scholarly journals The Relationship between Mollusks and Oxygen Concentrations in Todos Santos Bay, Baja California, Mexico

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
J. Gabriel Kuk-Dzul ◽  
Victoria Díaz-Castañeda
Keyword(s):  
Organic Matter ◽  
Dissolved Oxygen ◽  
Bottom Water ◽  
Organic Matter Content ◽  
Oxygen Depletion ◽  
Matter Content ◽  
The Other ◽  
Natural Conditions ◽  
The Relationship ◽  
Oxygen Concentrations

This study describes the relationship between mollusks, physicochemical properties of seawater, and sediments under natural conditions of low impact. Thirty-nine stations were sampled in October 1994 using a Van Veen grab (0.1 m−2). Temperature, salinity, and dissolved oxygen (DO) concentrations of bottom water were obtained with a CTD. Organic matter content and sediment grain analysis were determined. A total of 836 mollusks were collected. Gastropoda was the most abundant (52%) and diverse class with 27 genera, followed by Bivalvia with eight genera and Scaphopoda with only one genus. According to CCA analysis, dominant mollusks were significantly related with high DO concentrations.Donax,Natica,Acteocina,Bulla,Anachis,Odostomia, andCrucibulumcan be classified as sensitive genera because they were found mainly in high oxygen concentrations (3.1–5.6 mL L−1); on the other hand,Cardiomya,Nuculana,Laevicardium,Chione,Truncatella, andDentaliumcan be classified as tolerant genera (1.0–5.6 mL L−1). Todos Santos Bay hosts a diverse malacological fauna (36 genera); our results show that the dominant genera were mainly related to high dissolved oxygen concentrations. Mollusks can be a useful tool in environmental monitoring programs related with oxygen depletion in coastal areas.

The relationship between apparent retention time in the rumen, voluntary intake, and apparent digestibility of legume and grass diets in sheep

1973 ◽  
Vol 24 (6) ◽  
pp. 889 ◽  
Author(s):  
RF Thornton ◽  
DJ Minson
Keyword(s):  
Organic Matter ◽  
Retention Time ◽  
Daily Intake ◽  
Organic Matter Content ◽  
Matter Content ◽  
Apparent Digestibility ◽  
Jaw Movements ◽  
Digestible Organic Matter ◽  
Voluntary Intake ◽  
The Relationship

Eight grasses and six legumes were fed ad libitum at hourly intervals to wethers fitted with large rumen fistulas to determine voluntary intake, apparent digestibility, and the apparent retention time of organic matter in the rumen, as well as the quantity of rumen digesta and the organic matter content of the rumen digesta. The voluntary intake of legumes was 28% higher than that of equally digestible grasses. This difference was caused by a shorter retention time (17%) and a higher amount of organic matter (14%) in the rumen digesta from legume diets than from grass diets. The weight of wet digesta in the rumen of sheep fed on legumes was 7% lower than from those fed on grass. Neither the quantity of digesta nor the quantity of organic matter in the rumen was related to the voluntary intake, digestibility, or retention time of organic matter in the rumen. Number of jaw movements each day and rate of cotton thread digestion were not related to the retention time of the diets either. Daily intake of digestible organic matter (DOMI, g/day) was closely correlated with retention time (RTOM, hr) for the feeds in this study (r = –0.93) and the same relation applied to both temperate and tropical feeds, viz. DOMI = 1276–50.7 RTOM (r=0.96) Differences in voluntary intake between grasses and legumes were attributed to differences in retention time and the density to which the food was packed in the rumen.

Mobility of metsulfuron-methyl in tropical soils

Soil Research ◽  
1997 ◽  
Vol 35 (6) ◽  
pp. 1291 ◽  
Author(s):  
B. S. Ismail ◽  
K. Kalithasan
Keyword(s):  
Organic Matter ◽  
Soil Column ◽  
Organic Matter Content ◽  
Tropical Soils ◽  
Matter Content ◽  
Fresh Weight ◽  
Downward Movement ◽  
Natural Conditions ◽  
Metsulfuron Methyl ◽  
Rainfall Total

The mobility of metsulfuron-methyl in 5 soil series with different organic contents was determined in a greenhouse as well as under natural conditions. In these studies, the movement and biological activity of metsulfuron-methyl were determined by the bioassay method using long bean as a bioassay species. Bioactivity and movement of the herbicide down the soil profile were inversely related to the organic matter content of the soil. Phytotoxic levels of metsulfuron-methyl were restricted to the 10-cm depth of the column containing Selangor Series soil except when it received 40 mL of water daily (depth, 10–15 cm). In Munchung Series, the phytotoxic level was also mainly in the 5–10 cm layer. However, when the column received 40 mL daily or every 4 days, the residue was detected in 15–20 cm and 10–15 cm zones, respectively. The phytotoxic level moved downward to the 20–25 cm layer both in Sogomana and Holyrood Series when 40 mL of water was given daily. A phytotoxic level of metsulfuron herbicide was detected in the 20–25 cm layer when the soil column containing Serdang Series was leached with 40 mL of water every 4 days or with 20 mL daily; the phytotoxic level was detected at a depth of 25–30 cm when this soil was watered daily with 40 mL. The downward movement of metsulfuron under natural conditions showed a pattern similar to that found under simulated conditions. Phytotoxic effects of the residue could be detected in the 25–30 cm and 15–20 cm zone of Serdang and Holyrood Series, respectively, after exposure to 20 days of rainfall (total 111·9 mm). Phytotoxic residue in both Sogomana and Munchung Series soil was detected in the 10–15 cm layer, and in the 5–10 cm layer for Selangor Series soil, after exposure to 20 days of rainfall. After exposure to 40 days of rainfall (total 152·8 mm) under natural conditions, the residue could be detected in the 15–20 cm layer of Selangor Series. The phytotoxic level moved deeper in soil with low organic matter after exposure to 40 days of rainfall. Fresh weight reduction was greater in the 20–30 cm layer in Serdang Series than in the top layer.

The relationship between digestibility or energy losses as methane and metabolisable energy content of whole crop wheat

1996 ◽  
Vol 1996 ◽  
pp. 41-41
Author(s):  
A.T. Adesogan ◽  
E. Owen ◽  
D.I. Givens
Keyword(s):  
Organic Matter ◽  
Energy Content ◽  
Organic Matter Content ◽  
Matter Content ◽  
Energy Losses ◽  
Digestible Organic Matter ◽  
Metabolisable Energy ◽  
The Cost ◽  
The Relationship

Estimates of the metabolisable energy (ME) content of whole crop wheat (WCW) derived using measured energy losses as methane (ELMm) are lacking due to the cost of measuring ELMm. Published ME values of WCW are largely calculated using predicted energy losses as methane (ELMp, Blaxter and Clapperton, 1965) or digestible organic matter content (DOMD) in vivo. However, there appears to be no published information about the accuracy with which DOMD in vivo or ELMp predicts the ME content of WCW. Therefore, this study assessed the validity of such ME predictions by comparing them with ME contents calculated using ELMm.

Comparison of aggregate stability within six soil profiles under conventional tillage using various laboratory tests

Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Radka Kodešová ◽  
Marcela Rohošková ◽  
Anna Žigová
Keyword(s):  
Organic Matter ◽  
Soil Aggregates ◽  
Organic Matter Content ◽  
Aggregate Stability ◽  
Clay Content ◽  
Soil Aggregate ◽  
Matter Content ◽  
The Other ◽  
Structure Stability ◽  
Soil Aggregate Stability

AbstractSoil structure stability was studied in every diagnostic horizons of six soil types (Haplic Chernozem, Greyic Phaeozem, two Haplic Luvisols, Haplic Cambisol, Dystric Cambisol) using different techniques investigating various destruction mechanisms of soil aggregates. Soil aggregate stability, assessed by the index of water stable aggregates (WSA), varied depending on the organic matter content, clay content and pHKCl. The presence of clay and organic matter coatings and fillings, and presence of iron oxides in some soils increased stability of soil aggregates. On the other hand periodical tillage apparently decreased aggregate stability in the Ap horizons. Coefficients of aggregate vulnerability resulting from fast wetting (KV 1) and slow wetting (KV 2) tests showed similar trends of the soil aggregate stability as the WSA index, when studied for soils developed on the similar parent material. There was found close correlation between the WSA index and the KV 1 value, which depended also on the organic matter content, clay content and pHKCl. Less significant correlation was obtained between the WSA index and the KV 2 value, which depended on the organic matter content and clay content. Coefficients of vulnerability resulting from the shaking after pre-wetting test (KV 3) showed considerably different trends in comparison to the other tests due to the different factors affecting aggregate stability against the mechanical destruction. The KV 3 value depended mostly on cation exchange capacity, pHKCl and organic matter content.

Adsorption of pesticides by some Australian soils

Soil Research ◽  
1981 ◽  
Vol 19 (1) ◽  
pp. 61 ◽  
Author(s):  
GG Briggs
Keyword(s):  
Aqueous Solution ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
North American ◽  
Water Distribution ◽  
Organic Matter Content ◽  
Matter Content ◽  
Organic Chemicals ◽  
The Relationship

Adsorption of non-ionized organic chemicals from aqueous solution by 17 Australian soils was related to the organic matter content of the soils. The soil organic matter/water distribution (Kom) for each chemical was similar in all soils and could be predicted from the octanol/water distribution (Kow) of the chemical. The relationship between these two distributions, log Kom = 0.52log Kow, + 0.69, is similar to that reported for European and North American soils.

THE AVAILABLE BORON CONTENT OF THE GENETIC HORIZONS OF SOME ONTARIO SOILS: I. THE RELATIONSHIP BETWEEN WATER-SOLUBLE BORON AND OTHER SOIL PROPERTIES

1966 ◽  
Vol 46 (2) ◽  
pp. 133-138 ◽  
Author(s):  
N. S. Miljkovic ◽  
B. C. Matthews ◽  
M. H. Miller
Keyword(s):  
Organic Matter ◽  
Boron Content ◽  
Organic Matter Content ◽  
Clay Content ◽  
Important Variable ◽  
Matter Content ◽  
Parent Material ◽  
Water Soluble ◽  
Hot Water ◽  
The Relationship

The available boron content of the genetic horizons of eight Ontario soils was determined using a hot-water extraction and a sunflower test. The available boron was highest in the surface horizons and decreased in the zones of eluviation to a level equal to or lower than that in the parent material. The content in the horizons was generally higher than that in the C horizons.The water-soluble boron was closely related to the organic matter content in a quadratic regression (R2 = 0.691). When pH and clay content were included in regressions, a positive organic matter × pH component was the single most important variable, explaining 64.4% of the variability. Additional terms involving clay content and pH did not greatly increase the R2 value.

scholarly journals MACROBENTHIC COMMUNITIES IN A TEMPERATE URBAN ESTUARY OF HIGH DOMINANCE AND LOW DIVERSITY: MONTEVIDEO BAY (URUGUAY)

2015 ◽  
Vol 30 (1) ◽  
pp. 9
Author(s):  
P. Muniz ◽  
N. Venturini
Keyword(s):  
Organic Matter ◽  
Bottom Water ◽  
Organic Matter Content ◽  
Matter Content ◽  
Rio De La Plata ◽  
Río De La Plata ◽  
Small Surface ◽  
La Plata ◽  
Urban Estuary ◽  
Low Diversity

The macrobenthic subtidal community was studied between April 1997 and April 1998 in Montevideo bay, an urban estuary located in the fluvio marine system of the Río de la Plata (Uruguay) that receives a variety of industrial and sewage inputs. Monthly surveys were carried out at ten sampling stations where sediment samples were taken with a manual corer and analysed for granulometric parameters, organic matter content, chlorophyll a and phaeopigments content, redox potential, and macrobenthic fauna. The area presented high organic matter content in its sediments and several regions of the bottom were anoxic during a large part of the sampling period. The benthic macrofauna was dominated, both in numbers as well as in biomass, by the small surface deposit-feeder gastropod Heleobia cf. australis. Cluster analysis, Multidimensional Scaling and Canonical Correspondence Analysis revealed that the study area could be divided in two well-defined regions with different environmental characteristics and different faunal composition. The dissolved oxygen content in the bottom water and variables related to it were the most important factors in explaining the patterns of the benthic communities. At the phylum level, the meta-analysis of “production” showed a high disturbance status for all stations. The inner region, the most affected by anthropogenic activities, was the most compromised environmentally and biologically, and was characterised by a very low diversity and abundance, reduced conditions in the sediments and low oxygenated bottom water. In more external places of the bay, on the other hand, perhaps due to their location at a greater distance from the sources of organic material and in a region with higher hydrodynamic energy, the conditions for the development of benthic fauna were more favourable. Spatial and temporal faunistic patterns observed and their possible causes are analysed and discussed in relation to the natural and anthropogenic factors that act in this coastal ecosystem. Comunidades macrobentónicas en un estuario urbano templado de alta dominancia y baja diversidad: Bahía de Montevideo (Uruguay) Una comunidad macrobentónica submareal fue estudiada entre abril de 1997 y abril de 1998 en la Bahía de Montevideo, un estuario urbano localizado en el sistema marino fluvial del Río de la Plata (Uruguay) que recibe una variedad de descargas industriales y de alcantarillado. Se llevaron a cabo muestreos mensuales en diez estaciones donde se tomaron muestras de sedimento utilizando un nucleador y a estas les fueron analizadas los parámetros granulométricos, el contenido de materia orgánica, el contenido de clorofila a y de feopigmentos, potencial redox y fauna macrobentónica. El área presentó un alto contenido de materia orgánica en sus sedimentos y muchas regiones del fondo mostraron ser anóxicas durante una gran parte del mismo período. La fauna macrobentónica fue dominada en número y biomasa por los pequeños gasterópodosHeleobia cf. australis. Los análisis de conglomerados, de escala multidimensional y de correspondencia canónica revelaron que el área de estudio podría ser dividida en dos regiones bien definidas con diferentes características ambientales y composiciones faunísticas diferentes. El contenido de oxígeno disuelto en agua de fondo y las variables realcionadas con ella fueron los factores más importatntes en explicar los patrones de las comunidades bentónicas. Al nivel phylum, los meta análisis de la “producción” mostraron un alto estatus de perturbación y biológica que fue caracterizada por baja diversidad y abundancia, condiciones reducidas y agua de fondo poco oxigenada. Por otra parte, en los sitios más externos de la bahía, debido quizas a su localización a una gran distancia de las fuentes de materia orgánica con una alta energía hidrodinámica, las condiciones para el desarrollo de la fauna bentónica fueron favorables. Los patrones faunísticos espaciales y temporales observados y sus posibles causas fueron analizados y discutidos en relación con los factores naturales y antropogénicos que actúan sobre este ecosistema costero.

scholarly journals KEANEKARAGAMAN MOLUSKA BERDASARKAN TEKSTUR SEDIMEN DAN KADAR BAHAN ORGANIK PADA MUARA SUNGAI BETAHWALANG, KABUPATEN DEMAK (Molluscs Diversity based on Sediment Texture and Organic Matter Content in Betahwalang Estuary, Demak Regency)

2017 ◽  
Vol 13 (1) ◽  
pp. 58
Author(s):  
Hana Nisau Shalihah ◽  
Pujiono Wahyu Purnomo ◽  
Niniek Widyorini
Keyword(s):  
Organic Matter ◽  
Organic Matter Content ◽  
Matter Content ◽  
Survey Method ◽  
Sediment Texture ◽  
Positive Correlation ◽  
Purposive Sampling ◽  
Relationship Of ◽  
The Relationship ◽  
Contaminant Load

 Muara Sungai Betahwalang merupakan ekosistem yang mendapat masukan dari kegiatan penduduk daerah pemukiman sekitar dan dari Sungai Jajar. Muatan pencemar akan mempengaruhi kondisi muara terutama substrat dasar pada sungai Betah walang. Tekstur dan kandungan bahan organik di dalam sedimen menentukan keberadaan moluska. Tekstur sedimen merupakan tempat untuk menempel dan merayap atau berjalan, sedangkan bahan organik merupakan sumber makanan bagi moluska. Tujuan dari penelitian ini adalah untuk mengetahui keanekaragaman moluska, tekstur sedimen dan kadar bahan organik, serta untuk mengetahui hubungan antara variabel. Metode yang digunakan adalah metode survey dengan pengambilan sampel menggunakan metode Purposive Sampling. Sampel diambil pada 5 stasiun dan masing-masing stasiun terdiri dari 3 titik. Hasil penelitian menyebutkan bahwa terdapat 10 genera dari kelas Gastropoda yaitu Littorina, Cerithidea, Turritella, Clathrodrillia, Fasciolaris, Conus, Filopaludina, Pila, Melanoides dan Telescopium dan 4 genera dari kelas Bivalvia yaitu Anadara, Mesodesma, Mytilus dan Donax. Karakteristik substrat di muara Sungai Betahwalang adalah liat dan liat berpasir dengan kadar bahan organik berkisar antara 6,2-17,4 %. Hubungan moluska dengan tekstur sedimen terutama liat mempunyai korelasi positif dengan persamaan y = 6.94x + 224.0 (r = 0.535). Hubungan moluska dengan bahan organik mempunyai korelasi positif dengan persamaan y = 33.44x + 271.1 (r = 0.507) dan R2 = 0.257   Betahwalang Estuary is an ecosystem that gets input from the activities of the surrounding residents area and from the Jajar River. Contaminant load from upstream will affect the condition of the substrate in Betah walang river. Texture and organic matter content in the sediments determine the presence of molluscs. Sediment texture is a place for molluscs to stick, crawl or walk, while organic matter is a source of food for them. The purpose of this research is to know the diversity of molluscs, sediment textures and organic matter content, and to know the relationship between those variables. The method used is survey method with sampling using Purposive Sampling method. Samples were taken at 5 stations and each station consisted of 3 spots. The results show that 10 genera of the Gastropod class were Littorina, Cerithidea, Turritella, Clathrodoillia, Fasciolaris, Conus, Filopaludina, Pila, Melanoides and Telescopium and 4 genera of Bivalves class were Anadara, Mesodesma, Mytilus and Donax. Betahwalang estuary are characterized by clay and sandy clay with organic material content between 6,2-17,4%. The relationship of molluscs with sediment texture, especially clay, has a positive correlation with the equation y = 6.94x + 224.0 (r = 0.535). The relationship of molluscs with organic matter has a positive correlation with the equation y = 33.44x + 271.1 (r = 0.507). 

scholarly journals Influence of climatic factors on the energy potential of broadleaf phytocoenosis forest bedding

2021 ◽  
Vol 4 ◽  
pp. 32-36
Author(s):  
Iryna Vyshenska ◽  
Alina Ginzhaliuk
Keyword(s):  
Organic Matter ◽  
Forest Ecosystem ◽  
Deciduous Forest ◽  
Climatic Factors ◽  
Meteorological Data ◽  
Organic Matter Content ◽  
Matter Content ◽  
Monthly Precipitation ◽  
Energy Potential ◽  
The Relationship

The study of the energy potential of forest bedding in the deciduous forest areas of the “Lisnyky” Nature Reserve of the Holosiivsky National Nature Park revealed the nonlinear nature of its annual dynamics. The main sources of replenishment of the organic stock of this component of broadleaf forest phytocoenosis were the active development of herbaceous vegetation in spring and significant leaf rainfall in autumn. At the same time, significant changes in the processes of accumulation and decomposition of organic matter of forest bedding occurred under the influence of climatic factors such as temperature and precipitation. The experimental site was located in moderately moist oak forest ass. Convallario majali-Quercetum roboris Shevchyk & V. Sl. in Shevchyk & al. 96. The age of the old Quercus robur oak trees, which occupy the first tier of the forest, exceeds 100 years. The second tier is formed by other broadleaf species, Acer platanoides, A. campestre, A. tataricum, Carpinus betulus, Fraxinus excelsior and Tilia cordata, up to 30 years old. The energy reserve was calculated from the dry organic matter content. The obtained data were compared with  meteorological data of the corresponding month of the year and correlation coefficients were calculated. Correlation analysis confirmed the relationship between climatic factors and the energy potential of forest bedding. The inverse of the mean force (R = -0.515) shows the relationship between the energy potential of the forest bedding and the average monthly temperature and the high direct correlation between the energy potential and the amount of average monthly precipitation (R = 0.755). In general, forest bedding can be considered an important component of the ecosystem, which responds quickly to external factors and characterizes the state of the forest ecosystem, and its energy potential can be an effective indicator of forest ecosystem stability in climate change monitoring.

Sign in / Sign up

Export Citation Format

Share Document