First Experimental Evidence for the Presence of Potentially Virulent Klebsiella oxytoca in 14 Species of Commonly Consumed Aquatic Animals, and Phenotyping and Genotyping of K. oxytoca Isolates

Klebsiella oxytoca is a recently emerging pathogen that can cause necrotizing enterocolitis, hemorrhagic colitis, sepsis-associated purpura fulminans, and infective endocarditis in humans. The bacterium is ubiquitous in water and soil environments. Nevertheless, current literature on K. oxytoca in aquatic products is rare. In this study, we surveyed K. oxytoca contamination in 41 species of consumable aquatic animals sold in July, August, and September of 2018 and 2019 in Shanghai, China, 40 of which had no history of carrying this bacterium. K. oxytoca was for the first time isolated from 14 species with high abundance in benthic animals. None of the K. oxytoca isolates (n = 125) harbored toxin genes mviM, tisB, and yqgB. However, a high occurrence of virulence-associated genes was observed, including brkB (73.6%), cdcB (66.4%), pduV (64.8%), and virk (63.2%). Resistance to sulphamethoxazole-trimethoprim (56.0%) was the most predominant among the isolates, followed by chloramphenicol (6.4%), tetracycline (5.6%), and kanamycin (3.2%). Approximately 8.0% of the isolates displayed multidrug resistant phenotypes. Meanwhile, high percentages of the isolates tolerated the heavy metals Cu2+ (84.8%), Pb2+ (80.8%), Cr3+ (66.4%), Zn2+ (66.4%), and Hg2+ (49.6%). Different virulence and resistance profiles were observed among K. oxytoca isolates in 3 types and 14 species of aquatic animals. The ERIC-PCR-based genome fingerprinting of the 125 K. oxytoca isolates revealed 108 ERIC genotypes with 79 singletons, which demonstrated the genetic diversity of the isolates. The results of this study fill gaps for policy and research in the risk assessment of K. oxytoca in consumable aquatic animals.

Community structure and ecological distribution of benthic animals in Tien Hai mangrove forest, Northern Vietnam

Mangroves are a diverse and rich ecosystem, in which many animals are associated, including benthos. Species composition and occurrence of these animals are driven by the mangroves and tidal conditions. To examine how the benthic animal is distributed in mangrove habitats from northern Vietnam, two surveys in 2019 were conducted in Tien Hai Wetland Nature Reserve, which resulted in a total of 89 species, belonging to 56 genera and 35 families of zoobenthos. This is the first publication of these animals in the study site. The two major groups of benthic animals in the ecosystem were Crustacea and Mollusca, which occupy 54.02% and 36.78% of the total species, respectively. There are several new records of these animals from the coastal mangroves of Vietnam. Two species were new data for northern Vietnam (Scopimera curtelsoma and Parasesarma eumolpe), and four species were new records for Vietnam (Laemodonta punctigera, Cassidula nucleus, Pythia cecillei and Microtralia alba). Also, the present study shows distributional characteristics of the benthic animal community in mangrove forests. The present study indicates that benthic animals show an increase in species diversity and density from the river mouth to the continent. Seasonally quantitative data of benthic from the study site are the first work in mangrove forests of Vietnam. Recent findings are fundamental data for further studies on zoobenthos and related issues to preserve biodiversity in the mangrove forests in Vietnam.

Coupling and Decoupling of Reproduction and Larval Recruitment

Stock-recruitment relationships for managing commercial fisheries are difficult to measure and notoriously poor, so marine ecologists have relied on larval recruitment as a proxy for how planktonic processes regulate populations and communities. However, my literature review revealed that coupling between reproductive output and recruitment in benthic populations was common, occurring in 62% of 112 studies and 64% of 81 species. Coupling was considerably stronger for studies on brooders (72%) than broadcast-spawners (46%) and taxa with short (74%) than long (56%) planktonic larval durations (PLDs); hence, it was highest for brooders with short PLDs (94%). Coupling was similar in studies on benthic animals (63%) and seagrasses and kelp (56%). Coupling was detected more often by quantifying both reproductive output and settlement (79%) than adult density and recruitment (60%). It also was detected in 83% of just 21% of studies that estimated dispersal. Coupling was even detected by 55% of the 46% of studies conducted at just one site and 58% of the 65% of studies lasting no longer than 3 years. Decoupling was detected 33 times in invertebrates and fishes, occurring more often in the plankton (48.5%) and during reproduction (45.5%) than after settlement (6%), and nine times in seagrasses and kelp, occurring more often during reproduction (44.4%) than postsettlement (33.3%) or in the plankton (22.2%). Widespread coupling between reproductive output and settlement for sedentary, benthic species suggests that the poor stock-recruitment relationships typical of vagile, wide-ranging, pelagic species may be due more to the difficulty of detecting them than decoupling.

Macrozoobenthos in mid-mountain lakes of river Multa basin (Republic of Altai)

In August 2020, taxonomic composition and quantitative characteristics of zoobenthos from 4 lakes located in the upper reaches of the R. Multa basin (the R. Ob basin) were studied. Because of the basin inaccessibility the hydrobiological information about these lakes was previously fragmentary or absent at all. The data on macrozoobenthos composition and its structure were not available. In these lakes, 49 species of benthic invertebrates from 7 classes were identified, i.e. Demospongiae (1), Turbellaria (1), Oligochaeta (3), Gastropoda (4), Euchelicerata (1), Crustacea (1) and Insecta (38). Among insects, Diptera were the most diverse (22 chironomids out of 23 species). Beetles, mayflies and caddisflies were also found. In terms of species number, abundance and biomassб chironomids were the dominant taxonomic group in the studied lakes. The species composition of macrozoobenthos consisted of species widely spread in the Palearctic and Holarctic. The investigated lakes differed in species composition of zoobenthos. When comparing the species lists of benthic animals, lakes Sredneye Multinskoye and Poperechnoye were similar at most, whereas the fauna of Lake Nizhneye Multinskoye was the most original. The studied water bodies were distinguished by poor macroinvertebrate development and thereby corresponded to ultra-oligotrophic and oligotrophic reservoir types. The oligochaete index by Goodnight and Whitley corresponded to quality class I–II, i.e. “conditionally clean” and “slightly polluted waters”. We defined the trophic structure of macrozoobenthos of lakes and identified five main trophic groups of hydrobionts (Deposit feeders, Сollectors-detritus feeders and facultative filter feeders, Collectors-obligate filter feeders, Shredders, Predators), among which Collectors-detritus feeders and facultative filter feeders dominated.

Results of zoobentos research in river Sotka, PINEZHSKY STATE RESERVE (Arkhangelsk region, Russia)

В статье рассмотрен качественный состав (видовое и таксономическое разнообразие) и количественные показатели (встречаемость, численность и биомасса) зообентоса р. Сотка в пространственном аспекте. Выявлены участки реки с минимальной и максимальной численностью и биомассой. Определены доминирующие группы донных животных по численности (личинки хирономид и малощетинковые черви) и биомассе (двукрылые, олигохеты и двустворчатые моллюски). На основе кластерного анализа (по видовому сходству) станции отбора бентосных проб объединены в 2 группы. Качество вод оценено как условно чистое - слабо загрязненное. Проведенные исследования зообентоса в уникальной реке на территории заповедника Пинежский будут использованы при ведении комплексного мониторинга качества вод и биотической части ее экосистемы (фито- и зоопланктон, зообентос, ихтиофауна), включая и приточную систему. The article considers the qualitative composition (species and taxonomic diversity) and quantitative indicators (occurrence, number and biomass) of zoobenthos of river Sotka in the spatial aspect. The sections of the river with the minimum and maximum abundance and biomass were identified. The dominant groups of benthic animals were determined by their numbers (chironomid larvae and small-bristle worms) and biomass (dipterans, oligochaetes and bivalve mollusks). Comparison of quantitative indicators in the annual aspect revealed a significant increase in biomass and relative stability of abundance over a 20-year period at the Filippovskoye site, as well as a decrease in numbers and biomass at the Moiseev Nos site. Based on cluster analysis (by species similarity), benthic sampling stations are combined into 2 groups. Water quality is assessed as conditionally pure, slightly polluted. Studies of zoobenthos in a unique river on the territory of the Pinezhsky reserve will be used to conduct a comprehensive monitoring of water quality and the biotic part of its ecosystem (phyto- and zooplankton, zoobenthos, ichthyofauna), including the inflow system.

Benthic animals and plants and what they do to sediments

This chapter explores the interactions of plants and animals with their immediate sedimentary environment. Plants and animals fundamentally change the physical and chemical characteristics of their sedimentary environment. The changes they effect are dependent on their size, living position, feeding mode and mobility. The types of changes are discussed as well as the resultant ability of plants and animals to actually create seafloor habitats and contribute to sediment heterogeneity at both small and large scales. Seafloor habitats are therefore best defined by a mix of physical and biology rather than physical descriptors alone. But the differences between how different animals feed and move and their ability to create structures such as tubes and burrows that influence the flows of oxygen and porewater within the sediments and across the sediment–water interface mean that there are not only a variety of vegetated seafloor habitats but a variety of non-vegetated ones.

Factors determining parasite abundance in European perch, Perca fluviatilis, European whitefish, Coregonus lavaretus, and Arctic charr, Salvelinus alpinus, in an oligotrophic lake, southern Norway

Time and spatial variations in macroparasite status were investigated in European perch, Perca fluviatilis, European whitefish, Coregonus lavaretus, and Arctic charr, Salvelinus alpinus in Lake Norsjø (Southern Norway), based on gillnet fishing in three locations in the spring, summer, and fall 2018. In addition, length, weigth, age, sex, δ13C, and δ15N were determined. Parasite abundance was modelled using negative binomial generalized linear models in relation to fish metrics, season, and sampling location. The most prevalent parasite species were determined by the diet and habitat of the host. European perch was mainly infected by acanthocephalans, European whitefish mainly infected by acanthocephalans and cestodes, and Arctic charr mainly infected by cestodes. The most prevalent parasites in European perch are transmitted by benthic animals. Parasites in European whitefish are transmitted by both benthic animals and copepods, while the most prevalent parasites in Arctic charr are copepod transmitted. This corresponds well with the δ13C signatures in the three species, indicating that European perch primarily fed in the littoral zone (δ13C: -24.9 ± 2.5 ‰), Arctic charr in the pelagic and profundal zone (δ13C: -29.4 ± 1.1 ‰), while European whitefish both fed in the littoral and pelagic zone (δ13C: -28.3 ± 2.3 ‰) of Lake Norsjø. Individual abundances of parasites depended on host age, length, sex, δ15N, and season. Positive correlations between parasite abundance and host age, length, or trophic level measured as δ15N were most common, and occurred in all three host species. Many parasites accumulate with age, and larger hosts provide more diverse habitats for parasites.

Bioinspired underwater legged robot for seabed exploration with low environmental disturbance

Robots have the potential to assist and complement humans in the study and exploration of extreme and hostile environments. For example, valuable scientific data have been collected with the aid of propeller-driven autonomous and remotely operated vehicles in underwater operations. However, because of their nature as swimmers, such robots are limited when closer interaction with the environment is required. Here, we report a bioinspired underwater legged robot, called SILVER2, that implements locomotion modalities inspired by benthic animals (organisms that harness the interaction with the seabed to move; for example, octopi and crabs). Our robot can traverse irregular terrains, interact delicately with the environment, approach targets safely and precisely, and hold position passively and silently. The capabilities of our robot were validated through a series of field missions in real sea conditions in a depth range between 0.5 and 12 meters.

EFFECT OF LIGHT POLLUTION ON THE SEVERAL AQUATIC COMMUNITIES OF LAKE BAIKAL

The nocturnal vertical migration activity of amphipods in the two coastal areas of Lake Baikal, exposed and not exposed to the influence of artificial lighting was investigated. In the conditions of prolonged artificial lighting, the migration activity of amphipods reduced on average by 20 times. Statistical analysis demonstrated significant differences between the two places of video surveillance indicating about the significant impact of light pollution on the nocturnal migration of the benthic animals.