The blue carbon of southern southwest Atlantic salt marshes and their biotic and abiotic drivers.

Coastal vegetated ecosystems are acknowledged for their capacity to sequester organic carbon (OC), known as blue C. Yet, blue C global accounting is incomplete, with major gaps in southern hemisphere data. It also shows a large variability suggesting that the interaction between environmental and biological drivers is important at the local scale. In southwest Atlantic salt marshes, to account for the space occupied by crab burrows, it is key to avoid overestimates. Here we found that southern southwest Atlantic salt marshes store on average 42.43 (SE = 27.56) Mg OC·ha-1 (40.74 (SE = 2.7) in belowground) and bury in average 47.62 g OC·m-2·yr-1 (ranging from 7.38 to 204.21). Accretion rates, granulometry, plant species and burrowing crabs were identified as the main factors in determining belowground OC stocks. These data lead to an updated global estimation for stocks in salt marshes of 185.89 Mg OC·ha-1 (n = 743; SE = 4.92) and a C burial rate of 199.61 g OC·m-2·yr-1 (n = 193; SE = 16.04), which are lower than previous estimates.

From UAV to PlanetScope: Upscaling fractional cover of an invasive species Rosa rugosa.

Invasive plant species pose a direct threat to biodiversity and ecosystem services. Among these, Rosa rugosa has had a severe impact on Baltic coastal ecosystems in recent decades. Accurate mapping and monitoring tools are essential to quantify the location and spatial extent of invasive plant species to support eradication programs. In this paper we combined RGB images obtained using an Unoccupied Aerial Vehicle, with multispectral PlanetScope images to map the extent of R. rugosa at seven locations along the Estonian coastline. We used RGB-based vegetation indices and 3D canopy metrics in combination with a random forest algorithm to map R. rugosa thickets, obtaining high mapping accuracies (Sensitivity = 0.92, specificity = 0.96). We then used the R. rugosa presence/absence maps as a training dataset to predict the fractional cover based on multispectral vegetation indices derived from the PlanetScope constellation and an Extreme Gradient Boosting algorithm (XGBoost). The XGBoost algorithm yielded high fractional cover prediction accuracies (RMSE = 0.11, R2 = 0.70). An in-depth accuracy assessment based on site-specific validations revealed notable differences in accuracy between study sites (highest R2 = 0.74, lowest R2 = 0.03). We attribute these differences to the various stages of R. rugosa invasion and the density of thickets. In conclusion, the combination of RGB UAV images and multispectral PlanetScope images is a cost-effective method to map R. rugosa in highly heterogeneous coastal ecosystems. We propose this approach as a valuable tool to extend the highly local geographical scope of UAV assessments into wider areas and regional evaluations.

Biogeochemical behaviour of cadmium in sediments and potential biological impact on mangroves under anthropogenic influence: A baseline survey from a protected nature reserve.

Cadmium is a toxic element and its effects are well understood for human health, but its biogeochemical behaviour is still poorly studied and understood in natural ecosystems. This work addresses knowledge gaps concerning its presence, biogeochemical behaviour and impacts in mangrove ecosystems. Through geochemical data and multivariate analysis (i.e., factor and cluster analysis) of data from mangroves of Isla del Carmen, one of the largest extents in Mexico we explored the biogeochemical behaviour of Cd, a potentially toxic element, to identify its anthropogenic sources and interactions with sediments. Pollution indices, including enrichment factor (EF), geo-accumulation index (Igeo), sediment quality guidelines (SQG) and toxicological studies were used to assess the biological impacts of Cd and infer the natural levels tolerated by mangrove trees that form the basis of this natural ecosystem. Our results highlighted that Cd accumulation is driven by interactions between organic matter (OM), sulphur and fine particles; whereas enrichment factor showed values of 6.9 (EF) and 3.5 (EF) associated with point sources and ranged between 2 and 2.9 (EF) in relation to non-point sources. Finally, our geochemical approach revealed that Cd enrichment originates from urban activities and from the poor management of urban residuals.

Coastal dynamism in Southern Thailand: An application of the CoastSat toolkit.

In Thailand, 17% of the population lives by the coast, approximately 11 million people. A combination of coastal erosion, sea level rise and coastal land subsidence are critical issues threatening the livelihoods of coastal communities. Thailand has invested a lot of money and installed conservation policies to restore and protect coastal mangroves and realign or replenish their beaches. This study assessed the use of the toolkit Coastsat to digitise a time series of shoreline positions from open access satellite images between 1990 and 2019 along 560 km of coastline in the provinces of Krabi and Nakhon Si Thammarat (NST). Based on these digitised shorelines and the use of the software Digital Shoreline Analysis System (DSAS), it was possible to identify shoreline change, which varied between -66 to +16.4 m/y in the mangroves of NST and -22.2 to +10.6 m/year on its sandy beaches. Shoreline change rates along the Krabi coast varied -34.5 to +21.7 m/year in the mangroves and -4.1 to +4 m/year on sandy beaches. Analysis of the spatial and temporal variations of the shoreline position during the survey period reveals a linkage between extreme weather conditions and coastal erosion along the NST coast while that linkage is less clear along the Krabi coast. CoastSat delivers crucial and accurate time series shoreline data over extensive areas that are vital to coastal managers and researchers in a completely remote manner, which is key with the presence of COVID-19 travel bans.

Environmental risk of trace metals and metalloids in estuarine sediments: An example from Southampton Water, U.K.

Industrial and commercial port activities are widely recognized worldwide as an important source of pollution to proximal estuaries. In this study, we analysed geochemical and sedimentological parameters including major and trace elements, organic matter and sediment texture in surface sediments from the estuarine environment of Southampton Water, U.K. Using these data, and multivariate statistical tools [correlation, factor and cluster analysis and pollution indices such as Enrichment Factor (EF), Pollution Load Index (PLI) and the Adverse Effect Index (AEI)], we examine sedimentary trace metal and metalloid contamination, contamination sources, and potential biological impacts of the contamination present. The geochemical data, multivariate statistical analysis and pollution indices indicate that the spatial distribution of trace metals and metalloids is influenced by both sediment composition (and mixing) and anthropogenic activities. Most trace metal and metalloid concentrations are close to local geological background levels, except for Cu, Zn and Pb. The spatial distribution of these elements indicates that the Exxon oil refinery, Southampton port, local marinas and runoff from domestic and industrial activities act effectively as point sources of these elements. Pollution indices calculations highlight a degraded environment as a result of these pollutants, and further work is needed to assess the current impact of trace metals and metalloids on local ecology.

Impacts of environmental pollution on mangrove phenology: Combining remotely sensed data and generalized additive models.

Mangrove ecosystems worldwide have been affected by anthropogenic activities that modify natural conditions and supply trace elements that affect mangrove health and development. In order to gain a better understanding of these ecosystems, and assess the influence of physicochemical (granulometry, pH, salinity and ORP) and geochemical variables (concentrations of V, Cr, Co, Ni, Cu, Zn, Pb, Rb, Sr and Zr) on mangrove phenology, we combined field and satellite derived remotely sensed data. Phenology metrics in combination with Generalized Additive Models showed that start of the season was strongly influenced by Pb and Cu pollution as well as salinity and pH, with a large percentage of deviance explained (92.10%) by the model. Start of season exhibited non-linear delays as a response to pollution. Other phenology parameters such as the length of season, timing of the peak of season, and growth peak also indicated responses to both trace elements and physicochemical and geochemical variables, with percentages of deviance explained by the models ranging between 33.90% and 97.70%. While the peak of season showed delays as a response to increased pH and decreased salinity, growth peak exhibited a non-linear decrease as a response to increased Sr concentrations. These results suggest that trace element pollution is likely to lead to altered phenological patterns in mangroves.

Microplastic distribution in urban vs pristine mangroves: Using marine sponges as bioindicators of environmental pollution.

Sessile benthic organisms are considered good bioindicators for monitoring environmental quality of coastal ecosystems. However, these environments are impacted by new pollutants such as microplastics (MPs), where there is limited information about organisms that can be used as reliable bioindicators of these emerging contaminants. We evaluated MP concentrations in three compartments: surface sediment, water and in three marine sponge species (Haliclona implexiformis, Halichondria melanadocia and Amorphinopsis atlantica), to determine whether these organisms accumulate MPs and reflect their possible sources. Results showed MPs in all three compartments. Average concentrations ranged from 1861 to 3456 items kg-1 of dry weight in marine sponges, 130 to 287 items L-1 in water and 6 to 11 items kg-1 in sediment. The maximum MP concentration was in the sponge A. atlantica, which registered 5000 items kg-1 of dry weight, in water was 670 items L-1 and in sediment was 28 items kg-1, these values were found in the disturbed study area. The three sponge species exhibited MP bioaccumulation and showed significant differences between disturbed and pristine sites (F = 11.2, p < 0.05), suggesting their use as bioindicators of MP.

Seagrass beds reveal high abundance of microplastic in sediments: A case study in the Baltic Sea.

Microplastic (MPL) contamination in the marine environment is extensively studied yet little is known about the extent of MPL abundance in seagrass beds. The aim of this study was to evaluate MPL accumulation in coastal seagrass (Zostera marina) beds in the Baltic Sea, Estonia. Surface water was sampled by pumping using 40 µm plankton net, and sediments by trowel. MPL was extracted with NaCl, identified by microscopy and ATR-FTIR on selected samples. Surface water in the seagrass beds had 0.04-1.2 (median 0.14) MPL/L, similar to other areas of the Baltic Sea. Sediments had 0-1817 (median 208) MPL/kg (dwt), much higher than previously recorded from adjacent unvegetated and offshore sediments, thereby suggesting a strong ability of the sediments in seagrass beds to retain MPL. Of identified MPL, blue fibres were dominant in both the sampled media. Sediment characterization showed a correlation between MPL counts with poorly sorted sediments.

Assessing the role of the "estuarine filter" for emerging contaminants: pharmaceuticals, perfluoroalkyl compounds and plasticisers in sediment cores from two contrasting systems in the southern U.K.

The environmental occurrence, fate and ecotoxicity of emerging contaminants (ECs) has been the subject of increasing research, policy and public concern over the past two decades. While a wide range of publications have examined the environmental persistence and sediment/soil interactions of ECs following their discharge into aquatic environments, the extent to which ECs are sequestered in estuarine sediments, and the impact of this on their environmental persistence and supply to the ocean, in comparison remains unclear. This Article examines the environmental concentrations of seven, relatively water-soluble and environmentally mobile, ECs (including pharmaceuticals, perfluoroalkyl compounds, and plasticisers) in dated intertidal saltmarsh cores from two contrasting estuarine sites in the southern U.K. (one heavily urbanised/industrial, the other non-urbanised). Mean sediment EC concentrations are similar in both estuarine systems (in the range 0.1 (acetaminophen) to 17 (4-hydroxyacetophenone) ng/g dry weight). Despite their variable reported Log Kow values (from ca. 0.5 to > 7), the ECs are all apparently mobile in the marsh systems studied, and where subsurface concentration maxima are present these most likely relate to local flushing or diffusive processes and cannot be clearly linked to likely input trends or changes in sediment geochemistry (including sedimentary organic carbon content). The "estuarine filter" here, at least with respect to intertidal saltmarsh sediments, shows reduced potential to sequester the seven ECs examined and mediate their supply to coastal and shelf environments.

Carbon sequestration and storage in Norwegian Arctic coastal wetlands: Impacts of climate change.

Coastal wetlands contain some of the largest stores of pedologic and biotic carbon pools, and climate change is likely to influence the ability of these ecosystems to sequester carbon. Recent studies have attempted to provide data on carbon sequestration in both temperate and tropical coastal wetlands. Alteration of Arctic wetland carbon sequestration rates is also likely where coastal forcing mechanisms interact directly with these coastal systems. At present there are no data available to provide a detailed understanding of present day and historical carbon sequestration rates within Arctic coastal wetlands. In order to address this knowledge gap, rates of carbon sequestration were assessed within five Arctic coastal wetland sites in Norway. This was undertaken using radiometric dating techniques (210Pb and 137Cs) to establish a geochronology for recent wetland development, and soil carbon stocks were estimated from cores. Average carbon sequestration rates were varied, both between sites and over time, ranging between 19 and 603 g C m2 y-1, and these were correlated with increases in the length of the growing season. Stocks ranged between 3.67 and 13.79 Mg C ha-1, which is very low compared with global average estimations for similar coastal systems, e.g. 250 Mg C ha-1 for temperate salt marshes, 280 Mg C ha-1 for mangroves, and 140 Mg C ha-1 for seagrasses. This is most likely due to isostatic uplift and sediment accretion historically outpacing sea level rise, which results in wetland progradation and thus a continuous formation of new marsh with thin organic soil horizons. However, with increasing rates of sea level rise it is uncertain whether this trend is set to continue or be reversed.

Environmental risk of trace elements in mangrove ecosystems: An assessment of natural vs oil and urban inputs.

The petrochemical industry and urban activities are widely recognized worldwide as a source of pollution to mangrove environments. They can supply pollutants such as trace elements that can modify the ecosystem structure and associated services, as well as human populations. Through geochemical data, multivariate statistical analysis and pollution indices such as the enrichment factor (EF), geo-accumulation index (Igeo), adverse effect index (AEI) and the pollution load index (PLI), we evaluated the factors that control trace element distribution, punctual sources and determined the pollution level of sediments and their potential biological impact in the mangrove ecosystem of Isla del Carmen, Mexico. The factor and cluster analysis highlighted that the distribution of trace elements is influenced by the mineralogy, texture as well as urban derived sources. The pollution indices showed values in the punctual sources from the urban area of EF > 10, Igeo > 3, AEI > 3, PLI > 1 by Cu, Zn and Pb. Finally, the results revealed that mangroves from Isla del Carmen has a major influence from urban activities and natural sources rather than oil industry and also indicate a degraded environment as a result of anthropogenic activities that could have knock-on effect for human health if polluted marine organisms derived from the urban mangroves are consumed. CAPSULE ABSTRACT: Surface sediments show the influence of point sources on selected trace element concentrations correlated with human activities within the mangroves of Isla del Carmen, Mexico.

Country-scale mapping of ecosystem services provided by semi-natural grasslands.

Semi-natural grasslands harbour high biodiversity and play a key role in the supply of ecosystem services (ES). However, abandonment, changes in traditional management practices and agricultural intensification constitute a major threat to these grasslands worldwide and these practices have led to declines in species diversity. In this paper the multi-functionality of semi natural-grasslands is assessed from the ES perspective, within a range of common semi-natural grassland types throughout Estonia. The analysis follows a stepwise approach based on the ES cascade model. Firstly, analyses of the relationships between plant species distribution patterns and environmental factors are described. Secondly, the effect of grassland abandonment on plant species diversity, as well as on the presence of rare and protected plant species is tested. In order to overcome the lack of data on ES at the national scale, plant species diversity and soil organic carbon are tested as surrogate indicators for five ESS: pollination, herbs for traditional medicinal use, nutrient cycling, nutrient retention and biomass production. In the final step, the spatial distribution of ES is assessed, based on an ES hotspots map obtained by detecting areas where high levels of plant species diversity and soil organic carbon overlap. The results show that the majority of ES hotspots are present in wooded meadows and pastures. However, there is an important threat to these hotspots because 45% are not eligible for agri-environmental support.

Modeling multi-decadal mangrove leaf area index in response to drought along the semi-arid southern coasts of Iran.

Leaf Area Index (LAI; as an indicator of the health) of the mangrove ecosystems on the northern coasts of the Persian Gulf and the Gulf of Oman was measured in the field and modeled in response to observed (1986-2017) and predicted (2018-2100) drought occurrences (quantified using the Standardized Precipitation Index [SPI]). The relationship of LAI with the normalized difference vegetation index (NDVI) obtained from satellite images was quantified, the LAI between 1986 and 2017 retrospectively estimated, and a relationship between LAI and SPI developed for the same period. Long-term climate data were used as input in the RCP8.5 climate change scenario to reconstruct recent and forecast future drought intensities. Both the NDVI and the SPI were strongly related with the LAI, indicating that realistic LAI values were derived from historic satellite data to portray annual changes of LAI in response to changes in SPI. Our findings show that projected future drought intensities modeled by the RCP8.5 scenario increase more and future LAIs decreased more on the coasts of the Gulf of Oman than the coasts of the Persian Gulf in the coming decades. The year 1998 was the most significant change-point for mean annual rainfall amounts and drought occurrences as well as for LAIs and at no time between 1998 and 2017 or between 2018 and 2100 are SPI and LAI values expected to return to pre-1998 values. LAI and SPI are projected to decline sharply around 2030, reach their lowest levels between 2040 and 2070, and increase and stabilize during the late decades of the 21st century at values similar to the present time. Overall, this study provides a comprehensive picture of the responses of mangroves to fluctuating future drought conditions, facilitating the development of management plans for these vulnerable habitats in the face of future climate change.

Feasibility and physiological effects of noninvasive neurally adjusted ventilatory assist in preterm infants.

BackgroundNoninvasive neurally adjusted ventilator assist (NIV-NAVA) was introduced to our clinical practice via a pilot and a randomized observational study to assess its safety, feasibility, and short-term physiological effects.MethodsThe pilot protocol applied NIV-NAVA to 11 infants on nasal CPAP, high-flow nasal cannula, or nasal intermittent mandatory ventilation (NIMV), in multiple 2- to 4-h periods of NIV-NAVA for comparison. This provided the necessary data to design a randomized, controlled observational crossover study in eight additional infants to compare the physiological effects of NIV-NAVA with NIMV during 2-h steady-state conditions. We recorded the peak inspiratory pressure (PIP), FiO2, Edi, oxygen saturations (histogram analysis), transcutaneous PCO2, and movement with an Acoustic Respiratory Movement Sensor.ResultsThe NAVA catheter was used for 81 patient days without complications. NIV-NAVA produced significant reductions (as a percentage of measurements on NIMV) in the following: PIP, 13%; FiO2, 13%; frequency of desaturations, 42%; length of desaturations, 32%; and phasic Edi, 19%. Infant movement and caretaker movement were reduced by 42% and 27%, respectively. Neural inspiratory time was increased by 39 ms on NIV-NAVA, possibly due to Head's paradoxical reflex.ConclusionNIV-NAVA was a safe, alternative mode of noninvasive support that produced beneficial short-term physiological effects, especially compared with NIMV.

Evaluation of Ultrasound-Based Sensor to Monitor Respiratory and Nonrespiratory Movement and Timing in Infants.

GOAL: To describe and validate a noncontacting sensor that used reflected ultrasound to separately monitor respiratory, nonrespiratory, and caretaker movements of infants. METHODS: An in-phase and quadrature (I & Q) detection scheme provided adequate bandwidth, in conjunction with postdetection filtering, to separate the three types of movement. The respiratory output was validated by comparing it to the electrical activity of the diaphragm (Edi) obtained from an infant ventilator in 11 infants. The nonrespiratory movement output was compared to movement detected by miniature accelerometers attached to the wrists, ankles, and heads of seven additional infants. Caretaker movement was compared to visual observations annotated in the recordings. RESULTS: The respiratory rate determined by the sensor was equivalent to that from the Edi signal. The sensor could detect the onset of inspiration significantly earlier than the Edi signal (23+/-69 ms). Nonrespiratory movement was identified with an agreement of 0.9 with the accelerometers. It potentially interfered with the respiratory output an average of 4.7+/-4.5% and 14.9+/15% of the time in infants not requiring or on ventilatory support, respectively. Caretaker movements were identified with 98% sensitivity and specificity. The sensor outputs were independent of body coverings or position. CONCLUSION: This single, noncontacting sensor can independently quantify these three types of movement. SIGNIFICANCE: It is feasible to use the sensor as trigger for synchronizing mechanical ventilators to spontaneous breathing, to quantify overall movement, to determine sleep state, to detect seizures, and to document the amount and effects of caretaker activity in infants.

Tidal volume threshold for colorimetric carbon dioxide detectors available for use in neonates.

OBJECTIVE: Colorimetric carbon dioxide detectors are used for confirmation of endotracheal intubation. The colorimetric carbon dioxide detectors that are used for neonates are labeled for use with infants and small children >1 and <15 kg. The objective of this study was to determine the minimal tidal volume that causes a breath-to-breath color change on 2 colorimetric carbon dioxide detectors. METHODS: Using an artificial-lung model, we determined the tidal volume threshold of 2 colorimetric carbon dioxide detectors (Pedi-Cap [Nellcor, Pleasanton, CA] or Mini StatCO(2) [Mercury Medical, Clearwater, FL]) during ventilation with a T-piece resuscitator or neonatal ventilator. Digital video recordings of the colorimetric carbon dioxide detectors were made during 20 seconds of ventilation at each tidal volume. Seven clinicians who were blinded to the tidal volume reviewed the videos in random order and graded the color change to determine adequacy for clinical application. RESULTS: The Mini StatCO(2) tidal volume threshold was 0.83 mL, and the Pedi-Cap tidal volume threshold was 1.08 mL. CONCLUSIONS: The lung model revealed that the tidal volume threshold for the tested colorimetric carbon dioxide detectors is less than the expected tidal volume of a 400-g infant and suggests that these devices are appropriate for use with any neonate to confirm intubation.

Using pegylated interferon and ribavirin to treat patients with chronic hepatitis C.

Hepatitis C virus is the most common chronic blood-borne infection in the United States. The advent of new treatment regimens using pegylated interferons in combination with ribavirin has led to improved sustained viral response rates for some genotypes in large multicenter trials. Advances in the management of side effects and toxicities have expanded the pool of treatable patients. A recent National Institutes of Health consensus conference recommended that all patients who have bridging hepatic fibrosis and moderate inflammation together with detectable viremia should receive treatment with pegylated interferon and ribavirin. Unfortunately, these medications are very expensive and have significant side effects. Hematologic toxicities include anemia and leukopenia. These can be managed with close monitoring, use of growth factors, or dose reductions. Depression also can be caused or exacerbated by these medicines and may require treatment with a selective serotonin reuptake inhibitor, comanagement with psychiatry, or cessation of pegylated interferon and ribavirin treatment. Contraception is imperative because ribavirin is highly teratogenic. Influenza-like symptoms of fatigue, nausea, and mild fevers can be helped by quality patient education and support including frequent office visits. Data from randomized controlled trials demonstrating improvements in long-term survival as a result of treatment are not yet available, but it appears that patients who have no detectable virus six months after treatment have a good chance of remaining virus free for at least five years.

Management of hepatitis C: evaluating suitability for drug therapy.

Chronic hepatitis C virus infection is a common and serious disease. Although an estimated 2.7 million persons in the United States have this disease, most have not yet been diagnosed. Recent advances in treatment provide successful cure in 50 to 80 percent of cases. Current drug therapy consists of a combination of pegylated interferon and ribavirin. Although all patients with chronic hepatitis C virus infection are potential candidates for treatment, pharmacologic therapy has a number of contraindications. Evaluation of suitability for treatment includes a thorough search for comorbid medical and psychiatric conditions that can be contraindications. Initial testing involves anti-hepatitis C virus antibodies, but definitive diagnosis of active disease requires detection of viral RNA. Most patients require a liver biopsy to determine the amount of hepatic fibrosis and ongoing hepatocellular inflammation. Viral genotype also should be determined: type 1 requires 12 months of treatment and does not respond as well as types 2 and 3, which require only six months of treatment. Common side effects of drug therapy include anemia, anorexia, depression, fatigue, fever, headache, myalgia, nausea, and erythema at the injection site.