Reduced root anchorage of freshwater plants in sandy sediments enriched with fine organic matter

2013 ◽  
Vol 59 (3) ◽  
pp. 427-437 ◽  
Author(s):  
Kaj Sand-Jensen ◽  
Claus Lindskov Møller
Keyword(s):  
Organic Matter ◽  
Root Anchorage ◽  
Freshwater Plants ◽  
Sandy Sediments ◽  
Fine Organic ◽  
Fine Organic Matter

The β-richness of two detritivore caddisflies affects fine organic matter export

Oecologia ◽  
2012 ◽  
Vol 172 (4) ◽  
pp. 1105-1115 ◽  
Author(s):  
Christopher J. Patrick ◽  
Dylan H. Fernandez
Keyword(s):  
Organic Matter ◽  
Fine Organic ◽  
Fine Organic Matter

Micromorphological report on Chalton B Layer 3

1983 ◽  
Vol 49 (S2) ◽  
pp. mf55-mf57
Author(s):  
Richard Macphail
Keyword(s):  
Organic Matter ◽  
Thin Section ◽  
Gravel Size ◽  
Coarse Grains ◽  
Small Grains ◽  
Fine Gravel ◽  
Fine Organic ◽  
Fine Organic Matter ◽  
Bt Horizon

Layer 3 was examined in the fiela and provisionally interpreted as a Bt horizon. A sample (locaxion shown on fig.5) was examined in thin section in order to throw further light on how the layer had formed. It can be described as follows using the method and terminology of Brewer 1964, Bullock and Murphy 1979:- Homogeneous; well developed fine and meciium subangular blocky; total macrovoids (> 20 μm) 13.1%; smoothed orthovughs and channels occur intrapedally; silt-size mineral grains dominantly quartz; includes fine gravel-size flint; coarse grains angular; small grains moderately rounded; many fine void argillans (few medium); few compound ferri-argillans; few embedded argillans; common to many fine to medium matrans and matri-argillans; common to many irregular, and linear intrapedal clay concentrations; few fine to medium distinct ferromanganiferous nodules; finely mixed organic matter and medium organic matter fragments in matrix; fine organic matter and charcoal fragments in matrans; silt layers within compound matrans ana matri-argillans; silasepic; porphyroskelic.

scholarly journals Smykiv – the new key section of the upper pleistocene of the Volyn Upland

2020 ◽  
Keyword(s):  
Organic Matter ◽  
Cold Event ◽  
Upper Pleistocene ◽  
Erosion Processes ◽  
Valley Slope ◽  
Humus Accumulation ◽  
Partial Chemical ◽  
Fine Organic ◽  
Fine Organic Matter

Formulation the problem. The new section at Smykiv in the Volyn Upland has an informative stratigraphic record, showing details of climatic phases in the Late Pleistocene. The site is located in the Rivne Oblast, 40 km south of Lutsk, on slope of the River Dezha (the tributary of the River Styr). Review of previous publications and studies. The loess-palaeosol sequence of the Volyn’ Upland has been intensively studied by Ukrainian, Russian and Polish researchers such as A. Bogucki, M. Lanczont, P. Voloshyn, A. Tsatskin, V. Nechaev, T. Morozova, L. Bezusko, J. Kusiak, S. Fedorowicz, J. Nawrocki, R. Dmytruk and many others. Methods. The section has been studied using lithostratigraphic, palaeopedological, palaeocryological, grain size, micromorphological and partial chemical methods, which enable the reconstruction of past climate and environment. The stratigraphy is applied follows the Quaternary Framework of Ukraine (Veklitch et al., 1993). All the stratigraphical units of the Upper Pleistocene are represented in the section; and, herein, these divided into smaller parts characterized by distinct environmental histories. The purpose of the article is to study the detailed stratified sequence at Smykiv by various methods in order to clarify the regional Quaternary palaeogeographical scheme. Results. The periglacial alluvium of the Dnipro unit, at the base of the sequence, and the analysis of the position of the site in the relief indicate the interpretation that it is located on the Dezha river’s terrace. The alluvium bed is distorted by syngenetic involutions. The overlying Kaydaky unit truncates the alluvium, and is inclined parallel to the present valley slope. Three pedogenetic phases during the Kaydaky times are identifiable: pedosediments formed in the first phase (kda), pedosediments of forest soil formed in the early optimum (kdb1) and a Retisol formed in the late optimum (kdb2). During the Tyasmyn cold event, a network of small soil veins formed. Renewed, but less intense than in the Kaydaky unit, erosion processes started in Pryluky times. It can be demonstrated that the Pryluky polygenetic soil was formed in three phases, divided by a cold event in mid Pryluky times (pl2). A Chernozem with signs of slight podzolisation and biogenic aggregation was formed during the first phase (pl1b2). The soil is disturbed by cryogenic features formed during pl2. An incipient Cambisol was enriched with a fine organic matter during the phase pl3b1. An incipient Calcic Cambisol (pl3b2), aggregated and slightly gleyed, formed at the end of the Pryluky time. Erosion processes were not strongly developed during Pleniglacial. At the beginning of the stadials (in Uday and Bug times), solifluction processes occurred. At the beginning of these stadials, other cryogenic features, such as soil veins, frost fissures and ice-wedges, were also formed. Upper Pleistocene loess beds show slight pedogenesis, particularly very weak humus accumulation and biogenic aggregation. Furthermore, all Pleniglacial units are enriched in carbonates in diverse forms: however, the most common is disperse powdery lime. These last are frequently interpreted as being the result of calcite crystallization under cryogenic processes. During Vytachiv and Dofinivka interstadial times, boreal soils were formed – Gleyic Cambisol and Calcic Gleyic Cambisol, respectively. The first is mostly represented by pedosediments (indicating intense erosion), whereas the second soil is preserved in situ and it is enriched in fine organic matter and is well-microaggregated. The last loess unit of the Upper Pleistocene, the Prychornomorsk loess unit, is subdivided into two loess subunits (pc1 and pc3) which are connected with cryogenic events, and a Gleysol (pc2), indicating a relatively warm period.

scholarly journals Spatial Distribution of Δ14C Values of Organic Matter in Surface Sediments Off Saru River in Northern Japan, One Year After a Flood Event in 2006

Radiocarbon ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 1068-1077
Author(s):  
Seiya Nagao ◽  
Tomohisa Irino ◽  
Takafumi Aramaki ◽  
Ken Ikehara ◽  
Hajime Katayama ◽  
...  
Keyword(s):  
Organic Matter ◽  
River Mouth ◽  
Flood Event ◽  
Terrestrial Organic Matter ◽  
Sampling Area ◽  
Restricted Area ◽  
One Year ◽  
Sandy Sediments ◽  
Riverine Suspended Solids ◽  
Northern Japan

Dispersion and deposition of terrestrial organic matter by flooding on the inner shelf were studied using C/N ratios, δ13C, and Δ14C values of sedimentary organic matter. Surface sediment samples (top 2 cm) were collected from coastal areas near the Saru River in southwestern Hokkaido, northern Japan, 1 yr after a flood event in 2006. Riverine suspended solids were also collected at a fixed station downstream during 2006–2008. Sandy sediments were located at the front of the river mouth and the western part of the sampling area, with the δ13C of organic matter ranging from −23.8‰ to −22.0‰, Δ14C of –655‰ to –388‰, and an organic carbon/total nitrogen (C/N) ratio of 5.9–7.7. On the other hand, silt and clay sediments were distributed in a restricted area 11–16 km from the river mouth, with lighter δ13C (–26.7‰ to −24.1‰) and higher Δ14C (–240‰ to –77‰) of organic matter and C/N ratio (7.8–13.3). From end-member analysis, the apparently younger and less degraded organic matter in the silt and clay sediments consists mainly of terrestrial organic matter released by flood events. They remain in the depression, although most flood deposits were moved to deep-sea environments.

scholarly journals Small-scale distribution of metazoan meiofauna and sedimentary organic matter in subtidal sandy sediments (Mediterranean Sea)

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Davide Moccia ◽  
Alessandro Cau ◽  
Maria Carmela Meloni ◽  
Antonio Pusceddu
Keyword(s):  
Organic Matter ◽  
Biochemical Composition ◽  
Nutritional Quality ◽  
Random Distribution ◽  
Sedimentary Organic Matter ◽  
Small Scale ◽  
Metazoan Meiofauna ◽  
Sandy Sediments ◽  
Meiofaunal Abundance

While variations in sedimentary organic matter (OM) quantity, biochemical composition and nutritional quality as well as in meiofaunal abundance and assemblage composition at the macro- and mesoscale are relatively well known, information about variations at the microscale is much scarcer. To shed some light on this issue, we tested the null hypothesis by which abundance and composition of the meiofaunal assemblages, and the quantity, biochemical composition and nutritional quality of sedimentary organic matter in coastal shallow environments do not vary within a frame of 1 m2. No significant variation within the frame emerged for OM quantity, nutritional quality, biochemical composition and the abundance of meiofaunal assemblages. On the other hand, the composition of meiofaunal assemblages varied significantly within the frame and exhibited a clear segregation of assemblages farther to the shore, as a likely result of local micro-hydrodynamic conditions. Spatial autocorrelation analysis revealed that lipid and protein sedimentary contents had a random distribution, whereas carbohydrate and biopolymeric C contents and meiofaunal total abundance were characterized by a patchy distribution, with discrete peaks within the sub-frame squares (ca. 0.1 m2). Phytopigments showed a spatial positive autocorrelation distribution, following the micro-hydrodynamic pattern, with patches larger than the sub-frame square, but smaller than the entire one (1 m2). Overall, our results suggest that, within 1 m2 of subtidal sandy sediments, three replicates could be sufficient to assess correctly OM attributes and the abundance of meiofauna, but could be possibly inadequate for assessing meiofaunal assemblages’ composition at a finer scale (<1 m2).

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 Environmental factors shaping assemblages of ostracods (Crustacea: Ostracoda) in springs situated in the River Krąpiel valley (NW Poland)

2021 ◽  
pp. 14
Author(s):  
Agnieszka Szlauer-Łukaszewska ◽  
Vladimir Pešić ◽  
Andrzej Zawal
Keyword(s):  
Organic Matter ◽  
Environmental Factors ◽  
Habitat Modification ◽  
Habitat Conditions ◽  
River Habitat ◽  
Fine Particulate ◽  
Spring Type ◽  
Cypridopsis Vidua ◽  
The Individual ◽  
Fine Organic

We investigated the ostracod assemblage structure in springs of a small lowland River Krąpiel valley. Environmental factors and the potential of ostracods as indicators of spring type were analysed. The analysis involved the type of spring, substrate, physicochemical parameters, and the river valley's hydrological status as environmental factors. A total of thirty ostracod species were recorded. The average count of ostracod individuals in a sample amounted to 100. The assemblages were dominated by juvenile Candona sp., juvenile Psychrodromus sp., Cypria ophtalmica, and Cypridopsis vidua. The spring species accounted for less than 1% of the individual counts, except for juvenile Psychrodromus sp. with 21% and Eucypris pigra with 4%. The average number of taxa per spring was 5. The ostracod assemblages were significantly influenced by limnocrene springs, spring flooding by the river overflow, the presence of coarse leaf litter, the presence of fine organic matter, a high content of NH4 as well as by BOD5, conductivity, pH, Fe, the river habitat modification index (RHM), the habitat modification score (HMS), and the river habitat quality (RHQ). The habitat conditions for the spring species appeared to be enhanced by the domination of mineral substrate over fine particulate organic matter, an elevated pH, the presence of leaf-derived organic matter, and the absence of flooding by the river. The spring species showed no association with the Krąpiel valley hydrological factors.

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