Water Environmental Conditions Research Articles

Microbial community composition across a coastal hydrological system affected by submarine groundwater discharge (SGD).

Mobile Bay, the fourth largest estuary in the USA located in the northern Gulf of Mexico, is known for extreme hypoxia in the water column during dry season caused by NH4+-rich and anoxic submarine groundwater discharge (SGD). Nutrient dynamics in the coastal ecosystem point to potentially elevated microbial activities; however, little is known about microbial community composition and their functional roles in this area. In this study, we investigated microbial community composition, distribution, and metabolic prediction along the coastal hydrological compartment of Mobile Bay using 16S rRNA gene sequencing. We collected microbial samples from surface (river and bay water) and subsurface water (groundwater and coastal pore water from two SGD sites with peat and sandy lithology, respectively). Salinity was identified as the primary factor affecting the distribution of microbial communities across surface water samples, while DON and PO43- were the major predictor of community shift within subsurface water samples. Higher microbial diversity was found in coastal pore water in comparison to surface water samples. Gammaproteobacteria, Bacteroidia, and Oxyphotobacteria dominated the bacterial community. Among the archaea, methanogens were prevalent in the peat-dominated SGD site, while the sandy SGD site was characterized by a higher proportion of ammonia-oxidizing archaea. Cyanobium PCC-6307 and unclassified Thermodesulfovibrionia were identified as dominant taxa strongly associated with trends in environmental parameters in surface and subsurface samples, respectively. Microbial communities found in the groundwater and peat layer consisted of taxa known for denitrification and dissimilatory nitrate reduction to ammonium (DNRA). This finding suggested that microbial communities might also play a significant role in mediating nitrogen transformation in the SGD flow path and in affecting the chemical composition of SGD discharging to the water column. Given the ecological importance of microorganisms, further studies at higher taxonomic and functional resolution are needed to accurately predict chemical biotransformation processes along the coastal hydrological continuum, which influence water quality and environmental condition in Mobile Bay.

Study of sustainable development in Yongkang city based on environmental capacity and pollutant control

Over the past centuries, due to the improvement of the understanding of the natural environment and social service function of rivers, many countries have started the research and practice of water environment protection. China also paid most of its attentions to the water environment in most of its cities and towns. Systematic calculation and analysis of the water environment status becomes famous in most of Chinese regions, which not only shows the current status of water environment protection in China but also indicates the methods to reduce the domestic pollution. In this study, Yongkang city is selected as a typical Chinese city, COD(Chemical Oxygen Demand) and NH3-N(Ammonia Nitrogen) are considered as two typical pollutants, both water environmental capacity and current pollution are calculated. The environmental bearing capacity coefficient is utilized to show the current status of pollution level. The comparison and analysis between the water environmental capacity and current pollution shows a good water quality status in Yongkang city. This study is also able to further improve the water quality and social development in Yongkang city in the future.

Strength Characteristics and Corrosion of Glass Fibre Reinforced Concrete Column Exposed in Sea Water Environmental Condition

This paper highlights the investigation on the strength and corrosion study of glass fibre reinforced concrete (GFRP) column in sea water environmental condition. Specimen of size 600 mm length x 150 mm wide x 300 mm deep columns were cast. Totally 8 columns were cast. Out of which, 4 columns were cured using potable water and 4 columns were cured using in artificial sea water. Among 8 reinforced concrete columns, two concrete columns were used, as the reference column containing steel rods both in longitudinal and horizontal ties and were cured both in potable and artificial sea water. For the corrosion study, 2 concrete columns reinforced by GFRP bars in the longitudinal direction and steel rods as horizontal ties and were cured using artificial sea water. Rebound hammer and Ultrasonic Pulse Velocity tests were performed on columns to evaluate the strength characteristics at the end of 7, 14, 28, 56 and 90 days of curing. The results will also be validated using destructive methods. Corrosion study was also performed by single Cu-CuSo4 Half-Cell equipment. Based on the observation, it was found that the compressive strength in artificial sea water curing exhibited better performance than in potable water curing.

Tara Pacific Expedition’s Atmospheric Measurements of Marine Aerosols across the Atlantic and Pacific Oceans: Overview and Preliminary Results

AbstractMarine aerosols play a significant role in the global radiative budget, in clouds’ processes, and in the chemistry of the marine atmosphere. There is a critical need to better understand their production mechanisms, composition, chemical properties, and the contribution of ocean-derived biogenic matter to their mass and number concentration. Here we present an overview of a new dataset of in situ measurements of marine aerosols conducted over the 2.5-yr Tara Pacific Expedition over 110,000 km across the Atlantic and Pacific Oceans. Preliminary results are presented here to describe the new dataset that will be built using this novel set of measurements. It will characterize marine aerosols properties in detail and will open a new window to study the marine aerosol link to the water properties and environmental conditions.

KELIMPAHAN DAN DISTRIBUSI LARVA IKAN DI PERAIRAN PESISIR LAMPUNG TIMUR

Information abundance and distribution of fish larvae in coastal waters of East Lampung currently very limited. The research aimed to improve the knowledge of the early life of organisms, in order to manag biodiversity and biological resources in the waters. Research station representing the several water sectors: in-shore, near-shore, and off-shore. The research was a representation of eastern monsoon (June) and transition monsoon (September) in 2017. Fish larvae was harvested using bon ggo-net tool while its identification to family level using portable Dino-lite . Based on the result the Abundance of fish larvae in eastern monsoon was higher than transition monsoon. This research found 81 families of fish larvae. There were 10 dominant families, that are Gobiidae, Pegasidae, Mullidae, Pomacentridae, Sillaginiidae, Bleniidae, Bythitidae, Carangidae, Pseudochromidae and Bothidae. The distribution of fish larvae in the lower in-shore was higher than near-shore and off-shore, while east and transitional seasons have not much different larval catches. Temperature, salinity and pH parameters indicated optimal range state for survival and growth of fish larvae, brightness and turbidity in accordance with water quality standards, currents velocity on eastern monsoon is very fast while transition monsoon is fast to very fast. Phytoplankton and zooplankton showed sufficient natural food availability for the life of fish larvae. Result Canonnical Corespondence Analysis (CCA) analysis to connectivity of abundance and larvae distribution showed that the brightness parameter forming a point projection while other water environment condition parameters form a vector projection in both period of monsoon. The abundance and fish larvae distribution in coastal waters of East Lampung in all three sectors of the waters had proportionality to the parameters of environmental conditions, especially the current parameters and the difference of the monsoon period.

Physiological Characteristics and Environment Adaptability of Reef-Building Corals at the Wuzhizhou Island of South China Sea.

The health of coral reef has declined significantly around the world due to the impact of human activities and natural environment changes, and corals have to develop effective resistance mechanisms to survive. In this study, we examined the physiological characteristics and Symbiodiniaceae types of four dominant scleractinian corals in the reefs at the Wuzhizhou Island (WZZ) in South China Sea. The water environmental conditions are complex on the north side of WZZ due to regional geography and tourism development, and all corals had their unique physiological conditions and Symbiodiniaceae types. For all corals of this study, the rETRmax and protein content were significantly lower and the SOD enzyme activity was significantly higher in the north than in the south. Interestingly, ITS2 genotyping showed that Galaxea fascicularis contained dominant Symbiodiniaceae either genotype C21 or D1a depending on the regional environmental stress, and had stronger heterotrophy than the other three coral species. In addition, the light use efficiency of the dominant Symbiodiniaceae type C1 for Pocillopora verrucosa was significantly lower in the north and the half saturating irradiance was stable. Besides, Montipora truncata and P. verrucosa increased their density of the symbiotic zooxanthella C1 in the north to offset the decline of photosynthetic efficiency and thus supply energy. For Porites lutea and G. fascicularis, their half saturating irradiance declined sharply in the north, where P. lutea resorted to heterotrophic feeding to balance the energy budget when the number of zooxanthellas fell short and G. fascicularis reduced its energy reserve significantly when the energy source was limited. We thus demonstrated the differences in the physiological responses and energy metabolism strategies between the zooxanthella and the host coral of the four reef-building coral species under the stress of complex water environment on the north side of WZZ. The corals were found to cope with natural and anthropogenic stressors by adjusting the nutrient input sources and the energy structure metabolism of coral hosts or adapting to more sustainable relationship with Symbiodiniaceae clades. The corals exhibited their capacity against long-term disturbances by developing their own successful resistance mechanisms at symbiotic relationship and energy metabolism level.

Investigation of nitrogen pollutants transformation and its pathways along the long-distance prechlorinated raw water distribution system

Understanding the transformation pattern of nitrogen (N) pollutants and its pathways in the prechlorinated raw water distribution system (PRWDS) is vital for controlling the stablitiy and safety of raw water qulity. This study investigated the N transformation, N functional genes and their correlations to find the N transformation pathways along the PRWDS. Results suggested that simultaneous nitrification, anaerobic ammonium oxidation and denitrification (SNAD) contribute to the N transformationin the PRWDS. Along the pipeline, anammox 16S rRNA (9.18 × 107–8.41 × 108 copies/g), limited by prechlorination, was the most abundant N functional genes and anammox process was the main pathway of ammonia nitrogen (NH4+-N). The decreasing NH4+-N was connected with Planctomycetes, Nitrospira and abundance of nxrA attributing to the joint effort of anammox and declined nitrification. The concentration of nitrate (NO3−-N) increasing at first and then decreasing, was correlated positively with Sphingomonas. because of the declined nitritication and increased denitrification. Besides, the NO3−-N→NO2−-N process was considered to be primary NO3−-N transformation pathways. Increases in the concentration of dissolved organic nitrogen (DON) and nitrite (NO2−-N) observed in the PRWDS had positive correlation with relative abundance of Pseudomonas. We believe that prechlorination shaped the particular bacterialcharacteristics in biofilms and influenced the N transformation pathways indirectly, resulting in the varying N transformation rules in PRWDSs. Moreover, systematic and extended research is particularly vital for determining the effects of changes in source water quality and environmental conditions on bacterial community structure and N conversion along PRWDSs.

Complex responses of suspended particulate matter in eutrophic river and its indicative function in river recovery process

Water environment and hydrodynamic condition of a river exerts a powerful influence on Suspended Particulate Matter (SPM) in rivers. Complex responses of SPM in rivers under changing water quality and hydrodynamic condition remain unclear and its indicative role in river recovery process is neglected. In this paper, twenty SPM samples were collected in June 2017 (rainy season) in Ziya River Mainstream (ZRM). The eutrophication levels of ZRM, sedimentation property and P fractions of SPM, and P-buffering intensity of the ZRM were investigated and compared with our previous research in arid season. The results showed eutrophication level was lower in rainy season than in arid season with mean Eutrophication Index (EI) values of 90.02 (seriously eutrophied) and 103.48 (extremely eutrophied), respectively. SPM in arid season has higher Loss On Ignition (LOI) content and was easier to remain suspension. The total amount of NaOH extracted Phosphorus (NaOH-P) and Organic Phosphorus (OP) fractions in SPM and Phosphorus (P) buffering intensity of ZRM were higher in arid season than in rainy season. Differences in water quality of a river can induce complex responses of SPM in its microstructure, P buffering ability and can act as a positive yet negative role in river eutrophication control. We put forward a P based river recovery process and suggest two-step river restoration measures, we point out rainy season is the reasonable timing to conduct measures in decreasing SPM concentration under the premise of mitigating P input. These results deepen our understanding on the role of SPM in P cycling in fluvial system and provide a new idea for river restoration work worldwide.

Study on the mechanism of the influence of flood storage at the end of the Three Gorges Reservoir on the phosphorus forms in the sediments of the tributary reservoir bay

This paper studies the influence of the impounding process during flood recession in the TGR on the distribution and rerelease of sediment phosphorus forms in the Xiangxi Bay in 2016. Influenced by the main stream of the Three Gorges Reservoir (TGR) flowing backward during impoundment, the water environmental conditions, sediment grain size and sediment-forming environment of the tributary bays change correspondingly. In this study, it is found that the water temperature (WT), turbidity and oxidation–reduction potential (ORP) of the overlying water in the Xiangxi Bay decrease, while the pH increases after impoundment in the TGR. The backward flow of the main stream containing a large amount of sediments increases the sediment content of the tributary bay, and the difference in sediment particle size between the main stream and tributaries narrows after resedimentation. The phosphorus adsorbed on the sediments increases the total phosphorus (TP) in the sediments of the Xiangxi River to 1.3 times its value before water impoundment. NaOH-P and HCl-P in the Xiangxi River sediments account for 42% and 38% of the TP, respectively, and the contents of the various phosphorus forms are ranked in the following order: NaOH-P > HCl-P > organic phosphorus (OP). After impoundment, HCl-P accounts for 67% of the TP, and the relative contents of the phosphorus forms are ranked as: HCl-P > OP > NaOH-P. Orthophosphate (PO43−-P) in the Xiangxi sediments before and after impoundment acts as a source, and the PO43−-P diffusion flux increases from approximately − 0.0029 to 0.0059 mg (m2 d)−1 before impoundment to 0.0067–0.1071 mg (m2 d)−1 after impoundment, which is mainly due to the increased difference in concentration of PO43−-P [ρ(PO43−-P)] between the sediment interstitial water and overlying water after impoundment. After nutrient recharge of the main stream of the Yangtze River, ρ(PO43−-P) of the overlying water is 3.7 times its value before impoundment, and after the release of NaOH-P in the sediments, ρ(PO43−-P) of the interstitial water is 8.3 times its value before water impoundment. Hence, the risk of nutrient release from the sediments in the Xiangxi Bay increases.

Database replication method for real-time measurement pH parameter of fishery using a wireless sensor system

The problem of mass fish mortality in Indonesia is already common, Environmental conditions determine the survival of fish. Determination of water environmental conditions has water parameters including water (depth, brightness, water temperature, acidity (pH), dissolved oxygen (DO) and ORP (Oxidation Reduction Potential)). Acidity (pH) is one of the important things in determining the water quality of water. The pH generally increases due to polluted waters. Environmental conditions that are always changing will affect the life processes of organisms in it, especially fish need to be monitored in realtime, especially to avoid massive fish mortality. This paper purpose the real-time acquisition builds with combine the wireless sensor system and database replication concept. From the result of implementation database replication method for real-time measurement pH parameter of fishery agriculture using wireless sensor system, that’s the system can perform continuously to real-time acquisition data online

Degraded functional structure of macroinvertebrates caused by commercial sand dredging practices in a flood plain lake

In parts of developing countries, the over-exploitation of sands from inland waters has led to serious environmental concerns. However, understanding of the impacts of commercial sand dredging on inland water ecosystem functions remains limited. Herein, we assess the effects of this activity on the functional structure of the macroinvertebrate community and its recovery processes based on a 4-year survey, in the South Dongting Lake in China. Our result showed a simplified macroinvertebrate functional structures within the dredged area, as evidenced by a loss of certain trait categories (e.g., oval and conical body form) and a significant reduction in trait values due to the direct removal of macroinvertebrates and indirect alternations to physical environmental conditions (e.g., water depth and %Medium sand). Moreover, clear increases were observed in certain trait categories (e.g., small body size and swimmer) resulting from the dredging-related disturbance (e.g., increased turbidity) within the adjacent area. Furthermore, one year after the cessation of dredging, a marked recovery in the taxonomic and functional structure of macroinvertebrate assemblages was observed with most lost trait categories returning and an increase in the trait values of eight categories (e.g., body size 1.00–3.00 cm and oval body form) within the dredged and adjacent area. In addition, dispersal processes and sediment composition were the main driver for the structuring of the macroinvertebrate taxonomic and functional assemblages during the dredging stages, whilst water environmental conditions dominated the taxonomic structure and dispersal processes determined the functional structure during the recovery stage. Implications of our results for monitoring and management of this activity in inland waters are discussed.

Eco-Efficiency of End-of-Pipe Systems: An Extended Environmental Cost Efficiency Framework for Wastewater Treatment

As a method for eco-efficiency analysis, environmental cost efficiency (ECE) indicators have been proposed for the end-of-pipe (EOP) systems that referred to the techniques achieving environmental benefit under economic cost. The wastewater treatment plant (WWTP) belongs to the EOP systems; however, few studies used the ECE indicators for the sustainability evaluation. Here, this study first proposed the following processes that had been excluded in the current ECE framework and thus limited the potential application in WWTP: (1) the direct impact of wastewater on receiving water, (2) the migration and transformation of water pollutants affected by the self-purification mechanisms of receiving water. To address the aforementioned processes, this study extended the framework of ECE indicators by means of incorporating the potential growth of microorganisms as the characterization state and integrating the water quality models with the characterization models. To investigate the applicability, a full-scale WWTP was selected as the study case and the eco-efficiency of the increasing levels of sewage treatment was evaluated. The case outcome showed that, with the extended ECE indicators, the analysis of eco-efficiency could be directly related to the specific locations and could determine the specific distance ranges within which the scenarios changing were considered efficient. Moreover, the eco-efficiency could be investigated under more concrete and flexible situations because the extended framework of ECE indicators was able to include more information, such as different types of receiving water or different environmental conditions of certain water body.

Evaluation and Analysis of Water Quality of Marine Aquaculture Area.

In the rapid development of marine aquaculture, the water quality of aquatic environments is regarded as a main limiting factor. Therefore, it is necessary to assess the water quality and environmental conditions in marine aquaculture areas and find out the main influencing factors regarding damage to the water quality environment. In the present research, pond aquaculture and cage aquaculture areas were sampled in May, August and November in 2018. Nine water quality indicators were detected, including pH, temperature, salinity, dissolved oxygen, molybdate-reactive phosphorus, chemical oxygen demand, chlorophyll a, inorganic nitrogen and antibiotic resistance genes (ARGs). Principal component analysis (PCA) was used to analyze the water quality conditions, spatial–temporal changes, and the driving factors in pond and cage aquaculture areas. The results showed that three main components were extracted from the pond aquaculture area, which explained 66.82% of the results, the most relevant factors are salinity, dissolved oxygen and ARGs. For the cage aquaculture area, three main components were extracted which can account for 72.99% of the results, the most relevant factors are chlorophyll a, salinity and dissolved oxygen. The comprehensive scores of the principal components indicated that the heaviest polluted months in pond and aquaculture areas were August and November, respectively. The water quality of the pond aquaculture area is mainly limited by the volume of the pond, while aquaculture activities and seasonality are the main factors for cage aquaculture. ARGs in cage culture areas showed more variety and frequency compared with pond culture areas, which indicated that terrestrial input might be one of the sources for ARGs occurrence. The results would be helpful for the relevant authorities to select water quality monitoring parameters in marine aquaculture areas.

The spatial dimensions of agricultural development in Saudi Arabia(Study in development geography): الأبعاد المكانية للتنمية الزراعية في المملكة العربية السعودية(دراسة في جغرافية التنمية)

This research aims to identify the historical development of agriculture in the Kingdom and the impact of high oil and population increase and projects that have been implemented. The researcher relied on theoretical research by selecting the subject of the research and then refer to the sources of the collection of scientific material for research and codification. n this research، I reached a number of conclusions and recommendations، the most important of which is the Kingdom's self-sufficiency of many agricultural crops، the most important of which are cereals and the superiority of Riyadh city from the rest of the crop area. Conducting technical and economic studies on the types and quantities of non-traditional agricultural resources such as marine fish farms and then assessing their use in light of the limited water resources and environmental conditions that are not suitable for traditional agriculture.

New risk control mechanism for innovative deepwater artificial seabed system through online risk monitoring system

The current offshore field development concepts (dry tree or subsea tree) have limitations for petroleum production in ultra-deep water (more than 1500 m), where the challenges are characterized by the depth of water, remoteness and harsh environmental conditions. A new alternative offshore field development solution, termed as Deepwater Artificial Seabed (DAS) system, is proposed. The new DAS system offers improved technical and commercial performance, higher levels of safety, reduced interface complexity and improved development flexibility for field development in deep and ultra-deep water. Central to the evaluation and application of the new DAS system is the inherent risk relative to the acceptance level. Hence, barriers in the new DAS system are established and maintained to prevent, control or mitigate undesired events or accidents. This paper investigates a new risk control mechanism for the innovative DAS system in accordance with the online risk monitoring and decision support principle. Firstly, main characteristics and design principle of the DAS system are presented. On this basis, the main hazards for the DAS system are identified, which includes well incident/ loss of well control, mooring system failure, ballast system failure, leak from riser, flexible jumper and subsea production facilities, and damage to riser, flexible jumper and subsea production facilities. The risk level of the identified hazards related to offshore petroleum systems already in use is analyzed and presented by the results from the risk assessment for the Norwegian Continental Shelf (NCS) in the period of 2008–2017. It has been demonstrated that the risk associated with the key sub-systems including the ballast system, mooring system, well system and external impact protection system is at a level that calls for further risk reduction. This is followed by the barrier management principles as well as a discussion of existing and potential barriers in the DAS system. Improved barrier functions in the key sub-systems are analyzed systematically and proposals for alternative barrier functions are suggested based on the online risk modeling and decision support principle. Further, a case study in regard to the DAS mooring system failure event is conducted to demonstrate how the new risk control mechanism works. The proposed new risk control mechanism could improve the safety of the DAS system and convince the offshore petroleum industry for application significantly.

Long-term data on plankton communities in Torey lakes, a shallow saline lakes, Transbaikalia, Russia

This study aims to investigate dynamics of environmental and plankton parameters during the drying and initial filling phases of Torey lakes. These lakes located in the South-East Transbaikalia are shallow saline fluctuating lakes. We conducted our studies during different water level phases of the hydrological cycle, including three periods for Zun-Torey Lake: high (1999 and 2003), intermediate (2007, 2011) and low (2014 and 2016) lake levels and two periods for Barun-Torey: high water level (1999 and 2003) and the initial filling phase (2014, 2016, 2018). Fluctuations in water level and environmental conditions (TDS, pH, dissolved oxygen content, water temperature) changes due to dilution and concentration have influence on phyto- and zooplankton structure. Fluctuations of plankton communities are different for each lake and conform the phases of the hydrological cycle. We have identified four stages in changes of plankton community for Zun-Torey Lake as the deeper and slowly drying, and three stages for Barun-Torey Lake as a shallower and rapidly drying.

Water Stability of Light Weight Soil Amended with Expanded Polystyrene Beads

To reveal the durability of light weight soil ground under water environment conditions, the influence laws of soaking time and dry–wet cycle times on mechanical properties of light weight soil are researched by density tests, unconfined compressive strength tests, water absorption tests and mass loss rate tests. Due to chemical compositions in the light weight soil interacting with each other, a kind of network cemented structure containing soft inclusions (expanded polystyrene beads) is formed in the specimens. Enough water has been provided for the mixed soil in the physical–chemical reaction process in the experiments, hydrolysis and hydration of cement, ion exchange, hardening reaction and carbonation action occur continuously. Under long term soaking conditions, the physical properties of light weight soil are extremely stable, the network cemented structure is the physical basis for the hydrophobicity. When soaking time is more than 90 days, the unconfined compressive strength of the specimens will reach a stable value gradually. Similarly, light weight soil does not appear cracking phenomenon, and keep the mechanical properties and material density stable under long term dry–wet cycle. Thus light weight soil has good water stability and durability, it is recommended that light weight soil can be widely used in civil engineering, such as ground improvement, soft subgrade engineering, embankment heightening, slope repair, excavation backfill, pipeline backfilling and so on.

A study on Chinese ancient jades with mercury alteration unearthed from Lizhou\u2019ao Tomb

“Alteration” geologically refers to chemical composition and/or structural changes of minerals under the influences of hydrothermal fluids, surface water, seawater, or other environmental conditions. In this paper, we use the word “alteration” to refer to chemical component and structural changes in jade artifacts caused by human activity and natural weathering, which is different from the term in geology. “Mercury alteration”, a kind of black alteration related to Hg, is unique among the several types of alteration that occur in Chinese ancient jades. Mercury alteration often appears on ancient jade artifacts unearthed from high-grade tombs of the pre-Qin period (before 221 B.C.). Therefore, ancient jades with mercury alteration have attracted substantial attention from Chinese archaeologists. This paper reports the use of materials analytic techniques to study such ancient jade fragments. The studied jade samples date to the middle and late periods of the Spring and Autumn Period (~500 B.C.) and were unearthed from Lizhou’ao Tomb in Jiangxi Province, China. Structural analyses revealed the internal microstructure of the ancient jade fragments and the microdistribution of the mercury alteration. The jade fragments exhibit typical characteristics of round holes and structural hierarchy, which imply that the jades were heated before burial. The black alteration on these jade samples was found to be rich in Hg. The results of this study will be widely useful in the study of ancient jade artifacts and jade culture in Chinese archeology.

The Early to Middle Eocene Transition: An Integrated Calcareous Nannofossil and Stable Isotope Record From the Northwest Atlantic Ocean (Integrated Ocean Drilling Program Site U1410)

AbstractThe early to middle Eocene is marked by prominent changes in calcareous nannofossil assemblages coinciding both with long‐term climate changes and modification of the North Atlantic deep ocean circulation. In order to assess the impact of Eocene climate change on surface water environmental conditions of the Northwest Atlantic, we developed calcareous nannoplankton assemblage data and bulk stable isotope records (δ18O and δ13C) across an early to middle Eocene interval (~52–43 Ma) at Integrated Ocean Drilling Program Site U1410 (Southeast Newfoundland Ridge, ~41°N). At this site, early Eocene sediments are pelagic nannofossil chalk, whereas middle Eocene deposits occur as clay‐rich drift sediments reflecting the progressive influence of northern‐sourced deep currents. Between the end of Early Eocene Climatic Optimum (EECO) and the Ypresian/Lutetian boundary, calcareous nannofossils switched from an assemblage mainly composed of warm‐water and oligotrophic taxa (Zygrhablithus,Discoaster,Sphenolithus,Coccolithus) to one dominated by the more temperate and eutrophic reticulofenestrids. The most prominent period of accelerated assemblage change occurred during a ~2‐Myr phase of relatively high bulk δ18O values possibly related to the post‐EECO cooling. Although the dominance of reticulofenestrids persisted unvaried throughout the middle Eocene interval, early Lutetian (~47.4 to 47 Ma) stable isotope records indicate a reversal in the paleoenvironmetal trends suggesting a potential restoration of warmer conditions. Importantly, our data indicate that the ~2‐Myr interval immediately following the EECO was crucial in establishing the modern calcareous nannofossil assemblage structure and also reveal that the establishment ofReticulofenestra‐dominated assemblage occurred prior to the onset of persistent deep current system in the Northwest Atlantic.

Multi-indicator analysis of the influence of old municipal landfill sites on the aquatic environment: case study

The study aim was to analyse the influence of a municipal solid waste landfill site in operation for over 10 years on the aquatic environment using multiple indicators. The water around the landfill area must be controlled due to the possibility of leachate interaction with harmful substances in the environment. The tests were carried out on the basis of 24 indicators, of which four were the most significant: depth of groundwater retention, ammoniacal nitrogen (NH4-N), dissolved oxygen (DO), and polycyclic aromatic hydrocarbons (PAHs). The assessment of the quality of the surface water and groundwater and the analysis of the leachate pollution indices enabled the interpretation of the influence of a specific municipal waste landfill on the nearby water environment condition, despite not exceeding the permissible content at the highest average concentration of NH4-N at 1.34 mg L−1. The differences were significant at the level of p < 0.05 in the content of DO in the water below the landfill. The concentration of NH4-N in the groundwater below the landfill was statistically significantly correlated with the depth of the groundwater deposits (r = 0.609). Similarly, the surface water below the landfill site showed a statistically significant relation in the piezometer, which was also below the landfill, to ammoniacal nitrogen (r = 0.749). This result confirmed the statistically significant differences in the aquatic environment and the correlations with NH4-N and that, below the landfill, the penetration water seepage is moderate with a low waste accumulation not exceeding 10 Mg per day.