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1

Deposition, return flux, and burial rates of nitrogen and phosphorus in the sediments of two high-Arctic fjords

Koziorowska K., Kuliński K., Pempkowiak J.

Oceanologia

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2018

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No. 60 (4)

431--445

EN

The aim of this study was to determine the burial rates of nitrogen (N) and phosphorus (P) in the sediments of two high-latitude fjords: Hornsund and Kongsfjorden (Spitsbergen). Both deposition to sediments and the return flux from sediments to the water column of the various species of these elements were, therefore, quantified. The burial rate was then calculated as the difference between deposition and return flux. The required concentrations of N and P species were measured in surface sediments, in pore water extracted from the sediments, and in the above-bottom water at sampling stations situated along the axes of the fjords. Annual deposition to sediments ranged between 2.3-8.3 g m−2 for N and 0.9-2.8 g m−2 for P. The nitrogen return fluxes ranged from 0.12 to 1.46 g m−2 y−1. At most stations, the N flux was predominantly of dissolved organic (about 60-70%) rather than inorganic N. The P return flux varied between 0.01 and 0.11 g m−2 y−1, with organic species constituting 60-97%. The N and P burial rates differed between fjords: 2.3-7.9 g N m−2 y−1 and 0.9-2.8 g P m−2 y−1 in Hornsund vs. 0.9-1.3 N g m−2 y−1 and 1.0-1.2 g P m−2 y−1 in Kongsfjorden. This was accompanied by a different efficiency of N and P burial – higher in Hornsund than in Kongsfjorden, in both cases. This suggests differences in the quality and quantity of N and P organic species deposited to sediments and therefore differences in the intensity of their mineralization and/or decomposition.

2

Comparison of the burial rate estimation methods of organic and inorganic carbon and quantification of carbon burial in two high Arctic fjords

Koziorowska K., Kuliński K., Pempkowiak J.

Oceanologia

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2018

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No. 60 (3)

405--418

EN

Quantifying the burial of organic carbon (OC) and inorganic carbon (IC) species in marine sediments contribute to a better understanding of carbon cycle. This is especially important in the Arctic, where carbon deposition is relatively high and expected to change with climate warming. This study aimed to quantify the burial rates of OC and IC in the sediments of two high-latitude fjords – Hornsund and Kongsfjorden (European Arctic). Comparison of the results from three methods quantifying carbon burial in marine sediments was carried out. Sediment cores, pore water, and over-bottom water samples were analyzed for OC and IC. The burial rates were established by considering: carbon deposition to sediments minus carbon return flux, carbon deposited to sediments 80-100 years ago and carbon deposited to sediments recently. The radiolead method was employed for sediment dating. Carbon return flux was obtained using dissolved carbon species concentrations in pore water and over-bottom water. Sediment linear and mass accumulation rates in the fjords were 0.12-0.20 cm y−1 and 1160-2330 g m−2y−1. The OC burial rates were 19.3-30.3 g OC m−2 y−1 in Hornsund and 5.7-10.0 g OC m−2y−1 in Kongsfjorden. IC burial was taken as equal to IC deposition and ranged from 10.7 to 20.8 g IC m−2 y−1 in Hornsund and 19.4-45.7 g IC m−2 y−1 in Kongsfjorden. The “return flux” model seems most appropriate for carbon burial rate studies. The data demonstrated that OC burial dominates in Hornsund, while in Kongsfjorden, IC burial is more important.

3

Diurnal and seasonal DOC and POC variability in the land-locked sea

Szymczycha B., Winogradow A., Kuliński K., Koziorowska K., Pempkowiak J.

Oceanologia

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2017

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No. 59 (3)

379--388

EN

Organic matter is a minor yet important component of the marine environment. The aim of this study was to investigate the diurnal and seasonal changes in dissolved and particulate organic carbon (DOC and POC, respectively). Thus, DOC and POC as well as chlorophyll a (Chl a), δ13C, NO3−, NO2−, NH4+, PO43-, salinity, pH, and temperature were regularly measured in samples collected for 24 h (2-h resolution) in the Gdańsk Deep (54°44.730′N, 19°08.531′E) at three water depths (1, 10, and 40 m) during sampling campaigns in 2011 (May), 2014 (May), and 2015 (January, March, May, July, September, November). Seasonal variations in DOC and POC followed the seasonality of Chl a (proportional trend) and nutrients (reverse trend) concentrations. Diurnal oscillations were detected in six out of the eight measurement series. The strongest diurnal variability in both POC and DOC occurred in May 2011 and March 2015, when phytoplankton activity was highest (high Chl a). The surprisingly low δ13C values (range: −28‰ to −24‰) measured over the course of the study revealed the gaps in our knowledge of the isotopic characteristics of terrestrial- vs. marine-derived particulate organic matter.

4

Accuracy and precision of selected analytical methods used in marine geochemical studies

Koziorowska K., Kuliński K., Pempkowiak J.

Inżynieria Morska i Geotechnika

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2016

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nr 3

123--129

EN

The studies based on hypothetical comparisons of the chemical composition of sediment samples collected in different time and/or from different place. Determination of the accuracy and the precision of the analytical methods used to estimate the basic properties of bottom sediments. The results assessment using various statistical methods. Results of the relative standard deviations for the methods used to determine the concentration of total and organic carbon, total nitrogen and heavy metals. Conclusions of the studies.

PL

Badania oparte na hipotetycznym porównania składu chemicznego osadów pobranych w różnym czasie i/lub miejscu. Wyznaczenie dokładności i precyzji metod analitycznych wykorzystywanych do określenia podstawowych właściwości osadów dennych. Zastosowanie różnych metod statystycznych: Wyniki odchyleń standardowych dla pomiarów wykonanych w celu określenia stężenia całkowitego i organicznego węgla, całkowitego azotu oraz metali ciężkich. Wnioski z przeprowadzonych badań.