scholarly journals Contrasting Effects of an Alien Worm on Benthic N Cycling in Muddy and Sandy Sediments

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 465 ◽  
Author(s):  
Sara Benelli ◽  
Marco Bartoli ◽  
Cristina Ribaudo ◽  
Elisa Fano
Keyword(s):  
Oxygen Demand ◽  
Relative Effect ◽  
Sediment Oxygen Demand ◽  
Inorganic N ◽  
N Loss ◽  
Nutrient Mobilization ◽  
The North ◽  
N Fluxes ◽  
Muddy Sediments ◽  
Sandy Sediments

The North American oligochaete Sparganophilus tamesis is widespread in European freshwaters. Its ecological effects on benthic nitrogen (N) biogeochemistry were studied in two contrasting environments: the organic-rich muddy sediments of the eutrophic Mincio River (Italy) and the organic-poor sandy sediments of the oligotrophic Cazaux-Sanguinet Lake (France). Oxygen and inorganic N fluxes and denitrification rates (IPT) were measured by dark incubation of intact cores with different worm biomass. Sediment oxygen demand and denitrification were higher in muddy than in sandy sediments; however, at the two sites, bioturbation by the oligochaetes stimulated differing microbial O2 and NO3− respiration and NH4+ production. In particular, the relative effect of S. tamesis on sediment metabolism was greater in Cazaux-Sanguinet Lake than in the Mincio River. As a result, S. tamesis favored net N loss in the Mincio River, whereas it increased NH4+ recycling and lowered denitrification efficiency in the Cazaux-Sanguinet Lake. Our results suggest that the effects of S. tamesis on N biogeochemistry might differ depending on local trophic settings. These results have implications for the conservation of isoetids in the French Lake, whose persistence can be menaced by oligochaete-induced nutrient mobilization.

scholarly journals Denitrification, Nitrogen Uptake, and Organic Matter Quality Undergo Different Seasonality in Sandy and Muddy Sediments of a Turbid Estuary

2021 ◽  
Vol 11 ◽  
Author(s):  
Marco Bartoli ◽  
Daniele Nizzoli ◽  
Mindaugas Zilius ◽  
Mariano Bresciani ◽  
Antonio Pusceddu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Nitrogen Uptake ◽  
Oxygen Demand ◽  
Benthic Diatoms ◽  
N Fixation ◽  
N Availability ◽  
Inorganic N ◽  
Organic Matter Quality ◽  
Muddy Sediments ◽  
Sandy Sediments

The interaction between microbial communities and benthic algae as nitrogen (N) regulators in poorly illuminated sediments is scarcely investigated in the literature. The role of sediments as sources or sinks of N was analyzed in spring and summer in sandy and muddy sediments in a turbid freshwater estuary, the Curonian Lagoon, Lithuania. Seasonality in this ecosystem is strongly marked by phytoplankton community succession with diatoms dominating in spring and cyanobacteria dominating in summer. Fluxes of dissolved gas and inorganic N and rates of denitrification of water column nitrate (Dw) and of nitrate produced by nitrification (Dn) and sedimentary features, including the macromolecular quality of organic matter (OM), were measured. Shallow/sandy sites had benthic diatoms, while at deep/muddy sites, settled pelagic microalgae were found. The OM in surface sediments was always higher at muddy than at sandy sites, and biochemical analyses revealed that at muddy sites the OM nutritional value changed seasonally. In spring, sandy sediments were net autotrophic and retained N, while muddy sediments were net heterotrophic and displayed higher rates of denitrification, mostly sustained by Dw. In summer, benthic oxygen demand increased dramatically, whereas denitrification, mostly sustained by Dn, decreased in muddy and remained unchanged in sandy sediments. The ratio between denitrification and oxygen demand was significantly lower in sandy compared with muddy sediments and in summer compared with spring. Muddy sediments displayed seasonally distinct biochemical composition with a larger fraction of lipids coinciding with cyanobacteria blooms and a seasonal switch from inorganic N sink to source. Sandy sediments had similar composition in both seasons and retained inorganic N also in summer. Nitrogen uptake by microphytobenthos at sandy sites always exceeded the amount loss via denitrification, and benthic diatoms appeared to inhibit denitrification, even in the dark and under conditions of elevated N availability. In spring, denitrification attenuated N delivery from the estuary to the coastal area by nearly 35%. In summer, denitrification was comparable (~100%) with the much lower N export from the watershed, but N loss was probably offset by large rates of N-fixation.

scholarly journals Sediment oxygen demand and bottom sediment environment in the northern part of the North Basin of Lake Biwa, Japan

2017 ◽  
Vol 78 (2) ◽  
pp. 169-178
Author(s):  
Naoshige GOTO ◽  
Kaname FUKUDA ◽  
Saori OMURA ◽  
Aoi YOSHIMURA ◽  
Shuhei BAN
Keyword(s):  
Bottom Sediment ◽  
Lake Biwa ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
The North

Considering the impact of intermittent discharges when modelling overflows

1998 ◽  
Vol 38 (10) ◽  
pp. 23-30
Author(s):  
Sarah Jubb ◽  
Philip Hulme ◽  
Ian Guymer ◽  
John Martin
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Preliminary Investigation ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Combined Sewer Overflows ◽  
River Hydraulics ◽  
Combined Sewer ◽  
The Impact ◽  
Curve Equation

This paper describes a preliminary investigation that identified factors important in the prediction of river water quality, especially regarding dissolved oxygen (DO) concentration. Intermittent discharges from combined sewer overflows (CSOs) within the sewerage, and overflows at water reclamation works (WRW) cause dynamic conditions with respect to both river hydraulics and water quality. The impact of such discharges has been investigated under both wet and dry weather flow conditions. Data collected from the River Maun, UK, has shown that an immediate, transient oxygen demand exists downstream of an outfall during storm conditions. The presence of a delayed oxygen demand has also been identified. With regard to modelling, initial investigations used a simplified channel and the Streeter-Phelps (1925) dissolved oxygen sag curve equation. Later, a model taking into account hydrodynamic, transport and dispersion processes was used. This suggested that processes other than water phase degradation of organic matter significantly affect the dissolved oxygen concentration downstream of the location of an intermittent discharge. It is proposed that the dynamic rate of reaeration and the sediment oxygen demand should be the focus of further investigation.

Non-steady variations of SOD and phosphate release rate due to changes in the quality of the overlying water

2000 ◽  
Vol 42 (3-4) ◽  
pp. 265-272 ◽  
Author(s):  
T. Inoue ◽  
Y. Nakamura ◽  
Y. Adachi
Keyword(s):  
Release Rate ◽  
Oxygen Demand ◽  
Phosphate Concentration ◽  
Sediment Oxygen Demand ◽  
Biochemical Reactions ◽  
Overlying Water ◽  
Phosphate Release ◽  
Do Concentration ◽  
The Difference

A dynamic model, which predicts non-steady variations in the sediment oxygen demand (SOD) and phosphate release rate, has been designed. This theoretical model consists of three diffusion equations with biochemical reactions for dissolved oxygen (DO), phosphate and ferrous iron. According to this model, step changes in the DO concentration and flow velocity produce drastic changes in the SOD and phosphate release rate within 10 minutes. The vigorous response of the SOD and phosphate release rate is caused by the difference in the time scale of diffusion in the water boundary layer and that of the biochemical reactions in the sediment. Secondly, a negative phosphate transfer from water to sediment can even occur under aerobic conditions. This is caused by the decrease in phosphate concentration in the aerobic layer due to adsorption.

Approaching daily life at Late Palaeolithic camps: The case of Lubrza 10, Western Poland

2020 ◽  
Vol 95 (2) ◽  
pp. 311-333
Author(s):  
Iwona Sobkowiak-Tabaka ◽  
Aleksandr Diachenko
Keyword(s):  
Daily Life ◽  
Site Formation ◽  
Site Formation Processes ◽  
The North ◽  
Locational Analysis ◽  
Research Procedure ◽  
Sandy Sediments ◽  
Integrative Social ◽  
Late Palaeolithic

AbstractThe aim of this paper is to develop a systematic approach to understanding daily life at Late Palaeolithic camps and identifying its impact on broader site formation processes. Late Palaeolithic contexts are often poorly preserved, especially those found in the sandy sediments of the North European Plain. However, taphonomic obstacles may be overcome through the introduction of spatial statistics into research procedures. We illustrate our approach using a case study of Federmesser and Swiderian campsites at the site of Lubrza 10, Western Poland. The locational analysis of hearths, features that constitute the most important integrative social foci of Palaeolithic camps, provides information on activity areas, seasonality and occupational duration. Additionally, we examine the function of spatially distinct artefact concentrations and their methods of aggregation. The presented research procedure enables us to trace the contribution of individuals to group behaviour, as well as specific individual activities at both camps.

scholarly journals Geostatistical modeling of the spatial distribution of sediment oxygen demand within a Coastal Plain blackwater watershed

Geoderma ◽  
2010 ◽  
Vol 159 (1-2) ◽  
pp. 53-62 ◽  
Author(s):  
M. Jason Todd ◽  
R. Richard Lowrance ◽  
Pierre Goovaerts ◽  
George Vellidis ◽  
Catherine M. Pringle
Keyword(s):  
Spatial Distribution ◽  
Coastal Plain ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Geostatistical Modeling

Experimental manipulations of the biomass of introduced carp (Cyprinus carpio) in billabongs. II. Impacts on benthic properties and processes1

1997 ◽  
Vol 48 (5) ◽  
pp. 445 ◽  
Author(s):  
A. I. Robertson ◽  
M. R. Healey ◽  
A. J. King
Keyword(s):  
Algal Biomass ◽  
Solid Phase ◽  
Negative Impact ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Sediment Surface ◽  
Nutrient Concentrations ◽  
Nutrient Ratios ◽  
Biofilm Development ◽  
The Impact

Two billabongs on the floodplain of the Murrumbidgee River, Australia, were partitioned in half with impermeable plastic barriers and the biomass of carp was manipulated to establish high- and low-carp biomass treatments in each billabong. Measurements of benthic variables (rates of particle settlement, biofilm development, sediment respiration, macrophyte detritus decomposition, sediment solid-phase nutrient concentrations and benthic algal biomass) were performed over four months from summer to winter 1995. Rates of particle settlement were greater in the high-carp treatment of each billabong throughout the experiment. High carp biomass had a negative impact on the autotrophic component of the biofilm developing on wood blocks placed at different heights above the sediment surface but the mechanism responsible differed between billabongs. Sediment oxygen demand became greater in the presence of a higher biomass of carp during the experiment but time courses differed between billabongs. Manipulations of carp biomass did not influence algal biomass on the sediment surface, the rate of decomposition of macrophyte detritus or sediment solid-phase nutrients or nutrient ratios. The impact of carp on benthic and surficial processes was significant but the mechanisms of change differed between billabongs.

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