Association Between Early-Stage Juveniles of Sailfin Catfish (Pterygoplichthys, Loricariidae) and Floating Hydrophytes: Behaviour Supports Species Dispersal?

The vertical distribution of early-stage juvenile sailfin catfish (Pterygoplichthys, Loricariidae), an invasive species, were investigated in littoral habitats and the center of channel with floating hydrophytes from the Red River system in Vietnam. Sailfin catfish were sampled from the upper water column with associated floating hydrophytes of the invasive water hyacinth (Eichhornia crassipes) and native water spinach (Ipomoea aquatic) and the bottom using hand nets (2-mm mesh sizes). Significantly higher numbers of early-stage juveniles were associated with floating hydrophytes compared to bottom sampling. The association between early stages of sailfin catfishes and floating hydrophytes, especially the free-floating invasive water hyacinth, supports the potential mechanism in the dispersal of an invasive fish.

Seismic stratigraphy of the East-Siberian and Chukchi seas as a key to the Amerasia Basin stratigraphy end evolution

<p>Based on new seismic survey, offshore drilling and geological structure of the adjacent onshore a new model of geological evolution of sedimentary basins of the East-Siberian and Chukchi seas since the Mesozoic has been constructed. The main stages of their tectonic history are highlighted: 1) forming of the foreland basin in Jurassic – Early Creatceous time; 2) synrift extension in Aptian-Albian time; 3) start of postrift subsidence in Later Cretaceous; 4) uplift and deformations at the turn of Cretaceous and Paleogene, start of forming of the thick (up to 4-6 km) clinoform complex; 5) episode of synrift extension in Middle-Later Eocene, forming of the system of multiple low-amplitude normal faults; 6) inversion deformations in Oligocene-Miocene; 7) relatively calm tectonic conditions in Neogene-Quaternary time. Boundaries of the interpreted seismic complexes corresponding to these stages has been extended to the entire Amerasia basin with regards to the ages of magnetic anomalies in the Gakkel Ridge and sea-bottom sampling on the Mendeleev Rise. Volcanic areas of the De Long Islands and the North Wrangel High has been traced on the seismic profiles toward Mendeleev Rise and Podvodnikov Basin and dated as ±125 Ma. According to the seismic interpretation, the age of the Podvodnikov and Toll basins is not older than Aptian. The reported study was funded by RFBR and NSFB, project number 18-05-70011, 18-05-00495 and 18-35-00133.</p>

‘Simple’ can be good, too: testing three hard bottom sampling methods on macrobenthic and meiobenthic assemblages

Subtidal hard bottoms are of particular scientific and economic value as they are highly productive systems. They are less well studied compared with soft bottoms, as they often require manual sample collection via scuba diving. Although a multitude of sampling devices is available for soft bottoms, only a few are suitable for hard substrates, and their performance is largely unstudied. In the present study, three hard bottom sampling methods were compared, regarding their sampling efficiency and the damage they may cause to macrobenthic and meiobenthic organisms. Two of the sampling methods examined are typically employed for the study of hard bottom substrates (manual collection, airlift device), while the third involves a newly constructed sampler (MANOSS – Manual Operated Suction Sampler). All three sampling methods were tested at 12 m depth on a hard bottom substrate with algal coverage dominated by Cystoseira spp. No overall significant differences were observed between the sampling efficiency and the damage caused by the three sampling methods regarding the macrofaunal assemblages, with the exception of the MANOSS method which collected more species than the manual method. In addition, significant differences were observed in the collecting performance for the meiobenthic assemblages, presenting significantly higher densities of meiofauna sampled by the MANOSS compared with the manual collection method, while the airlift device presented an intermediate efficiency. However, taking into account other factors such as cost, ease of use and the scope of each study, none of the methods clearly outperforms the others.

Analysis of Seafloor Sediment Distribution using Multibeam Backscatter Data

Multibeam sonars use an acoustic wave to provide a view of seafloor topography and collect its backscatter. Seafloor backscatter image can be used as a means of quantitative classification of seafloor lithology. This allows sediment expert to examine spatial distributions of seafloor sediment types and discriminate among them. This method is expected to reduce expensive bottom-sampling programs. The research examined multibeam data collected from Indonesia Exploration 2010 Project. This project employed a Kongsberg EM302 multibeam system to collect seafloor topography and backscatter data at Sangihe Talaud Sea, North Sulawesi. The average depth of the area study is approximately 2400 m. The research applied the Angular Response Curve (ARC) method to analyze the echo strength of the backscatter as a function of the grazing angle. The range of backscatter intensity in this area is from -9dB to - 67dB. Based on the backscatter data, there are five types of sediment in this area: clay, mud, gravel, sand, and boulder.

SEDIMENTOLOGICAL AND PALAEOENVIRONMENTAL CHARACTER OF LAKE KORONIA SEDIMENTS

The aim of the present study is to investigate the sedimentological characteristics of Lake Koronia down to a depth of 3.5m below lake bottom. Sampling operations took advandage of a season that the lake bottom was exposed to subaerial conditions. The sedimentological analysis proved that sediments consist of mud to sandy mud, with 2 phases of very fine sand fractions. The proportion of dry organic matter contained into sediment, appears to be generally small while the rates of moisture and volatiles are relatively high. Furthermore, this study examines the distribution of ostracod populations in the sediments of the lake in relation to depth, grain size and other environmental conditions of this water body. Four ostracod species were identified: Candona neglecta, Darwinula stevensoni, Heterocypris spp. and Limnocythere inopinata. The study of freshwater ostracods provides information for the palaeoecological/palaeoenvironmental conditions during the sedimentation.

Concentrations and enrichment of metals in sediment cores: geochemistry and correlations with geoaccumulation index

The Mãe d’Água dam was built in 1962 to supply the Federal University of Rio Grande do Sul’s water demanding. Thus, the paper aims to measure Nickel (Ni) and Zinc (Zn) concentrations in many depths of the dam’s bottom, sampling cores of sediments silted in it. The samplings were carried out in June, 2014, and it was sampled four sediment cores in pre-defined points of the dam. The methodology for extraction of sediment cores was ‘Piston Core’. Sediment particles smaller than 63 μm were separated and used for chemical analysis. EPA 3050 acid digestion methodology is used by the U.S. Environment Protection Agency and it was also used in this study. Analyses were carried out in duplicate and two USGS reference materials were used for quality control: SGR-1b and SCO-1. Zn and Ni concentrations were over than local background values and increasing concentrations of the deepest sendiments to the most recent layers as a result of urbanization activities. Geoaccumulation index was able to characterize decreasing of metal concentrations in depth.

Subsea uplifts origin of the rugozerskaya bay and the great Salma channel (Kandalaksha bay)

Lots of shallow Rugozerskaya firth (Kandalaksha Bay of the White Sea) were studied on the basis of integrated explorationsincluding continuous seismic profiling, side scan sonar (SSS), bottom sampling and diver inspection. As a result a number of regularities in the geological structure of the region was identified, in particular - the origi of certain bottom forms and coast terrain was revealled.

PENDUGAAN NUTRIENT BUDGET TAMBAK INTENSIF UDANG, Litopenaeus vannamei

Penelitian ini bertujuan untuk mendapatkan nutrient budget tambak intensif udang Litopenaeus vannamei sebagai acuan alokasi input produksi pada tingkat kapasitas asimilasi lingkungan perairan. Pendugaan nutrient budget tambak udang intensif menggunakan pendekatan mass balance, dihitung berdasarkan input nutrien nitrogen - N dan fosfor – P yang berasal dari pakan, benih, pupuk, media probiotik, inflow, dan output nutrien yang ada pada produksi udang, outflow, dan endapan lumpur di dasar tambak. Sampel air, tanah, sedimen, plankton diambil sebelum penebaran dan setiap dua minggu selama pemeliharaan dari tiga petak tambak, masing-masing 5 titik sampel per petak tambak contoh. Analisis nitrogen dan fosfor dilakukan untuk sampel pakan, karkas udang awal dan akhir. Data managemen budi daya meliputi padat penebaran benur 50 ekor m-2, produksi 1.188—1.489 kg/0,25 ha, dan FCR 1,69—2,14; maka total input nutrien tambak udang Litopenaeus vannamei antara 171,9155—179,3778 (176 ± 3,9586) kgN dan 95,2533—99,4180(97,8340 ± 2,3348) kg P. Pakan mendominasi input N sebesar 61,96% ± 0,66%; disusul inflow 30,93% ± 0,70%; pupuk 6,52% ± 0,15%, serta media probiotik dan benur masing-masing <1%. Pola yang sama terjadi pada input phosphorous dengan komposisi 87,75% ± 0,24% dari pakan; 7,73% ± 0,19% pupuk; 4,05% ± 0,25% inflow dan media probiotik < 1%. Total output nitrogen tambak udang vannamei antara 107,1279-110,1438 (108,4957 ± 1,5274) kg N dan 51,6362—63,6576 (56,1292 ± 6,5604) kg P. Komposisi output nitrogen adalah outflow sebanyak 29,82% ± 3,20%; kemudian udang yang dipanen 21,32% ± 1,33%, lumpur atau sludge 10,40% ± 0,81%. Sedangkan komposisi output phosphorous didominasi oleh lumpur 39,03% ± 6,59%; kemudian udang yang dipanen 15,22% ± 0,85% dan outflow 3,09% ± 0,26%. Efisiensi pakan dan air melalui managemen budi daya yang benar menjadi peubah dominan penentu beban limbah tambak udang.This research was aimed to find out nutrient budget on L. vannamei intensive ponds as input allocation reference produce at environmental assimilation capacity level. Nutrient budget assessment was used mass balance approach, calculate based on nutrient input of nitrogen (N) and phosphor (P) from feed, seed, fertilizer, probiotic media, and inflow and nutrient output within pond yield, outflow, and sludge sedimentation at pond bottom. Sampling for water quality, sediment, and plankton was carried out at three ponds and five stations within each pond before stocking and continued fortnightly as long as culture periods. Nitrogen and phosphor analyzed for feed, and shrimp carcass of both of initial stocking and harvest. The data of culture management consist of shrimp yield reached 1,188—1,489 kg/0.25 ha with stocking density of 50 ind/m2 and FCR 1.69—2.14. Total input nutrients within L. vannamei ponds are 171.9155—179.3778 (176 ± 3.9586) kg N and 95.2533—99.4180 (97.8340 ± 2.3348) kg P. Food given domination on N input N with 61.96% ± 0.66% followed by inflow by 30.93% ± 0.70%, fertilizer 6.52% ± 0.15%, and both of probiotic media and seed supply less than1% respectively. There are the same pattern with phosphorous input with following composition 87.75% ± 0.24% from food, 7.73% ± 0.19% fertilizer, 4.05% ± 0.25% inflow and probiotic media less than 1%. Total output nitrogen from L vannamei ponds between 107.1279—110.1438 (108.4957 ± 1.5274) kg N and 51.6362—63.6576 (56.1292 ± 6.5604) kg P. Composition of nitrogen output is dominated by outflow 29.82% ± 3.20%, followed by shrimp harvest 21.32% ±1.33%, and sludge 10.40 ± 0.81%. Meanwhile, composition of phosphorous output dominated by sludge 39.03% ± 6.59%, shrimp harvest 15.22% ± 0.85% and outflow 3.09% ± 0.26%. Both food and water efficiency under good culture management are the mainfactors of waste load from shrimp culture ponds.

Distribution, diversity and some ecological characteristics of benthic amphipods in the Kapidağ Peninsula (Marmara Sea, Turkey)

The aim of this study was to determine the environmental factors affecting the fauna and the distribution of benthic amphipod species occurring on the Kapıdağ Peninsula, which is located in the south of the Marmara Sea. A total of 31 amphipod species were identified during the course of this study. In both seasons, Jassa marmorata (Holmes, 1905) and Protohyale schmidtii (Heller, 1866) were the most abundant species. During the study, temperature varied between 11.0 and 17.8°C, while salinity varied between 12.5 and 18.7 PSU; values of dissolved oxygen and pH ranged from 7.2 to 11.4 mg l-1 and 7.2 to 8.5 respectively at the coastal sites where hard bottom sampling was conducted. However, with regard to other sites where soft bottom sampling was carried out, the temperature varied between 8.0 and 18.0°C, salinity between 17.7 and 29.2 PSU, while values for dissolved oxygen and pH ranged from 5.1 to 11.4 mg l-1 and 7.8 to 8.7, respectively. In addition, the study of the amphipod species distribution revealed that the number of species was higher in spring compared to autumn while the number of individuals was higher in autumn compared to spring.

New deep-water cnidarian sites in the southern Adriatic Sea

Recent ROV (Remotely Operated Vehicle) exploration and bottom sampling in the southern Adriatic Sea (Apulian and Montenegrin margins) resulted in the discovery of cnidarian-rich deep-sea habitats in the depth range of ca. 400-700 m. In particular, ROV inspection of Montenegrin canyons reveals the existence of megabenthic communities dominated by a variety of cnidarians, including scleractinians (Madrepora oculata, Lophelia pertusa, Dendrophyllia cornigera), antipatharians (Leiopathes glaberrima) and gorgonians (Callogorgia verticillata) as major habitat forming taxa, often in association with sponges and, subordinately, serpulids. All such cnidarians are new records for the southeastern side of the Adriatic Sea. Our investigation indicates that an almost continuous belt of patchy cold water coral sites occurs along the entire southwestern margin (Apulian), basically connecting the Adriatic populations with those inhabiting the Ionian margin (Santa Maria di Leuca coral province).