Subdivisions of the Benthic Environment of the Upper Great Lakes, with Emphasis on Lake Michigan

1968 ◽  
Vol 25 (6) ◽  
pp. 1181-1197 ◽  
Author(s):  
Charles F. Powers ◽  
Andrew Robertson
Keyword(s):  
Organic Carbon ◽  
Thin Layer ◽  
Lake Michigan ◽  
Silty Sand ◽  
Sediment Type ◽  
Organic Carbon Content ◽  
Upper Great Lakes ◽  
Sediment Types ◽  
Clayey Silt ◽  
Benthic Environment

An effort has been made to introduce a greater degree of standardization and reliability into descriptions of the benthic environment made by biologically oriented observers. Comparisons of field descriptions and mechanical analyses showed an encouraging ability to distinguish among four major sediment types in Lake Michigan. The bottom of the lake has been described in terms of these types, which usually occur in the following order with respect to depth: sand, silty sand–sandy silt, silt–clayey silt in a thin layer overlying stiff plastic clay, and silt–clayey silt only. Each sediment type tends to exhibit its own range of organic carbon values, with the amount of carbon increasing with depth. Hard or rocky bottom occurs in more restricted areas and is considered a fifth recognizable bottom category. Certain features of the distribution of the sediments may be related to gross water movements and to the locations of the mouths of large tributary rivers. Limited comparative studies in Lakes Huron and Superior showed similar distributions of sediment types and organic carbon content. It is suggested that the observed uniformity of maximum organic carbon values in the sediments of all three lakes may be related to processes of oxidation.

scholarly journals Response of stream ecosystem function and structure to sediment metal: Context-dependency and variation among endpoints

Elem Sci Anth ◽  
2014 ◽  
Vol 2 ◽  
Author(s):  
David M. Costello ◽  
G. Allen Burton
Keyword(s):  
Dose Response ◽  
Environmental Context ◽  
Context Dependency ◽  
Acid Volatile Sulfide ◽  
Sediment Type ◽  
Organic Carbon Content ◽  
Ecological Context ◽  
Sediment Types ◽  
Sediment Metals ◽  
Sediment Metal

Abstract Physicochemical and ecological attributes of ecosystems (i.e., environmental context) can modify the exposure and effects of metals, which presents a challenge for ecosystem management. Furthermore, the functional and structural attributes of an ecosystem may not respond equally to metals or be uniformly responsive to environmental context. We explored how physicochemical and ecological context modified sediment metal dose-response for a suite of functional and structural measures. Two sediments with high (HB) and low (LB) acid volatile sulfide and organic carbon content (i.e., physicochemical context) were amended with copper and nickel to establish a gradient of treatments from non-toxic to potentially toxic. Sediments were deployed in each of two streams (i.e., ecological context), incubated for four weeks, and measured for sediment microbe, biofilm, and macroinvertebrate dose-response to metal. The dose-response of microbial function was affected by physicochemical context, with cotton decomposition negatively related to sediment metal only on LB sediments. The abundance of invertebrates from the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) responded negatively to sediment metal only on LB sediments; however, this dose-response was only observed in one stream, likely because of greater abundance of sensitive EPT taxa (i.e., Baetidae and Ephemerellidae). Biofilm structure was negatively affected by sediment metal in only one stream and there was no difference in dose-response between the two sediment types. Biofilm function was affected by sediment type and stream; production by biofilms exposed to HB sediment was negatively related to sediment metal in only one stream. In all, the majority of our endpoints exhibited responses that were modified by environmental context; however, each component of the ecosystem exhibited unique context dependency. For management of sediment metals, an understanding of context dependency is useful for informed decision-making, but the application of simple contextual filters are unlikely to protect all elements of an ecosystem.

REFLECTION COEFFICIENTS AND BOTTOM LOSSES AT NORMAL INCIDENCE COMPUTED FROM PACIFIC SEDIMENT PROPERTIES

Geophysics ◽  
1970 ◽  
Vol 35 (6) ◽  
pp. 995-1004 ◽  
Author(s):  
Edwin L. Hamilton
Keyword(s):  
Normal Incidence ◽  
Silty Sand ◽  
Reflection Coefficients ◽  
Silty Clay ◽  
Sediment Properties ◽  
Compressional Waves ◽  
Sea Floor ◽  
Sediment Types ◽  
The Pacific ◽  
Clayey Silt

Rayleigh reflection coefficients and bottom losses of compressional waves at normal incidence on the water‐sediment interface are computed with values of density and velocity measured in sea‐floor sediment samples; main sediment types in three major environments of the Pacific and adjacent areas are included. Some typical average computed values of acoustic bottom loss at normal incidence in db are (1) continental shelf: sands, 8; silty sand, 10; sandy silt, 14; silty clay, 16; (2) abyssal plain: clayey silt, 17; silty clay and clay, 21; and (3) abyssal hill: silty clay and clay, 17. Comparisons with actual measurements at sea by several investigators demonstrate the validity of the approach.

scholarly journals THE CORRELATION BETWEEN BENTHIC FORAMINIFERA AND SEDIMENT TYPES OF SOUTH MAKASSAR STRAIT

2016 ◽  
Vol 29 (2) ◽  
pp. 53
Author(s):  
Sheilla Zallesa ◽  
Kresna Tri Dewi ◽  
Noor C.D. Aryanto
Keyword(s):  
Community Structure ◽  
Benthic Foraminifera ◽  
Diversity Index ◽  
Silty Sand ◽  
Sediment Type ◽  
Sediment Characteristics ◽  
Core Sediment ◽  
Sandy Silt ◽  
Sediment Types ◽  
The Pacific

South Makassar Strait is located between Kalimantan and Sulawesi Islands that is an important oceanographic pathway connecting between the Pacific and Indian oceans. This area is a part of sedimentary basin that has specific seabed morphology and sediment characteristics, including foraminifera as a component of sediments. The purpose of this study is to determine community structure of benthic foraminifera related to sediment characteristics. This study used 20 top core sediment samples from water depth between 200 and 1500 m. There are identified 38 species of benthic foraminifera and some of them are characterized the study area: Anomalinoides colligerus, Lenticulina suborbicularis, Planulina wuellerstorfi, , and Pseudonodosaria discrete. The diversity index is categorized as moderate values (1.0=H'= 3) and the average of evenness values is about 0.79. The dominance values are less than 0.5 indicate that there is no dominant species in the study area. In relation to sediment characteristics, it shows that the high abundance of benthic foraminifera occurs in sediment type of silty sand and sandy silt. Moderate abundance appears in sand following by low abundance in silt and sandy silt sediment types. Keywords: benthic foraminifera, community structure, sediment types and Makassar Strait Makassar bagian selatan terletak diantara Pulau Kalimantan dan Sulawesi yang merupakan jalur oseanografik yang penting menghubungkan Samudera Pasifik dan. Wilayah ini merupakan bagian dari cekungan sedimen yang mempunyai morfologi dasar laut dan karakteristik sedimen tertentu termasuk foraminifera sebagai komponen sedimen. Tujuan dari penelitian ini adalah untuk mengetahui struktur komunitas foraminifera bentik dalam kaitannya dengan tipe sedimen dasar laut. Penelitian ini menggunakan 20 sampel sedimen bagian atas dari pemercontoh inti pada kedalaman antara 200 dan 1500 m. Ada 38 spesies foraminifera bentik dan beberapa diantaranya mencirikan daerah penelitian: Anomalinoides colligerus, Lenticulina suborbicularis, Planulina wuellerstorfi, dan Pseudonodosaria discrete. Indeks keanekaragaman termasuk dalam kategori sedang (1,0=H’=3) dan nilai rata-rata keseragaman sekitar 0,79. Nilai dominasi lebih kecil dari 0,5 itu menandakan tidak ada spesies yang dominan pada lokasi penelitian. Terkait dengan karakteristik sedimen menunjukkan bahwa kelimpahan foraminifera bentik tinggi terdapat pada jenis sedimen pasir lanauan dan lanau pasiran. Kelimpahan sedang ditemukan pada jenis sedimen pasir diikuti kelimpahan rendah yang dijumpai pada sedimen lanau dan lanau pasiran. Kata kunci: foraminifera bentik, struktur komunitas, jenis sedimen, Selat Makassar.

Space-time monitoring of soil organic carbon content across a semi-arid region of Australia

2021 ◽  
Vol 24 ◽  
pp. e00367
Author(s):  
Patrick Filippi ◽  
Stephen R. Cattle ◽  
Matthew J. Pringle ◽  
Thomas F.A. Bishop
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Content ◽  
Arid Region ◽  
Space Time ◽  
Organic Carbon Content ◽  
Soil Organic Carbon Content ◽  
Semi Arid Region ◽  
Semi Arid

scholarly journals Influence of Slope Gradient and Aspect on Soil Organic Carbon Content in the Region of Niš, Serbia

2021 ◽  
Vol 13 (15) ◽  
pp. 8332
Author(s):  
Snežana Jakšić ◽  
Jordana Ninkov ◽  
Stanko Milić ◽  
Jovica Vasin ◽  
Milorad Živanov ◽  
...  
Keyword(s):  
Land Use ◽  
Spatial Distribution ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Slope Aspect ◽  
Available Phosphorus ◽  
Organic Carbon Content ◽  
Slope Gradient ◽  
Phosphorus And Potassium ◽  
Uncultivated Land

Topography-induced microclimate differences determine the local spatial variation of soil characteristics as topographic factors may play the most essential role in changing the climatic pattern. The aim of this study was to investigate the spatial distribution of soil organic carbon (SOC) with respect to the slope gradient and aspect, and to quantify their influence on SOC within different land use/cover classes. The study area is the Region of Niš in Serbia, which is characterized by complex topography with large variability in the spatial distribution of SOC. Soil samples at 0–30 cm and 30–60 cm were collected from different slope gradients and aspects in each of the three land use/cover classes. The results showed that the slope aspect significantly influenced the spatial distribution of SOC in the forest and vineyard soils, where N- and NW-facing soils had the highest level of organic carbon in the topsoil. There were no similar patterns in the uncultivated land. No significant differences were found in the subsoil. Organic carbon content was higher in the topsoil, regardless of the slope of the terrain. The mean SOC content in forest land decreased with increasing slope, but the difference was not statistically significant. In vineyards and uncultivated land, the SOC content was not predominantly determined by the slope gradient. No significant variations across slope gradients were found for all observed soil properties, except for available phosphorus and potassium. A positive correlation was observed between SOC and total nitrogen, clay, silt, and available phosphorus and potassium, while a negative correlation with coarse sand was detected. The slope aspect in relation to different land use/cover classes could provide an important reference for land management strategies in light of sustainable development.

Sign in / Sign up

Export Citation Format

Share Document