet spot. Meanwhile, the organic matter was well-preserved in the anoxic zone. Volcanic ash caused algae bloom, which promoted primary productivity and ensured the supply of organic matter. The composition and distribution pattern of biomarkers prove that phytoplankton is the most important source of organic matter in the study area and the contribution of higher plants is insignificant. The relationship between parameters of paleoproductivity and the redox condition versus total organic carbon (TOC) suggests that compared with the preservation conditions, the input of organic carbon is the most important controlling factor of organic matter accumulation in the study area.

Effects of reduced organic matter loading through membrane filtration on the microbial community dynamics in recirculating aquaculture systems (RAS) with Atlantic salmon parr (Salmo salar)

A key challenge in recirculating aquaculture systems (RAS) is the accumulation of particulate organic matter, especially the fine and colloidal fraction due to low removal efficiency of today's technology. The supply of organic matter is typically the limiting resource determining the carrying capacity (CC) of heterotrophic bacteria in the system. An appropriate and stable CC is proposed as a strategy for an optimal microbial environment in RAS with less blooms of opportunistic bacteria and more stable community dynamics. In this study, we investigated the effects of including a membrane for ultrafiltration in the RAS water treatment loop (treating 10–15% of the total water flow) to reduce the amount of fine and colloidal organic matter. Atlantic salmon parr (Salmo salar) were reared in two pilot-scale RAS (mRAS: membrane, cRAS: conventional). To evaluate the bacterial dynamics with and without membrane filtration at different organic loadings, the water exchange rates of the systems were manipulated equally to create periods with high and low loading of organic matter. The results showed that in the mRAS water, the level of organic matter was more stable throughout the experiment for the changing organic matter loadings. As a consequence, water in mRAS had higher microbial diversity, lower and shorter bacterial blooms and generally lower bacterial densities than in cRAS. All variables indicate a better microbial environment in the water of the system with membrane filtration. Also, the physicochemical water quality was better in mRAS in terms of lower turbidity and particulate organic matter (POC), and slightly lower concentrations of total ammonia nitrogen (TAN). The composition of the microbial communities was significantly different between the two systems, and temporal variations in the community dynamics were observed in both systems during the periods with different organic loadings. At high organic loading, the genus Mycobacterium had high relative abundance in the cRAS water (up to 0.25) compared to mRAS (0.01–0.03). The fish in mRAS were significantly bigger (14%) than fish in cRAS at the end of the experiment, however it is hard to conclude whether the better growth in mRAS was due to higher temperatures (caused by membrane operation) or better water quality, as it was probably a combination of both. We can conclude that membrane filtration gave more stable and better physicochemical and microbial water quality, which will reduce the probability for microbially related accidents in RAS.

Multiproxy evidence of the Neoglacial expansion of Atlantic Water to eastern Svalbard

Abstract. The main goal of this study is to reconstruct the paleoceanographic development of Storfjorden during the Neoglacial (∼4 cal ka BP). Storfjorden is one of the most important brine factories in the European Arctic and is responsible for deepwater production. Moreover, it is a climate-sensitive area influenced by two contrasting water masses: warm and saline Atlantic Water (AW) and cold and fresh Arctic Water (ArW). Herein, a multiproxy approach was applied to provide evidence for existing interactions between the inflow of AW and sea ice coverage, which are the major drivers of environmental changes in Storfjorden. The sedimentary and microfossil records indicate that a major reorganization of oceanographic conditions in Storfjorden occurred at ∼2.7 cal ka BP. The cold conditions and the less pronounced presence of AW in Storfjorden during the early phase of the Neoglacial were the prerequisite conditions for the formation of extensive sea ice cover. The period after ∼2.7 cal ka BP was characterized by alternating short-term cooling and warming intervals. Warming was associated with pulsed inflows of AW and sea ice melting that stimulated phytoplankton blooms and organic matter supply to the bottom. The cold phases were characterized by heavy and densely packed sea ice, resulting in decreased productivity. The ancient environmental DNA (aDNA) records of foraminifera and diatoms support the occurrence of the major pulses of AW (∼2.3 and ∼1.7 cal ka BP) and the variations in sea ice cover. The episodes of enhanced AW inflow were marked by an increase in the percentage of DNA sequences of monothalamous foraminifera associated with the presence of fresh phytodetritus. Cold and less productive intervals were marked by an increased proportion of monothalamous taxa known only from environmental sequencing. The diatom aDNA record indicates that primary production was continuous during the Neoglacial, regardless of the sea ice conditions. However, the colder periods were characterized by the presence of diatom taxa associated with sea ice, whereas the present-day diatom assemblage is dominated by open-water taxa.

Riverine export of water, sediment and carbon during flood events in the arid to semi‐arid Wuding River on the Chinese Loess Plateau

AbstractFloods have become increasingly important in fluvial export of water, sediment and carbon (C). Using high‐frequency sampling, the export of water, sediment and C was examined in the Wuding River catchment on the Chinese Loess Plateau. With groundwater as an important contributor to runoff all year round, floods were relatively less important in the export of water. However, large floods were disproportionately important in exporting sediment and inorganic C (DIC) and organic C (DOC and POC). The three largest floods in each year transported 53.6–97.3 and 41.4–77% of the annual sediment and C fluxes, respectively. An extreme flood in 2017 alone contributed 94.6 and 73.1% of the annual sediment and C fluxes, respectively, in just 7 days, which included 20.3, 92.1 and 35.7% of the annual DOC, POC and DIC fluxes, respectively. A stable carbon isotope (δ13C) analysis of POC indicated that modern soils and C3 plants were its primary source. Furthermore, floods greatly accelerated CO2 degassing due to elevated gas transfer velocity, although stream water CO2 partial pressure (pCO2) exhibited a decreasing trend with flow discharge. Although these results illustrated that increasing runoff diluted pCO2, the timing and magnitude of floods were found to be critical in determining the response of pCO2 to flow dynamics. Low‐magnitude floods in the early wet season increased pCO2 because of enhanced organic matter input, while subsequent large floods caused a lower pCO2 due to greatly reduced organic matter supply. Finally, continuous monitoring of a complete flood event showed that the CO2 efflux during the flood (2348 ± 664 mg C m–2 day–1) was three times that under low‐flow conditions (808 ± 98 mg C m–2 day–1). Our study suggests that infrequent, heavy storm events, which are predicted to increase under climate change, will greatly alter the transport regimes of sediment and C. © 2020 John Wiley & Sons, Ltd.

Long term monitoring of cold-water coral growth shows response to episodic meteorological events in the NW Mediterranean

Lophelia pertusa and Madrepora oculata, two cosmopolitan coral species of the deep ocean, build reef-like structures that provide ecological niches and nurseries for many species. These cold-water corals (CWCs) are thought to grow slowly making associated communities vulnerable to disturbance. However, in situ growth dynamics remains poorly known. The aim of this study was thus to quantify the growth rates of L. pertusa and M. oculata and their variability in relation to environmental conditions that are expected to influence their physiological functions. Such data can be useful to ground-truth physiological rates and improve the prediction of their sensitivity to global change.As part of a long-term monitoring programme of the Lacaze-Duthiers canyon in the Northwestern Mediterranean Sea, fragments of the two species were repeatedly sampled and redeployed at 530 m depth, from November 2010 to May 2018. Budding rates and linear extensions of L. pertusa and M. oculata were hence quantified and their inter-annual variability documented. The data were analyzed in relation to in situ monitoring of water temperature, current speed and turbidity.This study presents the longest in situ survey of the growth patterns of L. pertusa and M. oculata. The observations revealed a strong inter-annual variability in growth rates, both for L. pertusa and M. oculata, and suggest an influence of hydrological conditions on the growth dynamics. Particularly, as regard to episodic water plumes events such as NW wind-induced dense water shelf cascades and E-SE storm-induced downwellings in autumn-winter. In this study, three types of responses were observed: (i) high budding rates but low colony linear extension for strong water plume events periods (ii) high budding rates and high linear extension associated to organic matter supply during medium intensity water plume events, and (iii) low budding rates, low linear extension and high mortality due to high sedimentation rates in the absence of water plume event. Lophelia pertusa appears to be more resilient to these hydrological changes. Disturbance of the regional circulation patterns, in addition to longer-term change in water mass properties such as warming, deoxygenation and acidification, are thus important parameters to consider for CWC reef stability. This is particularly important since increased storminess, and decreased cascading/downwelling intensities, are predicted to occur within the next century.

The recent deposition of laminated sediments in highly eutrophic Lake Kierskie, western Poland: 1\xa0year pilot study of limnological monitoring and sediment traps

Accurate lake sediment-derived palaeoenvironmental reconstructions require in-depth knowledge on sediment record formation processes. In order to understand formation of laminated sediments in the eutrophic Lake Kierskie (western Poland) we conducted a year-round (November 2015–October 2016), monthly sediment trap study along with physico-chemical water properties, water transparency, hardness, alkalinity, nutrients and solute content, trophic state indices, and the phytoplankton assemblage monitoring. Sedimentation in Lake Kierskie primarily resulted from the activity of photosynthetic organisms. The maxima of biogenic silica accumulation were synchronous with the bloom of centric diatoms observed in March and April. These were followed by the most intensive precipitation of CaCO3 noted between mid-April and mid-June, that corroborated with the domination of Stephanodiscus hantzschii and small flagellate forms acting as nucleation sites for crystal formation. At the same time shift from the diatom-dominated assemblages to the communities composed of chlorophytes, cryptophytes, and dinoflagellates, the groups with cellulose external covering, resulted in decreased proportion between SiO2 and organic matter. CaCO3 precipitation continued in the summer months, however its amount decreased simultaneously with a drop in S. hantzschii biomass. The significant overall flux of biogenically mediated materials from epilimnion was promoted by eutrophic towards hypertrophic conditions in Lake Kierskie revealed by the trophic state indices. Mixing of the water column in autumn triggered resuspension and redeposition of the previously deposited sediments resulting in the second, after the early spring, maximum sediment flux. Minima of sediment accumulation were observed during the winter water stratification when the smallest particles sedimented from suspension. The sediment flux to the lake bottom recorded by us in a 1-year, monthly sediment trap study matches a sequence of pale, whitish lamina deposited during spring and summer, followed by dark, grayish or black lamina deposited in the autumn and winter, observed in the macroscopic investigation of the short (0.5 m) core from Lake Kierskie. Preservation of distinct laminations in the dimictic Lake Kierskie is supported by anoxic hypolimnion developed under the high supply of organic matter from epilimnion of this highly eutrophic lake.

Trophic structure and potential carbon and nitrogen flow of a rhodolith bed at Santa Catalina Island inferred from stable isotopes

In many coastal marine systems with low productivity, cross-habitat exchange of subsidies has been shown to have significant bottom-up effects. California rhodolith beds (Lithothamnion australe Foslie) support invertebrate communities whose biomass doesn’t appear to be supported by the limited productivity of rhodoliths. Detrital subsidies from the water column and adjacent giant kelp Macrocystis pyrifera forests may supplement the base of the food web in these beds. Stable isotope analyses were conducted using seawater organic matter, sediment organic matter, and macroalgae as endmembers to determine their relative importance to consumers and create trophic structure of a rhodolith bed off Santa Catalina Island. Using cluster analysis on carbon δ13C and nitrogen δ15N values of 13 invertebrate consumer taxa, five trophic groups were identified: planktivore, zooplanktivore, detritivore, herbivore, and carnivore. The isotope ratios of sediment organic matter from within rhodoliths were similar to benthic and drifting kelp M. pyrifera tissue, suggesting neighboring kelp habitats, or other unmeasured sources, may contribute to the organic matter within rhodoliths. Detritivores, herbivores, and carnivores appeared to consume particulate organic matter from the water column directly or indirectly through prey. Follow-up experiments indicated that increasing surface area of giant kelp pieces increased drift rates while smaller kelp material moved less and may have greater potential to be retained within rhodolith beds during periods of increased water motion. Overall, temporal fluctuations in the supply and export of suspended particulate organic matter from the water column and drift macroalgal subsidies from adjacent kelp forests may have considerable effects on secondary production and community structure of rhodolith beds.

Utilization of Sanitized Human Excreta and Wood Ash for Establishing Multipurpose <i>Ficus Thonningii</i> Blume in a Degraded Tantalum Technosol

The inclusion of native trees in mine land reclamation has been promoted over the years yet that of highvalue multipurpose species for people’s livelihoods has been overlooked. Also, studies utilizing human excreta (HE), i.e. fecal matter, (FM) and human urine fertilizer HUF), and wood ash (WA) in land reclamation are scarce. Yet, these are indispensable in areas with a limited supply of organic materials and high demand for natural resources. This study evaluated the effects of HE and WA on the growth and establishment of Ficus thonningii Blume (ficus) in a pegmatite-rich tantalum Technosol. Hardwood cuttings of ficus from homesteads in Western Rwanda were planted in 20.4 × 19 cm diameter pots containing 5 kg forest soil (FS) and 6 kg Technosol. Five treatments including No amendment; HUF alone (100 mL/pot); HUF+WA (100 mL + 60 g/pot); FM (200 g/pot); and FM+WA (200 g + 60 g/pot) were prepared in ten replicates each. Plant height, number of leaves, shoot and root biomass were determined after five and seven months after planting. The HE andWA treatments significantly increased (P = 0.003) ficus height (FS = 39 – 42 cm and Technosol = 31 – 34 cm) after seven months. Shoot biomass weights ranged from 17 – 21 g in the FS and 10 – 16 g in the Technosol. Ficus exhibited an efficient rooting system that stabilized the loose particles of the Technosol, suggesting the potential of using ficus, HE, and WA indegraded mine soil reclamation in future research. Keywords: Fecal matter; Human urine fertilizer; Root and shoot biomass; Pegmatite

Multitrophic biodiversity patterns and environmental descriptors of sub‐Arctic lakes in northern Europe

Abstract Arctic and sub‐Arctic lakes in northern Europe are increasingly threatened by climate change, which can affect their biodiversity directly by shifting thermal and hydrological regimes, and indirectly by altering landscape processes and catchment vegetation. Most previous studies of northern lake biodiversity responses to environmental changes have focused on only a single organismal group. Investigations at whole‐lake scales that integrate different habitats and trophic levels are currently rare, but highly necessary for future lake monitoring and management. We analysed spatial biodiversity patterns of 74 sub‐Arctic lakes in Norway, Sweden, Finland, and the Faroe Islands with monitoring data for at least three biological focal ecosystem components (FECs)—benthic diatoms, macrophytes, phytoplankton, littoral benthic macroinvertebrates, zooplankton, and fish—that covered both pelagic and benthic habitats and multiple trophic levels. We calculated the richnessrelative (i.e. taxon richness of a FEC in the lake divided by the total richness of that FEC in all 74 lakes) and the biodiversity metrics (i.e. taxon richness, inverse Simpson index (diversity), and taxon evenness) of individual FECs using presence–absence and abundance data, respectively. We then investigated whether the FEC richnessrelative and biodiversity metrics were correlated with lake abiotic and geospatial variables. We hypothesised that (1) individual FECs would be more diverse in a warmer and wetter climate (e.g. at lower latitudes and/or elevations), and in hydrobasins with greater forest cover that could enhance the supply of terrestrial organic matter and nutrients that stimulated lake productivity; and (2) patterns in FEC responses would be coupled among trophic levels. Results from redundancy analyses showed that the richnessrelative of phytoplankton, macrophytes, and fish decreased, but those of the intermediate trophic levels (i.e. macroinvertebrates and zooplankton) increased with decreasing latitude and/or elevation. Fish richnessrelative and diversity increased with increasing temporal variation in climate (temperature and/or precipitation), ambient nutrient concentrations (e.g. total nitrogen) in lakes, and woody vegetation (e.g. taiga forest) cover in hydrobasins, whereas taxon richness of macroinvertebrates and zooplankton decreased with increasing temporal variation in climate. The similar patterns detected for richnessrelative of fish, macrophytes, and phytoplankton could be caused by similar responses to the environmental descriptors, and/or the beneficial effects of macrophytes as habitat structure. By creating habitat, macrophytes may increase fish diversity and production, which in turn may promote higher densities and probably more diverse assemblages of phytoplankton through trophic cascades. Lakes with greater fish richnessrelative tended to have greater average richnessrelative among FECs, suggesting that fish are a potential indicator for overall lake biodiversity. Overall, the biodiversity patterns observed along the environmental gradients were trophic‐level specific, indicating that an integrated food‐web perspective may lead to a more holistic understanding of ecosystem biodiversity in future monitoring and management of high‐latitude lakes. In future, monitoring should also focus on collecting more abundance data for fish and lower trophic levels in both benthic and pelagic habitats. This may require more concentrated sampling effort on fewer lakes at smaller spatial scales, while continuing to sample lakes distributed along environmental gradients.

Architecture, process, and environmental diversity in a late Cretaceous slope channel system

ABSTRACT Arroyo San Fernando, on the Pacific coast of Baja California, Mexico, provides a superb view of the architecture of a Maastrichtian active margin slope channel system and the record of its evolution through a third-order sea-level cycle. The succession is organized into architectural building blocks (channel-complex sets) consisting of a channel belt with an axial region and a channel-belt margin of terraces and internal levees. The channel belt is confined by an external levee on one side and by an erosion surface into the slope on the other. Each channel-complex set can be subdivided into three stages of evolution: Stage I consists of highly amalgamated coarse-grained channel complexes, Stage II consists of gravelly meander belts with marginal and stratigraphically intervening thin-bedded turbidites, and Stage III consists of mudstones representing abandonment. This succession is associated with repeated and therefore predictable changes in architecture, facies distribution, inferred seafloor morphology, and sedimentary process. We describe variability in the sedimentology, ichnology, palynology, provenance, and inferred sedimentary processes between and within these architectural elements. Channel formation and fill are attributed to erosion, sediment transport, and deposition by turbidity currents and lesser debris flows. Ichnology indicates enhanced oxygenation and supply of organic material, substrate type, and turbidity within the channel belt; the axial region can be differentiated from the terraces by differing response to turbidity-current intensity. Levee environments show ichnological gradients away from the channel towards background slope. Palynology reflects confinement of the supply of terrigenous material to the channel belt, but is also indicative of stratification within the turbidity-currents, as is the distribution of heavy minerals. Provenance is from the extinct part of the continental-margin arc to the east, via high-gradient gravelly streams and across a steep shoreline, with direct supply of coastal material to deep water. Architectural hierarchy bears comparison with other slope channel systems, but in common with them the fill represents only a small fraction of the time that the system was active.

Plant growth and yield of butter kale (Brassica oleracea L. var. acephala), as influenced by the combined application of bovine manure and rock powder

The supply of organic matter in soil of arid and semiarid in Brazilian regions is very import, as it allows to increase crop yields. However, there are few studies on alternative sources of fertilizer for vegetables. Therefore, the objective was to evaluate the effect of different doses of bovine manure and rock powder (RP) on growth characteristics, concentration of chlorophyll, and physiological indices and production of (B. oleracea L. var. acephala). The treatments were arranged in five randomized blocks in a factorial 4 x 4 reference doses of bovine manure (60, 120, 180 and 240 g pit-1) combined with doses of rock powder (6, 12, 18 and 24 g pit-1). Doses of bovine manure and rock powder of 180 and 18 g, respectively, increased the growth of B. oleracea by plant height, stem diameter, leaf number. The combination doses of bovine manure 120 g + 12 g rock powder and 120 g of bovine manure + 18 g rock powder, provided, in this order, larger leaf area results for the productivity of B. oleracea. The bovine manure promotes greater concentration of CO2, net photosynthesis and stomatal conductance of B. oleracea plant, while rock powder limits these characteristics. Intermediate doses of bovine manure and RP promote higher growth and yield of B. oleracea.

The number of cultured heterotrophic bacteria and the total bacterial number in the surface microlayer, water column and epilithic biofilms of the littoral zone of Lake Baikal

We have shown that the number of heterotrophic bacteria in the surface microlayer and periphyton is reliably higher than in the water column, which characterizes these biotopes as sites of intense destruction of suspended organic matter. Average values of the total bacterial number, the number of cultured heterotrophic bacteria and the K index indicate the elevated supply of labile organic matter at the stations near the Listvyanka settlement, the Olkhonskiye Vorota Strait and Aya Bay.

The presence of earthworm Pontoscolex corethrurus rather than organic matter sources indirectly controls N2O flux in tropical plantation soils

Both organic matter status and earthworm activity may affect the microbial-mediated N2O production in tropical plantations which contribute greatly to the global N2O emission. The representative pantropical earthworm Pontoscolex corethrurus was likely to be increasingly dominant in degraded lands due to intensified disturbances such as understory removal and soil erosion. We noticed that the relatively fertile surface soil plays key roles in fueling both microbes and earthworms. Therefore, we hypothesized that N2O production was stimulated most by earthworm P. corethrurus in less-disturbed tropical plantations where the surface soil layer was conserved. To determine the effect of organic matter sources and P. corethrurus activity on N2O flux in tropical plantation soils, a field mesocosm experiment including four organic treatments with and without earthworms was then conducted. In plant-free mesocosms, mineral soils (60–80 cm layer) received four organic matter treatments: no organic matter (CK), non-fragmented fallen leaves (NL), partially fragmented leaves (PL) and surface soil containing decomposed litter (0–5 cm, SS), which were used to simulate different levels of disturbance-mediated resource depletion. We found that although the population of P. corethrurus declined with the intensity of food resource limitation, mostly P. corethrurus stimulated N2O flux, but occasionally reduced N2O flux in the organic matter-depleted control soils. In contrast, organic matter sources did not exert significant effects on N2O flux. This study indicates that, although the disturbance-induced changes in organic matter supply altered earthworm population size, the presence of P. corethrurus rather than organic matter sources is the determinant of N2O flux in the studied tropical soils. Although the occasionally negative earthworm effects on N2O flux brings uncertainty, the population size-independent positive earthworm effect on N2O flux may simplify the modeling of earthworm contributions to greenhouse gas fluxes.

Characteristics and origin of the Lower Oligocene marine source rocks controlled by terrigenous organic matter supply in the Baiyun Sag, northern South China Sea

To analyze the dominant factors of the origin of marine source rocks of the northern South China Sea (SCS), this paper focuses on the Lower Oligocene neritic source rocks in the Baiyun Sag of the Pearl River Mouth Basin. This study assesses the source rocks based on the principles and methods of sedimentology, geochemistry, and palynology and data on pyrolysis parameters, biomarker compounds, major and trace elements, and sedimentary organic debris. The paleoproductivity, input of terrigenous organic matter (TOM), redox conditions and sediment flux are characterized by the above parameters. The dominant effects of organic matter (OM) supply, preservation, and dilution on the origin of the source rocks are studied, and a depositional model of the source rocks is established. Finally, the origin of the Lower Oligocene marine source rocks in the northern SCS is clarified. The results show that the main source of the marine source rocks was terrestrial higher plants, while the contribution of planktonic algae was small. The origin of the marine source rocks was strongly controlled by the input of TOM during the depositional period. The source rocks developed in an oxic environment, and the correlation between the redox indices and OM abundance is poor, which indicates that the redox conditions were not the main factor dominating the origin of the source rocks. With an increase in the sediment flux and the barrier formed by low uplifts, the dilution of the OM decreased, and the contact time between OM and oxygen was markedly reduced; therefore, some OM in the oxic bottom water was not oxidized but instead became enriched, thereby forming the source rocks.