scholarly journals Effects of environmental parameters on the nycthemeral migratory behaviour of copepod species in the Al Massira reservoir, Morocco

2020 ◽  
Vol 13 (3) ◽  
pp. 162-173
Author(s):  
Khadija Mokhliss ◽  
Mohammed Moncef

To improve our knowledge of nocturnal and diurnal migratory activity in copepods and in order to assess the effect of abiotic parameters on this activity, we have undertaken at the level of the Al Massira dam reservoir (dam located on the wadi Oum Erbia, in Morocco) the monitoring of the migration of the main species, during a 24-hour nycthemeral cycle. To be done; the measurement and sampling step is carried out every 4 hours; at different depths of the prospected station. The temperature, pH, dissolved oxygen and chlorophyll a measurements are taken. The systematic position of the main species of copepods and their density are determined. Most of the results obtained show that the main species of copepods inventoried within the reservoir are Neolovenula alluaudi and Acanthocyclops robustus. The nauplii of these two species present the maximum of densities at a depth of -5 m at 12 h; i.e. 70400 individual / m3 (ind / m3). The development stages of N. alluaudi are preferentially concentrated at -2 m at midnight, with 1900 ind / m3, while at 12 h and 16 h this density is less than 500 ind / m3. The maximum density for the stages of A. robustus is noted at midnight on the surface (at -5 m), i.e. 3400 ind / m3 for C1-2 and 3200 ind / m3 for stages C3-4-5 at -2 m at the same time. Therefore, the migratory behavior of these species seems to depend on the temperature, the concentration of dissolved oxygen and the variation of the food during the different phases of the cycle.

2013 ◽  
Vol 1 (1) ◽  
pp. 26
Author(s):  
Irma Pulukadan ◽  
Rene Ch Keppel ◽  
Grevo S Gerung

Alga is a marine resource of potential to fisheries and marine sector. It has an important economic value to promote the economy in Indonesia. Nowdays, algae have been used as a relatively high value fisheries commodity since it has been used for food, industrial, pharmaceutical and cosmetic raw materials. This important potential needs to be supported with understanding of its biology and ecology, so that its utilization could increase the livelihood of the coastal villagers. This study was aimed at inventorying and identifying the members of genus Caulerpa found in North Minahasa Regency waters and studying some biological and ecological aspects of the algae in the area. Resuls showed that there were 7 species recorded, Caulerpa racemosa, C. racemosa var. macrophysa, C. sertularioides, C. taxifolia, C. serrulata,C. lentillifera and C. peltata. Ecologically, the environmental parameters, such as water temperature, salinity, pH, dissolved oxygen, turbidity, were in tolerable ranges for algal growth. Bottom substrate supported the growth of genus Caulerpa as well© Saat ini alga dijadikan sebagai komoditas hasil perikanan dengan nilai ekonomis yang relatif tinggi karena manfaatnya sebagai bahan makanan serta bahan baku industri, farmasi, dan kosmetik. Potensi yang cukup penting ini harus ditunjang dengan ilmu pengetahuan tentang biologi dan ekologi dari alga laut, sehingga pemanfaatannya dapat meningkatkan taraf hidup masyarakat pesisir. Penelitian tentang kajian bioekologi alga makro genus Caulerpa di perairan Minahasa Utara ini dilaksanakan dan diharapkan dapat memberikan informasi ilmiah tentang bioekologi alga makro genus Caulerpa, sehingga dapat dimanfaatkan untuk pengembangan pemanfaatan bagi kepentingan masyarakat pesisir khususnya dan industri alga makro umumnya. Penelitian ini bertujuan untuk menginventarisasi dan mengidentifikasi alga makro genus Caulerpa di perairan Kabupaten Minahasa Utara, dan mengkaji aspek bioekologinya. Hasil penelitian menunjukkan bahwa ditemukan 7 spesies, yaitu Caulerpa racemosa, C. racemosa var. macrophysa, C. sertularioides, C. taxifolia, C. serrulata, C. lentillifera dan C. peltata. Parameter lingkungan seperti suhu, salinitas, pH, oksigen terlarut, tingkat kecerahan air berada pada kisaran yang dapat ditolerir untuk pertumbuhan alga makro, sedangkan substrat juga mendukung pertumbuhan alga makro ini©


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tahnee Manning ◽  
Arjun Venkatesh Thilagaraj ◽  
Dmitri Mouradov ◽  
Richard Piola ◽  
Clare Grandison ◽  
...  

Abstract Background Dinoflagellates are a ubiquitous and ecologically important component of marine phytoplankton communities, with particularly notable species including those associated with harmful algal blooms (HABs) and those that bioluminesce. High-throughput sequencing offers a novel approach compared to traditional microscopy for determining species assemblages and distributions of dinoflagellates, which are poorly known especially in Australian waters. Results We assessed the composition of dinoflagellate assemblages in two Australian locations: coastal temperate Port Phillip Bay and offshore tropical waters of Davies Reef (Great Barrier Reef). These locations differ in certain environmental parameters reflecting latitude as well as possible anthropogenic influences. Molecular taxonomic assessment revealed more species than traditional microscopy, and it showed statistically significant differences in dinoflagellate assemblages between locations. Bioluminescent species and known associates of HABs were present at both sites. Dinoflagellates in both areas were mainly represented by the order Gymnodiniales (66%—82% of total sequence reads). In the warm waters of Davies Reef, Gymnodiniales were equally represented by the two superclades, Gymnodiniales sensu stricto (33%) and Gyrodinium (34%). In contrast, in cooler waters of Port Phillip Bay, Gymnodiniales was mainly represented by Gyrodinium (82%). In both locations, bioluminescent dinoflagellates represented up to 0.24% of the total sequence reads, with Protoperidinium the most abundant genus. HAB-related species, mainly represented by Gyrodinium, were more abundant in Port Phillip Bay (up to 47%) than at Davies Reef (28%), potentially reflecting anthropogenic influence from highly populated and industrial areas surrounding the bay. The entire assemblage of dinoflagellates, as well as the subsets of HAB and bioluminescent species, were strongly correlated with water quality parameters (R2 = 0.56–0.92). Significant predictors differed between the subsets: HAB assemblages were explained by salinity, temperature, dissolved oxygen, and total dissolved solids; whereas, bioluminescent assemblages were explained only by salinity and dissolved oxygen, and had greater variability. Conclusion High-throughput sequencing and genotyping revealed greater diversity of dinoflagellate assemblages than previously known in both subtropical and temperate Australian waters. Significant correlations of assemblage structure with environmental variables suggest the potential for explaining the distribution and composition of both HAB species and bioluminescent species.


2017 ◽  
Author(s):  
Dong-Mei Wu ◽  
Jian-Xin Wang ◽  
Xiao-Hui Liu ◽  
Ying-Ping Fan ◽  
Ran Jiang ◽  
...  

The objective of this study was to characterize the structure and function of microbial communities in surface seawater from the Changjiang Estuary and adjacent areas, China. Sample water was collected at 12 sites and environmental parameters were measured. Community structure was analyzed using high-throughput sequencing of 16S rDNA genes. Predictive metagenomic approach was used to predict the function of bacterial communities. Result showed that sample site A0102 had the highest bacterial abundance and diversity. The heatmap indicated that different samples could be clustered into six groups. Phylogenetic analysis showed that Proteobacteria was the predominant phylum in all samples, followed by Bacteroidetes and Actinobacteria. Alphaproteobacteria and Gammaproteobacteria were the dominant classes. The analysis of predictive metagenomic showed carbon fixation pathways in prokaryotes, nitrogen metabolism, carbon fixation in photosynthetic organisms, photosynthesis and polycyclic aromatic hydrocarbon degradation were enriched in all samples. Redundancy analysis (RDA) identified that dissolved oxygen (DO) and PO43– concentration had positive correlations with the bacterial communities while chemical oxygen demand (COD), dissolved oxygen (DO) and PO43– concentration were significantly associated with microbial functional diversity. This study adds to our knowledge of functional and taxonomic composition of microbial communities.


2017 ◽  
Vol 15 (1) ◽  
pp. 13
Author(s):  
Arif Wibowo ◽  
Mas Tri Djoko Sunarno ◽  
Safran Makmur

Penelitian mengenai parameter fisika, kimia, dan biologi penciri habitat ikan belida (Chitala lopis) dilakukan tahun 2005 - 2006 di perairan umum daratan di Sumatera, Kalimantan, dan Jawa. Tujuan nya adalah untuk mendapatkan informasi parameter lingkungan yang menjadi karakteristik habitat ikan belida dari berbagai badan air di Jawa, Sumatera, dan Kalimantan. Metode survei dan kegiatan laboratorium digunakan dalam penelitian ini. Parameter lingkungan yang diamati meliputi suhu udara, suhu air, Total Dissolved Solid (TDS), Daya Hantar Listrik (DHL), klorofil-a, kecepatan arus, Biological Oxygen Demand (BOD), oksigen terlarut, pH, alkalinitas, CO2 bebas, kedalaman air, dan kecerahan pada 116 lokasi pengambilan yang ditentukan secara sengaja di Sungai Tulang Bawang (Provinsi Lampung), Sungai Kampar, Sungai Siak (Provinsi Riau), Sungai Musi (Provinsi Sumatera Selatan), Sungai Citarum (Provinsi Jawa Barat), Sungai Kapuas (Provinsi Kalimantan Barat), dan Waduk Riam Kanan (Provinsi Kalimantan Selatan). Analisis data menggunakan pendekatan analisis multivariabel regresi berganda Metode Backward yang didasarkan pada Analisis Komponen Utama (Principal Component Analysis) dan pembeda (Discriminant Analysis), serta korespondensi analisis (correspondency analysis). Hasil penelitian menunjukkan habitat ikan belida dapat dibedakan menjadi tiga tipe, yaitu tipe yang menyerupai sungai utama, waduk, dan anak sungai. Pembeda utama sekaligus parameter lingkungan utama adalah parameter TDS yang paling besar, dan selanjutnya parameterparameter DHL, suhu udara, klorofil-a, kecepatan arus, BOD, Oksigen terlarut, pH, alkalinitas, dan CO2 bebas menyumbang yang paling sedikit. Kehadiran plankton genus Ulothrix dan Mytilina secara tidak langsung teridentifikasi sebagai penciri habitat spesifik ikan belida. Research on physical, chemical, and biological parameters indicating specific habitat of clown knife fish (Chitala lopis) was carried out at 2005 - 2006 in inlands waters of Sumatera, Borneo, and Java. This study purposed to obtain information of environmental parameters indicating habitat characteristic of the knife fish in various inland waters bodies in Sumatera, Borneo, and Java. Survey method and laboratory activities were employed in this research. Environmental parameters observed were air temperature, water temperature, Total Dissolved Solid (TDS), conductivity, water velocity, Biological Oxygen Demand (BOD), dissolved oxygen, pH, alkalinity, free C02, water depth, and water transparancy taken on 116 sampling stations distributing in Tulang Bawang River (Lampung Province), Kampar and Siak River (Riau Province), Musi River (South Sumatera Province), Kapuas River (West Kalimantan Province), Riam Kanan Reservoar (South Kalimantan Province), and Citarum River (West Java Province). Data analysis used multivariate approach of multiple regression of Backward Method such as Principal Component Analysis, Discriminant Analysis, and Corre spondency Analysis. The results showed that the clown knife fish habitats could be divided by three types of specific habitat, namely water bodies similar with main rivers, reservoir, and tributaries. Parameter of TDS indicated the primary differentization as well as habitat characteristics of the clown knife fish.Whilst the parameters of conductivity, air temperature, chlorophyill-a, water current, BOD, dissolved oxygen, pH, alcalinity, and free CO2 contributed less significance. The existence of plankton from genus Ulothrix and Mytilina was identified indirectly as the specific habitat of the clown knife fish.


2012 ◽  
Vol 13 (2) ◽  
pp. 179 ◽  
Author(s):  
M.M. DORGHAM ◽  
M.M. EL-SHERBINY ◽  
M.H. HANAFI

Environmental properties (temperature, dissolved oxygen, nutrients and chlorophyll a) of the epipelagic zone off SharmEl-Sheikh, Red Sea, Egypt were studied seasonally throughout a year from March 1995 to March 1996. Water samples werecollected from five water depths (0, 25, 50, 75 & 100 m). The studied parameters exhibited clear seasonal variability along the water column. The vertical distribution of water temperature showed thermal homogeneity during most seasons, and thermal stratification in summer. Dissolved oxygen attained slightly high concentrations (5.3-7.8 mg l-1) in the whole water column, with slight seasonal variation. The concentrations of nutrients reflected dominant oligotrophic conditions in the epipelagic zone and occasional mesotrophic status at some depths. Phosphate fluctuated between 0-0.7 μM, ammonium (0-2.27 μM), nitrite (0-0.72 μM), nitrate (0-1.49 μM) and silicate (0-6.48 M). Phytoplankton biomass was generally low in the epipelagic zone throughout the study, whereas chlorophyll a was less than 0.5 μg l-1, except relatively high concentration (0.7-1.12 μg l-1) in deep layers in spring. In comparison with previous studies on the Gulf of Aqaba all environmental parameters during present study showed pronouncedlydifferent values.


2020 ◽  
Vol 287 (1923) ◽  
pp. 20193011 ◽  
Author(s):  
Tiago de Zoeten ◽  
Francisco Pulido

Migratory behaviour is rapidly changing in response to recent environmental changes, yet it is difficult to predict how migration will evolve in the future. To understand what determines the rate of adaptive evolutionary change in migratory behaviour, we simulated the evolution of residency using an individual-based threshold model, which allows for variation in selection, number of genes, environmental effects and assortative mating. Our model indicates that the recent reduction in migratory activity found in a population of Eurasian blackcaps ( Sylvia atricapilla ) is only compatible with this trait being under strong directional selection, in which residents have the highest fitness and fitness declines exponentially with migration distance. All other factors had minor effects on the adaptive response. Under this form of selection, a completely migratory population will become partially migratory in 6 and completely resident in 98 generations, demonstrating the persistence of partial migration, even under strong directional selection. Resident populations will preserve large amounts of cryptic genetic variation, particularly if migration is controlled by a large number of genes with small effects. This model can be used to realistically simulate the evolution of any threshold trait, including semi-continuous traits like migration, for predicting evolutionary response to natural selection in the wild.


2019 ◽  
Vol 19 (4) ◽  
Author(s):  
Marcelo Rodrigues dos Anjos ◽  
Nadja Gomes Machado ◽  
Mizael Andrade Pedersoli ◽  
Nátia Regina Braga Pedersoli ◽  
Bruno Stefany Barros ◽  
...  

Abstract: This study presents an inventory of the ichthyofauna of the lower Roosevelt River sub-basin and its associated tributaries. Fish sampling with fishing nets and measurements of environmental parameters of water occurred in November/2012 (rising water), February/2013 (flooding), May/2013 (falling water) and August/2013 (drought). Depth mean was 8.86 m, water transparency was 0.6 m, conductivity was 22.7 µS.cm-1, pH was 6.59, dissolved oxygen was 7.63 mg.l-1 and temperature was 28°C. The total estimated capture area was 68,829.6 m2 during 2,880 hours. The catch per unit Effort (CPUE) was 0.37 individuals m-2.day-1. Species were spatially aggregated in all sampling points and river water levels. A total of 5,183 individuals distributed in 7 orders, 29 families, 104 genders and 188 species were sampled in this survey. The diversity index was 4.121 and equitability index was 0.789. The Characiforms order was the most abundant with 106 species, followed by Siluriforms with 63 species and Cichliforms with 23 species. The most abundant species was Serrasalmus rhombeus (Linnaeus, 1766) with 327 individuals (5.9%), followed by Chalceus epakros (Cope, 1870) with 309 individuals (5.6%) and Acestrorhynchus microlepis (Schomburgk, 1841) with 250 individuals (4.5%). Trophicity was characterized by omnivorous (28.6%), piscivorous (14.3%), carnivorous (13.8%) and detritivorous (12.8%). According to IBAMA's regulation, 29.25% of captured species presents ornamental potential.


2019 ◽  
Vol 19 (3B) ◽  
pp. 149-162
Author(s):  
Do Huy Cuong ◽  
Bui Thi Bao Anh ◽  
Nguyen Xuan Tung ◽  
Nguyen The Luan ◽  
Le Dinh Nam ◽  
...  

The remote sensing images, including images of MODIS, VNREDSAT-1 and altimeter, are applied for researching marine environment with the different resolutions. On the basis of different time remote sensing images, we concentrated on the assessment of several characteristics including the SST, chlorophyll-a concentration and sea surface current at the different depths in different monsoons as well. With the large areas, we used the images of MODIS and altimeter. The detailed research area focuses on the Nam Yet island, and the images of VNREDSAT-1 are used. The analysis method of environmental parameters of SST and chlorophyll-a used the regression functions based on the single and combined bands to enhance the accuracy of the analysis result. The marine parameters collected at different depths in the latest field surveys on Truong Sa archipelago in the years of 2015 and 2018 are presented in this paper. On the basis of these parameters, we can analyse the relationships and compare the real field survey data and corresponding results interpreted from remote sensing images.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Misgana Dabessa ◽  
Aschalew Lakew ◽  
Prabha Devi ◽  
Hirpasa Teressa

Ethiopia is experiencing deterioration in river quality resulting in adverse effects on human health and hydrobionts. This study aimed to analyse the effects of specific environmental stressors on the distribution and abundance of macroinvertebrates in the Upper Awash River. The study was conducted from January 2018 to March 2018. Macroinvertebrates were collected from five sites using standard handheld nets. Physicochemical parameters including electrical conductivity, dissolved oxygen, total phosphorous, nitrate-nitrogen, pH, dissolved oxygen and water temperature that can affect the distribution and abundance of macroinvertebrates were assessed. A total of 14,465 individuals belonging to 33 families of insects and 5 families of the noninsect group were identified. Among all recorded taxa, Diptera was the most abundant and diversified order. Macroinvertebrates among the five sites showed variation in species evenness, richness, and Shannon Diversity Index. Values obtained from biotic indices and environmental parameters indicated the presence of organic pollution at different levels. The impacted downstream site paper mill waste (Walgata) had the relatively highest H-FBI index followed by Osole (more agricultural activities) indicating that Walgata and Osole were poorer in benthic faunal diversity than other sites. In addition, as habitat and water quality degradation increased, the number and percentage of Plecoptera, Ephemeroptera, and Trichoptera (EPT) decreased. The selected metrics will be also useful for the monitoring and assessment of the riverine systems and to access the impact of different stressors. As perturbation increased, species diversity, ETHbios index, Average Score Per Taxon, and family richness decreased, while the percentage of Chironomidae, Diptera, Dominant Taxa, and Hilsenhoff Family-Level Biotic Index increased indicating that tolerant species become abundant in degraded river bodies. Environmental protection agencies of governmental and nongovernmental organizations should make awareness for the local people so that they reduce activities that affect the river. Paper factory should also monitor its effluent from directly discharging into the Upper Awash River.


2017 ◽  
Vol 3 (5) ◽  
pp. 299
Author(s):  
Sri Endah Purnamaningtyas ◽  
Amran Ronny Syam ◽  
Didik WahjuHendro Tjahjo

Eksploitasi sumber daya di daerah mangrove kawasan pantai utara Jawa telah mengalami degradasi lingkungan. Untuk melakukan perbaikan, diperlukan data dan informasi keanekaragaman plankton dalam rantai makanan disuatu perairan. Perairan Mayangan merupakan perairan estuari yang mempunyai potensi perikanan yang cukup besar karena daerah ini merupakan daerah penjebak zat hara sehingga mempunyai produktivitas yang tinggi dari perairan lainnya. Tujuan dari penelitian ini adalah untukmengetahui keragaman plankton dan lingkungan perairan di sekitar perairan mangrove Desa Mayangan, Subang, Jawa Barat. Penelitian ini dilakukan pada bulan Pebruari, Mei, dan Desember 2007. Pengambilan contoh plankton menggunakan kemmerer bottle sampler secara vertikal dengan plankton net nomor 25 pada kedalaman antara 0,5-2,0 m. Parameter lingkungan yang diamati meliputikecerahan 17-62 cm, oksigen terlarut 1,9-3,7 mg/l, nitrit 0,007-0,187 mg/l, nitrat 2,483-3,986mg/l, amonium1,589-2,648mg/l, orthofosfat 0,026-0,334mg/l, dan salinitas 19,27-33,08‰. Hasil penelitian ini menunjukkan komposisiplankton di perairan tersebut terdiri atas lima kelas fitoplankton dan empat kelas zooplankton serta satu kelompok larva naupli. Kelimpahan fitoplankton didominansi oleh kelas Bacillariophyceae (26 spesies), sedangkan zooplanktondidominansi oleh kelas Crustacea (tiga spesies), dan Ciliata (tiga spesies). Perairan mangrove Desa Mayangan termasuk perairan dengan kesuburan sedang, dengan kelimpahan fitoplankton berkisar antara 4.024-99.594 sel/l (35.210±19.313) dan kelimpahan zooplankton berkisar antara 1.006-23.138 ind./l (8.249±5.132). Indeks keragaman fitoplankton dan zooplankton menunjukan kondisi kestabilan komunitas dalam kategori sedang. Selama tiga periode pengamatan komunitas plankton tersusun dari 35 komponen (spesies fitoplankton) dan sembilan komponen (spesies zooplankton). Exploitation of resources in the area of mangroves in coastal areas north of Java has suffered environmental degradation. To make improvements, necessary data and information on the diversity of plankton in the food chain in the waters.Mayangan estuarine waters are waters that have potential for significant fisheries for this area is an area of trap nutrients that have a higher productivity than other waters. The purpose of this study is to investigate the diversity of plankton and marine environment in waters around mangrove Mayangan Village, Subang, West Java. Research done in February, May, and December 2007. Plankton sampling using kemmerer bottle sampler plankton net vertically with nomor 25 at depths between 0.5-2 m. Environmental parameters observed included brightness, tranparancy 17-62 cm, dissolved oxygen 1.9-3.7 mg/l, nitrite 0.007-0.187 mg/l, nitrate 2.483-3.986 mg/l, ammonium 1.589-2.648 mg/l, orthophosphate 0.026-0.334 mg/l, and salinity 19.27-33.08‰. The results showed the composition of plankton in these waters consist of five classes of phytoplankton and three classes and one group of zooplankton, larval naupli. Phytoplankton abundance class was dominated by Bacillariophyceae (26 species), while the zooplankton was dominated by the Crustacea (3 species) and Ciliate (3 species).Mangrove waters Village Mayangan including waters with medium fertility, with phytoplankton abundance ranged from 4,024-99,594 cells/l (35,210±19,313) and the abundance of zooplankton ranged between 1,006-23,138 ind./l (8,249±5,132). Diversity index of phytoplankton and zooplankton communities show stable condition in the medium category. During the three observation periods of plankton community composed of 35 components (phytoplankton species) and 9 components (species of zooplankton).


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