δ15N dynamics of ammonium and particulate nitrogen in a temperate eutrophic estuary

Abstract. The objective of this research was to investigate the relationship between water and sediment discharge on the transport of nutrients: nitrogen and phosphorus. Water discharge, suspended sediment concentration and dissolved and particulate forms of nitrogen and phosphorus were monitored on the 105 km2 River Owenabue catchment in Ireland. Water discharge was found to have an influence on both particulate and dissolved nutrient transport, but more so for particulate nutrients. The particulate portion of N and P in collected samples was found to be 24 and 39%, respectively. Increased particulate nitrogen concentrations were found at the onset of high discharge events, but did not correlate well to discharge. High concentrations of phosphorus were associated with increased discharge rates and the coefficient of determination (r2) between most forms of phosphorus and both discharge and suspended sediment concentrations were observed to be greater than 0.5. The mean TN yield is 4004 kg km−2 yr−1 for the full 29-month monitoring period with a mean PN yield of 982 kg km−2 yr−1, 25% of the TN yield with the contribution to the yield of PN and PP estimated to be 25 and 53% respectively. These yields represent a PN and PP contribution to the suspended sediment load of 5.6 and 0.28% respectively for the monitoring period. While total nitrogen and total phosphorus levels were similar to other European catchments, levels of bio-available phosphorus were elevated indicating a potential risk of eutrophication within the river.

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Quality of surface water related to land use: a case study in a catchment with small farms and intensive vegetable crop production in southern Brazil

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832014000200030 ◽

2014 ◽

Vol 38 (2) ◽

pp. 656-668 ◽

Cited By ~ 10

Author(s):

Karina Hacke Ribeiro ◽

Nerilde Favaretto ◽

Jeferson Dieckow ◽

Luiz Cláudio de Paula Souza ◽

Jean Paolo Gomes Minella ◽

...

Keyword(s):

Water Quality ◽

Electrical Conductivity ◽

Land Use ◽

Surface Water ◽

Total Nitrogen ◽

Total Phosphorus ◽

Oxygen Demand ◽

Lower Percentage ◽

Native Forest ◽

Particulate Nitrogen

Water degradation is strongly related to agricultural activity. The aim of this study was to evaluate the influence of land use and some environmental components on surface water quality in the Campestre catchment, located in Colombo, state of Parana, Brazil. Physical and chemical attributes were analyzed (total nitrogen, ammonium, nitrate, total phosphorus, electrical conductivity, pH, temperature, turbidity, total solids, biological oxygen demand, chemical oxygen demand and dissolved oxygen). Monthly samples of the river water were taken over one year at eight monitoring sites, distributed over three sub-basins. Overall, water quality was worse in the sub-basin with a higher percentage of agriculture, and was also affected by a lower percentage of native forest and permanent preservation area, and a larger drainage area. Water quality was also negatively affected by the presence of agriculture in the riparian zone. In the summer season, probably due to higher rainfall and intensive soil use, a higher concentration of total nitrogen and particulate nitrogen was observed, as well as higher electrical conductivity, pH and turbidity. All attributes, except for total phosphorus, were in compliance with Brazilian Conama Resolution Nº 357/2005 for freshwater class 1. However, it should be noted that these results referred to the base flow and did not represent a discharge condition since most of the water samples were not collected at or near the rainfall event.

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Concentrations, ratios, and sinking fluxes of major bioelements at Ocean Station Papa

Elem Sci Anth ◽

10.1525/elementa.2020.00166 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Montserrat Roca-Martí ◽

Claudia R. Benitez-Nelson ◽

Blaire P. Umhau ◽

Abigale M. Wyatt ◽

Samantha J. Clevenger ◽

...

Keyword(s):

Soft Tissue ◽

Late Summer ◽

Euphotic Zone ◽

Particulate Phosphorus ◽

Particulate Nitrogen ◽

Sinking Particles ◽

Ocean Station Papa ◽

Particle Size Classes

Fluxes of major bioelements associated with sinking particles were quantified in late summer 2018 as part of the EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) field campaign near Ocean Station Papa in the subarctic northeast Pacific. The thorium-234 method was used in conjunction with size-fractionated (1–5, 5–51, and >51 μm) concentrations of particulate nitrogen (PN), total particulate phosphorus (TPP), biogenic silica (bSi), and particulate inorganic carbon (PIC) collected using large volume filtration via in situ pumps. We build upon recent work quantifying POC fluxes during EXPORTS. Similar remineralization length scales were observed for both POC and PN across all particle size classes from depths of 50–500 m. Unlike bSi and PIC, the soft tissue–associated POC, PN, and TPP fluxes strongly attenuated from 50 m to the base of the euphotic zone (approximately 120 m). Cruise-average thorium-234-derived fluxes (mmol m–2 d–1) at 120 m were 1.7 ± 0.6 for POC, 0.22 ± 0.07 for PN, 0.019 ± 0.007 for TPP, 0.69 ± 0.26 for bSi, and 0.055 ± 0.022 for PIC. These bioelement fluxes were similar to previous observations at this site, with the exception of PIC, which was 1 to 2 orders of magnitude lower. Transfer efficiencies within the upper twilight zone (flux 220 m/flux 120 m) were highest for PIC (84%) and bSi (79%), followed by POC (61%), PN (58%), and TPP (49%). These differences indicate preferential remineralization of TPP relative to POC or PN and larger losses of soft tissue relative to biominerals in sinking particles below the euphotic zone. Comprehensive characterization of the particulate bioelement fluxes obtained here will support future efforts linking phytoplankton community composition and food-web dynamics to the composition, magnitude, and attenuation of material that sinks to deeper waters.

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Seasonal variations in nitrate isotope composition of three rivers draining into the North Sea

Biogeosciences Discussions ◽

10.5194/bgd-7-6051-2010 ◽

2010 ◽

Vol 7 (4) ◽

pp. 6051-6088 ◽

Cited By ~ 1

Author(s):

A. Deek ◽

K. Emeis ◽

U. Struck

Keyword(s):

Isotopic Composition ◽

North Sea ◽

Isotope Composition ◽

Atmospheric Oxygen ◽

Isotope Effects ◽

Nitrate Sources ◽

Particulate Nitrogen ◽

Soil Nitrification ◽

Mean Values ◽

Δ 15N

Abstract. Nitrate loading of coastal ecosystems by rivers that drain industrialised catchments continues to be a problem in the South Eastern North Sea, in spite of significant mitigation efforts over the last 2 decades. To identify nitrate sources, sinks, and turnover in three German rivers that discharge into the German Bight, we determined δ 15N-NO3- and δ18O- NO3- in nitrate and δ 15N of particulate nitrogen for the period 2006–2009 (biweekly samples). The nitrate loads of Rhine, Weser and Ems varied seasonally in magnitude and δ 15N-NO3- (6.5–21‰), whereas the δ 18O-NO3- (-0.3–5.9‰) and δ 15N-PN (4–14‰) were less variable. Overall temporal patterns in nitrate mass fluxes and isotopic composition suggest that a combination of nitrate delivery from nitrification of soil ammonia in the catchment and assimilation of nitrate in the rivers control the isotopic composition of nitrate. Nitrification in soils as a source is indicated by low δ 18O-NO3- in winter, which traces the δ 18O of river water. Mean values of δ 18O-H2O were between –9.4‰ and –7.3‰; combined in a ratio of 2:1 with the atmospheric oxygen δ 18O of 23.5‰ agrees with the found δ 18O of nitrate in the rivers. Parallel variations of δ 15N-NO3- and δ 18O-NO3- within each individual river are caused by isotope effects associated with nitrate assimilation in the water column, the extent of which is determined by residence time in the river. Assimilation is furthermore to some extent mirrored both by the δ 15N of nitrate and particulate N. Although δ 15-NO3- observed in Rhine, Weser and Ems are reflected in high average δ 15N-PN (between 6‰ and 9‰, both are uncorrelated in the time series due to lateral and temporal mixing of PN. That a larger enrichment was consistently seen in δ 15N-NO3- relative to δ 18O-NO3- is attributed to constant additional diffuse nitrate inputs deriving from soil nitrification in the catchment area. A statistically significant inverse correlation exists between increasing δ 15N-NO3- values and decreasing NO3- concentrations. This inverse relationship – observed in each seasonal cycle – together with a robust relationship between human dominated land use and δ 15N-NO3- values demonstrates a strong influence of human activities and riverine nitrate consumption efficiency on the isotopic composition of riverine nitrate.

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Particulate organic matter composition and organic carbon flux in Arctic valley glaciers: examples from the Bayelva River and adjacent Kongsfjorden

Biogeosciences Discussions ◽

10.5194/bgd-12-15655-2015 ◽

2015 ◽

Vol 12 (18) ◽

pp. 15655-15685

Author(s):

Z.-Y. Zhu ◽

Y. Wu ◽

S.-M. Liu ◽

F. Wenger ◽

J. Hu ◽

...

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Particulate Organic Matter ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Concentration Data ◽

Particulate Nitrogen ◽

Organic Carbon Flux ◽

Doc Concentration ◽

The Face

Abstract. In the face of ongoing global warming and glacier retreat, the composition and flux of organic matter in glacier–fjord systems are key variables for updating the carbon cycle and budget, whereas the role of Arctic valley glaciers seems unimportant when compared with the huge Greenland Ice Sheet. Our field observations of the glacier-fed Bayelva River, Svalbard, and the adjacent Kongsfjorden allowed us to determine the compositions of particulate organic matter from glacier to fjord and also to estimate the flux of organic carbon, both for the river and for Svalbard in general. Particulate organic carbon (POC) and dissolved organic carbon (DOC) in the Bayelva River averaged 56 and 73 μM, respectively, in August 2012. Amino acids (AAs) and phytoplankton pigments accounted for ~ 10 % of the particulate organic matter (POM) in the Bayelva River, while AAs represented > 90 % of particulate nitrogen in fjord surface water, suggesting the strong in situ assimilation of organic matter. Bacteria accounts for 13 and 19 % of the POC in the Bayelva River and the Kongsfjorden, respectively, while values for particulate nitrogen (PN) are much higher (i.e., 36 % in Kongsfjorden). The total discharge from the Bayelva River in 2012 was 29 × 106 m3. Furthermore, we calculated the annual POC, DOC, and PN fluxes for the river as 20 ± 1.6, 25 ± 5.6, and 4.7 ± 0.75 t, respectively. Using the POC content and DOC concentration data, we then estimated the annual POC and DOC fluxes for Svalbard glaciers. Although the estimated POC (0.056 ± 0.02 × 106 t yr−1) and DOC (0.02 ± 0.01 × 106 t yr−1) fluxes of Svalbard glaciers are small compared with those of the Greenland Ice Sheet, the area-weighted POC flux of Svalbard glaciers is twice that of the Greenland Ice Sheet, while the flux of DOC can be 4 to 7 times higher. Therefore, we propose that valley glaciers are efficient high-latitude sources of organic carbon.

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The effect of lake restoration by the hypolimnetic withdrawal method on the intensity of ambient odour

Journal of Limnology ◽

10.4081/jlimnol.2016.1400 ◽

2016 ◽

Cited By ~ 1

Author(s):

Renata Tandyrak ◽

Iwona Gołaś ◽

Katarzyna Parszuto ◽

Magdalena Bowszys ◽

Daniel Szymański ◽

...

Keyword(s):

Organic Carbon ◽

River Water ◽

Water Samples ◽

Lake Restoration ◽

Ambient Air ◽

Ammonium Nitrogen ◽

Particulate Nitrogen ◽

Dissolved Nitrogen ◽

Microbiological Parameters ◽

Stagnation Period

The objective of this study was to evaluate the effect of lake restoration by the hypolimnetic withdrawal method on the intensity of ambient odour in the vicinity of the pipeline outlet. The study was carried out in 2012-2013 from the beginning of the summer stagnation period in Lake Kortowskie to complete overturn in fall. Samples of river water and ambient air were collected from two sites: near the pipeline outlet (PO) and behind the academic campus (AC). A total of 44 air samples and 44 water samples were analysed. Odour intensity was measured in samples of ambient air. The following physicochemical parameters of water were determined: flow rate, dissolved oxygen (DO), hydrogen sulphide (H2S), sulphate (SO4), ammonium nitrogen (NH4-N), total nitrogen (TN), dissolved nitrogen (DN), total particulate nitrogen (T-PN), total organic carbon (TOC), dissolved organic carbon (DOC) and total particulate organic carbon (T-POC). Water samples were also analysed to determine total bacterial abundance (TBA) and the counts of bacterial rods, cocci and spiral-shaped bacteria, and sulphate-reducing bacteria (SRB). Significant variations in odour intensity were noted between years and sampling sites. Odour was significantly determined by the proportion of lake water in river water. It was also significantly correlated (P<0.01, P<0.001) with most of the analysed physicochemical and microbiological parameters. The multiple regression analysis revealed that odour intensity was influenced directly by TOC and DN and indirectly by H2S, NH4-N, TBA and counts of SRB, rod- and spiral-shaped bacteria only in.

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A comprehensive biogeochemical record and annual flux estimates for the Sabaki River (Kenya)

Biogeosciences ◽

10.5194/bg-15-1683-2018 ◽

2018 ◽

Vol 15 (6) ◽

pp. 1683-1700

Author(s):

Trent R. Marwick ◽

Fredrick Tamooh ◽

Bernard Ogwoka ◽

Alberto V. Borges ◽

François Darchambeau ◽

...

Keyword(s):

Suspended Sediment ◽

Sediment Yield ◽

Particulate Phosphorus ◽

Poor Correlation ◽

Inland Waters ◽

Base Line ◽

Nutrient Export ◽

Wet Season ◽

Particulate Nitrogen ◽

Organic C

Abstract. Inland waters impart considerable influence on nutrient cycling and budget estimates across local, regional and global scales, whilst anthropogenic pressures, such as rising populations and the appropriation of land and water resources, are undoubtedly modulating the flux of carbon (C), nitrogen (N) and phosphorus (P) between terrestrial biomes to inland waters, and the subsequent flux of these nutrients to the marine and atmospheric domains. Here, we present a 2-year biogeochemical record (October 2011–December 2013) at biweekly sampling resolution for the lower Sabaki River, Kenya, and provide estimates for suspended sediment and nutrient export fluxes from the lower Sabaki River under pre-dam conditions, and in light of the approved construction of the Thwake Multipurpose Dam on its upper reaches (Athi River). Erratic seasonal variation was typical for most parameters, with generally poor correlation between discharge and material concentrations, and stable isotope values of C (δ13C) and N (δ15N). Although high total suspended matter (TSM) concentrations are reported here (up to ∼ 3.8 g L−1), peak concentrations of TSM rarely coincided with peak discharge. The contribution of particulate organic C (POC) to the TSM pool indicates a wide biannual variation in suspended sediment load from OC poor (0.3 %) to OC rich (14.9 %), with the highest %POC occurring when discharge is < 100 m3 s−1 and at lower TSM concentrations. The consistent 15N enrichment of the particulate nitrogen (PN) pool compared to other river systems indicates anthropogenic N loading is a year-round driver of N export from the Sabaki Basin. The lower Sabaki River was consistently oversaturated in dissolved methane (CH4; from 499 to 135 111 %) and nitrous oxide (N2O; 100 to 463 %) relative to atmospheric concentrations. Wet season flows (October–December and March–May) carried > 80 % of the total load for TSM (∼ 86 %), POC (∼ 89 %), dissolved organic carbon (DOC; ∼ 81 %), PN (∼ 89 %) and particulate phosphorus (TPP; ∼ 82 %), with > 50 % of each fraction exported during the long wet season (March–May). Our estimated sediment yield (85 Mg km−2 yr−1) is relatively low on the global scale and is considerably less than the recently reported average sediment yield of ∼ 630 Mg km−2 yr−1 for African river basins. Regardless, sediment and OC yields were all at least equivalent or greater than reported yields for the neighbouring dammed Tana River. Rapid pulses of heavily 13C-enriched POC coincided with peak concentrations of PN, ammonium, CH4 and low dissolved oxygen saturation, suggesting that large mammalian herbivores (e.g. hippopotami) may mediate the delivery of C4 organic matter to the river during the dry season. Given recent projections for increasing dissolved nutrient export from African rivers, as well as the planned damming of the Athi River, these first estimates of material fluxes from the Sabaki River provide base-line data for future research initiatives assessing anthropogenic perturbation of the Sabaki Basin.

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Investigation of a nutrient-growth model using a continuous culture of natural phytoplankton

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400056861 ◽

1978 ◽

Vol 58 (4) ◽

pp. 923-941 ◽

Cited By ~ 15

Author(s):

K. J. Jones ◽

P. Tett ◽

A. C. Wallis ◽

B. J. B. Wood

Keyword(s):

Growth Rate ◽

Continuous Culture ◽

Algal Growth ◽

Nutrient Status ◽

Inorganic Phosphorus ◽

Particulate Phosphorus ◽

Particulate Carbon ◽

Particulate Nitrogen ◽

Rate Of Increase ◽

Dominance Pattern

Phytoplankton from Loch Creran, Argyll was maintained in continuous culture for 41 days. During most of this time the mixture of species retained the diversity and dominance pattern typical of summer phytoplankton in the loch, notwithstanding the manipulation of algal nutrient status to bring about phosphorus control of growth. Results suggest that most detritus was washed out early in the experiment.The aim of the experiment was to test the applicability to natural multispecies phytoplankton of part of Droop's (1974, 1975) model of nutrient-limited algal growth. ‘Quasi-steady states’ with respect to concentration of chlorophyll, particulate carbon (PC), particulate phosphorus (PP) and particulate nitrogen (PN), wereobserved at two levels of input of dissolved inorganic phosphorus. At other times the algal phosphorus quota (estimated from the ratio of PP to PC) varied from about 0·002 to 0·015 atoms P per atom C. Specific growth rate was estimated from the rate of increase of PC. During part of the experiment, growth rate was linearly related to reciprocal phosphorus quota, thus confirming the applicability of the model.

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Inshore–Offshore Sedimentation Differences Resulting from Resuspension in the Eastern Basin of Lake Erie

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f82-103 ◽

1982 ◽

Vol 39 (5) ◽

pp. 748-759 ◽

Cited By ~ 53

Author(s):

J. Bloesch

Keyword(s):

Lake Erie ◽

Sediment Cores ◽

Dry Weight ◽

Sediment Traps ◽

Particulate Phosphorus ◽

Particulate Nitrogen ◽

Eastern Basin ◽

Fine Grained ◽

Lake Bottom ◽

Offshore Station

From June through October 1978 sediment traps were moored at three stations in an inshore–offshore transect in the Eastern Basin of Lake Erie. Settling fluxes measured with the traps exposed close to lake bottom were rather similar at all three stations during summer stratification, averaging 6.1 g∙m−2∙d−1 for dry weight, 293 mg∙m−2∙d−1 for particulate organic carbon (POC), 38 mg∙m−2∙d−1 for particulate nitrogen (PN), and 5.44 mg∙m−2∙d−1 for particulate phosphorus (PP). A comparison of the hypolimnetic traps with the epilimnetic traps at the offshore station indicated that considerable resuspension takes place even in summer. During fall, however, the nearshore sedimentation rates were markedly increased because of storm-induced bottom resuspension. By comparing the trap catches with sediment cores taken at all three stations, a resuspension model for dry weight, POC, and PN was developed. The calculations showed that newly formed organic material is resuspended and redeposited more frequently at nearshore locations than offshore. This repeated nearshore resuspension enhances decomposition of detritus, as shown by low relative phytoplankton activity in the hypolimnetic traps, and results in horizontal transport of fine-grained organic matter in the offshore direction. The significant POC and PN concentration differences found in the inshore–offshore transect of the bottom sediments can be explained by these two processes.Key words: sedimentation, sediment traps, sediment cores, resuspension, inshore–offshore differences

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