High Sedimentation Rate Research Articles

Storm-driven variations in depositional environments modify pyrite sulfur isotope records

The sulfur isotopic composition of marine pyrite (δ34Spyr) is one of the major geochemical tools to reconstruct global changes in Earth's surface environment. Storm-driven variations in depositional environments, however, can play key roles in modifying the δ34Spyr signal. Here we present δ34Spyr values in a complete Holocene muddy storm deposit on the East China coastal plain, which is identified by comprehensive analyses of sediment components, organic matter composition, bulk organic carbon isotopic ratios, carbon and oxygen isotopic ratios of carbonates and trace element concentrations. We find that positive (+5.8‰ to +15.8‰) and negative (−9.0‰ to −19.7‰) δ34Spyr values were preserved in two successive intervals of the muddy storm deposit (ca. 62 cm long), corresponding to the high-energy storm peak phase (HESPP) and the waning-energy late storm phase (WELSP), respectively. We propose that the 34S enrichment in pyrite from the HESPP is most likely due to a combination of storm reworking of sediments and high sedimentation rates, which involves various physical and chemical processes leading to the accumulation of 34S-enriched pyrite, such as oxidation of near-surface sulfides, reduced exchange of sulfate between sediment pore fluids and the overlying water column, and/or input of excess reactive iron minerals. In contrast, lower sedimentation rates and limited sedimentary remobilization during the WELSP allow the isotopic signal of early-formed 32S-enriched pyrite to be preserved. The striking shift in δ34Spyr values, therefore, reflects a dramatic change in the local depositional environment between the HESPP and WELSP, suggesting that non-steady-state deposition induced by storm activity facilitates the formation of isotopically “heavy” pyrite. This sharp shift can be further generalized as a characteristic feature of δ34Spyr values in storm deposits. Our work highlights the critical impact of weather- and climate-event-driven depositional variations on δ34Spyr values, adding to the growing evidence emphasizing the local environmental and diagenetic controls on these records.

Factors Affecting Survival on Biologic Treatments in Patients with Rheumatoid Arthritis: A Single-Center Study From Turkey

Objective: In our study, we aimed to determine the factors affecting survival on biologic treatment in adult rheumatoid arthritis (RA) patients using biolog- ical drugs. Materials and Methods: In our study, the data of 245 patients who were followed up with the diagnosis of RA in the Rheumatology Clinic of Trakya University Medical Faculty Hospital between 2013 and 2016 were analyzed retrospectively. 37 patients were excluded due to missing data. The data of the remaining 208 patients were evaluated. Results: In our study, we found that drug survival was reduced by 0.48 times (95% CI 0.23-0.97) in elderly patients and 3 times (95% CI 1.09-10.3) in females. According to the results of our study, drug survival is shortened 8 times (95% CI 2.12-32.5) in patients with hyperlipidemia and 1.03 times (95% CI 1.01-1.04) in patients with high pretreatment erythrocyte sedimentation rate (ESR). In addition, we found that shorter drug survival 9.2 times (95% CI 2.4-35.3) in patients with Hepatitis B surface antigen (HBsAg) positivity, 2.9 times (95% CI 1.3-6.4) in patients with antibody positivity against citrullinated protein (ACPA), in patients using glucocorticoids 0.36 times (95% CI 0.17-0.76). Despite that; in patients with chronic kidney disease, drug survival was prolonged by 0.18 times (95% CI 0.06-0.57). Conclusion: When starting biologic drugs in RA patients, some parameters may help to predict drug survival. According to the order of effect; while HBsAg positivity, presence of hyperlipidemia, female gender, ACPA positivity, high ESR, advanced age and glucocorticoid use were negative markers for drug survival; chronic kidney damage can be a positive marker.

Emplacement history of volcaniclastic turbidites around the central Azores volcanic islands: Frequencies of slope landslides and eruptions

Volcanic islands export clastic material to their surrounding oceans by explosive eruptions, lava emissions, biogenic production on their shelves, and failure of their slopes, amongst other processes. This raises the question of whether geological events (in particular, eruptions and landslides) can be detected offshore and dated, and whether any relationships (for example, with climate changes) can be revealed using sediment cores. The volcanically active central Azorean islands (Faial, Pico, São Jorge, and Terceira), with their neighboring submarine basins, are potentially good candidates for such an analysis. Here, chronostratigraphies of four gravity cores collected amongst the islands are constructed based on twelve radiocarbon dates and two dates derived by geochemically correlating primary volcaniclastic turbidites with ignimbrites on Faial and Terceira Islands. Age-depth models are built from the hemipelagic intervals to estimate individual turbidite dates. Volumes of turbidites are modeled by multiplying basin areas with bed thickness, allowing for various turbidite thinning rates and directions. The volumes of landslide-generated turbidites are only comparable with the largest volumes of their adjacent upper-slope submarine landslide valleys; therefore, such turbidites in the cores likely derive from these largest landslides. Emplacement intervals between turbidites originating from both landslides and pyroclastic density currents are found to be mostly a few thousand years. Frequencies of landslide-generated turbidites and hemipelagic sedimentation rates were both highest in the past 8 k.y. compared to preceding periods up to 50 k.y. High hemipelagic sedimentation rates are interpreted to be related to sea-level rise, allowing more shelf bioproduction and release of particles by coastal erosion. The coincident increased frequencies of submarine landslides may also be associated with the increased sediment supply from the islands, resulting in a more rapid build-up of unstable sediments on submarine slopes. Notably, the emplacement frequencies of turbidites of pyroclastic density current origins do not suggest the decreased eruption frequency toward the Holocene that has been found elsewhere.

Near equatorial paleoclimatic evolution and control on organic matter accumulation during the Cenomanian in the Abu Gharadig Basin, southern Tethys: Insights from palynology, organic petrography, and geochemistry

The beginning of the Late Cretaceous (Cenomanian) attested to a major marine transgression interrupted by sea level falls in north Africa, which led to significant environmental perturbation and widespread accumulation of organic matter-rich sediments. During this period, northern Egypt was located at the southern edge of the Tethys Ocean and deposition of thick siliciclastic alternations between shales, siltstones, and sandstones of the Bahariya Formation took place in the BED2 gas field of the Abu Gharadig Basin, north Western Desert. An integrated approach of palynofacies analysis and palynomorph composition, organic petrography, and geochemical analysis of total organic carbon (TOC)/Rock-Eval pyrolysis, carbonate content, XRD analysis, and clay mineralogy of thirty-nine cutting samples obtained from the lower-middle Cenomanian Bahariya Formation was conducted. This approach was used to characterize organic matter and possible occurrence of source rock intervals, paleoenvironmental and paleoclimatic conditions and their role in organic matter accumulation. Moderate to high proportions of pteridophyte and water fern spores and pollen grains of Araucariaceae (Araucariacites), Cheirolepidiaceae (mainly Classopollis), and Gnetalean (Elaterate pollen) and Afropollis versus the sparsely recorded xerophilous ephedroids (Ephedripites) indicate prevalent conditions of a warm and humid climate. This is consistent with clay mineral composition that is dominated mainly by kaolinite and smectite compared to low illite and the lack of chlorite, which indicated a predominantly warm-humid climate state. Palynofacies analysis showed two assemblages; the first one is dominated by phytoclasts and indicates gas-prone Type III kerogen and deposition in a fluvio-deltaic environment. The second palynofacies assemblage is characterized by moderate abundance of phytoclasts and AOM mostly of terrestrial origin, suggesting a mixed Type III/II kerogen and deposition in a marginal to shallow neritic shelf environment. The organic geochemical characterization showed relatively low average values of TOC, S2, and HI, indicating that the Bahariya Formation is characterized by Type III gas-prone kerogen. Thermal maturity of the Bahariya Formation ranges from immature to the early stage of the oil window. Additionally, organic matter characteristics of the Bahariya Formation are qualitatively and quantitatively similar to their equivalents from nearby basins. Low TOC contents are attributed to a high sedimentation rate and an increased terrestrial input of sand- and silt-sized fractions at shallow water column settings that controlled strong dilution and decomposition versus low burial efficiency of the organic matter.

Geochemical factors associated with deposition of lower Aptian organic-rich sediments during OAE1a in the Basque-Cantabrian Basin, northern Spain

Introduction: The Early Aptian Oceanic Anoxic Event 1a (OAE1a) is characterized by organic matter (OM) bearing rocks identified worldwide, which also occur in the hemipelagic succession of the Cuchía section, North Basque-Cantabrian Basin (NBCB) in Northern Spain. Previous works identified OAE1a using δ13C calibrated with biostratigraphy of planktonic foraminifera, calcareous nannoplankton, and ammonites. However, the geochemical characteristics that controlled OM sources and the redox conditions during OAE1a are yet to be determined. Therefore, here we present the results of a high-resolution complementary study along 67 m of the succession at Playa de los Caballos beach that highlights how local factors in the basin modulated the effects of increased precipitation during enhanced global hydrological cycles.Methods: Samples were analyzed for total inorganic carbon (TIC), total organic carbon (TOC), δ13C, major elements (Al, Ti, Si), redox sensitive trace elements (RSTEs), clay mineralogy, bulk mineralogy, and biomarkers.Results and Discussion: Carbon isotope segments C2 to C6 were recognized to determine the age of the outcrop. Lipid biomarkers indicated that OM is predominantly marine with significant terrestrial contribution. Terrigenous OM was carried to the basin through pulses of fluvial input as attested by the major elements and by high relative proportions of quartz, feldspar, and clay minerals. Increased terrestrial inputs also enhanced primary production and facilitated OM preservation. Periods with hightened RSTE content correspond with increases in the major elements, thus implying their common provenance. High sedimentation rates together with the presence of less labile OM and the interaction with clay minerals most likely played a major role in preserving the OM. This study further highlights how enhanced hydrological cycles significantly influenced the marine conditions that controlled the expression of OAE1a in the NBCB.

MicroRNA-125b as a valuable predictive marker for outcome after autologous hematopoietic stem cell transplantation

BackgroundRelapse is a frequent occurrence in autologous hematopoietic stem cell transplantation (AHSCT), and early relapse after AHSCT results in poor survival and low quality of life. Predictive marker determination for AHSCT outcomes could be helpful in the prevention of relapse through personalized medicine. Here the predictive value of circulatory microRNAs (miRs) expression for AHSCT outcomes was studied.Methods50 MM and lymphoma candidates for AHSCT participated in this study. Two plasma samples were obtained before AHSCT from each candidate; one before mobilization and the other after conditioning. Extracellular vesicles (EVs) were isolated by ultracentrifugation. miR-125b, miR-126, miR-150, and miR-155 expression were analyzed in both plasma and EVs using real time polymerase chain reaction analysis. Other data related to AHSCT and its outcomes were also collected. The predictive value of miRs and other factors for outcomes was assessed by multi-variant analysis.ResultsBy 90 weeks follow up after AHSCT, multi-variant and ROC analysis showed miR-125b as a predictive marker for relapse, high lactate dehydrogenase (LDH), and high erythrocyte sedimentation rate (ESR). The cumulative incidence of relapse, high LDH, and high ESR increased with an increase in circulatory miR-125b expression.ConclusionmiR-125b could be applicable in prognosis evaluation and also create a possible new targeted therapy opportunity for enhanced outcomes and survival after AHSCT.Trial registrationThe study was retrospectively registered. Ethic code No: IR.UMSHA.REC.1400.541.

Acute mastoiditis in children: A tertiary care center experience in 2015-2021.

Acute mastoiditis is a suppurative infection of mastoid air cells and is the most common intratemporal complication of otitis media. This study aimed to evaluate the demographic and clinical characteristics and treatment outcomes of children with acute mastoiditis (AM). We retrospectively reviewed the medical records of hospitalized pediatric patients aged between 1 month and 18 years with a diagnosis of AM between May 2015 and December 2021. A total of 28 hospitalized children with AM were enrolled in this study, of whom 22 (78.6%) were males and 6 (21.4%) were females with a mean ± standard deviation age of 93.5 ± 53.2 months (range = 6 months-16.1 years). The most common clinical symptoms were postauricular erythema (n = 17, 60.7%), tenderness (n = 16, 57.1%), swelling (n = 14, 50%), fever (n = 14, 50%), and auricular protrusion (n = 7, 25%). Mastoiditis complications occurred in 10 (35.7%) children. The most common extracranial complication was subperiosteal abscess (n = 8, 28.6%). The erythrocyte sedimentation rate (ESR) and the rate of antibiotic use before hospitalization were higher in patients with complicated mastoiditis (P = 0.006 and P = 0.039, respectively). Surgery was performed in 12 (42.9%) patients. Statistically, more surgical interventions were performed in patients who developed complications (P = 0.003). AM continues as an important disease of childhood. Successful results are obtained with systemic antibiotic therapy and additional surgical intervention as necessary. A careful evaluation of patients with a high ESR and those who received antibiotic therapy before hospitalization is appropriate due to the correlation between these factors and the risk of complication development.

Influence of Seasonal Post‐Depositional Processes on the Remanent Magnetization in Varved Sediments From Glacial Lake Ojibway (Canada)

AbstractThe natural remanent magnetization (NRM) of high sedimentation rate sediments provides significant information about paleomagnetic secular variation of the Earth's magnetic field and can also potentially be used for stratigraphy. However, NRM acquisition depends on conditions inherent to the depositional environment. In addition to recording a precise annual chronology, varved sediments reflect marked annual sedimentary changes. The Earth's magnetic field does not vary significantly over such a short period, so magnetic changes recorded by varves are expected to reflect the influence of depositional parameters on the recording process. We focus here on a sequence of 27 ± 1 varves from the former proglacial Lake Ojibway (∼8.5 ka cal BP) from which individual cm‐thick summer and winter beds were sampled. Paleomagnetic, granulometric and geochemical analyses were conducted on each bed. A mean inclination shallowing of 24.3° is observed in winter beds, along with an 11.3° shallowing in summer beds. Magnetic declinations follow, on average, the expected field direction, but differences of up to 20° occur between successive beds. Summer beds are thicker than winter beds and have stronger magnetic susceptibility, higher Ca/Fe ratios and coarser sedimentary and magnetic grains. This grain size pattern reflects the input of coarser detrital particles during summer, while the finer fraction remained in suspension until it was deposited in winter. A combination of differential compaction between the winter and summer beds, seasonally varying physical and magnetic properties of sediments, and delayed NRM acquisition explains the variable and coercivity‐dependent inclination shallowing.

Thermal Selection of Microbial Communities and Preservation of Microbial Function in Guaymas Basin Hydrothermal Sediments.

The Guaymas Basin in the Gulf of California is characterized by active seafloor spreading, hydrothermal activity, and organic matter accumulation on the seafloor due to high sedimentation rates. In the hydrothermal sediments of Guaymas Basin, microbial community compositions and coexistence patterns change across steep gradients of temperature, potential carbon sources, and electron acceptors. Nonmetric multidimensional scaling and guanine-cytosine percentage analyses reveal that the bacterial and archaeal communities adjust compositionally to their local temperature regime. Functional inference using PICRUSt shows that microbial communities consistently maintain their predicted biogeochemical functions in different sediments. Phylogenetic profiling shows that microbial communities retain distinct sulfate-reducing, methane-oxidizing, or heterotrophic lineages within specific temperature windows. The preservation of similar biogeochemical functions across microbial lineages with different temperature adaptations stabilizes the hydrothermal microbial community in a highly dynamic environment. IMPORTANCE Hydrothermal vent sites have been widely studied to investigate novel bacteria and archaea that are adapted to these extreme environments. However, community-level analyses of hydrothermal microbial ecosystems look beyond the presence and activity of particular types of microbes and examine to what extent the entire community of bacteria and archaea is adapted to hydrothermal conditions; these include elevated temperatures, hydrothermally generated carbon sources, and inorganic electron donors and acceptors that are characteristic for hydrothermal environments. In our case study of bacterial and archaeal communities in hydrothermal sediments of Guaymas Basin, we found that sequence-inferred microbial function was maintained in differently structured bacterial and archaeal communities across different samples and thermal regimes. The resulting preservation of biogeochemical functions across thermal gradients is an important factor in explaining the consistency of the microbial core community in the dynamic sedimentary environment of Guaymas Basin.

Associations of hypomagnesemia in patients seeking a first treatment of alcohol use disorder

IntroductionHypomagnesemia (hypoMg) has not yet been extensively studied in alcohol use disorder (AUD) . We hypothesize that chronic, excessive alcohol consumption favors oxidative stress and pro-inflammatory alterations that may be exacerbated by hypoMg. The objective of this study was to analyze the prevalence and associations of hypoMg in AUD. Patients and MethodsCross-sectional study in patients admitted for a first treatment of AUD in six tertiary centers between 2013 and 2020. Socio-demographic, alcohol use characteristics, and blood parameters were ascertained at admission. Results753 patients (71% men) were eligible; age at admission was 48 years [IQR, 41–56 years]. Prevalence of hypoMg was 11.2%, higher than that observed for hypocalcemia (9.3%), hyponatremia (5.6%), and hypokalemia (2.8%). HypoMg was associated with older age, longer duration of AUD, anemia, higher erythrocyte sedimentation rate, gamma-glutamyl transpeptidase, glucose levels, advanced liver fibrosis (FIB-4 ≥3.25) and estimated glomerular filtration rate (eGFR) < 60 mL/min. In multivariate analysis, advanced liver fibrosis (OR, 8.91; 95% CI, 3.3–23.9) and eGFR < 60 mL (OR, 5.2; 95% CI, 1.0–26.2) were the only factors associated with hypoMg. ConclusionsMg deficiency in AUD is associated with liver damage and glomerular dysfunction suggesting that both comorbidities should be assessed in the course of serum hypoMg.

Low Muscle Mass Is Associated with Readmission for Inflammatory Bowel Disease.

Patients with inflammatory bowel disease tend to have malnutrition, frailty, and low muscle mass, which impact on poor clinical outcomes. Abdominal computed tomography is frequently used to assess body composition. This study aimed to evaluate the association of low muscle mass and readmission within 1 year in patients with inflammatory bowel disease during hospitalization and follow-up. A total of 211 patients with inflammatory bowel disease who had undergone computed tomography scans were included retrospectively. They were divided into subgroups based on disease activity. The male patients with skeletal muscle index ≤45.4 cm2/m2 and the female patients with skeletal muscle index ≤ 34.3 cm2/m2 were considered to have low muscle mass. Sociodemographic, clinical, and prognostic data were recorded. The analyses were done using the Statistical Package for the Social Sciences 25.0 software. The prevalence rate of low muscle mass was 64.7%. Low body mass index and hemoglobin, high erythrocyte sedimentation rate, smoking, and gastrointestinal surgery history were risk factors for low muscle mass (P < .05). Patients using steroids and biologics and using them more than 7 months were prone to develop low muscle mass and readmission (P < .05), while patients using immunomodulators were not. Inflammatory bowel disease patients with visceral fat area/subcutaneous fat area ≥0.71 were likely to readmit within 1 year than those with visceral fat area/subcutaneous fat area <0.71 (P < .05). Overweight or obese inflammatory bowel disease patients with low muscle mass had a shorter time to readmission than those without low muscle mass (P < .05). Overweight/obese inflammatory bowel disease patients with low muscle mass and patients using steroids and biologics have shorter time to readmission within 1 year regardless of disease activity.

Seasonal variation observed in microplastic deposition rates in boreal lake sediments

PurposeThe sediment trap method allows measurements of vertical microplastic flux rate into sediments and provides comparable information of the spatial microplastic deposition rates. Such data are essential for comparison of the microplastic pollution rates in different sedimentary systems and for future risk assessments.Materials and methodsWe monitored microplastic fluxes using sediment traps in a boreal lake seasonally during 1 year. The sites represent different level of exposure to anthropogenic activities, from construction work to the open water site. Microplastic fluxes were compared to sediment characteristics (organic content) and sediment accumulation rates.Results and discussionThe highest annual microplastic deposition rate (2300 items m−2 year−1) was recorded at snow disposal site, a location where the snow collected from the city streets during winter is transported. The lowest rate was observed at the control site (660 items m−2 year−1) upstream from the city. Our results reveal the seasonal variation in microplastic deposition rates. In general, the highest microplastic flux rates were measured during growing season, accompanied with higher sedimentation rate. The low microplastic deposition rate during winter is likely explained by ice cover, frozen soil, and snow cover in the catchment. In contrast, microplastic concentration was higher in winter samples due to ceased sediment transport from catchment to lake. The sediment accumulation rate did not predict microplastic accumulation rate.ConclusionOur data suggest seasonal variation in microplastic deposition rates. The microplastic flux rates compared to their concentrations indicates that sites with high sedimentation rates can lead to underestimation of microplastic deposition and hence hamper recognition of hot spots.Graphical

Characteristics and risk factors of mortality in patients with systemic sclerosis-associated interstitial lung disease

Background Systemic sclerosis (SSc) is a heterogeneous autoimmune disease characterized by dysregulation of fibroblast function, which often involves the lungs. Interstitial lung disease (ILD) associated with SSc (SSc-ILD) is a major cause of death among patients with SSc. Our study aimed to identify risk factors for mortality and compare the clinical characteristics of patients with SSc-ILD. Patients and methods Patients were retrospectively enrolled between 2010 and 2018 in a tertiary hospital in Korea. Patients with SSc-ILD were classified depending on the first pulmonary function test or radiologic findings: extensive (n = 46, >20% disease extent on computed tomography (CT) or forced vital capacity [FVC] < 70% in indeterminate cases) and limited (n = 60, <20% disease extent on CT or FVC ≥70% in indeterminate cases). Results Patients in the extensive group were younger (mean age ± SD 49.3 ± 11.5) than those in the limited group (53.9 ± 12.5, p = .067) at diagnosis. The extensive group showed frequent pulmonary hypertension (43.5% vs. 16.7%, p = .009) and higher erythrocyte sedimentation rate (61.3 ± 33.7 vs. 42.1 ± 26.0, p = .003) and mortality (32.6%, mean duration of follow-up, 100.0 ± 44.7 months vs. 10.0%, 86.0 ± 53.4 months, p = .011). ILD was detected within five years from the first visit (median years 3.5 (1.0, 6.0) vs. 4.5 (0.6, 9.0), survivors vs. non-survivors), and mortality occurred in 19.8% of all patients during a 15-year follow-up. Older age, lower FVC, and initial disease stage (limited or extensive) were associated with mortality, but FVC decline was similar in the limited and extensive groups, such as 15–20% in the first year and 8–10% in the next year, regardless of the initial extent of the disease. Conclusions Approximately 10% of patients with SSc-ILD in the limited and extensive group showed progression. ILD was detected at a median of less than five years from the first visit; therefore, it is necessary to carefully monitor patients’ symptoms and signs from an early stage. Long-term surveillance is also required. Key messages Patients with systemic sclerosis-interstitial lung disease manifested a heterogeneous disease course. Approximately 10% of the patients in the limited group showed progression, which was similar to the proportion of patients in the extensive group. Interstitial lung disease was detected at a median of less than five years from the first visit.

The formation conditions of gigantic dolomite concretions including whale bones exposed in Unosaki coast, Oga peninsula, Japan

Carbonate concretions occur in sedimentary rocks of widely varying geological ages throughout the world. Recently, more than 100 gigantic carbonate concretions with diameters ranging from 1 to 9 m have been identified along the Unosaki coast of Oga Peninsula, Akita Prefecture, Japan. The formation process of such gigantic concretions, some of which along the Unosaki coast contain whale bones, remains uncertain. A mineral composition analysis reveals that the major mineral of the concretions is dolomite. Considering the location of dolomite precipitation, their composition implies that the concretions were formed in a reducing environment in which sulfate ions were removed. Stable carbon and oxygen isotopic analysis reveals that the CaCO3 of whale bone and concretions contains light δ13C and heavy δ18O, suggesting that whale organic matter contributed to the formation of the concretions. The gigantic carbonate concretions were presumably formed by the accumulation and burial of whale carcasses with high sedimentation rates, and subsequent reaction of carbon decomposed by benthic and microbial activity with seawater.

High sedimentation rates lead to rapid vegetation recovery in tidal brackish wetland restoration

IntroductionTidal wetland restoration in the Bay of Fundy involves restoring tidal hydrology to sites with tidal restrictions. Most have focused on salt marsh sites close to the mouth of estuaries, but there are also many tidally restricted wetlands closer to the freshwater end of tidal rivers. Recovery of salt marsh vegetation has been rapid in past projects, but little is known about sediment and vegetation dynamics post restoration in tidal brackish or freshwater environments.MethodsWe implemented tidal wetland restoration projects on two tidal rivers near the inland limit of saltwater. Hydrological restoration involved breaching (St. Croix) or realigning agricultural dykes (Belcher Street). We monitored hydrology, sediment accretion and vegetation at replicated plots on restoration sites and nearby reference tidal marshes; and conducted habitat mapping and elevation surveys using drones.ResultsAfter re-establishing tidal flow, sediment accretion was very rapid, leading to a deep layer of new sediments. Plant colonization at both sites resulted in a high diversity of halophytes in the first 2 years post restoration, but the St. Croix site transitioned to freshwater wetland species dominating by the fifth year post- restoration. The Belcher St. site has a mix of freshwater and brackish wetland species after the fourth-year post-restoration.DiscussionHigh suspended sediment concentrations at both sites suggest that each site was positioned closed to the estuarine turbidity maximum within its river. Tidal wetland restoration at the head of estuaries may benefit from the large ecological disturbance associated with rapid sediment accretion, providing a productive substrate with little competition from prior vegetation. However ultimate vegetation patterns may take longer to develop as elevation gains alter tidal flooding frequency. Low salinities suggest that the physical disturbance of sediment burying prior vegetation is the main mechanism creating a clean slate for plant recolonization, rather than mortality of terrestrial vegetation due to salt water. The majority of elevation change was due to allochthonous sediment deposition, with belowground processes playing a minor role. The wetlands restored showed substantial net elevation gains in the first years following tidal hydrological restoration, but long-term monitoring is required to track their overall resilience in the face of sea level rise.

A simple gradient centrifugation method for bacteria detection in skim milk

Development of simple methods for bacteria detection is of great importance, especially in the undeveloped countries where there are limited resources for microbial testing. Herein, we present a simple gradient centrifugation-based optical detection (GCB-OD) method for bacteria testing in skim milk. Our method incorporates capturing bacteria using nanoparticles in Eppendorf tubes, followed by separation of bacteria-captured particles in the sucrose gradient within 6 min of centrifugation. Using a simple mobile phone-setup, images of sucrose-gradients are captured, and optical density of the particle-bound bacteria zones are measured with a MATLAB software, without requirement of a sophisticated optical instrument. In this approach, different nanoparticles are compared according to delta-E (ΔE) color difference value and sedimentation rate to obtain detectable narrow particle-bound bacteria zones. The spherical shaped carbon nanoparticles (CNP) with mean diameters of 119 nm, are found suitable for low concentrations of bacteria detection for having high sedimentation rates comparing to smaller sized particles and having higher ΔE than other particles as well. For CNP-captured bacteria band detection, sucrose-gradient consist of 1 ml of 60–65–70 % (w/v) and 2 ml of 75 % (w/v) sucrose was found suitable.Escherichia coli(E. coli) was used as model fecal indicator bacteria, and the correlation of optical density andE. coliconcentration showed linearity in the range of 1.5x100–1.5x104CFU/mlE. coliin skim milk. The culture plating and transmission electron micrographs were utilized to evaluate bacterial capture performance. The developed simple centrifugation-based method that allows detection of 2 CFU/ml and 3 CFU/ml E. coliin 1XPBS and skim milk, can be useful for microbial testing in resource limited areas.

Unique benthic foraminiferal communities (stained) in diverse environments of sub-Antarctic fjords, South Georgia

Abstract. Sub-Antarctic fjords are among the environments most affected by the recent climate change. In our dynamically changing world, it is essential to monitor changes in these vulnerable settings. Here, we present a baseline study of “living” (rose-bengal-stained) benthic foraminifera from fjords of South Georgia, including fjords with and without tidewater glaciers. Their distribution is analyzed in the light of new fjord water and sediment property data, including grain size and sorting, total organic carbon, total sulfur, and δ13C of bulk organic matter. Four well-defined foraminiferal assemblages are recognized. Miliammina earlandi dominates in the most restricted, near-shore and glacier-proximal habitats, Cassidulinoides aff. parkerianus in mid-fjord areas, and Globocassidulina aff. rossensis and an assemblage dominated by Ammobaculites rostratus, Reophax subfusiformis, and Astrononion echolsi are in the outer parts of the fjords. Miliammina earlandi can tolerate strong glacial influence, including high sedimentation rates in fjord heads and sediment anoxia, as inferred from sediment color and total organic carbon / sulfur ratios. This versatile species thrives both in the food-poor inner reaches of fjords that receive mainly refractory petrogenic organic matter from glacial meltwater and in shallow-water coves, where it benefits from an abundant supply of fresh, terrestrial, and marine organic matter. A smooth-walled variant of C. aff. parkerianus, apparently endemic to South Georgia, is the calcareous rotaliid best adapted to inner-fjord conditions characterized by moderate glacial influence and sedimentation rates and showing no preference for particular sedimentary redox conditions. The outer parts of fjords with clear, well-oxygenated bottom water are inhabited by G. aff. rossensis. Ammobaculites rostratus, R. subfusiformis, and A. echolsi dominate in the deepest-water settings, with water salinities ≥ 33.9 PSU and temperatures 0.2–1.4 ∘C, characteristic of winter water and Upper Circumpolar Deep Water. The inner- and mid-fjord foraminiferal assemblages seem specific to South Georgia, although with continued warming and deglaciation, they may become more widespread in the Southern Ocean.

Reservoir Potential Assessment of the Tortonian–Calabrian Sediments from Offshore Makran (Southwest Pakistan) through a Multidisciplinary Approach

AbstractThe Tortonian–Calabrian strata of Offshore Makran (Pakistan) is investigated for the purpose of reservoir assessment. The stratigraphy and petrophysics indicate that the Neogene sediments have tight reservoir potential with porosities in the range of 3%–9% and 40%–50% water saturation. The mineralogical cross plots indicate a mixed lithology with an abundance of dolomite and calcite, together with minor quartz content and shale. The seismic interpretation demonstrates medium–high amplitude reflection patterns, mud diapirs coupled with onlapping strata and the occurrence of bottom simulating reflectors (BSRs). The BSRs are characterized by diminished amplitude, low continuity and exhibiting acoustic blanking zones. The high formation pressure results indicate overpressure zones, suggesting the occurrence of overpressured shales in the Jal Pari‐1A. The presence of mud diapirs and gas chimneys are the result of tectonic forces acting at the junction of the Arabian, Indian and Eurasian plates, whereas, BSRs prove the existence of gas charged sediments supporting the formation of mud diapirism in the region. It is concluded that the high rates of sedimentation during the Neogene are likely to have contributed to the development of the high formation pressure. Revised mud weights, casing policies, pore pressure transients and geophysical inversion studies will help alleviate drilling risks in future exploration strategies.

North Atlantic Drift Sediments Constrain Eocene Tidal Dissipation and the Evolution of the Earth‐Moon System

AbstractCyclostratigraphy and astrochronology are now at the forefront of geologic timekeeping. While this technique heavily relies on the accuracy of astronomical calculations, solar system chaos limits how far back astronomical calculations can be performed with confidence. High‐resolution paleoclimate records with Milankovitch imprints now allow reversing the traditional cyclostratigraphic approach: Middle Eocene drift sediments from Newfoundland Ridge are well‐suited for this purpose, due to high sedimentation rates and distinct lithological cycles. Per contra, the stratigraphies of Integrated Ocean Drilling Program Sites U1408–U1410 are highly complex with several hiatuses. Here, we built a two‐site composite and constructed a conservative age‐depth model to provide a reliable chronology for this rhythmic, highly resolved (&lt;1 kyr) sedimentary archive. Astronomical components (g‐terms and precession constant) are extracted from proxy time‐series using two different techniques, producing consistent results. We find astronomical frequencies up to 4% lower than reported in astronomical solution La04. This solution, however, was smoothed over 20‐Myr intervals, and our results therefore provide constraints on g‐term variability on shorter, million‐year timescales. We also report first evidence that the g4–g3 “grand eccentricity cycle” may have had a 1.2‐Myr period around 41 Ma, contrary to its 2.4‐Myr periodicity today. Our median precession constant estimate (51.28 ± 0.56″/year) confirms earlier indicators of a relatively low rate of tidal dissipation in the Paleogene. Newfoundland Ridge drift sediments thus enable a reliable reconstruction of astronomical components at the limit of validity of current astronomical calculations, extracted from geologic data, providing a new target for the next generation of astronomical calculations.

An open, retrospective study on the duration of virus shedding for Shanghai patients infected with SARS-CoV-2 omicron variants.

An open, retrospective study on the duration of virus shedding for Shanghai patients infected with SARS-CoV-2 omicron variants.