Benthic Meiofaunal Diversity in Four Zones of Pichavaram Mangrove Forest, India

ABSTRACT The community structure of meiofauna was assessed relative to environmental parameters in four zones (non-mangrove, Avicennia zone, mixed zone, and Rhizophora zone) of Pichavaram Mangrove Forest, which is located along the southeast coast of India. Field sampling was carried out from June 2016–May 2017. The meiofaunal data were evaluated using univariate and multivariate statistics. The highest abundance of meiofauna (434 ind/10 cm−2) was recorded in the Rhizophora zone and the lowest (270 ind/10 cm−2) in the non-mangrove zone. A total of 62 species representing four meiofaunal groups were recorded, including 38 species of foraminifera, 12 species of nematodes, seven species of ostracods, and five species of harpacticoids. Diversity (Shannon H′) mostly ranged from 3–4, and was highest (3.86±0.26) in the Avicennia zone and averaged ∼3.3 in the other three zones. The Margalef richness index was ∼6 in the Avicennia and Rhizophora zones and ∼5 in the non-mangrove and mixed zones. The BIO-ENV and CCA analyses identified sediment texture and organic matter as key variables influencing the distribution of meiofauna, while % calcium carbonate, salinity, and sediment pH were also important. Monitoring studies of meiofaunal taxa may help elucidate their roles in coastal blue-carbon cycling and will also contribute to understanding how mangrove-associated habitats influence meiofaunal distributions.

Marine-Sediment Characteristics and Thickness Over The Eroded Sayung Coast, Demak, Indonesia

An over whelming erosion occurred in Sayung waters is related to sedimentary processes. That is why the deeper determination of sediment characteristics through direct survey and acoustic data retrieval is crucial. Several previous related studies had been conducted revealing the rate and model of sedimentation. This study aimed to describe the sedimentary processes according to its features and deposition. In this study, we conducted a grab-sampling, bathymetry surveys and also hydrodynamical model. Grain size analysis was employed to observe the characteristics of sediment and its deposition environment. At the same time, we applied dual-frequency bathymetry data for estimating sediment thickness which reflects the accumulation sediment over Sayung waters. We found that sediment texture varies from sand to clay, while coarse sediment fraction is dominant in the western part. Near the coastline area of Sayung waters reflecting the more potent transport mechanism in the deposition environment, proven by the less-accumulated sediment from 0-2.5 km from the coastline. In sea-ward regions, we observed the finer sediment fraction, showing that the low-transport mechanism takes place. The topographical alteration has intensively occurred at 2.5-3.2 km from the coastline. Tidal current has an essential role in inducing local transport whereby the speed varies ranging from 0-0.14 m/s, other than that, the more substantial current features have observed in Surodadi and Bedono coast moving perpendicularly toward the beach. In contrast, in the southern Sayung waters, the current profiles tend to be weak inducing higher sedimentation. Besides, the emergence of the sandbar has a role in reflecting sediment texture predomination in Sayung waters.

Identifying Changes in Sediment Texture along an Ephemeral Gravel-Bed Stream Using Electrical Resistivity Tomography 2D and 3D

Differences in deposit geometry and texture with depth along ephemeral gravel-bed streams strongly reflect fluctuations in bedload which are due to environmental changes at the basin scale and to morphological channel adjustments. This study combines electrical resistivity tomography (ERT) with datasets from borehole logs to analyse the internal geometry of channel cross-sections in a gravel-bed ephemeral stream (southeast Spain). The survey was performed through longitudinal and transverse profiles in the upper channel stretch, of 14 to 30 m in length and 3 to 6 m in depth, approximately. ERT values were correlated with data on sediment texture as grain size distribution, effective grain sizes, sorting, and particle shape (Zingg’s classification). The alluvial channel-fills showed the superposition of four layers with uneven thickness and arrangement: (1) the softer rocky substrate (<1000 Ω.m); (2) a thicker intermediate layer (1000 to 2000 Ω.m); and (3) an upper set composed of coarse gravel and supported matrix, ranging above 2000 Ω.m, and a narrow subsurface layer, which is the most resistive (>5000 Ω.m), corresponding to the most recent armoured deposits (gravel and pebbles). The ERT results coupled with borehole data allowed for determining the horizontal and vertical behaviour of the materials in a 3D model, facilitating the layer identification.

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.

Distribusi Vertikal Logam Pb, Zn, Cr dan Keterkaitannya Terhadap Karbon Organik Sedimen di Pantai Marunda, Jakarta

Pantai Marunda terletak di Teluk Jakarta dan berdekatan dengan muara Sungai Tiram. Kegiatan antropogenik di sekitar Pantai Marunda sangat tinggi, sehingga dapat menyumbang limbah yang mengandung logam berat Pb, Zn dan Cr. Limbah logam berat yang terakumulasi dalam perairan, akan mengendap dalam sedimen dan seiring berjalannya waktu akan mengalami peningkatan. Tujuan dari penelitian ini, untuk mengetahui konsentrasi Pb, Zn, dan Cr berdasarkan kedalaman vertikal, hubungannya dengan karbon organik total (KOT) dan ukuran butir sedimen di Pantai Marunda. Sampel sedimen diambil menggunakan polietylen sediment core dan dipisahkan berdasarkan kedalamannya (1-3 cm, 4-6 cm, dan 7-9 cm). Logam berat dalam sedimen dianalisis menggunakan metode destruksi asam dan diukur nilai absorbansinya menggunakan AAS, karbon organik total menggunakan metode loss of ignition (LOI) dan analisa tekstur sedimen dengan metode pengayakan dilanjutkan pemipetan. Hasil menunjukkan bahwa konsentrasi rerata logam berat Pb, Zn, Cr secara berurutan pada lapisan atas sebesar 5,14; 107,19; dan 12,79 ppm, lapisan tengah sebesar 4,41; 100,20; 12,28 ppm serta lapisan bawah sebesar 4,8; 101,30; 14,10 ppm. Logam berat Zn dan Cr berkorelasi positif kuat terhadap KOT dan persentase lumpur, sedangkan terhadap Pb berkorelasi negatif. Hasil penelitian ini menggambarkan bahwa distribusi logam berat Pb, Zn dan Cr secara vertikal menunjukkan konsentrasi tinggi pada lapisan permukaan yaitu pada kedalaman sedimen 1-3 cm dan keberadaanya ditentukan oleh konsesntrasi KOT dan fraksi sedimen jenis lumpur. The Marunda Beach is located on the Jakarta Bay and adjacent to the mouth of the Tiram River. Anthropogenic activity around Marunda Beach is very high, so it can contribute the heavy metals such as Pb, Zn and Cr. The heavy metal will accumulate in the sediment and over time will be increase. The purpose of this study was to determine the vertical distribution of Pb, Zn, Cr, and their relationship to total organic carbon (TOC) and the grain size. Sediment samples were taken using polyethylene cores and this sample separated based on their depth (1-3 cm, 4-6 cm, and 7-9 cm). The heavy metals were analyzed using acid destruction and absorbance values were measured using AAS, TOC using the loss of ignition (LOI) and sediment texture with a sifting method, followed by pipetting. The results showed that the average concentration of Pb, Zn, Cr in the upper layer was 5.14; 107.19; 12.79 ppm, in the middle layer of 4.41; 100.20; 12.28 ppm and in the lower layer 4.8; 101.30; 14.10 ppm, respectively. Zn and Cr are strongly positively correlated to TOC and mud, and vice versa, the relationship to Pb is negative. The results of this study found that the vertical distribution of Pb, Zn and Cr was high in the surface layer (1-3 cm) and their presence was determined by TOC concentration and mud fraction.

Habitat Preferences of PokeA (Batissa violacea var. celebensis von Martens, 1897) Basic on Substrat Characterisation in Pohara River Southeast Sulawesi

This research is motivated by the lack of information about the habitat preferences of pokea clams in Pohara River, Southeast Sulawesi. This study aims to determine the density, distribution pattern and habitat preferences of pokea clams in the Pohara River, Southeast Sulawesi. This research was conducted for 6 months (April-September 2011). Sampling of pokea, water quality, and sediment texture was carried out in the Pohara River and analyzed at the FPIK UHO Laboratory. The density and distribution of pokea were calculated using a standard formula and analyzed using Mann Whitney and Chi Square respectively, while the habitat preferences based on different substrate textures were analyzed using Principal Component Analysis (PCA) and Cluster Analysis (CA) in the Multivariate Statistical Package (MVSP). The results showed that the density of pokea clams ranged from 117±96.78-816±594.84 ind/m2 which was distributed in cluster over the entire cross-section of the river. Pokea clams were found in all substrate textures from gravel to clay. The habitat preference of pokea clams indicated by the highest density was found in the clay texture. Pokea clams relatively do not like the habitat of coarse sand and gravel texture which is characterized by pokea population with the lowest density

A STUDY OF AQUATIC OLIGOCHAETES COMMUNITY IN THE UPPER PART OF AL- ABBASYIA RIVER / MIDDIE OF IRAQ

In the current study aquatic oligochaetes worms were collected monthly from five sites along AL- Abbasyia river / Al-Najaf province, South Iraq for a period between February 2018 to January 2019. Physical and chemical parameters for river water were examined which include: Air and Water temperature, pH ,Electrical conductivity ,Salinity, Dissolved oxygen , Biological oxygen demand and Sediment texture. The results showed a number of 5039 individuals of aquatic Oligochaeta were identified as three families Naididae ,Lumbriculdae and Enchytraaeidae .Tow species of Naididae Allonais pectinata (Stephenson, 1910) and Dero (Dero) dorsalis Forroniere, 1899 are considered as a new records in Euphrates River . Results showed the site S4 was highest number of worms site, 1323 worms of 17 species were found, while the lowest number of 579 individuals of 11 species were recorded in S2. J-card index for similarity showed that the highest similarity was between site S2 and site S3. Temporally, the highest individual numbers were recorded during September, while in April the lowest individual's number was recorded.