scholarly journals Historical trends in the trade wind inversion in the tropical North Atlantic Ocean and Caribbean

2021 ◽  
Author(s):  
Craig A. Ramseyer ◽  
Paul W. Miller
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Trade Wind ◽  
Historical Trends ◽  
Tropical North Atlantic ◽  
Trade Wind Inversion

scholarly journals A quest for the biological sources of long chain alkyl diols in the western tropical North Atlantic Ocean

2018 ◽  
Vol 15 (19) ◽  
pp. 5951-5968 ◽  
Author(s):  
Sergio Balzano ◽  
Julie Lattaud ◽  
Laura Villanueva ◽  
Sebastiaan W. Rampen ◽  
Corina P. D. Brussaard ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Water Column ◽  
North Atlantic ◽  
18S Rrna ◽  
North Atlantic Ocean ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Tropical North Atlantic ◽  
Biological Sources ◽  
Long Chain

Abstract. Long chain alkyl diols (LCDs) are widespread in the marine water column and sediments, but their biological sources are mostly unknown. Here we combine lipid analyses with 18S rRNA gene amplicon sequencing on suspended particulate matter (SPM) collected in the photic zone of the western tropical North Atlantic Ocean at 24 stations to infer relationships between LCDs and potential LCD producers. The C30 1,15-diol was detected in all SPM samples and accounted for >95 % of the total LCDs, while minor proportions of C28 and C30 1,13-diols, C28 and C30 1,14-diols, as well as C32 1,15-diol were found. The concentration of the C30 and C32 diols was higher in the mixed layer of the water column compared to the deep chlorophyll maximum (DCM), whereas concentrations of C28 diols were comparable. Sequencing analyses revealed extremely low contributions (≈0.1 % of the 18S rRNA gene reads) of known LCD producers, but the contributions from two taxonomic classes with which known producers are affiliated, i.e. Dictyochophyceae and Chrysophyceae, followed a trend similar to that of the concentrations of C30 and C32 diols. Statistical analyses indicated that the abundance of 4 operational taxonomic units (OTUs) of the Chrysophyceae and Dictyochophyceae, along with 23 OTUs falling into other phylogenetic groups, were weakly (r≤0.6) but significantly (p value <0.01) correlated with C30 diol concentrations. It is not clear whether some of these OTUs might indeed correspond to C28−32 diol producers or whether these correlations are just indirect and the occurrence of C30 diols and specific OTUs in the same samples might be driven by other environmental conditions. Moreover, primer mismatches were unlikely, but cannot be excluded, and the variable number of rRNA gene copies within eukaryotes might have affected the analyses leading to LCD producers being undetected or undersampled. Furthermore, based on the average LCD content measured in cultivated LCD-producing algae, the detected concentrations of LCDs in SPM are too high to be explained by the abundances of the suspected LCD-producing OTUs. This is likely explained by the slower degradation of LCDs compared to DNA in the oxic water column and suggests that some of the LCDs found here were likely to be associated with suspended debris, while the DNA from the related LCD producers had been already fully degraded. This suggests that care should be taken in constraining biological sources of relatively stable biomarker lipids by quantitative comparisons of DNA and lipid abundances.

scholarly journals Long-term trends in aerosol and precipitation composition over the western North Atlantic Ocean at Bermuda

2014 ◽  
Vol 14 (5) ◽  
pp. 7025-7066 ◽  
Author(s):  
W. C. Keene ◽  
J. L. Moody ◽  
J. N. Galloway ◽  
J. M. Prospero ◽  
O. R. Cooper ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Flow Regimes ◽  
The United States ◽  
Open Ocean ◽  
Anthropogenic Sources ◽  
Trade Wind ◽  
Chemical Compositions ◽  
Near Surface

Abstract. Since the 1980s, emissions of SO2 and NOx (NO + NO2) from anthropogenic sources in the United States (US) and Europe have decreased significantly suggesting that the export of oxidized S and N compounds from surrounding continents to the atmosphere overlying North Atlantic Ocean (NAO) has also decreased. The chemical compositions of aerosols and precipitation sampled daily on Bermuda (32.27° N, 64.87° W) from 1989 to 1997 and from 2006 to 2009 were evaluated to quantify the magnitudes, significance, and implications of associated tends in atmospheric composition. The chemical data were stratified based on FLEXPART retroplumes into four discrete transport regimes: westerly flow from the eastern North America (NEUS/SEUS); easterly trade-wind flow from northern Africa and the subtropical NAO (Africa); long, open-ocean, anticyclonic flow around the Bermuda High (Oceanic); and transitional flow from the relatively clean open ocean to the polluted northeastern US (North). Based on all data, annual average concentrations of non-sea-salt (nss) SO42- associated with aerosols and annual VWA concentrations in precipitation decreased significantly (by 22 and 49%, respectively) whereas annual VWA concentrations of NH4+ in precipitation increased significantly (by 70%). Corresponding trends in aerosol and precipitation NO3- and of aerosol NH4+ were insignificant. Nss SO42- in precipitation under NEUS/SEUS and Oceanic flow decreased significantly (61% each) whereas corresponding trends in particulate nss SO42- under both flow regimes were insignificant. Trends for precipitation were driven in part by decreasing emissions of SO2 over upwind continents and associated decreases in anthropogenic contributions to nss SO42- concentrations. Under NEUS/SEUS and Oceanic flow, the ratio of anthropogenic to biogenic contributions to to nss SO42- in the column scavenged by precipitation were relatively greater than those in near surface aerosol, which implies that, for these flow regimes, precipitation is a better indicator of overall anthropogenic impacts on the lower troposphere. Particulate nss SO42- under African flow also decreased significantly (34%) whereas the corresponding decrease in nss SO42- associated with precipitation was marginally insignificant. We infer that these trends were driven in part by reductions in the emissions and transport of oxidized S compounds from Europe. The lack of significant trends in NO3- associated with aerosols and precipitation under NEUS/SEUS flow is notable in light of the large decrease (39%) in NOx emissions in the US over the period of record. Rapid chemical processing of oxidized N in marine air contributed to this lack of correspondence. Decreasing ratios of nss SO42- to NH4+ and the significant decreasing trend in precipitation acidity (37%) indicate that the total amount of acidity in the multiphase gas-aerosol system in the western NAO troposphere decreased over the period of record. Decreasing aerosol acidities would have shifted the phase partitioning of total NH3 (NH3 + particulate NH4+) towards the gas phase thereby decreasing the atmospheric lifetime of total NH3 against wet plus dry deposition. The trend of increasing NH4+ in precipitation at Bermuda over the period of record suggests that NH3 emissions from surrounding continents also increased. Decreasing particulate nss SO42- in near-surface air under NEUS/SEUS flow over the period of record suggests a lower limit for net warming in the range of 0.1–0.3 W m-2 resulting from the decreased shortwave scattering and absorption by nss SO42- and associated aerosol constituents.

scholarly journals From In Situ to satellite observations of pelagic Sargassum distribution and aggregation in the Tropical North Atlantic Ocean

PLoS ONE ◽  
2019 ◽  
Vol 14 (9) ◽  
pp. e0222584 ◽  
Author(s):  
Anouck Ody ◽  
Thierry Thibaut ◽  
Léo Berline ◽  
Thomas Changeux ◽  
Jean-Michel André ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Satellite Observations ◽  
Tropical North Atlantic

scholarly journals The pathways and properties of the Amazon River Plume in the tropical North Atlantic Ocean

2013 ◽  
Vol 118 (12) ◽  
pp. 6894-6913 ◽  
Author(s):  
Victoria J. Coles ◽  
Maureen T. Brooks ◽  
Julia Hopkins ◽  
Michael R. Stukel ◽  
Patricia L. Yager ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
River Plume ◽  
Amazon River ◽  
Tropical North Atlantic ◽  
Amazon River Plume

The Role of Aerosols in the Evolution of Tropical North Atlantic Ocean Temperature Anomalies

Science ◽  
2009 ◽  
Vol 324 (5928) ◽  
pp. 778-781 ◽  
Author(s):  
A. T. Evan ◽  
D. J. Vimont ◽  
A. K. Heidinger ◽  
J. P. Kossin ◽  
R. Bennartz
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Ocean Temperature ◽  
Temperature Anomalies ◽  
Tropical North Atlantic
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