SEDIMENTATION VELOCITY OF POLLEN PARTICLES OF ANEMOPHILIC PLANTS GROWING ON TERRITORY OF THE CSBG SB RAS

The settling of pollen particles of four species of anemophilic plants ( Populus alba L., Salix hybrida , Miscanthus sinensis Andersson, Chosenia arbutifolia (Pall.) A. K. Skvortsov) growing in the exposition of the CSBS SB RAS was investigated. These species are widely used in landscaping cities of the Novosibirsk region and are producers of impressive amounts of allergenic pollen, which can be carried by the wind over significant distances. The presence of a significant proportion of clusters, which include two or more pollen grains, is shown. Settling rates were determined as individual pollen grains of these plant species and their clusters, which included from two to six pollen grains. Dependence of cluster sedimentation rate on number of pollen grains included in it is established.

A novel approach to investigate the deposition of (bio)chemical sediments: The sedimentation velocity of cyanobacteria–ferrihydrite aggregates

ABSTRACT Sedimentation velocities of various chemical sediments are typically calculated using Stokes's law. However, applying it to chemical sediments that form in situ in the water column is not ideal because the particle properties do not fulfill many of the assumptions underpinning the applicability of Stokes' law. As a consequence, it has been difficult to predict the sedimentation rate of ancient chemical sediments, such as Precambrian banded iron formations (BIF), because their primary sediments likely comprised aggregates of ferric hydroxides, such as ferrihydrite [Fe(OH)3], and marine bacterial biomass, including cyanobacteria. In this work we use a new experimental method to address the mechanisms by which primary BIF sediment, formed by the oxidation of dissolved Fe(II) by O2 and simultaneously incubated with cyanobacterium Synechococcus sp., were deposited to the Archean ocean. Specifically, we formed the aggregates in situ over a wide range of initial pH and Fe(II) concentrations, continuously recorded the entire settling processes of aggregates under each condition, and then processed the data in MATLAB according to different settling mechanisms. Our results demonstrate that ferrihydrite–cyanobacteria aggregates settled to the ocean floor either through the formation of uniformly descending concentration fronts or through convective plumes. The sedimentation mechanism depended on both initial Fe(II) concentration and the pH. Correspondingly, two algorithms were developed to characterize the sedimentation velocity. These algorithms tracked the alteration of light intensity from low to high as sediments descended from an initially homogeneous state through a water tank, and as well calculated the average light intensity over time, from which vertical time series were constructed allowing calculation of the sedimentation velocity. Our method not only provides an accurate estimation of the in situ sedimentation velocity of cell–mineral aggregates, but also provides new insights into the physical mechanisms by which the primary sediments composing BIF were deposited.

Quantifying the concentration dependence of sedimentation coefficients for globular macromolecules: a continuing age-old problem

This retrospective investigation has established that the early theoretical attempts to directly incorporate the consequences of radial dilution into expressions for variation of the sedimentation coefficient as a function of the loading concentration in sedimentation velocity experiments require concentration distributions exhibiting far greater precision than that achieved by the optical systems of past and current analytical ultracentrifuges. In terms of current methods of sedimentation coefficient measurement, until such improvement is made, the simplest procedure for quantifying linear s-c dependence (or linear concentration dependence of 1/s) for dilute systems therefore entails consideration of the sedimentation coefficient obtained by standard c(s), g*(s) or G(s) analysis) as an average parameter ($$ \overline{s} $$ s ¯ ) that pertains to the corresponding mean plateau concentration (following radial dilution) ($$ \overline{c} $$ c ¯ ) over the range of sedimentation velocity distributions used for the determination of $$ \overline{s} $$ s ¯ . The relation of this with current descriptions of the concentration dependence of the sedimentation and translational diffusion coefficients is considered, together with a suggestion for the necessary improvement in the optical system.

Kajian Karakteristik Sedimen Dasar di Perairan Sungailiat untuk Mendukung Pengembangan Pelabuhan Perikanan Nusantara Sungailiat, Kab. Bangka

Tingkat sedimentasi di muara S. Jelitik sangat tinggi sehingga ketika air laut surut, kapal-kapal tidak dapat keluar masuk ke Pelabuhan Perikanan Nusantara (PPN) Sungailiat. Untuk menangani masalah tersebut, pemerintah secara periodik melakukan pengerukan yang berbiaya tinggi. Oleh karena itu, Pemprov Bangka Belitung merencanakan membangun infrastruktur pengendali sedimen. Dalam perencanaan infrastruktur pengendali sedimen diperlukan data-data karakteristik sedimen dasar. Saat ini kajian khusus karateristik sedimen dasar di kawasan ini masih belum ada. [A1] Oleh karena itu dilakukan kajian ini dengan tujuan mengetahui pola sebaran karakteristik sedimen dasar seperti berat jenis, tekstur sedimen, ukuran d50 butir sedimen dan analisis stastik sedimen dasar. Karakteristik ini sangat penting untuk kajian sedimentasi selanjutnya terutama sebagai data masukan perhitungan kecepatan sedimentasi baik secara analitik maupun dengan pemodelan numerik. Metode yang digunakan dalam kajian ini adalah survei lapangan, pengambilan sampel sedimen dasar, analisis laboratorium dan analisis statistik sedimen. Berdasarkan kajian ini sedimen dasar di perairan Sungailiat ini didominasi oleh pasir sedikit campuran kerikil dengan nilai d50 berkisar antar 1-1,5 mm dan terpilah buruk. Kondisi sedimen dasar berupa pasir mempunyai daya dukung yang baik untuk pengembangan pelabuhan.Sedimentation in the S Jelitik estuary is very high, so when the tide is low, the ships traffic at the Sungailiat Fisheries Port is disturbed. So far, dredging has been done to solve this problem, which requires high costs. To overcome this, the Provincial Government of Bangka Belitung plans to build a sediment control infrastructure. In planning the sediment control infrastructure, sea bottom sediment characteristics data are needed. Currently, there is no specific study of se bottom sediment characteristics in this area. Therefore, this study was conducted with the aim of knowing the distribution pattern of seabottom sediment characteristics such as density, sediment texture, d50 grain size and analysis of the basic sediment statistics. This characteristic is very important for further sedimentation studies, especially as input data for calculating the sedimentation velocity both analytically and by numerical modeling. The methods used in this study are field surveys, sediment sampling, laboratory analysis and sediment statistical analysis. Based on this study, the seabottom sediment in Sungailiat waters is dominated by sand, a little mixture of gravel, with d50 values ranging from 1-1.5 mm and poorly segregated. The seabottom sediment in the form of sand have good capacity for port development.