Exotic Halophila stipulacea is an introduced carbon sink for the Eastern Mediterranean Sea

Carbon and nitrogen storage in exotic Halophila stipulacea were compared to that in native Posidonia oceanica and Cymodocea nodosa meadows and adjacent unvegetated sediments of the Eastern Mediterranean Sea and to that in native H. stipulacea of the Red Sea at sites with different biogeochemical conditions and level of human pressure. Exotic H. stipulacea possessed considerable storing capacity, with 2-fold higher Corg stock (0.71 ± 0.05 kg m−2 in the top 20 cm of sediment) and burial (14.78 gCorg m−2 y−1) than unvegetated areas and C. nodosa meadows and, surprisingly, comparable to P. oceanica. N (0.07 ± 0.01 kg m−2) and Cinorg (14.06 ± 8.02 kg m−2) stocks were similar between H. stipulacea and C. nodosa or unvegetated sediments, but different to P. oceanica. Corg and N stocks were higher in exotic than native H. stipulacea populations. Based on isotopic mixing model, organic material trapped in H. stipulacea sediments was mostly allochthonous (seagrass detritus 17% vs seston 67%). Corg stock was similar between monospecific and invaded C. nodosa meadows by H. stipulacea. Higher stocks were measured in the higher human pressure site. H. stipulacea introduction may contribute in the increase of carbon sequestration in the Eastern Mediterranean

Palaeoenvironmental implications of a marine geoarchaeological survey conducted in the SW Argosaronic gulf, Greece

AbstractA marine geoarcheological survey was conducted at the southwestern end of the Argosaronic gulf in Greece, an area of archaeological importance. The survey was initiated by the discovery of a Late Bronze Age (LBA) shipwreck off Modi Islet. The survey which employed echo-sounding, sub-bottom profiling, side scan sonar systems and sediment coring extended to the area between Poros Island, Modi Islet and Argolid peninsula, aiming to evaluate the changes of the coastal zone extent in the past. The evolution of the palaeo-shoreline over the last 20ka is proposed based on the interpretation of the acquired bathymetric and seismic records, the estimation of the thickness of the marine sediments and the examination of existing datasets of the relative sea level changes in the area.The produced scenarios suggest that major changes marked the extent of the coastal zone since the Paleolithics. During the Upper Paleolithic period, the coast was larger by at least 11km2 and Poros and Modi islands were connected to the Peloponnesus. The sea level rise during the Mesolithic period formed a well-protected bay between Poros Island and Peloponessus and disconnected the Modi Islet from Poros Island. The coastal zone reached the present configuration around Late Bronze Age. The detection and mapping of scarps on the seismic profiles imply that the sea level rise presented standstills at least from the Last Glacial maximum until the onset of Holocene. However, the submerged coasts could be potential areas of archaeological interest since the examined area is habited continuously from the Paleolithic period.The acoustic data sets produced high resolution geomorphological maps at the wreck site which constitute data base for the monitoring of the site. In addition, the examination of the seafloor texture at the wreck site suggests that the seafloor characteristics were unfavorable for the preservation of the shipwreck

Factors influencing organic carbon recycling and burial in Skagerrak sediments

Different factors influencing recycling and burial rates of organic carbon (OC) were investigated in the continental margin sediments of the Skagerrak (NE North Sea). Two different areas, one in the southern and one in the northeastern part of the Skagerrak were visited shortly after a spring bloom (March 1999) and in late summer (August 2000). Results suggested that: (1) Organic carbon oxidation rates (Cox) (2.2–18 mmol C m-2d-11) were generally larger than the O2 uptake rates (1.9 –25 mmol m-2d-1). Both rates were measured in situ using a benthic lander. A mean apparent respiration ratio (Cox:O2corr) of 1.3±0.5 was found, indicating some long-term burial of reduced inorganic substances in these sediments. Measured O2 fluxes increased linearly with increasing Cox rates during the late summer cruise but not on the early spring cruise, indicating a temporal uncoupling of anaerobic mineralization and reoxidation of reduced substances. (2) Dissolved organic carbon (DOC) fluxes (0.2–1.0 mmol C m-2d-1) constituted 3–10% of the Cox rates and were positively correlated with the latter, implying that net DOC production rates were proportional to the overall sediment OC remineralization rates. (3) Chlorophyll a (Chl-a) concentrations in the sediment were significantly higher in early spring compared to late summer. The measured Cox rates, but not O2 fluxes, showed a strong positive correlation with the Chl-a inventories in the top 3 cm of the sediment. (4) Although no relationship was found between the benthic fluxes and the macrofaunal biomass in the chambers, total in situ measured dissolved inorganic carbon (CT) fluxes were 1–5.4 times higher than diffusive mediated CT fluxes, indicating that macrofauna have a significant impact on benthic exchange rates of OC remineralization products in Skagerrak sediments. (5) OC burial fluxes were generally higher in northeastern Skagerrak than in the southern part. The same pattern was observed for burial efficiencies, with annual means of ~62% and ~43% for the two areas respectively. (6) On a basin-wide scale, there was a significant positive linear correlation between the burial efficiencies and sediment accumulation rates. (7) The calculated particulate organic carbon (POC) deposition, from benthic flux and burial measurements, was only 24 –78% of the sediment trap measured POC deposition, indicating a strong near-bottom lateral transport and resuspension of POC. (8) A larger fraction of the laterally advected material of lower quality seemed to settle in the northeastern Skagerrak rather than in the southern Skagerrak. (9) Skagerrak sediments, especially in the northeastern part, act as an efficient net sink for organic carbon, even in a global continental margin context

The effect of dose-interval on antibody response to mRNA COVID-19 vaccines: a prospective cohort study

BackgroundVaccination against COVID-19 is highly effective in preventing severe disease and hospitalization, but primary COVID mRNA vaccination schedules often differed from those recommended by the manufacturers due to supply chain issues. We investigated the impact of delaying the second dose on antibody responses to COVID mRNA-vaccines in a prospective cohort of health-care workers in Quebec.MethodsWe recruited participants from the McGill University Health Centre who provided serum or participant-collected dried blood samples (DBS) at 28-days, 3 months, and 6 months post-second dose and at 28-days after a third dose. IgG antibodies to SARS-CoV2 spike (S), the receptor-binding domain (RBD), nucleocapsid (N) and neutralizing antibodies to the ancestral strain were assessed by enzyme-linked immunosorbent assay (ELISA). We examined associations between long (≤89 days) versus short (<89 days) between-dose intervals and antibody response through multivariable mixed-effects models adjusted for age, sex, prior covid infection status, time since vaccine dose, and assay batch.FindingsThe cohort included 328 participants who received up to three vaccine doses (>80% Pfizer-BioNTech). Weighted averages of the serum (n=744) and DBS (n=216) cohort results from the multivariable models showed that IgG anti-S was 31% higher (95% CI: 12% to 53%) and IgG anti-RBD was 37% higher (95% CI: 14% to 65%) in the long vs. short interval participants, across all time points.InterpretationOur study indicates that extending the covid primary series between-dose interval beyond 89 days (approximately 3 months) provides stronger antibody responses than intervals less than 89 days. Our demonstration of a more robust antibody response with a longer between dose interval is reassuring as logistical and supply challenges are navigated in low-resource settings

Long-Term Health Outcomes in Children Born to Mothers with Diabetes: A Population-Based Cohort Study

BACKGROUND: To examine whether prenatal exposure to parental type 1 diabetes, type 2 diabetes, or gestational diabetes is associated with an increased risk of malignant neoplasm or diseases of the circulatory system in the offspring. METHODS/PRINCIPAL FINDINGS: We conducted a population-based cohort study of 1,781,576 singletons born in Denmark from 1977 to 2008. Children were followed for up to 30 years from the day of birth until the onset of the outcomes under study, death, emigration, or December 31, 2009, whichever came first. We used Cox proportional hazards model to estimate hazard ratios (HR) with 95% confidence intervals (95% CI) for the outcomes under study while adjusting for potential confounders. An increased risk of malignant neoplasm was found in children prenatally exposed to maternal type 2 diabetes (HR = 2.2, 95%CI: 1.5-3.2). An increased risk of diseases of the circulatory system was found in children exposed to maternal type 1 diabetes (HR = 2.2, 95%CI: 1.6-3.0), type 2 diabetes (HR = 1.4, 95%CI: 1.1-1.7), and gestational diabetes (HR = 1.3, 95%CI: 1.1-1.6), but results were attenuated after excluding children with congenital malformations. An increased risk of diseases of the circulatory system was also found in children exposed to paternal type 2 diabetes (HR = 1.5, 95%CI: 1.1-2.2) and the elevated risk remained after excluding children with congenital malformations. CONCLUSIONS: This study suggests that susceptibility to malignant neoplasm is modified partly by fetal programming. Diseases of the circulatory system may be modified by genetic factors, other time-stable family factors, or fetal programming

Self-reported screen time and cardiometabolic risk in obese dutch adolescents

BACKGROUND: It is not clear whether the association between sedentary time and cardiometabolic risk exists among obese adolescents. We examined the association between screen time (TV and computer time) and cardiometabolic risk in obese Dutch adolescents. METHODS AND FINDINGS: For the current cross-sectional study, baseline data of 125 Dutch overweight and obese adolescents (12-18 years) participating in the Go4it study were included. Self-reported screen time (Activity Questionnaire for Adolescents and Adults) and clustered and individual cardiometabolic risk (i.e. body composition, systolic and diastolic blood pressure, low-density (LDL-C), high-density (HDL-C) and total cholesterol (TC), triglycerides, glucose and insulin) were assessed in all participants. Multiple linear regression analyses were used to assess the association between screen time and cardiometabolic risk, adjusting for age, gender, pubertal stage, ethnicity and moderate-to-vigorous physical activity. We found no significant relationship between self-reported total screen time and clustered cardiometabolic risk or individual risk factors in overweight and obese adolescents. Unexpectedly, self-reported computer time, but not TV time, was slightly but significantly inversely associated with TC (B = -0.002; CI = [-0.003;-0.000]) and LDL-C (B = -0.002; CI = [-0.001;0.000]). CONCLUSIONS: In obese adolescents we could not confirm the hypothesised positive association between screen time and cardiometabolic risk. Future studies should consider computer use as a separate class of screen behaviour, thereby also discriminating between active video gaming and other computer activities