scholarly journals Variability of macrofauna distribution along a dissipative log-spiral sandy beach in Rio de Janeiro, Southeastern Brazil

2017 ◽  
Vol 81 (1) ◽  
pp. 111 ◽  
Author(s):  
Carlos A.M. Barboza ◽  
Tatiana Cabrini ◽  
Gustavo Mattos ◽  
Viviane Skinner ◽  
Ricardo Cardoso
Keyword(s):  
Grain Size ◽  
Organic Matter ◽  
Community Structure ◽  
Organic Matter Content ◽  
Principal Component ◽  
Matter Content ◽  
Southeastern Brazil ◽  
Individual Species ◽  
Beach Slope ◽  
Sediment Sorting

Log-spiral beaches display defined physical gradients alongshore. However, the majority of studies focus on the variability of a single population of macrofauna species. We aimed to investigate the variation in species distribution and in community structure along ten transects on a log-spiral beach. Principal component analysis indicated a clear physical gradient alongshore. Redundancy analysis showed that the sheltered end was related to smaller particle sizes, higher organic matter content and high densities of polychaetes. The exposed end was characterized by coarser sand, lower organic matter content and a high presence of crustaceans. Model selection indicated that the “best fit” to explain the variability in the number of individuals included grain size and beach slope. Variability of the polychaete Scolelepis squamata was best explained by grain size, slope and sediment sorting. The best model for the cirolanid Excirolana armata only included sediment sorting. The physical gradient in sediment texture and the beach slope explained more than one-third of the variability in community structure. The physical variables were also correlated with the distribution of the individual species. We showed that the physical gradient on log-spiral coasts may be an important driver of macrofauna variability, even at mesoscales and in dissipative conditions.

scholarly journals Parameter Selection for the Evaluation of Compost Quality

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1567
Author(s):  
Haydee Peña ◽  
Heysa Mendoza ◽  
Fernando Diánez ◽  
Mila Santos
Keyword(s):  
Electrical Conductivity ◽  
Organic Matter ◽  
Pore Space ◽  
Linear Regression Analysis ◽  
Organic Matter Content ◽  
Principal Component ◽  
Primary Component ◽  
Matter Content ◽  
Germination Index ◽  
Soil Restoration

This work studies variables measured from the first phase of composting through the acquisition of the final product, with the goal of identifying those that are more strongly related to quality and are most useful for developing an index. The necessity to establish quality control procedures thus exists for the classification of raw materials in the same way as for the finished products. To accomplish this, three mixtures were prepared, with the goal of achieving a C/N ratio of 30 and a moisture content of 60%. The primary component of each mixture was: fruit processing waste (C1), sewage sludge from the food industry (C2), and the manufacturing waste of fried foods (C3). Temperatures were measured over 107 days, with the corresponding data fit to a logistical model where T °C ~ α / ((1 + exp (− (Time − β) / − γ))) + δ, with interaction compost * time being statistically significant (p < 0.001). This allowed for the temperatures, in keeping with health concerns, to be confirmed. Likewise, a linear regression analysis demonstrated the decomposition of organic matter at 0.82%/week. Statistically, the parameters, measured during the process, with the least variability were selected, which differed in the average contrasts: germination index (cucumber), electrical conductivity, and average moisture. A principal component analysis (PCA) and Spearman’s correlation analysis revealed the best Germination Index (GI) values for C1, due to lower electrical conductivity (EC) and bulk density (Bd) along with higher organic matter content (TOM). For its part, C2 induced a higher Relative emergence (RE) of the cucumber thanks to its higher content of total nitrogen (TN) and lower contribution of Cu, Zn and K. C3 showed a higher presence of salts, less favorable physical characteristics (>Bd and <TPS, total pore space) and higher content of Zn and Cu. Composting carried out with appropriate mixtures can offer high-quality products for use as fertiliser, in soil restoration, and as an alternative substrate to peat and virgin mountain soil.

scholarly journals Superficial sediments and their relation to polyehaete families in a subtropieal embayment, Mexico

2015 ◽  
pp. 237-238
Author(s):  
Nuria Méndez ◽  
María Green Ruiz
Keyword(s):  
Grain Size ◽  
Organic Matter ◽  
Organic Matter Content ◽  
Fine Sand ◽  
Matter Content ◽  
Pearson’S Correlation ◽  
Pearson's Correlation ◽  
Superficial Sediments ◽  
Soft Bottoms

The soft bottoms in front of Mazatlan Bay and "Isla de la Piedra" Peninsula were studied to produce maps (depth, grain size and organic matter content in sediments). Sixty samples were óbtained with a 30 x 30 van Veen grab (4-21 m depth) and polychaetes were extracted from 21 subsamples. Grain size ranged from -1.05 phi (gravel) to 3 .81 phi (very fine sand), with fme sand predominl\ting. Organic matter content in sediment was 0.91-3.06 % (most values = 1-2 %). Thirty polychaete families (905 individuals/m2 in mean) were found, and Cirratulidae, Spionidae, Onuphidae, and Pilargiidae were domiuant. Pearson's correlation of grain size.

Impact of lightning on organic matter-rich soils: influence of soil grain size and organic matter content on underground fires

2007 ◽  
Vol 45 (1) ◽  
pp. 19-31 ◽  
Author(s):  
Vittorio Zanon ◽  
Fátima Viveiros ◽  
Catarina Silva ◽  
Ana Rita Hipólito ◽  
Teresa Ferreira
Keyword(s):  
Grain Size ◽  
Organic Matter ◽  
Organic Matter Content ◽  
Matter Content ◽  
Soil Grain Size

scholarly journals The Effect of Stormwater Discharge on the Nearshore Benthic Environment of Inner Wellington Harbour

2021 ◽  
Author(s):  
◽  
Lesley Anne Bolton-Ritchie
Keyword(s):  
Grain Size ◽  
Organic Matter ◽  
Organic Matter Content ◽  
Control Site ◽  
Matter Content ◽  
Sediment Grain Size ◽  
Metal Concentrations ◽  
Biological Community ◽  
Benthic Environment ◽  
Over Time

<p>To investigate the spatial and temporal effects of stormwater discharge on the nearshore benthic environment of inner Wellington Harbour, sediment grain size, organic matter content, concentrations of As, Cr, Cu, Ni, Pb and Zn and the presence and abundance of the benthic macrobiota were measured at a number of stations at both stormwater outlets and at control sites. Correlations between the biological and the sedimentological and chemical variables were also investigated. In the vicinity of some outlets the sediment grain size distribution was altered and the sediment organic matter content was up to 5.5 times higher and metal concentrations were up to 11 times higher, than that at control sites. In general organic matter content and metal concentrations were highest close to an outlet and decreased with increasing distance seaward. With increasing distance from outlets the biological communities changed and there were significant differences in one or more of total, polychaete, arthropod and mollusc taxa, polychaete and mollusc individuals, diversity and the abundance of 12 taxa. The spatial extent of the impact of stormwater discharge on the benthic environment ranged from l0 to more than 45 metres from an outlet. Over time the largest range in organic matter content at an outlet was 6.1-42.8% while at a control it was 4-9%. For As, Cu, Pb and Zn the range in concentration over time was larger at stations closer to than those further from the outlet and larger at outlet than control site stations e.g. at 2 m in front of one outlet the Pb concentration range was 25l-1367 ppm, at 20 m from the outlet it was 15-22 ppm and at the associated control site 2 m station it was 15-20 ppm. Over time the direction of change in the biological community was different, and there were significant differences in the number of total, mollusc, polychaete and arthropod taxa and individuals and diversity, between that at the outlet and the associated control site. 27 taxa were more abundant at outlet than control sites and 45 taxa were more abundant at control than outlet sites over time. The biological community at outlet and control sites was best correlated to combinations of 2-5 of the sedimentological/chemical variables. Of these variables, organic matter content was the only commonly occurring variable at outlet sites and did not occur as one of the variables at the control sites. Where the organic matter content was >22% there were a low number of taxa and individuals, and with an increase in organic matter content there was a significant decrease in the number of total and arthropod taxa. The abundance of two taxa was significantly correlated to organic matter content and the abundance of six taxa was significantly correlated to metal concentrations.</p>

scholarly journals Molecular Characterization of Diazotrophic and Denitrifying Bacteria Associated with Mangrove Roots

2007 ◽  
Vol 73 (22) ◽  
pp. 7308-7321 ◽  
Author(s):  
Ana L. Flores-Mireles ◽  
Stephen C. Winans ◽  
Gina Holguin
Keyword(s):  
Organic Matter ◽  
Oxygen Concentration ◽  
Pore Water ◽  
Phylogenetic Trees ◽  
Organic Matter Content ◽  
Principal Component ◽  
Matter Content ◽  
Water Oxygen ◽  
Mangrove Roots ◽  
Biogeochemical Parameters

ABSTRACT An analysis of the molecular diversity of N2 fixers and denitrifiers associated with mangrove roots was performed using terminal restriction length polymorphism (T-RFLP) of nifH (N2 fixation) and nirS and nirK (denitrification), and the compositions and structures of these communities among three sites were compared. The number of operational taxonomic units (OTU) for nifH was higher than that for nirK or nirS at all three sites. Site 3, which had the highest organic matter and sand content in the rhizosphere sediment, as well as the lowest pore water oxygen concentration, had the highest nifH diversity. Principal component analysis of biogeochemical parameters identified soil texture, organic matter content, pore water oxygen concentration, and salinity as the main variables that differentiated the sites. Nonmetric multidimensional scaling (MDS) analyses of the T-RFLP data using the Bray-Curtis coefficient, group analyses, and pairwise comparisons between the sites clearly separated the OTU of site 3 from those of sites 1 and 2. For nirS, there were statistically significant differences in the composition of OTU among the sites, but the variability was less than for nifH. OTU defined on the basis of nirK were highly similar, and the three sites were not clearly separated on the basis of these sequences. The phylogenetic trees of nifH, nirK, and nirS showed that most of the cloned sequences were more similar to sequences from the rhizosphere isolates than to those from known strains or from other environments.

scholarly journals Sediments of watersheds from Frutal and Bebedouro Streams (Frutal, MG, Brazil) as an indicator of human activities

2017 ◽  
Vol 12 (1) ◽  
pp. 17 ◽  
Author(s):  
Sofia Luiza Brito ◽  
Thiago Torres Costa Pereira ◽  
Inez Cristina Martins
Keyword(s):  
Organic Matter ◽  
Human Activities ◽  
Riparian Vegetation ◽  
Organic Matter Content ◽  
Principal Component ◽  
Quality Parameters ◽  
Matter Content ◽  
Particle Size Measurement ◽  
Minas Gerais State

Soil degradation is a physical process intensified by political and socioeconomic factors, and by the population growth of the 20th century. In this study, we evaluated the sediments of the Frutal and Bebedouro Streams, located in Frutal municipality, Minas Gerais State, Brazil, and their relation to major human activities that are responsible soil erosion and silting. Samples were collected between 2012 and 2013 for the determination of granulometric composition, organic matter content, and minerals in sediments. The Wentworth scale was used for particle size measurement, and then the size classes regrouped to ABNT scale (NBR 6502/1995). The results found that agriculture and cattle ranching are the main activities that cause intense erosion and silting in both watersheds. Bebedouro Stream is better preserved, as it is completely located in rural area with larger riparian vegetation, unlike the mid-stretch of Frutal Stream, which is located in an urban area. Quartz is the predominant mineral in the sediments as the soils of the region are formed by sandstones; consequently, few nutritional elements were found in the studied samples. Principal component analysis showed that water quality parameters are correlated to silt/clays and organic matter content in most of the collected stations.

The Holocene paleoenvironmental history of Western Caucasus (Russia) reconstructed by multi-proxy analysis of the continuous sediment sequence from Lake Khuko

The Holocene ◽  
2020 ◽  
pp. 095968362097278
Author(s):  
Alexei M Grachev ◽  
Elena Y Novenko ◽  
Evgeniy A Grabenko ◽  
Mikhail Y Alexandrin ◽  
Elya P Zazovskaya ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Susceptibility ◽  
Organic Matter ◽  
Sediment Core ◽  
Organic Matter Content ◽  
Matter Content ◽  
Western Caucasus ◽  
Climate History ◽  
The Holocene ◽  
The Western Caucasus

This paper presents new multi-proxy records of the Holocene environmental and climatic changes in the Western Caucasus revealed from a continuous sediment sequence from mountainous Lake Khuko (Caucasus State Natural Biospheric Reserve, 1744 m a.s.l.). Palaeoecological analyses of a sediment core for grain size, magnetic susceptibility, loss on ignition, and pollen allowed us to determine five principal climatic phases with several subphases since 10.5 ka BP. The age model is based on seven accelerator mass spectrometry 14C dates, supplemented by 210Pb data for the uppermost part of the sediment core. Warm periods (10.5–6.7, 6.7–5.5, 3.5–2.4, 0.8–0.5 ka BP) were characterized by high biological productivity in the lake as indicated by high organic matter content and expansion of forests, typical of modern low and middle mountain zones, as indicated by the increase in abundance of Quercus, Ulmus, Corylus, and Tilia in the pollen assemblages. Cold periods (5.5–3.5, 2.4–0.8, and 0.5 ka BP–present) are marked by a consistent decrease in organic matter content in lake deposits and possibly higher intensity of the catchment erosion. The changes in pollen assemblages (for instance peaks of Abies, Picea, and Pinus) suggested a potential elevational decline in the boundaries of vegetation belts and expansion of high-altitude woodlands. Abrupt changes in the lake ecosystem were identified between 4.2 and 3.5 ka cal BP marked by a short-term variation in sediment regime shown by variation in organic matter content, magnetic susceptibility values, and sediment grain size. This was probably caused by climatic fluctuations in the Western Caucasus region as a result of complex shifts in the ocean-atmosphere system during the 4.2 ka event. Overall, the first Holocene multi-proxy continuous lake sediment record provides new insights into the climate history in the Western Caucasus.

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