Nutrient Inputs Research Articles

Effects of different nutrient inputs in organic parsley cultivation

ABSTRACT Parsley (Petroselinum crispum Mill.) can play a key role in healthy nutrition for people. This study evaluated the effects of different fertilisers on parsley grown in organic greenhouse conditions in the Samsun province of Turkey. Three organic fertilisers (liquids based on compost, nettles and wood ash) were tested and compared with chemical fertiliser and a control with no fertiliser. The results showed that application of wood ash solution significantly increased EC and concentrations of P and K in the soil, compared with the no fertiliser control. The nettle extract and the compost solution had the most prominent effects on concentrations of nutrients in the parsley leaf tissue. The highest total yields were obtained in the treatments with nettle extract (8.95 kg m−2) and wood ash solution (8.71 kg m−2), which were similar to the yield in the treatment with chemical fertiliser (8.48 kg m−2). The present results suggested that nettle extract and wood ash solution provided effective fertilisers to achieve high yields and quality in organic parsley cultivation. Further studies were recommended to test combinations of nettle extract and wood ash solutions in different proportions for edible leafy species.

Impact of vegetation composition and seasonality on sensitivity of modelled CO2 exchange in temperate raised bogs

Encroachment of vascular plants (VP) in temperate raised bogs, as a consequence of altered hydrological conditions and nutrient input, is widely observed. Effects of such vegetation shift on water and carbon cycles are, however, largely unknown and identification of responsible plant physiological traits is challenging. Process-based modelling offers the opportunity of gaining insights into ecosystem functioning beyond observations, and to infer decisive trait shifts of plant functional groups. We adapted the Soil–Vegetation–Atmosphere Transfer model pyAPES to a temperate raised bog site by calibration against measured peat temperature, water table and surface CO2 fluxes. We identified the most important traits determining CO2 fluxes by conducting Morris sensitivity analysis (MSA) under changing conditions throughout the year and simulated VP encroachment. We further investigated transferability of results to other sites by extending MSA to parameter ranges derived from literature review. We found highly variable intra-annual plant traits importance determining ecosystem CO2 fluxes, but only a partial shift of importance of photosynthetic processes from moss to VP during encroachment. Ecosystem respiration was dominated by peat respiration. Overall, carboxylation rate, base respiration rate and temperature sensitivity (Q10) were most important for determining bog CO2 balance and parameter ranking was robust even under the extended MSA.

Long-term declines in chlorophyll a and variable phenology revealed by a 60-year estuarine plankton time series

Long-term ecological time series provide a unique perspective on the emergent properties of ecosystems. In aquatic systems, phytoplankton form the base of the food web and their biomass, measured as the concentration of the photosynthetic pigment chlorophyll a (chl a), is an indicator of ecosystem quality. We analyzed temporal trends in chl a from the Long-Term Plankton Time Series in Narragansett Bay, Rhode Island, USA, a temperate estuary experiencing long-term warming and changing anthropogenic nutrient inputs. Dynamic linear models were used to impute and model environmental variables (1959 to 2019) and chl a concentrations (1968 to 2019). A long-term chl a decrease was observed with an average decline in the cumulative annual chl a concentration of 49% and a marked decline of 57% in winter-spring bloom magnitude. The long-term decline in chl a concentration was directly and indirectly associated with multiple environmental factors that are impacted by climate change (e.g., warming temperatures, water column stratification, reduced nutrient concentrations) indicating the importance of accounting for regional climate change effects in ecosystem-based management. Analysis of seasonal phenology revealed that the winter-spring bloom occurred earlier, at a rate of 4.9 ± 2.8 d decade-1. Finally, the high degree of temporal variation in phytoplankton biomass observed in Narragansett Bay appears common among estuaries, coasts, and open oceans. The commonality among these marine ecosystems highlights the need to maintain a robust set of phytoplankton time series in the coming decades to improve signal-to-noise ratios and identify trends in these highly variable environments.

Control of Vibrio vulnificus proliferation in the Baltic Sea through eutrophication and algal bloom management

Due to climate change the pathogenic bacterium Vibrio vulnificus proliferates along brackish coastlines, posing risks to public health, tourism, and aquaculture. Here we investigated previously suggested regulation measures to reduce the prevalence of V. vulnificus, locally through seagrass and regionally through the reduction of eutrophication and consequential formation of algal blooms. Field samples collected in the summer of 2021 covered the salinity and eutrophication gradients of the Baltic Sea, one of the largest brackish areas worldwide. Physico-, biological- and hydrochemical parameters were measured and variables explaining V. vulnificus occurrence were identified by machine learning. The best V. vulnificus predictors were eutrophication-related features, such as particulate organic carbon and nitrogen, as well as occurrence of potential phytoplankton blooms and associated species. V. vulnificus abundance did not vary significantly between vegetated and non-vegetated areas. Thus, reducing nutrient inputs could be an effective method to control V. vulnificus populations in eutrophied brackish coasts.

Temperature and nutrients drive distinct successions between diatoms and dinoflagellates over the past 40 years: Implications for climate warming and eutrophication

Diatoms and dinoflagellates are two typical functional groups of phytoplankton, playing important roles in ecosystem processes and biogeochemical cycles. Changes in diatoms and dinoflagellates are thought to be one of the possible mechanisms for the increase in harmful algal blooms (HABs), due to changing hydrological conditions associated with climate change and human activities. However, little is known about their ability to adapt to changing ocean environments, thus making it difficult to know whether and how they are adapting. By analyzing a 44-year monitoring dataset in the central Bohai Sea during 1978–2021, we found that the abundance ratio of diatoms to dinoflagellates showed a decreasing trend seasonally and ecologically, indicating that the phytoplankton community underwent distinct successional processes from diatom dominance to diatom-dinoflagellate co-dominance. These processes exhibited varying responses to temperature, nutrient concentrations and ratios, and their interactions, of which temperature primarily drove the seasonal succession whereas nutrients were responsible for the ecological succession. Specifically, diatoms showed a preference for lower temperatures and higher DIP concentrations, and were able to tolerate lower DIN at lower temperatures. In contrast, dinoflagellates tended to prevail at conditions of warming and high N/P ratios. These different traits of diatoms and dinoflagellates reflected the fact that warming as a result of rising temperature and eutrophication as a consequence of nutrient input would favor dinoflagellates over diatoms. Moreover, the increasing dominance of dinoflagellates indicated that dinoflagellate blooms were likely to become more frequent and intense in the central Bohai Sea.

Variation in macroinvertebrate assemblages and water quality as a test for different levels of ecological impairment across an Ethiopian highland river system

The Ethiopian highlands is an area under high anthropogenic pressure. Despite being a hotspot for freshwater biodiversity, there is no regular monitoring of the ecological status of local rivers. Physicochemical and nutrient water-quality parameters and macroinvertebrate assemblages were sampled monthly from the Megech River and its tributaries from January to March 2021. Sampling locations were designated as being either upstream or downstream of the Gondar City urban area. We tested for temporal (monthly) and spatial (location, river) variation in water quality and spatial (location, river) variation in macroinvertebrate assemblage structure, and examined which water quality parameters were most associated with patterns in macroinvertebrate assemblages. Water quality varied significantly between locations and months, but not between rivers. Water quality differences were particularly driven by higher nutrient, salinity, dissolved solids and conductivity levels downstream, and higher pH and dissolved oxygen levels upstream. Despite macroinvertebrate assemblages being more abundant and diverse downstream, biotic index scores generally indicated slightly increased ecological impairment downstream. There was a clear spatial pattern in macroinvertebrate assemblages between locations. We detected a significant difference between rivers, with pairwise differences between sampling locations, particularly due to high dissimilarity between the upstream and downstream locations of the Angereb, Shinta and Qeha rivers. BIO-ENV Pearson correlations indicated that variation in macroinvertebrate assemblages were mostly explained by dissolved oxygen, salinity and nutrient parameters including nitrate, ammonium, and sulphate. Our findings confirm the need for more rigorous monitoring of Ethiopian highland rivers and improved management of nutrient inputs.

Assessment of nitrogen, phosphorus and potassium flows in China's food system during 2010–2019: Implications for integrated management

Nitrogen (N), phosphorus (P), and potassium (K) are essential nutrients for food production. However, the mismanagement of these elements has resulted in numerous environmental problems and poses a threat to resource security. This study aims to measure the flows of N, P, and K through China's food system during 2010–2019 by applying a dynamic flow accounting method. Our results show that China's food system is characterized by substantial nutrient inputs and significant nutrient losses, with moderate levels of nutrient recycling. The nutrient management had been improved during this study period. However, there were certain issues that should be further addressed, which were identified in this study. More efforts should be made to control nutrient inputs, minimize nutrient losses, and enhance nutrient recycling. By considering both synergies and trade-offs among N, P, and K management, we propose a holistic and integrated approach to nutrient management.

Interannual Variability of Marine Nitrogen Fixation in the Western Tropical Atlantic

AbstractN2 fixation is a central process of the marine nitrogen cycle, yet little is known about how this process varies from year‐to‐year. Here, we investigate this variability in the Western Tropical Atlantic (WTA), a region where N2 fixation is prevalent, fueled, in part, by the nutrient input from the Amazon River. We use hindcast simulations from 1983 through 2019 with the Regional Oceanic Modeling System (ROMS) coupled to the Biogeochemical Elemental Cycling (BEC) model expanded to include Diatom‐Diazotroph Assemblages (DDAs). Throughout the WTA, we find a substantial level of interannual variability of N2 fixation, altering it by up to 33%, and locally by up to nearly 60%. Part of this interannual variability is driven by variations in the Amazon River discharge, which during high discharge events leads to reduced rates in the upper parts of the plume and strongly enhanced rates in the downstream part. This dipole pattern is a consequence of the riverine inputs of phosphorus and the competition with non‐diazotrophs for this limiting resource. Another part of the N2 fixation variability is driven by the Atlantic Meridional Mode (AMM), and the El Niño‐Southern Oscillation (ENSO). These processes alter N2 fixation primarily through the supply of the limiting nutrients phosphorus and iron by vertical mixing, while the role of top‐down control through grazing is relatively limited in our model. The high, and so far not well recognized interannual N2 fixation variability can lead to erroneous extrapolation of field measurements and inaccuracies in the marine nitrogen budget, if unaccounted for.

Addressing the safety of new food sources and production systems.

New food sources and production systems (NFPS) are garnering much attention, driven by international trade, changing consumer preferences, potential sustainability benefits, and innovations in climate-resilient food production systems. However, NFPS can introduce new challenges for food safety agencies and food manufacturers. Most food safety hazards linked to new foods have been identified in traditional foods. However, there can be some food safety challenges that are unique to new foods. New food ingredients, inputs, and processes can introduce unexpected contaminants. To realize the full potential of NFPS, there is a need for stakeholders from governments, the food industry, and the research community to collectively work to address and communicate the safety of NFPS products. This review outlines known food safety hazards associated with select NFPS products on the market, namely, plant-derived proteins, seaweeds, jellyfish, insects, microbial proteins, as well asfoods derived from cell-based food production, precision fermentation, vertical farming, and 3D food printing. We identify common elements in emerging NFPS regulatory frameworks in various countries/regions. Furthermore, we highlight current efforts in harmonization of terminologies, use of recent scientific tools to fill in food safety knowledge gaps, and international multi-stakeholder collaborations to tackle safety challenges. Although there cannot be a one-size-fits-all approach when it comes to the regulatory oversight for ensuring the safety of NFPS, there is a need to develop consensus-based structured protocols or workflows among stakeholders to facilitate comprehensive, robust, and internationally harmonized approaches. These efforts increase consumers' confidence in the safety of new foods and contribute toward fair practices in the international trade of such foods.

Paleoceanographic Significance of Calcareous Nannofossil Assemblages in the Tropic Shale of Utah during Oceanic Anoxic Event 2 at the Cenomanian/Turonian Boundary

Oceanic Anoxic Event 2 (OAE2) at the Cenomanian/Turonian Boundary (CTB: 93.9Ma) involved the global deposition of organic carbon-rich sediments, a distinctive positive shift in carbon isotope values, and significant species turnover, including changes in calcareous nannofossil assemblages. While it is thought that volcanism triggered organic C-rich sediment deposition during OAE2, it is unclear whether enhanced productivity, increased stratification, of some combination of the two increased organic matter preservation. Calcareous nannofossil assemblages have the potential to qualitatively assess changes in ocean nutrient and temperature conditions to disentangle such ecological dynamics during OAE2. Here we study an expanded section of the Tropic Shale in a drill core in southern Utah near the western margin of the Western Interior Seaway (WIS) to understand how circulation changed during the event and how this may have influenced primary productivity and organic carbon burial. Relative abundance data of well-preserved nannoplankton are complemented with measurements of trace metal, and organic carbon and carbonate concentrations to determine changes in temperature and water column structure, as well as controls on surface water productivity. Detailed statistical analysis helps refine species paleoecologies combined with information from planktic and benthic foraminiferal assemblages and organic biomarkers. Changes in calcareous nannofossil assemblages indicate that near the start of OAE2 the western WIS surface ocean actually cooled for a short time. Following this, surface waters became warmer and more stratified as a Tethyan water mass invaded the seaway. Assemblages suggest that warmth persisted for much of the OAE2 interval, while stratification waxed and waned. The local seaway cooled near the end of OAE2 as Boreal water masses streamed along the western margin. Variations, including the decrease in the abundance of Biscutum constans and short-lived peaks in the abundance of Eprolithus spp. are super regional or possibly global in extent. There is no correlation between calcareous nannofossil assemblages and trace metal concentrations, suggesting they were unaffected by volcanism-related nutrient inputs. Assemblages support other data that suggest increased stratification influenced organic carbon burial in the Western Interior Seaway, and possibly elsewhere, during OAE2.

Nutrient Dynamics in Small West-Flowing Tropical Mountainous Rivers of India

In this study, the distribution of dissolved inorganic nitrogen (DIN), phosphorus (DIP), and silicate (DSi) in surface waters of 70 coastal rivers in India's Western Ghats (WG) has been determined. The nutrient concentrations in individual rivers appear to be influenced by catchment geology, land use, and climate. The entire WG region contributes 0.31 Tg of DIN, 0.03 Tg of DIP, and 5.65 Tg of DSi annually to the coastal Arabian Sea. The annual ratios of N:P, Si:N, and Si:P suggest that most of these rivers are limited by P rather than N, and there is an excess supply of Si, primarily from natural sources. P limitation is severe during monsoon periods, while N limitation is observed in the Deccan Traps region. The annual export of 0.31 Tg of DIN from WG rivers could support 2.05 Tg of carbon (new production) on the Arabian Sea coast, indicating that the riverine export of DIN can significantly remove atmospheric CO2 through biological pumps in the Arabian Sea. The study also confirms that the excess input of Si from natural processes relative to the anthropogenic supply of limited P and N further supports the idea that riverine nutrient inputs from small west-flowing tropical mountainous rivers do not contribute to coastal eutrophication along the Eastern Arabian Sea coast.

Modeling attenuation of photosynthetically active radiation across the optical gradient in the Laurentian Great Lakes with application to Lake Erie

Representation of subsurface photosynthetically active radiation (PAR) in biophysical models of the Laurentian Great Lakes (LGL) is imperative to their utility as tools for research and management. Here we consolidated measured vertical profiles of subsurface PAR with concurrent water quality (WQ) data from four LGL. We estimated the diffuse attenuation coefficient of PAR (Kd(PAR)) by fitting an exponential function to measured PAR over depth, and evaluated 68 regressions predicting Kd(PAR) as a function of water quality variables (Kd-WQ regressions). We compare four of the top cross-lake calibrated regressions against two published regressions trained on western Lake Erie (WLE) data. Then, as a case study, we demonstrate the utility of our cross-lake calibrated Kd-WQ regressions with a simplified biophysical model of Lake Erie consisting of the Finite Volume Community Ocean Model with submodules for simulating suspended sediment and dissolved organic carbon (FVCOM-SS-DOC). Twenty-five Kd-WQ regressions were identified as candidates for use in biophysical models based on their skill determined via cross-validation. WLE-trained Kd-WQ regressions were less able to simulate Kd(PAR) and PAR in more transparent waters compared to cross-lake calibrated Kd-WQ regressions, which translated to considerable differences in primary production estimates for the central and eastern basins when using WQ data simulated by FVCOM-SS-DOC. A cross-lake calibrated Kd-WQ regression was installed into FVCOM-SS-DOC, which then simulated spatial patterns of suspended sediments and Kd(PAR). These calibrated Kd-WQ regressions can be used in a variety of biophysical models across optically-distinct waters of the LGL to support adaptive management of nutrient inputs and fisheries

Arctic cyanobacterial mat community diversity decreases with latitude across the Canadian Arctic.

Cyanobacterial mats are commonly reported as hotspots of microbial diversity across polar environments. These thick, multi-layered microbial communities provide a refuge from extreme environmental conditions, with many species able to grow and coexist despite the low allochthonous nutrient inputs. The visibly dominant phototrophic biomass is dependent on internal nutrient recycling by heterotrophic organisms within the mats, however the specific contribution of heterotrophic protists remains little explored. In this study, mat community diversity was examined along a latitudinal gradient (55-83°N), spanning subarctic taiga, tundra, polar desert, and the High Arctic ice shelves. The prokaryotic and eukaryotic communities were targeted respectively by V4 16S and V9 18S rRNA gene amplicon high-throughput sequencing. Prokaryotic and eukaryotic richness decreased, in tandem with decreasing temperatures and shorter seasons of light availability, from the subarctic to the High Arctic. Taxonomy-based annotation of the protist community revealed diverse phototrophic, mixotrophic and heterotrophic genera in all mat communities, with fewer parasitic taxa in High Arctic communities. Co-occurrence network analysis identified greater heterogeneity in eukaryotic than prokaryotic community structure among cyanobacterial mats across the Canadian Arctic. Our findings highlight the sensitivity of microbial eukaryotes to environmental gradients across northern high latitudes.

Risk transference between climate variability and financial derivatives: Implications for global food security

We investigate the impacts of the El Niño-Southern Oscillation (ENSO) on global food security by using information embedded in financial derivatives. Using a state-of-the-art general circulation model (GCM) climate forecasting system that generates observations on the phase and magnitude of ENSO, we create novel indices that track its uncertainty throughout time. Together with the option implied volatilities of core food inputs (wheat, maize, rice, and soybean), we model the time-varying volatility spillover from ENSO to each commodity, capturing the direction and intensity of risk transference. Simulating Gaussian and non-Gaussian impulse responses that mimic an increase in climate variability show a persistent impact on the price uncertainty of the commodities lasting up to three months. We also show that shocks are contingent on the phase of ENSO, with warmer conditions in the Eastern Pacific (i.e., the El Niño phase) increasing risk transference for soybean and rice. In contrast, the La Niña phase has a material influence on the uncertainty of wheat and maize. In all, we reveal a volatility transmission channel of climate variability that affects financial markets, suggesting valuable inferences about the impact of climate shocks can be derived from the rich information embedded in commodity-linked derivatives.

Crop cover and nutrient levels mediate the effects of land management type on aquatic invertebrate richness in prairie potholes.

Aquatic invertebrates provide important ecosystem services, including decomposition and nutrient cycling, and provide nutrition for birds, fish, amphibians, and bats. Thus, the effects of agricultural land management practices on aquatic invertebrates are relevant to farmers, wildlife biologists, and policymakers. Here, we used data on aquatic invertebrates (159 taxa, 73 to species, 75 to genus/family) collected in 40 wetlands in the Canadian prairies to test for direct and indirect relationships among land management types (perennial cover, organic, minimum tillage, conventional), landscape structure (cropland and wetland cover within the surrounding landscape), and water quality (total nutrient levels, turbidity) on species richness of invertebrates using structural equation modelling. Additionally, we assessed variation in community composition within and among wetlands in different land use management types using a direct gradient analysis and variance partitioning. The direct effects of land management type were not supported but we found strong supportive evidence that effects of land management on richness were significantly mediated through cropland cover, nutrient levels, and turbidity. After controlling for these indirect effects, aquatic invertebrate richness decreased along a gradient from the lowest to the highest farming intensity, i.e., richness decreased from perennial cover sites to organic to minimum tillage to conventional sites. Support was also found for negative effects of nutrient levels and turbidity on richness. We did not find significant support for differences in gamma diversity or a simple test (homogeneity of multivariate dispersions) of differences in turnover among land management types; however, land management had a significant effect in distance-based redundancy analysis. Taken together, these results suggest that focusing conservation efforts on reducing cropland erosion and nutrient inputs to wetlands and creating more permanent cover may be effective strategies for conserving richness of aquatic invertebrates in agricultural landscapes in this region.

Phenotypic and genomic characterization of Methanothermobacter wolfeii strain BSEL, a CO2-capturing archaeon with minimal nutrient requirements.

A new variant of Methanothermobacter wolfeii was isolated from an anaerobic digester using enrichment cultivation in anaerobic conditions. The new isolate was taxonomically identified via 16S rRNA gene sequencing and tagged as M. wolfeii BSEL. The whole genome of the new variant was sequenced and de novo assembled. Genomic variations between the BSEL strain and the type strain were discovered, suggesting evolutionary adaptations of the BSEL strain that conferred advantages while growing under a low concentration of nutrients. M. wolfeii BSEL displayed the highest specific growth rate ever reported for the wolfeii species (0.27 ± 0.03 h-1) using carbon dioxide (CO2) as unique carbon source and hydrogen (H2) as electron donor. M. wolfeii BSEL grew at this rate in an environment with ammonium (NH4+) as sole nitrogen source. The minerals content required to cultivate the BSEL strain was relatively low and resembled the ionic background of tap water without mineral supplements. Optimum growth rate for the new isolate was observed at 64°C and pH 8.3. In this work, it was shown that wastewater from a wastewater treatment facility can be used as a low-cost alternative medium to cultivate M. wolfeii BSEL. Continuous gas fermentation fed with a synthetic biogas mimic along with H2 in a bubble column bioreactor using M. wolfeii BSEL as biocatalyst resulted in a CO2 conversion efficiency of 97% and a final methane (CH4) titer of 98.5%v, demonstrating the ability of the new strain for upgrading biogas to renewable natural gas.IMPORTANCEAs a methanogenic archaeon, Methanothermobacter wolfeii uses CO2 as electron acceptor, producing CH4 as final product. The metabolism of M. wolfeii can be harnessed to capture CO2 from industrial emissions, besides producing a drop-in renewable biofuel to substitute fossil natural gas. If used as biocatalyst in new-generation CO2 sequestration processes, M. wolfeii has the potential to accelerate the decarbonization of the energy generation sector, which is the biggest contributor of CO2 emissions worldwide. Nonetheless, the development of CO2 sequestration archaeal-based biotechnology is still limited by an uncertainty in the requirements to cultivate methanogenic archaea and the unknown longevity of archaeal cultures. In this study, we report the adaptation, isolation, and phenotypic characterization of a novel variant of M. wolfeii, which is capable of maximum growth with minimal nutrients input. Our findings demonstrate the potential of this variant for the production of renewable natural gas, paving the way for the development of more efficient and sustainable CO2 sequestration processes.

Millets as Nutricereal Climate Resilient Smart Crop: A Review

Worldwide climate change and extreme weather variations are the most threatening challenge to agriculture and allied activities. The entire food production system has faced serious challenges due to increase in average temperature, intensity and frequency of drought and flood, aberration of rainfall patterns, and elevation in CO2 concentration. In today’s world climate change is a major concern. Review of different literature from different reports and studies for different nutritional benefit of millets and how it can thrive in climate change conditions are important. Different literature have been searched from different sources and complied. Millets are considered highly nutrition-rich and climate-resilient coarse grain cereals and it can enhance income as well as improve food and nutrition security. Millets have climate-resilient features and that’ s why they can thrive in adjust to a vast changing ecological conditions, less water requirements, low nutrient input conditions and also they have more resistance to environmental hassels. In comparison to cereals, millets have more dietary fibres, resistant starches and are nutritionally superior. Millet require less time to complete its life cycle than rice and wheat, so they have the capacity to escape the stresses. Millets also provide several health benefits as they have nutritious. The cost of cultivation is also less compare to other cereals. As population growth increases and climate is changing day by day so millets are the alternative choice for today’s world. In Karnataka most of the farmers already have started to cultivate drought resistant millets than more water required crop like rice, sugarcane, and maize to due to climate change. They commonly grown millets from domestic purposes are sorghum, pearl millet, finger - millet, barnyard, foxtail, kodo, proso and Little millet.

Unravelling the genetic mechanisms and paleoenvironmental controls of early Cretaceous Oyster Mass occurrences (OMOs), Neuquén Basin, west-central Argentina

Lower Valanginian oyster mass occurrences (OMOs) from the Neuquén Basin of Argentina are analyzed using a multidisciplinary approach, including the description of their sedimentological signature and stratigraphic contacts, assessment of taphonomical attributes, and paleontological and paleoecological characteristics. These OMOs present a wide distribution in the study area, with lateral continuity for at least 2.5 km and up to 12 m thick. They occur within a single stratigraphic interval, constrained in terms of sequence stratigraphy and biostratigraphy. Three stacked tabular OMOs separated by mudstone levels were recorded in all the studied localities. The associated lithofacies point to a mainly outer ramp paleoenvironment, below storm wave base and occasionally disturbed by exceptional, distal storm flows. Internally, the OMOs share a common vertical trend characterized, from base to top, by a gradual increase in oyster abundance and a transition from mainly reclining, disarticulated oysters to articulated, cementing oysters conforming build-ups. Hence, a mainly biogenic origin is proposed, with autobiostromes grading vertically to bioherms. This vertical trend was interpreted in terms of development stages, namely, colonization, expansion, climax and extinction, which were in turn related to specific paleoenvironmental controls. Particularly, the OMOs establishment and development were associated to low sedimentation rates, salinity fluctuations and high nutrient input as a result of high primary productivity. At a larger scale, the overall paleoenvironmental conditions and subtropical geographical position of the basin were detrimental for most reef builders typical of the Cretaceous period (e.g., corals, sponges, rudists), and could have favored oyster proliferation and OMOs development instead.

Increases in the soil ammonia oxidizing phylotypes and their rechange due to long-term irrigation with wastewater.

Wastewater irrigation is a common practice for agricultural systems in arid and semiarid zones, which can help to overcome water scarcity and contribute with nutrient inputs. Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are key in the transformation of NH4+-N in soil and can be affected by variations in soil pH, EC, N and C content, or accumulation of pollutants, derived from wastewater irrigation. The objective of this study was to determine the changes in the ammonia oxidizing communities in agricultural soils irrigated with wastewater for different periods of time (25, 50, and 100 years), and in rainfed soils (never irrigated). The amoA gene encoding for the catalytic subunit of the ammonia monooxygenase was used as molecular reporter; it was quantified by qPCR and sequenced by high throughput sequencing, and changes in the community composition were associated with the soil physicochemical characteristics. Soils irrigated with wastewater showed up to five times more the abundance of ammonia oxidizers (based on 16S rRNA gene relative abundance and amoA gene copies) than those under rainfed agriculture. While the amoA-AOA: amoA-AOB ratio decreased from 9.8 in rainfed soils to 1.6 in soils irrigated for 100 years, indicating a favoring environment for AOB rather than AOA. Further, the community structure of both AOA and AOB changed during wastewater irrigation compared to rainfed soils, mainly due to the abundance variation of certain phylotypes. Finally, the significant correlation between soil pH and the ammonia oxidizing community structure was confirmed, mainly for AOB; being the main environmental driver of the ammonia oxidizer community. Also, a calculated toxicity index based on metals concentrations showed a correlation with AOB communities, while the content of carbon and nitrogen was more associated with AOA communities. The results indicate that wastewater irrigation influence ammonia oxidizers communities, manly by the changes in the physicochemical environment.

Urbanization exacerbates climate sensitivity of eastern United States broadleaf trees.

Tree growth is a key mechanism driving carbon sequestration in forest ecosystems. Environmental conditions are important regulators of tree growth that can vary considerably between nearby urban and rural forests. For example, trees growing in cities often experience hotter and drier conditions than their rural counterparts while also being exposed to higher levels of light, pollution, and nutrient inputs. However, the extent to which these intrinsic differences in the growing conditions of trees in urban versus rural forests influence tree growth response to climate is not well known. In this study, we tested for differences in the climate sensitivity of tree growth between urban and rural forests along a latitudinal transect in the eastern United States that included Boston, Massachusetts, New York City, New York, and Baltimore, Maryland. Using dendrochronology analyses of tree cores from 55 white oak trees (Quercus alba), 55 red maple trees (Acer rubrum), and 41 red oak trees (Quercus rubra) we investigated the impacts of heat stress and water stress on the radial growth of individual trees. Across our three-city study, we found that tree growth was more closely correlated with climate stress in the cooler climate cities of Boston and New York than in Baltimore. Furthermore, heat stress was a significant hindrance to tree growth in higher latitudes while the impacts of water stress appeared to be more evenly distributed across latitudes. We also found that the growth of oak trees, but not red maple trees, in the urban sites of Boston and New York City was more adversely impacted by heat stress than their rural counterparts, but we did not see these urban-rural differences in Maryland. Trees provide a wide range of important ecosystem services and increasing tree canopy cover was typically an important component of urban sustainability strategies. In light of our findings that urbanization can influence how tree growth responds to a warming climate, we suggest that municipalities consider these interactions when developing their tree-planting palettes and when estimating the capacity of urban forests to contribute to broader sustainability goals in the future.