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Abstract: V knjigi, ki prinaša celovito predstavitev naših visokogorskih jezer, oceno njihovega ekološkega stanja in razlago dogajanj v njih skozi zgodovino, so zbrani rezultati več kot desetletnih raziskav 18 avtorjev. V delu je podan geografski opis in nastanek visokogorskih jezer, hidrološke povezave med njimi ter fizikalne in kemijske lastnosti jezerske vode. Opisano je življenje v njih in spremembe, ki so jih jezera doživela v zadnjih stoletjih, opozorjeno pa je tudi na problem onesnaževanja visokogorja.
Keywords: fizična geografija, hidrologija, rastlinstvo, živalstvo, onesnaževanje voda
Published in DiRROS: 09.08.2024; Views: 107; Downloads: 71
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Abstract: Groundwater is a vital ecosystem of the global water cycle, hosting unique biodiversity and providing essential services to societies. Despite being the largest unfrozen freshwater resource, in a period of depletion by extraction and pollution, groundwater environments have been repeatedly overlooked in global biodiversity conservation agendas. Disregarding the importance of groundwater as an ecosystem ignores its critical role in preserving surface biomes. To foster timely global conservation of groundwater, we propose elevating the concept of keystone species into the realm of ecosystems, claiming groundwater as a keystone ecosystem that influences the integrity of many dependent ecosystems. Our global analysis shows that over half of land surface areas (52.6%) has a medium-to-high interaction with groundwater, reaching up to 74.9% when deserts and high mountains are excluded. We postulate that the intrinsic transboundary features of groundwater are critical for shifting perspectives towards more holistic approaches in aquatic ecology and beyond. Furthermore, we propose eight key themes to develop a science-policy integrated groundwater conservation agenda. Given ecosystems above and below the ground intersect at many levels, considering groundwater as an essential component of planetary health is pivotal to reduce biodiversity loss and buffer against climate change.
Keywords: groundwater, keystone ecosystem, surface-subterranean connectivity
Published in DiRROS: 07.08.2024; Views: 106; Downloads: 108
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Abstract: The size and composition of fish eggs are related to female’s characteristics, such as age, size and individual conditions, and they have an impact on the properties of offspring that are important for their fitness. Electron transport system (ETS) activity and respiration rate (R) of early life history stages (i.e. non-fertilized eggs, eggs at eyed stage and larvae with yolk sac) of 13 females of marble trout (Salmo marmoratus) were measured separately in order to determine their metabolic properties in relation to size. The results showed that larger females produced larger eggs in higher numbers. Growth experiments on the survival of offspring of a single female revealed that the survival rate of early embryos was higher for smaller eggs during the earliest stages, but ultimately the percentage of surviving larvae did not correlate with egg size. The ETS activities and respiration rates of non-fertilized eggs, eyed eggs and larvae differed significantly between 13 females. Both parameters increased with increasing dry mass of the early life history stages, but the increase of respiration rate was greater than that of ETS activity. The lower ETS/R ratios in larger individuals therefore indicate that their energy metabolism was less adaptable to environmental changes than that of smaller ones. Larger egg size could be an advantage under favourable conditions, whereas smaller size could be optimal under stressing circumstances in which the higher metabolic potential enables production of the energy required for metabolism. This is first report on the relationship between ETS activity and respiration rate of the early life history stages in salmonids.
Keywords: Salmo marmoratus, fitness, metabolism, ETS activity, ETS/R ratio, fishes
Published in DiRROS: 29.07.2024; Views: 130; Downloads: 67
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Abstract: The number of freshwater species belonging to the genus Parastenocaris reported from ten countries of Southeast Asia is quite limited. Only two species have been reported so far from freshwater habitats there, compared to over 290 described species of the family Parastenocarididae worldwide. During the first study of the hyporheic zone of two small rivers in central Vietnam, two new species of the family Parastenocarididae were collected, Parastenocaris sontraensis sp. nov. and Parastencaris vugiaensis sp. nov. Both were collected from the gravel bar along the rivers (Suoi Da and Vu Gia river) using the Karaman–Chappuis method. Both the new species belong to the brevipes group of the genus Parastenocaris Kessler, 1913 sensu Lang (1948), and Reid (1995). Parastenocaris sontraensis sp. nov. is similar to P. hinumaensis Kikuchi, 1970 and Parastenocaris jane Karanovic, 2006 in the brevipes-group. Parastenocaris sontraensis sp. nov. differs from both Parastenocaris species by (i) Exp P3 with three segments in the male, (ii) caudal rami with seven setae, and (iii) caudal rami about 2.4 times as long as wide. Parastencaris vugiaensis sp. nov. can be distinguished from its congeners by the unique combination of the following characters: (i) the elliptical shape of caudal rami, (ii) apical seta (V) with bulbous base, and (iii) anal operculum extends beyond the end of anal somite. Until now, 14 stygobiotic species of Copepoda have been recorded in Vietnam (including two new species in this paper), which is relatively few compared with nearby Thailand with 25 species. Short comments on other stygobiotic Copepoda from Vietnam are added.
Keywords: Southeast Asia, groundwater fauna, hyporheic zone, Copepoda, new species, taxonomy
Published in DiRROS: 19.07.2024; Views: 114; Downloads: 96
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Abstract: Two new species of copepods of the genus Elaphoidella Chappuis, 1929 were discovered in a cave and a spring in northeastern Thailand. The first species, E. phuphamanensis sp. nov., belongs to species-group VII sensu Lang. It is most similar to E. turgisetosa Petkovski, 1980 in the armament of the male third exopod of the fourth swimming leg and the shape and armament of the fifth swimming leg in both sexes. However, it is easily distinguished from other congeners by the segmentation of the first swimming leg, the endopod of the fourth swimming leg, and the armature of the third exopod of swimming legs 2–4 in both sexes. The second species, E. propecabezasi sp. nov., is located in species-group I sensu Lang, where the male does not have a transformed seta on the third exopod of the fourth swimming leg and the female fifth swimming leg has four baseoendopodal robust setae, unequal in length. It is most similar to E. cabezasi Petkovski, 1982 and E. paraaffinis Watiroyram, Sanoamuang and Brancelj, 2017 in having the same armature formula as endopods 1–2 of female swimming legs 1–4. However, the ornamentation of the anal operculum, the shape of the caudal ramus, and the armature of the fifth swimming leg in both sexes distinguish them from each other. A rare gynandromorphic specimen of E. propecabezasi sp. nov. was recorded, and a revised key to Elaphoidella species in Southeast Asia is provided.
Keywords: cave-dwelling copepods, endemic distribution, groundwater habitats, intersex, morphology, zoology, Southeast Asia
Published in DiRROS: 17.05.2024; Views: 292; Downloads: 424
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