Artykuły w czasopismach na temat „Mudcrabs”
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Sunarto, Sulistiono i Isdradjad Setyobudiandi. "HUBUNGAN JENIS KEPITING BAKAU (Scylla Spp.) DENGAN MANGROVE DAN SUBSTRAT DI TAMBAK SILVOFISHERY ERETAN, INDRAMAYU (Relationship of Mudcrab (Scylla Spp.) with Mangrove and Substrate in Silvofishery Ponds, Eretan, Indramayu)". Marine Fisheries : Journal of Marine Fisheries Technology and Management 6, nr 1 (30.09.2016): 59. http://dx.doi.org/10.29244/jmf.6.1.59-68.
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<p>ABSTRACT<br />Mudcrab is one of the fishery commodity with high economic value in Indonesia. High market and price stimulated the development of the mudcrabs business in this country. The aim of this research was to evaluate interaction between habitat characteristics and the mudcrabs (Scylla spp.) species. The research was conducted in silvofishery ponds of Eretan village, Indramayu, West Java from September-November 2013 and August-September 2014. Sampling was conducted at five stations. They were BDR (Brackishwater dominated Rhizophora sp.), BDA (Brackishwater dominated Avicennia sp.), BCDR (Brackishwater cannal dominated Rhizopora sp.), BCDA (Brackishwater cannal dominated Avicennia sp.) and SMF (Side of the mangrove forest). The result showed there were two species of the mudcrabs Scylla paramamosain and Scylla olivacea. S. paramamosain was dominated than S. olivacea at all stations. Total number of the S. paramamosain was 107 ind (consisted of 67 male and 40 female), while total number of the S. olivacea was 28 ind (consisted of 17 male and 11 female). Composition of the mudcrabs species in each station was 91% S. paramamosain and 9% S. olivacea at BDR, 89% S. paramamosain and 11% S. olivacea at BDA, 86% S. paramamosain and 14% S. olivacea at BCDR, 68% S. paramamosain and 32% S. olivacea at BCDA, 73% S. paramamosain and 27% S. olivacea at SMF. Differences between kinds of mudcrab in each stations showed there are interaction between kinds of mudcrabs with habitat characteristics.</p><p><br />Keywords: Indramayu, mangrove, mudcrabs, substrate,</p><p>-------</p><p>ABSTRAK</p><p>Kepiting bakau (Scylla spp.) merupakan salah satu komoditas perikanan di Indonesia yang bernilai ekonomis tinggi. Luasnya pemasaran dan tingginya nilai jual kepiting bakau membuat bisnis tersebut semakin berkembang. Penelitian ini bertujuan untuk mengetahui hubungan keberadaan jenis kepiting bakau dengan karakteristik habitatnya. Penelitian ini dilakukan dari Agustus-November 2013 dan Agustus-September 2014 pada kawasan tambak silvofishery Desa Eretan, Indramayu, Jawa Barat. Pengambilan sampel dilakukan pada lima stasiun pengamatan diantaranya TSDR (Tambak silvofishery dominan Rhizopora sp.), TSDA (Tambak silvofishery dominan Avicennia sp.), KDR (Kanal dominan Rhizopora sp.), KDA (Kanal dominan Avicennia sp.) dan PHM (Pinggiran hutan mangrove). Hasil penelitian ini menunjukkan bahwa terdapat dua jenis kepiting bakau yaitu Scylla paramamosain dan S. olivacea. Di lokasi penelitian jumlah Scylla paramamosain yang tertangkap sebanyak 107 individu yang terdiri dari 67 jantan dan 40 betina, sedangkan jumlah S. olivacea yang tertangkap sebanyak 28 individu yang terdiri atas 17 jantan dan 11 betina. Hasil penelitian menunjukkan pada umumnya jumlah S. paramamosain yang tertangkap melebihi S. olivacea. Persentase kepiting bakau yang tertangkap pada tiap stasiun pengamatan yaitu 91% S. paramamosain dan 9% S. olivacea pada TSDR, 89% S. paramamosain dan 11% S. olivacea pada TSDA, 86% S. paramamosain dan 14% S. olivacea pada KDR, 68% S. paramamosain dan 32% S. olivacea pada KDA, 73% S. paramamosain dan 27% S. olivacea pada PHM. Perbedaan jumlah jenis kepiting bakau yang diperoleh pada tiap stasiun penangkapan menunjukan bahwa terdapat hubungan antara jenis kepiting bakau dengan habitat hidupnya.</p><p><br />Kata kunci: Indramayu, mangrove, kepiting bakau, substrat,</p>
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Poonon, Sheila C., i Hazel E. Soliven. "Supply Chain Improvement of Mud crab Industry in Northern Mindanao, Philippines". International Journal of Applied Science and Research 05, nr 04 (2022): 168–76. http://dx.doi.org/10.56293/ijasr.2022.5419.
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The study was conducted to assess the existing supply chain for mudcrab in Region 10 and to identify areas for improvement. The study covered major mudcrab producing areas in Region 10. Reconnaissance survey, courtesy calls and visits to the Local Government Units, Bureau of Fisheries and Aquatic Resources, and Department of Agriculture Offices in the mudcrab producing areas were done to identify the study sites. Results revealed that almost half (49.42%) of the mudcrab production in the country is from Region 10 which were majority caught/sourced from Panguil Bay. There are four specific supply chains traced. Computation of the marketing cost and margin for each key player revealed that the profit margin is higher towards downstream key players (traders). Also, the shorter the supply chain the more equitable distribution of income is observed. There is no face to face interaction between the local traders and the metro manila traders which resulted to information asymmetry. Some of the issues included mortality of mudcrabs during transport, price fluctuation, opportunistic behavior of the fisherman, and political intervention. Finally, common perception of the interviewed respondents pointed out that mudcrab supply is decreasing in Region 10. Therefore, the need for further intervention project on the production technology/ reinforcement of mudcrab industry should be done.
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Chowdhury, Abdullah Harun, i Md Ali Akber. "Study Of Impacts Of Oil Spill On The Sundarbans Mangrove Forest Of Bangladesh". Journal of the Asiatic Society of Bangladesh, Science 41, nr 1 (16.06.2015): 75–94. http://dx.doi.org/10.3329/jasbs.v41i1.46193.
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Studies were carried out on the recent oil spill in the Sundarbans of Bangladesh to findout the immediate impacts on the ecosystem of the Sundarbans after oil spilling. Morethan 500 km2 areas out of the total study area have been affected seriously by the oil spillcontamination on 9 December 2014. Recorded data of the physico-chemical conditions,oil content, productivity, diversity and abundance of phyto-zooplankton and benthos ofwater, and oil content in soil indicate that the water and soil of the Eastern part of theSundarbans were polluted by the oil contamination. Results also indicate that seedlings,mangrove algae, eggs and hatchlings of commercially valuable fishes, mudskippers, mudcrabs, snails, monitor lizards were affected due to oil spill. Regeneration of the Sundritrees; intertidal zone bird - ‘Masked finfoot’, common birds, fishing cat, otter, dolphins,crocodile would be affected due to the oil spill. Long term monitoring, in depth researchand proper implementation of all rules and regulations are necessary to save the fragileecosystem of the Sundarbans-the UNESCO declared world heritage site.
Asiat. Soc. Bangladesh, Sci. 41(1): 75-94, June 2015
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Pestrong, Ray. "Making Mudcracks". Journal of Geoscience Education 48, nr 5 (listopad 2000): 577. http://dx.doi.org/10.5408/1089-9995-48.5.577b.
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Matsubara, Hitoshi, Kosaburo Hirose, Taka-aki Edo, Kei-ichi Tamanaha, Hisao Hara i Tomonori Yamada. "Numerical modelling of mudcrack growth". Japanese Geotechnical Society Special Publication 2, nr 31 (2016): 1143–47. http://dx.doi.org/10.3208/jgssp.atc1-3-17.
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Nurussalam, Wildan, Kukuh Nirmala, Eddy Supriyono i Yuni Puji Hastuti. "The frequency of calcium and magnesium differences in recirculation systems for increasing production of mudcrab Scylla serrata seed". Jurnal Akuakultur Indonesia 16, nr 2 (1.07.2017): 144. http://dx.doi.org/10.19027/jai.16.2.144-153.
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<p><strong>ABSTRACT</strong></p><p>Molting phase is one of many factors that can inhibit mudcrab growth. Recirculation system in culturing mudcrab has a weakness which is the decreasing of ions. Calcium and magnesium in the water can affect the molting phase. The aim of this study was to evaluate the best additional frequency of calcium and magnesium in recirculation system. This research used mudcrab seeds that have weight of 54.856±2.195 gram. This research used completely randomized design with four treatments and three replicates. The treatments were additional frequency of Ca and Mg, comprised of four levels, without additional Ca and Mg (A), additional 30 mg/L Ca and 30 mg/L Mg in every five days (B), additional 30 mg/L Ca, and 30 mg/L Mg in every 10 days (C), and additional 30 mg/L Ca and 30 mg/L Mg in every 15 days (D). The result showed that total of biomass in every treatments were A (379.99±86.16 gram), B (517.65±103.94 gram), C (808.68±59.29 gram), and D (1,054.41±73.54 gram). The highest final biomass was the D treatment (1,054,41±73.54), which was significantly different to others (P<0.05).</p><p>Keywords: mudcrab, resirculation, calcium, magnesium, molting, production</p><p> </p><p> </p><p><strong>ABSTRAK</strong></p><p>Salah satu faktor penghambat pertumbuhan kepiting bakau adalah fase molting. Sistem resirkulasi budidaya kepiting bakau memiliki kelemahan yaitu berkurangnya ion-ion. Fase moting pada kepiting bakau sangat dipengaruhi oleh keberadaan ion kalsium dan magnesium dalam air. Penelitian ini bertujuan untuk menentukan frekuensi waktu penambahan kalsium dan magnesium terbaik dalam sistem resirkulasi. Penelitian ini menggunakan benih kepiting bakau dengan berat rata-rata 54,856±2,195 gram. Penelitian ini menggunakan rancangan acak lengkap (RAL) dengan empat perlakuan dan tiga ulangan. Perlakuan penambahan Ca dan Mg sebanyak 30 mg/L terdiri atas empat macam frekuensi, yaitu tanpa penambahan Ca dan Mg (A), frekuensi lima hari sekali (B), frekuensi 10 hari sekali (C), dan frekuensi 15 hari sekali (D). Hasil penelitian menunjukkan jumlah biomassa masing-masing perlakuan adalah A (379,99±86,16 gram), B (517,65±103,94 gram), C (808,68±59,29 gram), dan D (1.054,41±73,54 gram). Perlakuan terbaik diperoleh pada perlakuan D dengan jumlah biomassa sebesar (1.054,41±73,54 gram) ini berbeda nyata (P<0,05) dengan perlakuan lainnya.<br /> <br />Kata kunci: kepiting bakau, resirkulasi, kalsium, magnesium, molting, produksi</p>
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Nurussalam, Wildan, Kukuh Nirmala, Eddy Supriyono i Yuni Puji Hastuti. "The frequency of calcium and magnesium differences in recirculation systems for increasing production of mudcrab Scylla serrata seed". Jurnal Akuakultur Indonesia 16, nr 2 (1.07.2017): 155. http://dx.doi.org/10.19027/jai.16.2.155-164.
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<p>ABSTRACT</p><p>Molting phase is one of many factors that can inhibit mudcrab growth. Recirculation system in culturing mudcrab has a weakness which is the decreasing of ions. Calcium and magnesium in the water can affect the molting phase. The aim of this study was to evaluate the best additional frequency of calcium and magnesium in recirculation system. This research used mudcrab seeds that have weight of 54.856±2.195 gram. This research used completely randomized design with four treatments and three replicates. The treatments were additional frequency of Ca and Mg, comprised of four levels, without additional Ca and Mg (A), additional 30 mg/L Ca and 30 mg/L Mg in every five days (B), additional 30 mg/L Ca, and 30 mg/L Mg in every 10 days (C), and additional 30 mg/L Ca and 30 mg/L Mg in every 15 days (D). The result showed that total of biomass in every treatments were A (379.99±86.16 gram), B (517.65±103.94 gram), C (808.68±59.29 gram), and D (1,054.41±73.54 gram). The highest final biomass was the D treatment (1,054,41±73.54), which was significantly different to others (P<0.05).</p><p>Keywords: mudcrab, resirculation, calcium, magnesium, molting, production</p><p>ABSTRAK</p><p>Salah satu faktor penghambat pertumbuhan kepiting bakau adalah fase molting. Sistem resirkulasi budidaya kepiting bakau memiliki kelemahan yaitu berkurangnya ion-ion. Fase moting pada kepiting bakau sangat dipengaruhi oleh keberadaan ion kalsium dan magnesium dalam air. Penelitian ini bertujuan untuk menentukan frekuensi waktu penambahan kalsium dan magnesium terbaik dalam sistem resirkulasi. Penelitian ini menggunakan benih kepiting bakau dengan berat rata-rata 54,856±2,195 gram. Penelitian ini menggunakan rancangan acak lengkap (RAL) dengan empat perlakuan dan tiga ulangan. Perlakuan penambahan Ca dan Mg sebanyak 30 mg/L terdiri atas empat macam frekuensi, yaitu tanpa penambahan Ca dan Mg (A), frekuensi lima hari sekali (B), frekuensi 10 hari sekali (C), dan frekuensi 15 hari sekali (D). Hasil penelitian menunjukkan jumlah biomassa masing-masing perlakuan adalah A (379,99±86,16 gram), B (517,65±103,94 gram), C (808,68±59,29 gram), dan D (1.054,41±73,54 gram). Perlakuan terbaik diperoleh pada perlakuan D dengan jumlah biomassa sebesar (1.054,41±73,54 gram) ini berbeda nyata (P<0,05) dengan perlakuan lainnya.<br /> <br />Kata kunci: kepiting bakau, resirkulasi, kalsium, magnesium, molting, produksi</p>
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Agbayani, Renato F., Dan D. Baliao, Giselle P. B. Samonte, Reuel E. Tumaliuan i Romeo D. Caturao. "Economic feasibility analysis of the monoculture of mudcrab (Scylla serrata) Forsskal". Aquaculture 91, nr 3-4 (grudzień 1990): 223–31. http://dx.doi.org/10.1016/0044-8486(90)90190-x.
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Syafaat, Muhammad Nur, i Gunarto Gunarto. "BUDIDAYA PEMBESARAN KEPITING BAKAU Scylla tranquebarica (Fabricius, 1798) HASIL PEMBENIHAN PADA LOKASI TAMBAK YANG BERBEDA". Media Akuakultur 13, nr 1 (10.08.2018): 21. http://dx.doi.org/10.15578/ma.13.1.2018.21-30.
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Kegiatan pembesaran kepiting bakau hasil pembenihan di tambak masih terbatas dan pada umumnya masih merupakan kegiatan penelitian. Tujuan penelitian ini adalah untuk mengetahui pertumbuhan, sintasan, produksi, dan membuat analisis usaha pembesaran krablet kepiting bakau hasil pembenihan pada beberapa lokasi tambak tradisional. Penelitian dilakukan di tiga lokasi tambak yaitu Maros, Pangkep, dan Polewali Mandar (Polman). Tambak yang digunakan pada setiap lokasi merupakan tambak tradisional berkonstruksi tanah dengan sistem penggantian air berdasarkan pasang surut. Krablet kepiting bakau dengan kisaran bobot 0,05-0,1 g/ekor ditebar dengan kepadatan 0,24 ekor/m2 dan 0,27 ekor/m2 untuk Kabupaten Pangkep dan Polman secara berurutan sedangkan pada Kabupaten Maros dengan kepadatan 0,53 ekor/m2. Jenis pakan yang diberikan yaitu ikan rucah atau ikan liar yang ada di sekitar lokasi tambak dengan dosis 5%-10% dari biomassa dan diberikan dua atau tiga hari sekali. Hasil penelitian menunjukkan bahwa pertumbuhan kepiting bakau di tiga lokasi pada bulan ketiga diperoleh bobot akhir rata-rata dengan kisaran 131,05-199,50 g/ekor (163,17 ± 34,42); sintasan 22%-36,94% (30,41 ± 7,65); dan produksi 79,25-272,12 kg/ha (176,07 ± 96,43). Keuntungan tertinggi diperoleh pada lokasi Maros yaitu Rp5.454.750,00/ha/siklus dan terendah di lokasi Polman yaitu Rp317.150,00/ha/siklus. Nilai R/C rasio untuk semua lokasi menunjukkan lebih besar dari satu yang berarti bahwa usaha pembesaran kepiting bakau di tambak menggunakan krablet asal hatchery merupakan usaha yang layak. Ketersediaan pakan yang cukup, keberadaan shelter, pergantian air secara rutin dan kondisi kualitas air yang optimal merupakan faktor penting yang perlu diperhatikan untuk meningkatkan produksi pada ketiga lokasi di samping meningkatkan kepadatan sampai 1 ekor/m2.The grow-out cultures of hatchery-produced mudcrab seed in pond are rare and mostly part of research activities. The purpose of this study was to determine the performance of growth, survival rate, production, and develop a business analysis of mudcrab (S. tranquebarica) grow-out culture in different pond locations using hatchery-reared seed. The study was conducted in three pond areas in Maros, Pangkep, and Polewali Mandar (Polman). The ponds used in each location were traditional soil ponds with sufficient tidal system for water exchange. Crablets with a weight range of 0.05-0.1 g were reared in the ponds located in Pangkep, Polman and Maros with stocking densities of 0.24, 0.27 and 0.53 ind./m2, respectively. The feed used was trash fish or locally caught wild fish and given 5%-10% of the total crab biomass once every two or three days. The results showed that the average final weight of mudcrab in the three locations during three months rearing period was 131.05-199.50 g/ind. (163.17 ± 34.42) with survival rates of 22%-36.94% (30.41 ± 7.65), and crab production of 79.25-272.12 kg/ha (176.07 ± 96.43). The highest profit was obtained by grow-out culture in Maros location (IDR 5,454,750/ha/cycle) followed by Pangkep location (IDR 4,624,400/ha/cycle) and the lowest at Polman location (IDR 317,150/ha/cycle). The R/C ratio for all locations was greater than one which means that mudcrab culture in pond using seed from hatchery is economically feasibility.
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Suherman, Sutianto Pratama, Rahmatiya Marjan i Arafik Lamadi. "Octolasmic Octolasmis spp. parasite attack on mudcrab Scylla serrata in Tomini Bay". Tomini Journal of Aquatic Science 3, nr 2 (14.11.2022): 61–67. http://dx.doi.org/10.37905/tjas.v3i2.14179.
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The present study aimed to identify the Octolasmis spp. ectoparasite’s intensity and prevalence in mud crab in Pohuwato Regency. It employed survey and site observation methods with sampling technique of mud crabs in Pohuwato Regency. The research was carried out in three different sites: site 1 (Pohuwato Timur Village), site II (Bulili Village), and site III (Mootilango Village). The results showed that the parasites infesting mud crab in the three separate locations are Octolasmis angulata and Octolasmis cor. The highest intensity rate was at site III, which was dominated by Octolasmis cor. The prevalence of the parasite in sites I, II, and III was 60%, 40%, and 60% in consecutive order. Moreover, the parasite has a 100% and 46% prevalence in female and male crabs, respectively. The water quality indicator (involving temperature, pH level, and soluble oxygen) was at the appropriate rate for mud crab farming.
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Hirose, Kosaburo, i Hitoshi Matsubara. "Mechanisms of Mudcrack Formation and Growth in Bentonite Paste". Journal of Geotechnical and Geoenvironmental Engineering 144, nr 4 (kwiecień 2018): 04018017. http://dx.doi.org/10.1061/(asce)gt.1943-5606.0001853.
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Heasman, MP, DR Fielder i RK Shepherd. "Mating and spawning in the mudcrab, Scylla serrata (Forskaål) (Decapoda: Portunidae), in Moreton Bay, Queensland". Marine and Freshwater Research 36, nr 6 (1985): 773. http://dx.doi.org/10.1071/mf9850773.
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Mating activity in a southern Queensland population of S. serrata was at a maximum level in mid-spring and late summer-early autumn. Spawning activity, as indicated by the incidence of spent females, began early in spring and ended in early autumn while water temperatures exceeded approximately 22�C. Nevertheless, ovary condition was apparently held constant during the colder non-spawning half of the year. Ovary condition was not correlated with either ovary coloui or crab size.
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Shyne Anand, Panantharayil Sudhayam, Changaramkumarth Paran Balasubramanian, Christina Lalramchhani, Akshaya Panigrahi, Chavali Gopal, Tapas Kumar Ghoshal i Koyadan Kizhakedath Vijayan. "Comparison of mudcrab-based brackishwater polyculture systems with different finfish species combinations in Sundarban, India". Aquaculture Research 49, nr 9 (12.07.2018): 2965–76. http://dx.doi.org/10.1111/are.13755.
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Saha, Sanjib, Mitali Ray i Sajal Ray. "Behavioural shift of estuarine mudcrab as biomarker of arsenic exposure in Sundarbans estuary of West Bengal". Journal of Applied and Natural Science 2, nr 2 (1.12.2010): 258–62. http://dx.doi.org/10.31018/jans.v2i2.131.
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Mudcrab Scylla serrata (Crustacea: Decapoda) in an ecologically and economically important species of Sundarbans Biosphere Reserve was studied for its behaviour under the exposure of toxic arsenic - a common xenobiotic of this area. The behavioural profile of aquatic animals exposed to diverse toxicants are considered as an index to estimate the degree and nature of stress experienced by the animals both in nature and in experimental conditions. Present investigation involved study of selected behavioural shift of S. serrata under the sublethalconcentrations of 1, 2 and 3 ppm of sodium arsenite for 1, 2, 3 and 4 days in controlled laboratory condition. Exposure to arsenic resulted an appearance of selected abnormal behavioural manifestation including tendency of avoidance, hypersecretion of mucoid element and release of excess excretory products. Toxin induced alteration of studied behaviour is indicative to possible shift in the overall physiological functions and biological activities of this important species in its natural habitat. Chronic exposure to 3 ppm of sodium arsenite for 30 days may lead to decline this economically important species in Sundarbans Biosphere Reserve.
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Gopurenko, D., J. M. Hughes i C. P. Keenan. "Mitochondrial DNA evidence for rapid colonisation of the Indo-West Pacific by the mudcrab Scylla serrata". Marine Biology 134, nr 2 (7.07.1999): 227–33. http://dx.doi.org/10.1007/s002270050541.
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Yang, Ci-Jian, Chia-Hung Jen, Yeuan-Chang Cheng i Jiun-Chuan Lin. "Quantification of mudcracks-driven erosion using terrestrial laser scanning in laboratory runoff experiment". Geomorphology 375 (luty 2021): 107527. http://dx.doi.org/10.1016/j.geomorph.2020.107527.
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Baticados, Didi B., Renato F. Agbayani i Emilia T. Quinitio. "Community-Based Technology Transfer in Rural Aquaculture: The Case of Mudcrab Scylla serrata Nursery in Ponds in Northern Samar, Central Philippines". AMBIO 43, nr 8 (10.05.2014): 1047–58. http://dx.doi.org/10.1007/s13280-014-0528-5.
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Hayes, Michael J. "Surficial Physical Sedimentary Structures of Bahia la Choya". Paleontological Society Special Publications 2 (1987): 52–61. http://dx.doi.org/10.1017/s247526220000472x.
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I observed and measured the orientations of common physical sedimentary structures on the beach and spit, estero, tidal channel, and inner and outer tidal flats of Bahia la Choya. The spit is characterized by wind ripples and the beach typically displays swash marks. Mudcracks typify the high marsh portions of the estero while the meandering estero channel contains ripples and megaripples. The inner and outer tidal flats are dominated by small, ebb-oriented, straight-crested to undulatory current ripples. The current ripples are often superimposed on flood-oriented ridges and runnels of the outer flat. Rill marks, tool marks, and current crescents occur sporadically. Ebb-oriented megaripples, small current ripples, and primary current lineations occur in the tidal channel.Ripple crests trend from N15E - N40E on the southern tidal flats to N10W - N20W on the northern flats. The crests roughly parallel the shoreline and are normal to tidal currents.
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Karim, Muhammad Yusri, Hasni Y. Azis i Muslimin Muslimin. "PERTUMBUHAN KEPITING BAKAU Scylla olivacea DENGAN RASIO JANTAN-BETINA BERBEDA YANG DIPELIHARA PADA KAWASAN MANGROVE". Jurnal Perikanan Universitas Gadjah Mada 18, nr 1 (20.03.2016): 1. http://dx.doi.org/10.22146/jfs.12593.
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Mudcrab fattening is potential to develop in mangrove areas. The aim of the present study was to determine the best ratio of male and female in fattening of mud crab in the mangrove area. Research was conducted in the mangrove areas of Pangkep Regency, South Sulawesi Province. Test animals used were mud crab S. olivacea male and female measuring weight of 250 ± 10 g and were stocked at a density of 10 animals/cage. The bamboo cages measuring length, width, and height of 1.0 x 1.0 x 1.0 m3 were placed in the mangrove areas. Feed used was trash fish at 10% of the biomass with the feeding frequency of two times a day ie morning (30%) and afternoon (70%). The study used a completely randomized design (CRD) consisting of 4 treatments and 3 replications. The ratio of male and female crabs were 7:3; 6:4; 5:5; 4:6 and 3:7 crabs/cage, respectively. Results of analysis of variance showed that the treatment with the different ratio of male and female was not significant (p> 0.05) on the survival rate of crab, but was highly significant (p <0.01) on the absolute and daily growth rate. The resulting survival rate ranges from 93.33 to 100%, absolute growth and the highest daily growth rate of crabs produced at a ratio of males and females (7:3) and (6:4) crabs/cage ie: 56.99 and 1.35; 56.25 g and 1.36%/day, while the lowest was in the ratio (3:7) crabs/cage ie: 28.97 g and 0.73%/day.
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Clark, Benton C., i Vera M. Kolb. "Macrobiont: Cradle for the Origin of Life and Creation of a Biosphere". Life 10, nr 11 (12.11.2020): 278. http://dx.doi.org/10.3390/life10110278.
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Although the cellular microorganism is the fundamental unit of biology, the origin of life (OoL) itself is unlikely to have occurred in a microscale environment. The macrobiont (MB) is the macro-scale setting where life originated. Guided by the methodologies of Systems Analysis, we focus on subaerial ponds of scale 3 to 300 m diameter. Within such ponds, there can be substantial heterogeneity, on the vertical, horizontal, and temporal scales, which enable multi-pot prebiotic chemical evolution. Pond size-sensitivities for several figures of merit are mathematically formulated, leading to the expectation that the optimum pond size for the OoL is intermediate, but biased toward smaller sizes. Sensitivities include relative access to nutrients, energy sources, and catalysts, as sourced from geological, atmospheric, hydrospheric, and astronomical contributors. Foreshores, especially with mudcracks, are identified as a favorable component for the success of the macrobiont. To bridge the gap between inanimate matter and a planetary-scale biosphere, five stages of evolution within the macrobiont are hypothesized: prebiotic chemistry → molecular replicator → protocell → macrobiont cell → colonizer cell. Comparison of ponds with other macrobionts, including hydrothermal and meteorite settings, allows a conclusion that more than one possible macrobiont locale could enable an OoL.
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Mertz Jr., Karl A., i John F. Hubert. "Cycles of sand-flat sandstone and playa–lacustrine mudstone in theTriassic–Jurassic Blomidon redbeds, Fundy rift basin, Nova Scotia: implications for tectonic and climatic controls". Canadian Journal of Earth Sciences 27, nr 3 (1.03.1990): 442–51. http://dx.doi.org/10.1139/e90-039.
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The redbeds of the 220 m Blomidon Formation comprise more than 100 pairs of (i) sand-flat sandstone (distal alluvial fan) and (ii) playa sandy mudstone and (or) lacustrine claystone. These pairs are tectonic autocycles generated by rift-basin subsidence and sagging along the Glooscap fault zone that shifted loci of active fan sedimentation toward and away from the playa surface as fan lobes migrated into topographically low areas.Intervals of intense and prolonged aridity are recorded in many of the sand-flat sandstones and playa sandy mudstones by evaporite minerals, principally gypsum, precipitated by subsurface evolution of a CaSO4–NaCl brine. Aridity is further demonstrated by intense disruption of sediment fabrics beneath evaporite crusts, deep mudcracks, eolian-sandstone layers and patches, and the presence of authigenic Ca–Mg-rich illite–smectite and analcime. During relatively wetter intervals, claystone beds accumulated in shallow lakes that filled the playa depression, lapping onto the sand flats. The claystones lack evaporite minerals and textures, and many are partially bioturbated.The long-term climate became progressively wetter from latest Triassic to earliest Jurassic time, as evidenced by an increase upsection in the ratio of lacustrine claystone to playa sandy mudstone and by less evaporite mineralization in the sand-flat sandstones.
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Brogly, P. J., I. P. Martini i G. V. Middleton. "The Queenston Formation: shale-dominated, mixed terrigenous-carbonate deposits of Upper Ordovician, semiarid, muddy shores in Ontario, Canada". Canadian Journal of Earth Sciences 35, nr 6 (1.06.1998): 702–19. http://dx.doi.org/10.1139/e98-021.
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The Upper Ordovician Queenston Formation constitutes the westernmost part of the Taconic clastic wedge of eastern North America. In Ontario, the Queenston Formation consists of a mixed terrigenous-carbonate succession composed primarily of red silty shales, which are locally gypsiferous, alternating, in the middle and lower parts of the formation, with thin grey shales, calcareous siltstone and sandstone, and bioclastic limestone. Brachiopods, some ostracodes, and, in the lower beds, bryozoans constitute the body fossil assemblage. Diplocraterion, Skolithos, Chondrites, and occasional large vertical burrows of unknown origin form the ichnofauna. Plane beds, ripple marks, and occasional swaley and hummocky cross-stratifications are present in the calcareous units. Mudcracks, gypsum nodules, occasional halite hopper casts, and gilgai-like structures typically occur in horizons where shales alternate with siltstone and limestone. These features are indicative of prograding muddy and storm- and tide-affected shores. In southernmost Ontario, the upper part of the formation is mostly composed of a red shale, with local recognizable shale-filled channels. This shale is of paralic origin, and it is truncated by the unconformity separating the Ordovician from the Silurian units in this region. This last event may, in part, be related to a eustatic sea-level drop due to the contemporaneous Saharan glaciation, if not exclusively due to tectonic movements.
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Pratt, Brian R., i Juan J. Ponce. "Sedimentation, earthquakes, and tsunamis in a shallow, muddy epeiric sea: Grinnell Formation (Belt Supergroup, ca. 1.45 Ga), western North America". GSA Bulletin 131, nr 9-10 (15.02.2019): 1411–39. http://dx.doi.org/10.1130/b35012.1.
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AbstractInterpreting the deposits of ancient epeiric seas presents unique challenges because of the lack of direct modern analogs. Whereas many such seas were tectonically relatively quiescent, and successions are comparatively thin and punctuated by numerous sedimentary breaks, the Mesoproterozoic Belt Basin of western North America was structurally active and experienced dramatic and continuous subsidence and sediment accumulation. The Grinnell Formation (ca. 1.45 Ga) in the lower part of the Belt Supergroup affords an opportunity to explore the interplay between sedimentation and syndepositional tectonics in a low-energy, lake-like setting. The formation is a thick, vivid, red- to maroon-colored mudstone-dominated unit that crops out in northwestern Montana and adjacent southwestern Alberta, Canada. The mudstone, or argillite, consists of laminated siltstone and claystone, with normal grading, local low-amplitude, short-wavelength symmetrical ripples, and intercalations of thin tabular intraclasts. These intraclasts suggest that the muds acquired a degree of stiffness on the seafloor. Halite crystal molds and casts are present sporadically on bedding surfaces. Beds are pervasively cut by mudcracks exhibiting a wide variety of patterns in plan view, ranging from polygonal to linear to spindle-shaped. These vertical to subvertical cracks are filled with upward-injected mud and small claystone intraclasts. Variably interbedded are individual, bundled, or amalgamated, thin to medium beds of white, cross-laminated, medium- to coarse-grained sandstone, or quartzite. These are composed of rounded quartz grains, typically with subangular to rounded mudstone intraclasts. Either or both the bottoms and tops of sandstone beds commonly show sandstone dikes indicative of downward and upward injection. Both the mudcracks and the sandstone dikes are seismites, the result of mud shrinkage and sediment injection during earthquakes. An origin via passive desiccation or syneresis is not supported, and there is no evidence that the sediments were deposited on alluvial plains, tidal flats, or playas, as has been universally assumed. Rather, deposition occurred in relatively low-energy conditions at the limit of ambient storm wave base. The halite is not from in situ evaporation but precipitated from hypersaline brines that were concentrated in nearshore areas and flowed into the basin causing temporary density stratification. Sandstone beds are not fluvial. Instead, they consist of allochthonous sediment and record a combination of unidirectional and oscillatory currents. The rounded nature of the sand and irregular stratigraphic distribution of the sandstone intervals are explained not by deltaic influx or as tempestites but as coastal sands delivered from the eastern side of the basin by off-surge from episodic tsunamis generated by normal faulting mainly in the basin center. The sands were commonly reworked by subsequent tsunami onrush, off-surge, seiching, and weak storm-induced wave action. Although the Grinnell Formation might appear superficially to have the typical hallmarks of a subaerial mudflat deposit, its attributes in detail reveal that sedimentation and deformation took place in an entirely submerged setting. This is relevant for the deposits of other ancient epeiric seas as well as continental shelves, and it should invite reconsideration of comparable successions.
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de Wet, Carol B., Andrew P. de Wet, Linda Godfrey, Elizabeth Driscoll, Samuel Patzkowsky, Chi Xu, Sophia Gigliotti i Melina Feitl. "Pliocene short-term climate changes preserved in continental shallow lacustrine-palustrine carbonates: Western Opache Formation, Atacama Desert, Chile". GSA Bulletin 132, nr 9-10 (23.12.2019): 1795–816. http://dx.doi.org/10.1130/b35227.1.
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Abstract Multiple climate proxies indicate episodic changes in moisture levels within an ∼1 Ma duration (early–mid Pliocene) interval. Limestones within the Opache Formation, Calama Basin, Atacama Desert region, Chile, contain evidence for wetter and drier periods on short time scales. Proxies include carbonate lithological changes, paleontology (stromatolites, oncolites, gastropods, ostracods and diatoms), O and C stable isotopes, geochemistry, and mineralogical changes (aragonite, calcite, Mg-calcite, dolomite and gypsum) throughout a 30 m stratigraphic section. Stromatolite fossil cyanobacteria dark and light laminations and mesohaline to hypersaline diatom species suggest Pliocene annual seasonality. Short-term changes between wetter and drier conditions indicate that at least this part of the Atacama region was experiencing relatively rapid early–mid Pliocene climate instability. The predominance of limestone in the Opache Formation, in contrast to the 1500 m of Oligocene-Miocene siliciclastic conglomerates and sandstones, interpreted as arid climate alluvium, that underlie it, indicates a shift from arid or hyperarid climate to a semi-arid climate. Semi-arid conditions promoted limestone deposition in a shallow lacustrine-palustrine environment. In this setting, events such as storms with associated surface water flow, erosion, siliciclastic sand, gravel, and intraclast deposition, coupled with significant biological activity, represent sedimentation during more humid periods in a shallow lacustrine depositional environment. In contrast, limestone characterized by mudcracks, Navicula diatoms, and vadose syndepositional cementation, reflect periods of enhanced evaporation, water shallowing, and episodic desiccation, characteristic of a palustrine depositional system. These facies shifts, in conjunction with geochemical and isotopic proxy evidence, yield a sedimentary record of wetter and drier climate shifts.
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Benison, Kathleen, Jonathan Knapp, Adam Difrisco i Troy Rasbury. "The Permian Minnekahta Limestone: a Saline Lake Gypsum Replaced by Calcite". Mountain Geologist 55, nr 2 (kwiecień 2018): 59–73. http://dx.doi.org/10.31582/rmag.mg.55.2.59.
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The late Permian Minnekahta Limestone of the Black Hills of South Dakota is not a typical limestone. Sandwiched stratigraphically between continental redbed siliciclastics, it is distinct in its gray-pink appearance and carbonate mineralogy and is considered a local and regional marker bed. Based on its calcite composition and stromatolites, it has previously been interpreted as a tidal flat deposit, leading to speculation of a regional late Permian marine transgression. Here, we show observations that question the original composition, reexamine and refine the sedimentary and stratigraphic characteristics, and suggest an alternate depositional environment. Petrography and x-ray diffraction indicate that the Minnekahta Limestone is dominated by an interlocking crystal mosaic of calcite and gypsum. We have documented pseudomorphs after bottom-growth gypsum crystals, alternating laminae of mm-scale bottom growth gypsum crystal shapes and mud drapes, as well as mudcracks, raindrop imprints, and stromatolites. No carbonate grains, fossils, or tidal rhythmites were noted. These observations suggest that the carbonate phase is a replacement of gypsum. In addition to the sedimentology and petrography, close stratigraphic association with overlying and underlying continental redbeds indicates that this was likely a shallow saline-lake deposit. Other Permo-Triassic carbonate strata in continental redbed sequences throughout the midcontinent of North America, such as those in the Goose Egg, Chugwater, Nippewalla, and Spearfish strata, may have similar continental origin. This study serves as a lesson that paired petrographic observations and mineral identifications are important data necessary for the best interpretation of depositional environments and diagenetic histories.
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Hale, Dave, i Richard H. Groshong. "Conical faults apparent in a 3D seismic image". Interpretation 2, nr 1 (1.02.2014): T1—T11. http://dx.doi.org/10.1190/int-2013-0121.1.
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Map-scale geologic faults with a conical shape are apparent in a public-domain 3D seismic image of block F3 in the Dutch sector of the North Sea. These cone-shaped normal faults exist among many polygonal normal faults in fine-grained clay sediments. The conical faults were discovered using new algorithms for seismic image processing, but they are apparent without that processing. They appear circular in horizontal image slices and have an inverted-V shape in vertical sections for any azimuth through their vertical axes of symmetry. They form horsts bounded by planar strata above and below, with maximum throws of about 35 m roughly halfway between their bases and tops. The bases are up to 1 km wide, and dips of the conical faults are in the range 35º–38º. Because polygonal faults exist elsewhere at or near the seafloor with dips of about 60º, most such faults likely formed close to the depositional interface; the much lower dips of deeply buried faults, such as the faults observed here, are likely due to vertical compaction. We inferred that polygonal and conical fault geometries result from a uniform radial extension stress caused by volumetric contraction, analogous to the formation of mudcracks. Cone-shaped faults have been observed in laboratory experiments on rocks and ceramics, where the conical geometry results from uniaxial compression. In the subsurface, the formation of conical faults implies that stresses and sediments were exceptionally homogeneous. The cone shape suggests a pointlike heterogeneity near the depositional surface, which served as a trigger for downward propagation of the faults, rather unlike the random, in-plane propagation and linking inferred by others for polygonal faults.
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Rai, Santa Man. "Lithostratigraphy of the Nawakot Complex (Lesser Himalayan Sequence) from Malekhu area (south-west) to Syabrubensi area (north-east) along the Trishuli River, central Nepal Himalaya". Journal of Nepal Geological Society 42 (24.09.2011): 65–74. http://dx.doi.org/10.3126/jngs.v42i0.31451.
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All formations (Kuncha Formation, Fagfog Quartzite, Dandagoan Phyllite, Nourpul Formation, Dhading Dolomite of the Lower Nawakot Group and Benighat Slate, Malekhu Limestone and Robang Formation of the Upper Nawakot Group) of the Nawakot Complex are well exposed along the Malekhu-Thopal Khola and Galchi - Kaljeri section s, west of the Kathmandu Valley. The Phalangu Khola and Syabrubensi sections, north of the Kathmandu Valley do not show the exposures of all formations (exposures of the Kuncha Formation, Fagfog Quartzite, and Benighat Slate only). The stratigraphic sequences from the Kuncha Formation to Dhading Dolomite (Lower Nawakot Group) along the Malekhu-Thopal Khola section are overturned, showing the younging strata to the deeper sections shown by the sedimentary structures (ripple marks, mudcracks, etc.) and stromatolites. The se overturned sequences could be related to the development of the post Main Central Thrust (MCT)/Mahabharat Thrust (MT) deformational structure (Gorkha - Pokhara anticlinorium, Likhu Khola anticline). The stratigraphic sequences are normal in the formations of the Upper Nawakot Group along the Malekhu-Thopal Khola section. This normal sequence can be also observed along the Galchi - Kaljeri, Phalangu Khola and Syabrubensi sections. In the northern part of the study area along the Likhu Khola, Tadi Khola, Phalangu Khola and Syabrubensi sections, the rocks of the Benighat Slate just below the MCT are highly sheared, deformed, metamorphosed with the development of the garnet and staurolite (medium amphibolite facies metamorphism) due to the movement of the MCT. However, these minerals are not developed in the Robang Formation (immediate below the MT) along the Malekhu-Thopal Khola and Galchi - Kaljeri sections. This formation could be caused by shallow depth metamorphism (green-schist to lower amphibolite facies) along the movement of the MT.
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Pfeifer, Lily S., Gerilyn S. Soreghan, Stéphane Pochat i Jean Van Den Driessche. "Loess in eastern equatorial Pangea archives a dusty atmosphere and possible upland glaciation". GSA Bulletin 133, nr 1-2 (19.06.2020): 379–92. http://dx.doi.org/10.1130/b35590.1.
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Abstract Carboniferous–Permian strata in basins within the Central Pangean Mountains in France archive regional paleoequatorial climate during a unique interval in geological history (Pangea assembly, ice-age collapse, megamonsoon inception). The voluminous (∼1.5 km) succession of exclusively fine-grained red beds that comprises the Permian Salagou Formation (Lodève Basin, France) has long been interpreted to record either lacustrine or fluvial deposition, primarily based on a local emphasis of subaqueous features in the upper ∼25% of the section. In contrast, data presented here indicate that the lower-middle Salagou Formation is dominated by up to 15-m-thick beds of internally massive red mudstone with abundant pedogenic features (microscale) and no evidence of channeling. Up-section, limited occurrences of ripple and hummocky cross-stratification, and mudcracks record the intermittent influence of shallow water, but with no channeling nor units with grain sizes exceeding coarse silt. These data suggest that the most parsimonious interpretation for the Salagou Formation involves eolian transport of the sediment and ultimate deposition as loess in shallow, ephemeral lacustrine environments. Provenance analyses of the Salagou Formation indicate coarse-grained protoliths and, together with geochemical proxies (chemical index of alteration [CIA] and τNa) that correspond respectively to a low degree of chemical weathering and a mean annual temperature of ∼4 °C, suggest that silt generation in this case is most consistent with cold-weathering (glacial and associated periglacial) processes in the Variscan highlands. Together with previous studies that detailed voluminous Permian loess in western equatorial Pangea, this work shows a globally unique distribution of dust at low latitudes that can be linked either directly to glaciated alpine terranes or to reworked and deflated deposits of other types (e.g., fluvial outwash) where fine-grained material was originally generated from glacial grinding in alpine systems. These results further support a revised model for early Permian climate, in which extratropical ice sheets coexisted with a semiarid tropics that may have hosted significant ice at moderate elevation.
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Tye, Robert S., Donald R. Lowe i J. J. Hickey. "Ediacaran (Vendian)-period alluvial and coastal geomorphology applied to development of Verkhnechonskoye and Yaraktinskoye fields, East Siberia, Russian Federation". Journal of Sedimentary Research 90, nr 1 (22.01.2020): 67–101. http://dx.doi.org/10.2110/jsr.2020.8.
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ABSTRACT Ediacaran-age (635–542 Ma) oil-bearing strata in the Yarakta Horizon at the Verkhnechonskoye and Yaraktinskoye fields, East Siberia, consist of conglomerate, sandstone, dolomitic sandstone, and mudstone overlying and onlapping igneous to metasedimentary highlands of the East Siberia craton. Initial drainage networks formed within structurally defined valleys, and early deposition occurred in localized alluvial to shallow-marine depositional systems. Base-level-controlled depositional cycles aggraded the valleys; thus, as valleys aggraded, they buried interfluves and coalesced forming broad alluvial and coastal plains. Three to seven bedsets of variable net-to-gross content constitute a genetic cycle. Depositional cycles varied locally, as nine and eight cycles separated by decimeter- to multi-meter-thick mudstones are defined at Verknechonskoye and Yaraktinskoye, respectively. Within one genetic cycle, facies associations grade basinward from alluvial (channel-bar, channel-fill, floodplain, playa, and crevasse-splay) to shallow marine (sabkha, tidal-flat, estuarine-channel, and poorly developed shoreface). Coarse-grained lithofacies are typically arranged in decimeter- to meter-scale bedsets with sharp to scoured bases. Bedsets commonly, but not always, show an upward decrease in grain size, bed thickness, and scale of sedimentary structure. Typically, medium-grained sandstones exhibit low-angle cross bedding and are gradationally overlain by fine-grained sandstones exhibiting scour-and-fill, cuspate-ripple lamination, climbing-ripple lamination, and parallel lamination. Clay clasts and small pebbles are accessories. Interbedded mudstones, siltstones, and sandstones show ripple cross bedding, wavy to lenticular bedding, abundant soft-sediment deformation (e.g., shear, fluid-escape, slump features), and slickensides. Thin-bedded sandstones are micaceous and contain granule-size mud chips. Some mudstones exhibit crinkled to parallel laminae indicative of algal growth. Sandstone fills mudcracks. Interbedded green and black mudstones, plus pyrite and siderite cements, indicate alternating redox conditions. Alluvial facies have patchy quartz, anhydrite, and carbonate cements. Marine-influenced facies show early and well-developed quartz cement as well as abundant halite. Gypsum and halite dissolution formed secondary pores. Calculated estimates of fluvial-channel dimensions and sinuosities indicate that despite the lack of vegetation, fluvial channels in the Yarakta Horizon were shallow and relatively narrow, moderately sinuous, and exhibited varying degrees of mud-prone overbank deposition. Recognition and correlation of flooding surfaces and channel diastems bounding genetically related strata identified multiple stratigraphic compartments in each field. Porosity loss at chronostratigraphic boundaries accounts for complex water, oil, and gas contacts. Economic field development is hampered by locally varying reservoir quality and sandstone continuity caused by its channelized and onlapping stratigraphy and diagenesis. Reservoir simulation of varying geostatistical models demonstrate that differing porosity-distribution methods had little effect on estimates of in-place hydrocarbon volumes. Model differences in porosity and permeability distribution and lithofacies connectivity show large variations in recovery factor and productivity/injectivity.
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Liang, Mingjuan, Tiannan Yang, Zhen Yan, Chuandong Xue, Di Xin, Shaofeng Qi, Mengmeng Dong i in. "Early late triassic retro-foreland basin in response to flat subduction of the Paleo-Tethyan oceanic plate, SE tibet". Frontiers in Earth Science 10 (14.09.2022). http://dx.doi.org/10.3389/feart.2022.957337.
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Syn-subduction basins bear significant implications to understand tectonic evolution of any fossil subduction zone. The late Paleozoic to early Mesozoic (Paleo-Tethyan) tectonics of the eastern and southeastern Tibetan Plateau (i.e., the Sanjiang Orogenic Belt) is featured by ocean-continent subduction systems. A huge pile of volcanic-absent sedimentary succession developed in the middle segment of the Sanjiang orogenic belt, its age and tectonic nature remain unclear. Detailed geological mapping and zircon U-Pb dating results demonstrate that the early Late Triassic volcanic-absent succession comprises the nonmarine Maichuqing Formation in the lower part and the shallow marine Sanhedong Formation in the upper part. The Maichuqing Formation consists of coarse to fine-grained sandstone, siltstone and mudstone with abundant basal erosional surfaces, trough and planar cross-beddings, ripples, mudcracks, and plant fragments. The Sanhedong Formation comprises predominantly bioclastic limestones interlayered with marl, calcareous-muddy siltstone, and calcareous sandstone with abundant bivalve fossils. Syn-sedimentation deformation structures, such as slump folds and associated normal faults are common, suggesting intense tectonism during deposition. Synthesizing sedimentary data, paleocurrent and provenance results, combined with other available data, demonstrate that the volcanic-absent succession deposited within a retro-foreland basin along the rear part of the Permian-Triassic Jomda-Weixi-Yunxian arc in response to flat-subduction of the Paleo-Tethyan Ocean during the early Late Triassic time.