Drying-induced stimulation of ammonium release and nitrification in reflooded lake sediment

1996 ◽  
Vol 47 (3) ◽  
pp. 531 ◽  
Author(s):  
S Qui ◽  
AJ McComb
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Water Column ◽  
Sediment Cores ◽  
Freshwater Wetland ◽  
Ammonium Concentration ◽  
N Loss ◽  
Air Drying ◽  
Nitrate Concentrations ◽  
Stimulation Of

Air drying of intact sediment cores from a shallow freshwater wetland caused the release of a substantial amount of ammonium following reflooding. The increased ammonium concentration stimulated nitrification at a rate 10 times higher than in the original waterlogged sediments under aerated conditions. Under non-aerated conditions, nitrate concentrations decreased more rapidly in reflooded systems than in the waterlogged systems. Ammonium and nitrite had accumulated in the original waterlogged systems, but this was rare in reflooded dried cores because of the depletion of bioavailable organic carbon. These results suggest that drawdown and drying of wetlands can accelerate mineralization of the organic matter in sediment, and can temporarily increase ammonium and nitrate concentrations in the water column during reinundation. Drying and reflooding of wetland sediments may eventually increase N loss through promotion of denitrification.

Effects of Fe addition on sediment P dynamics in a eutrophic lake

2021 ◽  
Author(s):  
Melanie Münch ◽  
Rianne van Kaam ◽  
Karel As ◽  
Stefan Peiffer ◽  
Gerard ter Heerdt ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Surface Water ◽  
Water Column ◽  
Sediment Cores ◽  
Surface Water Quality ◽  
Water Interface ◽  
Eutrophic Lakes ◽  
Fe Addition

<p>The decline of surface water quality due to excess phosphorus (P) input is a global problem of increasing urgency. Finding sustainable measures to restore the surface water quality of eutrophic lakes with respect to P, other than by decreasing P inputs, remains a challenge. The addition of iron (Fe) salts has been shown to be effective in removing dissolved phosphate from the water column of eutrophic lakes. However, the resulting changes in biogeochemical processes in sediments as well as the long-term effects of Fe additions on P dynamics in both sediments and the water column are not well understood.</p><p>In this study, we assess the impact of past Fe additions on the sediment P biogeochemistry of Lake Terra Nova, a well-mixed shallow peat lake in the Netherlands. The Fe-treatment in 2010 efficiently reduced P release from the sediments to the surface waters for 6 years. Since then, the internal sediment P source in the lake has been increasing again with a growing trend over the years.</p><p>In 2020, we sampled sediments at three locations in Terra Nova, of which one received two times more Fe during treatment than the other two. Sediment cores from all sites were sectioned under oxygen-free conditions. Both the porewaters and sediments were analysed for their chemical composition, with sequential extractions providing insight into the sediment forms of P and Fe. Additional sediment cores were incubated under oxic and anoxic conditions and the respective fluxes of P and Fe across the sediment water interface were measured.</p><p>The results suggest that Fe and P dynamics in the lake sediments are strongly coupled. We also find that the P dynamics are sensitive to the amount of Fe supplied, even though enhanced burial of P in the sediment was not detected. The results of the sequential extraction procedure for P, which distinguishes P associated with humic acids and Fe oxides, as well as reduced flux of Fe(II) across the sediment water interface in the anoxic incubations, suggest a major role of organic matter in the interaction of Fe and P in these sediments.</p><p>Further research will include investigations of the role of organic matter and sulphur in determining the success of Fe-treatment in sequestering P in lake sediments. Based on these data in combination with reactive transport modelling we aim to constrain conditions for successful lake restoration through Fe addition.</p>

Influence of organic matter quality on organic matter degradability in river sediments

2020 ◽  
Author(s):  
Florian Zander ◽  
Julia Gebert ◽  
Rob N. J. Comans ◽  
Alexander Groengroeft ◽  
Timo J. Heimovaara ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Pore Water ◽  
Chlorophyll Concentration ◽  
Sediment Organic Matter ◽  
Rheological Parameters ◽  
Ammonium Concentration ◽  
Organic Matter Quality ◽  
Degradation Rates ◽  
Physical Density

<p>The project BIOMUD, part of the scientific network MUDNET (www.tudelft.nl/mudnet), investigates the decomposition of sediment organic matter (SOM) in the Port of Hamburg. The microbial turnover of sediment organic matter under reducing conditions leads to the formation of methane, carbon dioxide and others gases causing a change in the sediment rheological parameters. BIOMUD is aiming to explain the effect of organic matter lability on the rheological properties impacting the navigable depth of the harbour.</p><p>Samples of freshly deposited material were taken in 2018 and 2019 at nine locations in a transect of 30 km through the Port of Hamburg. Analyses included abiotic parameters (among others grain size distribution, standard pore water properties, standard solid properties, stable isotopes, mineral composition) and biotic parameters (among others anaerobic and aerobic organic matter degradation, DNA, protein and lipid content, microbial population). At four locations, physical density fractions and chemical organic matter fractions were analysed.</p><p>The quality of organic matter was described by normalising carbon released from microbial degradation under both aerobic and anaerobic conditions to the share of total organic carbon (mg C/g TOC). Organic matter pools with different degradation rates were used to quantify the lability of organic matter. The share of faster degradable (more labile) pools correlated strongly with the size of the hydrophilic DOC fraction, confirming results of Straathof et al. (2014) who investigated dissolved organic carbon pools in compost. The hydrophilic DOC fraction was closely correlated to the polysaccharide concentration, explaining the input of easily degradable organic matter. Moreover, the amount of organic carbon present in the sediment’s light density fraction < 1.4 g/cm<sup>3</sup> strongly correlated with the hydrophilic DOC fraction and, less strongly, with organic matter lability. High organic matter quality, i.e. the labile, easily degradable fraction, was further related to the chlorophyll concentration in the water column but also the ammonium concentration in the sediment’s pore water.</p><p>It was hypothesised that the observed toposequence of decreasing organic matter quality from upstream to downstream could be explained by a chronosequence of increasing degradation and therefore ageing of organic matter as the sediment passes through the harbour area. Further, it was hypothesized that the harbour received organic matter of higher degradability, originating from phytoplankton biomass, from the upstream part of the Elbe river, whereas the input from the tidal downstream area provided organic matter of lower quality (degradability).</p><p>This study was funded by Hamburg Port Authority.</p>

scholarly journals Organic matter mineralization and trace element post-depositional redistribution in Western Siberia thermokarst lake sediments

2011 ◽  
Vol 8 (11) ◽  
pp. 3341-3358 ◽  
Author(s):  
S. Audry ◽  
O. S. Pokrovsky ◽  
L. S. Shirokova ◽  
S. N. Kirpotin ◽  
B. Dupré
Keyword(s):  
Trace Elements ◽  
Organic Matter ◽  
Organic Carbon ◽  
Lake Sediments ◽  
Water Column ◽  
Western Siberia ◽  
Ecosystem Development ◽  
Thermokarst Lake ◽  
Fe And Mn ◽  
The Impact

Abstract. This study reports the very first results on high-resolution sampling of sediments and their porewaters from three thermokarst (thaw) lakes representing different stages of ecosystem development located within the Nadym-Pur interfluve of the Western Siberia plain. Up to present time, the lake sediments of this and other permafrost-affected regions remain unexplored regarding their biogeochemical behavior. The aim of this study was to (i) document the early diagenesic processes in order to assess their impact on the organic carbon stored in the underlying permafrost, and (ii) characterize the post-depositional redistribution of trace elements and their impact on the water column. The estimated organic carbon (OC) stock in thermokarst lake sediments of 14 ± 2 kg m−2 is low compared to that reported for peat soils from the same region and denotes intense organic matter (OM) mineralization. Mineralization of OM in the thermokarst lake sediments proceeds under anoxic conditions in all the three lakes. In the course of the lake development, a shift in mineralization pathways from nitrate and sulfate to Fe- and Mn-oxyhydroxides as the main terminal electron acceptors in the early diagenetic reactions was suggested. This shift was likely promoted by the diagenetic consumption of nitrate and sulfate and their gradual depletion in the water column due to progressively decreasing frozen peat lixiviation occurring at the lake's borders. Trace elements were mobilized from host phases (OM and Fe- and Mn-oxyhydroxides) and partly sequestered in the sediment in the form of authigenic Fe-sulfides. Arsenic and Sb cycling was also closely linked to that of OM and Fe- and Mn-oxyhydroxides. Shallow diagenetic enrichment of particulate Sb was observed in the less mature stages. As a result of authigenic sulfide precipitation, the sediments of the early stage of ecosystem development were a sink for water column Cu, Zn, Cd, Pb and Sb. In contrast, at all stages of ecosystem development, the sediments were a source of dissolved Co, Ni and As to the water column. However, the concentrations of these trace elements remained low in the bottom waters, indicating that sorption processes on Fe-bounding particles and/or large-size organo-mineral colloids could mitigate the impact of post-depositional redistribution of toxic elements on the water column.

scholarly journals Seasonal dynamics of organic carbon and metals in thermokarst lakes from the discontinuous permafrost zone of western Siberia

2015 ◽  
Vol 12 (2) ◽  
pp. 1975-2019
Author(s):  
R. M. Manasypov ◽  
S. N. Vorobyev ◽  
S. V. Loiko ◽  
I. V. Kritzkov ◽  
L. S. Shirokova ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Water Column ◽  
Permafrost Zone ◽  
Ice Formation ◽  
Thermokarst Lakes ◽  
Dissolved Carbon ◽  
Thermokarst Lake ◽  
Discontinuous Permafrost ◽  
Lake Waters

Abstract. Western Siberia's thermokarst (thaw) lakes extend over a territory spanning over a million km2; they are highly dynamic hydrochemical systems that receive chemical elements from the atmosphere and surrounding peat soil and vegetation, and exchange greenhouse gases with the atmosphere, delivering dissolved carbon and metals to adjacent hydrological systems. This work describes the chemical composition of ~ 130 thermokarst lakes of the size range from a few m2 to several km2, located in the discontinuous permafrost zone. Lakes were sampled during spring floods, just after the ice break (early June), the end of summer (August), the beginning of ice formation (October) and during the full freezing season in winter (February). Dissolved organic carbon (DOC) and the major and trace elements do not appreciably change their concentration with the lake size increase above 1000 m2 during all seasons. On the annual scale, the majority of dissolved elements including organic carbon increase their concentration from 30 to 500%, with a statistically significant (p < 0.05) trend from spring to winter. The maximal increase in trace element (TE) concentration occurred between spring and summer and autumn and winter. The ice formation in October included several stages: first, surface layer freezing followed by crack (fissure) formation with unfrozen water from the deeper layers spreading over the ice surface. This water was subsequently frozen and formed layered ice rich in organic matter. As a result, the DOC and metal concentrations were the highest at the beginning of the ice column and decreased from the surface to the depth. A number of elements demonstrated the accumulation, by more than a factor of 2, in the surface (0–20 cm) of the ice column relative to the rest of the ice core: Mn, Fe, Ni, Cu, Zn, As, Ba and Pb. The main consequences of discovered freeze-driven solute concentrations in thermokarst lake waters are enhanced colloidal coagulation and the removal of dissolved organic matter and associated insoluble metals from the water column to the sediments. The measured distribution coefficient of TE between amorphous organo-ferric coagulates and lake water (< 0.45 μm) were similar to those reported earlier for Fe-rich colloids and low molecular weight (< 1 kDa) fractions of thermokarst lake waters, suggesting massive co-precipitation of TE with amorphous Fe oxy(hydr)oxide stabilized by organic matter. Although the concentration of most elements is lowest in spring, this period of maximal water coverage of land creates a significant reservoir of DOC and soluble metals in the water column that can be easily mobilized to the hydrological network. The highest DOC concentration observed in the smallest (< 100 m2) water bodies in spring suggests their strongly heterotrophic status and, therefore, elevated CO2 flux from the lake surface to the atmosphere.

Geochemistry and depositional history of the Union Springs Member, Marcellus Formation in central Pennsylvania

2015 ◽  
Vol 3 (3) ◽  
pp. SV17-SV33 ◽  
Author(s):  
Anna K. Wendt ◽  
Mike A. Arthur ◽  
Rudy Slingerland ◽  
Daniel Kohl ◽  
Reed Bracht ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Water Column ◽  
Appalachian Basin ◽  
Depositional Environments ◽  
Source Rocks ◽  
Geochemical Data ◽  
Inorganic Elements ◽  
Central Pennsylvania ◽  
Marcellus Formation

Debate continues over paleoenvironmental conditions that prevail during deposition of organic-carbon (C)-rich marine source rocks in foreland basins and epicontinental seas. The focus of disagreement centers largely on paleowater depth and the prevalence of anoxia/euxinia. The issues of paleodepth and water column conditions are important for prediction of lateral variations in source quality within a basin because the viability of a hydrocarbon play depends on a thorough understanding of the distribution of source rock quality and depositional environments. We used inorganic geochemical data from the Middle Devonian Marcellus Shale in the Appalachian Basin to illustrate interpretive strategies that provided constraints on conditions during deposition. Source evaluation typically relies on the analysis and interpretation of organic geochemical indicators, potentially also providing evidence of the degree of thermal maturity and conditions of the preservation of the organic matter. The Marcellus Formation is thermally mature, making the evaluation of the organic-carbon fraction for geologic interpretation inadequate. Because most labile organic matter has largely been destroyed in the Marcellus Formation, analysis of inorganic elements may be used as an alternative interpretative technique. Several inorganic elements have been correlated to varying depositional settings, allowing for their use as proxies for understanding the paleodepositional environments of formations. A high-resolution geochemical data set has been constructed for the Union Springs Member along a transect of cores from proximal to distal in the Appalachian Basin in central Pennsylvania using major, minor, and trace elemental data. Our results suggested that during deposition, the sediment-water interface, and a portion of the water column, was anoxic to euxinic. As deposition continued, euxinia was periodically interrupted by dysoxia and even oxic conditions, and a greater influx of clastic material occurred. Such variations were likely related to fluctuations in water depth and progradation of deltaic complexes from the eastern margin of the Appalachian Basin.

The relationship between sediment and water quality, and riverine sediment loads in the wave-dominated estuaries of south-west Western Australia

2004 ◽  
Vol 55 (6) ◽  
pp. 581 ◽  
Author(s):  
L. C. Radke ◽  
I. P. Prosser ◽  
M. Robb ◽  
B. Brooke ◽  
D. Fredericks ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Soil Erosion ◽  
Organic Carbon ◽  
Water Column ◽  
Nitrogen And Phosphorus ◽  
Weathering Index ◽  
Sediment Loads ◽  
The Impact ◽  
Column Total

We examine surface sediment and water column total nutrient and chlorophyll a concentrations for 12 estuaries with average water depths <4 m, and calculated sediment loads ranging from 0.2 to 10.8 kg m−2 year−1. Sediment total nitrogen, phosphorus and organic carbon concentrations vary inversely with sediment loads due to: (i) the influx of more mineral-rich sediment into the estuaries; and (ii) increasing sediment sulfidation. Sediment total organic carbon (TOC) : total sulfur (TS) and TS : Fe(II) ratios correlated to sediment loads because enhanced sedimentation increases burial, hence the importance of sulfate reduction in organic matter degradation. Curvilinear relationships were found between a weathering index and organic matter δ13C in sediment, and sediment load. The rising phase of the curve (increasing weathering, lighter isotopic values) at low to intermediate loads relates to soil erosion, whereas regolith or bedrock erosion probably explains the declining phase of the curve (decreasing weathering, heavier isotopic values) at higher sediment loads. The pattern of change for water column total nutrients (nitrogen and phosphorus) with sediment loads is similar to that of the weathering index. Most water quality problems occur in association with soil erosion, and at sediment loads that are intermediate for the estuaries studied. Limited evidence is presented that flushing can moderate the impact of sediment loads upon the estuaries.

Water column features and their relationship with sediments and benthic communities along the Victoria Land coast, Ross Sea, summer 2004

2006 ◽  
Vol 18 (4) ◽  
pp. 603-613 ◽  
Author(s):  
Paolo Povero ◽  
Michela Castellano ◽  
Nicoletta Ruggieri ◽  
Luis S. Monticelli ◽  
Vincenzo Saggiomo ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Water Column ◽  
Nutritive Value ◽  
Latitudinal Gradient ◽  
Benthic Communities ◽  
Trophic Factors ◽  
Terra Nova Bay ◽  
Victoria Land ◽  
Terra Nova

The northern Victoria Land coastal marine environment was investigated during the late summer 2004, within the framework of the Latitudinal Gradient Project (LGP), to describe the physical, chemical and biological patterns of the water column and their relationship with the pelagic and benthic compartments, and to determine to what extent they change with latitude. A latitudinal gradient from Cape Adare to the Terra Nova Bay–Cape Russell area was determined on the basis of abiotic and trophic factors. Cape Adare had lower values of organic matter (particulate organic carbon < 150 μg l−1) available for the benthic communities, but this organic matter had good trophic quality. In Terra Nova Bay the particulate organic matter was quantitatively higher (organic carbon > 400 μg l−1), presumably reaching the bottom via faecal pellets, but was more detrital, although its nutritive value was still high (carbon protein content nearly 40%), as confirmed by the great quantity of phytopigments in the sediments (> 4.0 μg g−1). The benthic communities changed with latitude as well, partially reflecting the environmental and trophic gradient, but also showing a large within-area variability (except for the Cape Adare area), due to a complex array of variables that did not change with latitude.

scholarly journals Sulfurization of dissolved organic matter in the anoxic water column of the Black Sea

2021 ◽  
Vol 7 (25) ◽  
pp. eabf6199
Author(s):  
Gonzalo V. Gomez-Saez ◽  
Thorsten Dittmar ◽  
Moritz Holtappels ◽  
Anika M. Pohlabeln ◽  
Anna Lichtschlag ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Dissolved Organic Matter ◽  
Water Column ◽  
Black Sea ◽  
Large Scale ◽  
Global Climate ◽  
The Black Sea ◽  
Sulfur Species ◽  
Reduced Sulfur

Today’s oceans store as much dissolved organic carbon (DOC) in the water column as there is CO2 in the atmosphere, and as such dissolved organic matter (DOM) is an important component of the global carbon cycle. It was shown that in anoxic marine sediments, reduced sulfur species (e.g., H2S) abiotically react with organic matter, contributing to carbon preservation. It is not known whether such processes also contribute to preserving DOM in ocean waters. Here, we show DOM sulfurization within the sulfidic waters of the Black Sea, by combining elemental, isotopic, and molecular analyses. Dissolved organic sulfur (DOS) is formed largely in the water column and not derived from sediments or allochthonous nonmarine sources. Our findings suggest that during large-scale anoxic events, DOM may accumulate through abiotic reactions with reduced sulfur species, having long-lasting effects on global climate by enhancing organic carbon sequestration.

scholarly journals Sedimentation rate and organic matter dynamics shape microbiomes across a continental margin

2021 ◽  
Author(s):  
Sabyasachi Bhattacharya ◽  
Tarunendu Mapder ◽  
Svetlana Fernandes ◽  
Chayan Roy ◽  
Jagannath Sarkar ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Organic Matter ◽  
Organic Carbon ◽  
Sedimentation Rate ◽  
Bottom Water ◽  
Sediment Cores ◽  
Sediment Surface ◽  
Geochemical Data ◽  
Sediment Layer ◽  
Shelf Slope

Abstract. Marine sedimentation rate and bottom-water O2 concentration control the remineralization/sequestration of organic carbon across continental margins; but whether/how they shape microbiome architecture (the ultimate effector of all biogeochemical phenomena), across shelf/slope sediments, is unknown. Here we reveal distinct microbiome structures and functions, amidst comparable pore fluid chemistries, along 300 cm sediment horizons underlying the seasonal (shallow coastal) and perennial (deep sea) oxygen minimum zones (OMZs) of the Arabian Sea, situated across the western-Indian margin (water-depths: 31 m and, 530 and 580 m, respectively). The sedimentary geomicrobiology was elucidated by analyzing metagenomes, metatranscriptomes, and enrichment cultures, and also sedimentation rates measured by radiocarbon and lead excess (210Pbxs); the findings were then evaluated in the light of the other geochemical data available for the cores investigated. Along the perennial- and seasonal-OMZ sediment cores, microbial communities were dominated by Gammaproteobacteria and Alphaproteobacteria, and Euryarchaeota and Firmicutes, respectively. As a perennial-OMZ signature, a cryptic methane production-consumption cycle was found to operate near the sediment-surface (within the sulfate reduction zone); overall diversity, as well as the relative abundances of simple-fatty-acids-requiring anaerobes (methanogens, anaerobic methane-oxidizers, sulfate-reducers and acetogens), peaked in the topmost sediment-layer and then declined via synchronized fluctuations until the sulfate-methane transition zone was reached. The entire microbiome profile was reverse in the seasonal-OMZ sediment horizon. In the perennial-OMZ sediments organic carbon deposited was higher in concentration and marine components-rich, so it potentially degraded readily to simple fatty acids; lower sedimentation rate afforded higher O2 exposure time for organic matter degradation despite perennial hypoxia in the bottom-water; thus, the resultant abundance of reduced carbon substrates sustained multiple inter-competing microbial processes in the upper sediment-layers. Remarkably, the whole geomicrobial scenario was opposite in the sediments of the seasonal/shallow-water OMZ. Our findings create a microbiological baseline for understanding carbon-sulfur cycling across distinct marine depositional settings and water-column oxygenation regimes.

scholarly journals Sedimentation rate and organic matter dynamics shape microbiomes across a continental margin

2020 ◽  
Author(s):  
Sabyasachi Bhattacharya ◽  
Tarunendu Mapder ◽  
Svetlana Fernandes ◽  
Chayan Roy ◽  
Jagannath Sarkar ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Organic Matter ◽  
Organic Carbon ◽  
Sedimentation Rate ◽  
Bottom Water ◽  
Sediment Cores ◽  
Sediment Surface ◽  
Sediment Layer ◽  
Depositional Settings ◽  
Shelf Slope

AbstractMarine sedimentation rate and bottom-water O2 concentration control the remineralization/sequestration of organic carbon across continental margins; but whether/how they shape microbiome architecture (the ultimate effector of all biogeochemical phenomena), across shelf/slope sediments, is unknown. Here we reveal distinct microbiome structures and functions, amidst comparable pore-fluid chemistries, along ~3 m sediment-horizons underlying the seasonal (shallow coastal) and perennial (deep sea) oxygen minimum zones (OMZs) of the Arabian Sea, situated across the western-Indian margin (water-depths: 31 m and, 530 and 580 m, respectively). Along the perennial- and seasonal-OMZ sediment-cores microbial communities were predominated by Gammaproteobacteria/Alphaproteobacteria and Euryarchaeota/Firmicutes respectively. As a perennial-OMZ signature, a cryptic methane production-consumption cycle was found to operate near the sediment-surface; overall diversity, as well as the relative abundances of simple-fatty-acids-requiring anaerobes (methanogens, anaerobic methane-oxidizers, sulfate-reducers and acetogens), peaked in the topmost sediment-layer and then declined via synchronized fluctuations until the sulfate-methane transition zone was reached. The entire microbiome profile was reverse in the seasonal-OMZ sediment-horizon. We discerned that in the perennial-OMZ sediments organic carbon deposited was higher in concentration, and marine components-rich, so it potentially degraded readily to simple fatty acids; lower sedimentation rate afforded higher O2 exposure time for organic matter degradation despite perennial hypoxia in the bottom-water; thus, the resultant abundance of reduced metabolites sustained multiple inter-competing microbial processes in the upper sediment-layers. Remarkably, the whole geomicrobial scenario was opposite in the sediments of the seasonal/shallow-water OMZ. Our findings create a microbiological baseline for understanding carbon-sulfur cycling across distinct marine depositional settings and water-colum n oxygenation regimes.

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