Dynamics of dissolved organic carbon and total dissolved nitrogen in Maryland's coastal bays

The marine biogeochemistries of carbon and nitrogen have come under increased scrutiny because of their close involvement in climate change and coastal eutrophication. Recent studies have shown that the high-temperature combustion (HTC) technique is suitable for routine analyses of dissolved organic matter due to its good oxidation efficiency, high sensitivity, and precision. In our laboratory, a coupled HTC TOC-NCD system with a sample changer was used for the automated and simultaneous determination of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) in seawater samples. TOC control software was used for TOC instrument control, DOC data acquisition, and data analysis. TDN data acquisition and manipulation was undertaken under LabVIEW. The combined system allowed simultaneous determination of DOC and TDN in the same sample using a single injection and provided low detection limits and excellent linear ranges for both DOC and TDN. The risk of contamination has been remarkably reduced due to the minimal sample manipulation and automated analyses. The optimised system provided a reliable tool for the routine determination of DOC and TDN in marine waters.

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Correction to: Influence of Biochar from Slow Pyrolysis on Dissolved Organic Carbon and Total Dissolved Nitrogen Levels of Urban Storm-Water Runoff

Water Air & Soil Pollution ◽

10.1007/s11270-018-3927-6 ◽

2018 ◽

Vol 229 (8) ◽

Author(s):

Enrico Mancinelli ◽

Edita Baltrėnaitė ◽

Pranas Baltrėnas ◽

Raimondas Grubliauskas ◽

Eglė Marčiulaitienė ◽

...

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Storm Water ◽

Water Runoff ◽

Slow Pyrolysis ◽

Nitrogen Levels ◽

Dissolved Nitrogen ◽

Total Dissolved Nitrogen ◽

Storm Water Runoff ◽

Urban Storm

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The importance of riparian zones on stream carbon and nitrogen export in a temperate, agricultural dominated landscape

Biogeosciences Discussions ◽

10.5194/bgd-9-7465-2012 ◽

2012 ◽

Vol 9 (6) ◽

pp. 7465-7497 ◽

Cited By ~ 4

Author(s):

T. Wohlfart ◽

J.-F. Exbrayat ◽

K. Schelde ◽

B. Christen ◽

T. Dalgaard ◽

...

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Dissolved Organic Nitrogen ◽

Organic Nitrogen ◽

Agricultural Land ◽

Stream Water ◽

Soil Types ◽

Organic Soils ◽

Dissolved Nitrogen ◽

Total Dissolved Nitrogen

Abstract. The surrounding landscape of a stream has crucial impacts on the aquatic environment. This study pictures the hydro-biogeochemical situation of the Tyrebaekken creek catchment in central Jutland, Denmark. The intensively managed agricultural landscape is dominated by rotational croplands. One northern and one southern stream run through the catchment before converging to form a second order brook. The small catchments mainly consist of sandy soil types besides organic soils along the riparian zone of the streams. The aim of the study was to characterise the relative influence of soil type and land use on stream water quality. Nine snapshot sampling campaigns were undertaken during the growing season of 2009. On each sampling day, 20 points along the stream were sampled as well as eight drain outlets and two groundwater wells. Total dissolved nitrogen, nitrate, ammonium nitrogen and dissolved organic carbon (DOC) concentrations were measured and dissolved organic nitrogen (DON) was calculated for each grabbed sample. Electro-conductivity, pH and flow velocity were measured during sampling. Statistical analyses showed significant differences between the northern, southern and converged stream parts, especially for nitrate concentrations with average values of 9.6 mg N l−1, 1.4 mg N l−1 and 3.0 mg N l−1, respectively. Furthermore, throughout the sampling period DON concentrations increased from 0.1 mg N l−1 to 2.8 mg N l−1 and from 0.1 mg N l−1 to 0.8 mg N l−1in the northern and southern streams, respectively. This corresponded to a contribution of up to 81% to total dissolved nitrogen. Multiple-linear regression analyses performed between chemical data and landscape charateristics showed a significant negative influence of organic soils on instream N concentrations and corresponding losses in spite of their overall minor share of the agricultural land (12.9%). On the other hand, organic soil frequency was positively correlated to the corresponding dissolved organic carbon concentrations. Croplands also had a significant influence but with weaker correlations. For our case study we conclude that soil types and corresponding biogeochemical properties have a major influence on stream water chemistry. Meanwhile, the contribution of dissolved organic nitrogen to the total nitrogen budget was substantial in this agricultural dominated landscape.

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Small-scale distribution of microbes and biogeochemistry in the Great Barrier Reef

PeerJ ◽

10.7717/peerj.10049 ◽

2020 ◽

Vol 8 ◽

pp. e10049

Author(s):

Cátia Carreira ◽

Júlia Porto Silva Carvalho ◽

Samantha Talbot ◽

Isabel Pereira ◽

Christian Lønborg

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Great Barrier Reef ◽

Temporal Distribution ◽

Small Scale ◽

Barrier Reef ◽

Dissolved Nitrogen ◽

Total Dissolved Nitrogen ◽

Dissolved Inorganic Nutrients ◽

Small Scales

Microbial communities distribute heterogeneously at small-scales (mm-cm) due to physical, chemical and biological processes. To understand microbial processes and functions it is necessary to appreciate microbes and matter at small scales, however, few studies have determined microbial, viral, and biogeochemical distribution over space and time at these scales. In this study, the small-scale spatial and temporal distribution of microbes (bacteria and chlorophyll a), viruses, dissolved inorganic nutrients and dissolved organic carbon were determined at five locations (spatial) along the Great Barrier Reef (Australia), and over 4 consecutive days (temporal) at a coastal location. Our results show that: (1) the parameters show high small-scale heterogeneity; (2) none of the parameters measured explained the bacterial abundance distributions at these scales spatially or temporally; (3) chemical (ammonium, nitrate/nitrite, phosphate, dissolved organic carbon, and total dissolved nitrogen) and biological (chl a, and bacterial and viral abundances) measurements did not reveal significant relationships at the small scale; and (4) statistically significant differences were found between sites/days for all parameter measured but without a clear pattern.

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