Annual net community production (ANCP) in the subtropical Pacific Ocean was determined by using annual oxygen measurements from Argo profiling floats with an upper water column oxygen mass balance model. ANCP was determined to be from 2.0 to 2.4 mol C m−2 yr−1 in the western subtropical North Pacific, 2.4 mol C m−2 yr−1 in the eastern subtropical North Pacific, and near zero in the subtropical South Pacific. Error analysis with the main sources of uncertainty being the accuracy of oxygen measurements and the parameterization of bubble fluxes in winter suggested an uncertainty of ~0.3 mol C m−2 yr−1 in subtropical Pacific. The results are in good agreement with previous observations in locations where ANCP has been determined before. These are the first results from the western subtropical North Pacific and subtropical South Pacific where ANCP have not been evaluated before. ANCP for the subtropical South Pacific is significantly lower than in all other open ocean locations where it has been determined by mass balance. Comparison of our observations with net biological carbon export estimated from remote sensing algorithms indicates that observations from the subtropical North Pacific are higher than the satellite estimates, but those in the subtropical South Pacific are lower than satellite‐determined carbon export.

Vorapaxar provided rapid and sustained dose-related inhibition of platelet aggregation without affecting bleeding or clotting times.

Contributions of organic alkalinity (Org-Alk) to total alkalinity (TA) were investigated in surface waters from three different coastal environments (estuary, urban, mangrove) and offshore sites in the Gulf of Mexico. ∆TA was calculated as the difference between directly measured TA, and TA calculated from total dissolved inorganic carbon (DIC) and pH. In low nutrient surface waters, ∆TA should be dominated by Org-Alk with minor contributions from inorganic nutrients (e.g., HPO 4 2and SiO(OH) 3-). Average values of ∆TA were 0.1 ± 5.0 µmol kg-1 at coastal sites outside the Mississippi-Atchafalaya River Estuary (n = 17), 33.6 ± 18.0 µmol kg-1 in the Suwannee River Estuary (n = 17), 16.0 ± 25.4 µmol kg-1 in the Tampa Bay, Caloosahatchee River, and Ten Thousand Islands area (n = 55), and-1.0 ± 4.9 µmol kg-1 in offshore waters (n = 14) in the northern Gulf of Mexico. In addition to Org-Alk assessments based on ∆TA, procedures were developed for direct spectrophotometric measurements of Org-Alk via titrations of samples that were purged of CO 2. Two-step titrations of these DIC-free samples consisted of a first titration from pH 4.5 to 6.0 performed using bromocresol purple (BCP), and a second titration, from pH 6.0 to about 8, using cresol red (CR) as the indicator. By diluting all samples, including the offshore reference sample, to a common salinity (the lowest salinity of the coastal samples), borate alkalinity was presumed to be identical for all samples. Org-Alk values were calculated as differences between titration results obtained for coastal samples and the offshore reference sample and, through ancillary nutrient measurements, accounted for alkalinity contributions from silicate and phosphate. The direct titrations confirmed the existence of substantial Org-Alk in coastal samples. Spectrophotometric titration data were also used for model fitting in order to assess the dissociation constants (pK i) of the organic acids. The pK i of the organic acids were within the previously reported range for riverine fulvic acids.

Abstract. A large anomalously warm water patch (the “Blob”) appeared in the NE Pacific Ocean in the winter of 2013–2014 and persisted through 2016 causing strong positive upper ocean temperature anomalies at Ocean Station Papa (OSP, 50∘ N, 145∘ W). The effect of the temperature anomalies on annual net community production (ANCP) was determined by upper ocean chemical mass balances of O2 and dissolved inorganic carbon (DIC) using data from a profiling float and a surface mooring. Year-round oxygen mass balance in the upper ocean (0 to 91–111 m) indicates that ANCP decreased after the first year when warmer water invaded this area and then returned to the “pre-Blob” value (2.4, 0.8, 2.1, and 1.6 mol C m−2 yr−1 from 2012 to 2016, with a mean value of 1.7±0.7 mol C m−2 yr−1). ANCP determined from the DIC mass balance has a mean value that is similar within the errors as that from the O2 mass balance but without a significant trend (2.0, 2.1, 2.6, and 3.0 mol C m−2 yr−1 with a mean value of 2.4±0.6 mol C m−2 yr−1). This is likely due to differences in the air–sea gas exchange, which is a major term for both mass balances. Oxygen has a residence time with respect to gas exchange of about 1 month while the CO2 gas exchange response time is more like a year. Therefore the biologically induced oxygen saturation anomaly responds fast enough to record annual changes, whereas that for CO2 does not. Phytoplankton pigment analysis from the upper ocean shows lower chlorophyll a concentrations and changes in plankton community composition (greater relative abundance of picoplankton) in the year after the warm water patch entered the area than in previous and subsequent years. Our analysis of multiple physical and biological processes that may have caused the ANCP decrease after warm water entered the area suggests that it was most likely due to the temperature-induced changes in biological processes.

Autonomous in situ sensors are needed to document the effects of today's rapid ocean uptake of atmospheric carbon dioxide (e.g., ocean acidification). General environmental conditions (e.g., biofouling, turbidity) and carbon-specific conditions (e.g., wide diel variations) present significant challenges to acquiring long-term measurements of dissolved inorganic carbon (DIC) with satisfactory accuracy and resolution. SEAS-DIC is a new in situ instrument designed to provide calibrated, high-frequency, long-term measurements of DIC in marine and fresh waters. Sample water is first acidified to convert all DIC to carbon dioxide (CO2). The sample and a known reagent solution are then equilibrated across a gas-permeable membrane. Spectrophotometric measurement of reagent pH can thereby determine the sample DIC over a wide dynamic range, with inherent calibration provided by the pH indicator's molecular characteristics. Field trials indicate that SEAS-DIC performs well in biofouling and turbid waters, with a DIC accuracy and precision of ∼2 μmol kg(-1) and a measurement rate of approximately once per minute. The acidic reagent protects the sensor cell from biofouling, and the gas-permeable membrane excludes particulates from the optical path. This instrument, the first spectrophotometric system capable of automated in situ DIC measurements, positions DIC to become a key parameter for in situ CO2-system characterizations.

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Background Immunocompromised individuals and those with lung dysfunction readily acquire pulmonary bacterial infections, which may cause serious diseases and carry a heavy economic burden. Maintaining adequate antibiotic concentrations in the infected tissues is necessary to eradicate resident bacteria. To specifically deliver therapeutics to the infected pulmonary tissues and enable controlled release of payloads at the infection site, a ROS-responsive material, i.e. 4-(hydroxymethyl) phenylboronic acid pinacol ester-modified α-cyclodextrin (Oxi-αCD), was employed to encapsulate moxifloxacin (MXF), generating ROS-responsive MXF-containing nanoparticles (MXF/Oxi-αCD NPs). Results MXF/Oxi-αCD NPs were coated with DSPE-PEG and DSPE-PEG-folic acid, facilitating penetration of the sputum secreted by the infected lung and enabling the active targeting of macrophages in the inflammatory tissues. In vitro drug release experiments indicated that MXF release from Oxi-αCD NPs was accelerated in the presence of 0.5 mM H2O2. In vitro assay with Pseudomonas aeruginosa demonstrated that MXF/Oxi-αCD NPs exhibited higher antibacterial activity than MXF. In vitro cellular study also indicated that folic acid-modified MXF/Oxi-αCD NPs could be effectively internalized by bacteria-infected macrophages, thereby significantly eradicating resident bacteria in macrophages compared to non-targeted MXF/Oxi-αCD NPs. In a mouse model of pulmonary P. aeruginosa infection, folic acid-modified MXF/Oxi-αCD NPs showed better antibacterial efficacy than MXF and non-targeted MXF/Oxi-αCD NPs. Meanwhile, the survival time of mice was prolonged by treatment with targeting MXF/Oxi-αCD NPs. Conclusions Our work provides a strategy to overcome the mucus barrier, control drug release, and improve the targeting capability of NPs for the treatment of pulmonary bacterial infections.

Surface pCO2 data from the West Florida Shelf (WFS) have been collected during 25 cruise surveys between 2003 and 2012. The data were scaled up using remote sensing measurements of surface water properties in order to provide a more nearly synoptic map of pCO2 spatial distributions and describe their temporal variations. This investigation involved extensive tests of various model forms through parsimony and Principal Component Analysis, which led to the development of a multi-variable empirical surface pCO2 model based on concurrent MODIS (Moderate Resolution Imaging Spectroradiometer) estimates of surface chlorophyll a concentrations (CHL, mg m-3), diffuse light attenuation at 490 nm (Kd_Lee, m-1), and sea surface temperature (SST, ˚C). Validation using an independent dataset showed a pCO2 Root Mean Square Error (RMSE) of < 12 µatm and a 0.88 coefficient of determination (R 2) for measured and modelpredicted pCO2 ranging from 300 to 550 µatm. The model was more sensitive to SST than to CHL and Kd_Lee, with a 1 ˚C change in SST leading to a ~16 µatm change in the predicted pCO2. Application of the model to the entire WFS MODIS time series between 2002 and 2014 showed clear seasonality, with maxima (~450 µatm) in summer and minima (~350 µatm) in winter. The seasonality was positively correlated to SST (high in summer and low in winter) and negatively correlated to CHL and Kd_Lee (high in winter and low in summer). Inter-annual variations of pCO2 were consistent with inter-annual variations of SST, CHL, and Kd_Lee. These results suggest that surface water pCO2 of the WFS can be estimated, with known uncertainties, from