Contribution to the macroinvertebrate fauna of the Hungarian Danube. VII. Isopods (Crustacea: Malacostraca: Isopoda)

In this part of the series the records of aquatic isopods in the collection of the Danube Research nInstitute (former Hungarian Danube Research Station) are presented. Two species (Asellus aquaticus and Jaera sarsi) have been identified in 379 samples collected between 1994–2009 at 195 sites of the Hungarian Danube section (main channel, side branches, and adjacent wetlands)

Contribution to the macroinvertebrate fauna of the Hungarian Danube. V. Amphipods (Crustacea: Malacostraca: Amphipoda)

This paper provides occurrence data of amphipod species collected by the staff of the Hungarian Danube Research Station from 1994 to 2009. Altogether 751 samples from 209 sampling locations of the Hungarian Danube section (main channel, side branches, and adjacent wetlands) were processed, and 12 species were identified

Fermentative hydrogen production by conventionally and unconventionally heat pretreated seed cultures: a comparative assessment

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Fermentative hydrogen production by conventionally and unconventionally heat pretreated seed cultures: A comparative assessment

In this study, the effects of pretreatment temperature and time during conventional and unconventional, microwave-assisted heat shock on the hydrogen producing capability of anaerobic seed sludge from soluble starch was focused. It was found that the different heat transfer techniques resulted in seed cultures with comparable hydrogen production potentials, with the highest obtainable values of approximately 0.9 L H2/L-d. A comprehensive, statistical analysis revealed that both treatment temperature and time could be designated as significant process variables, however, in distinguishable extents for the two alternative methods. The results indicated that microwave-based sludge pretreatment needed remarkably shorter curing times (2 min) to eliminate H2-consuming, methanogenic activity in comparison to the conventional heat shock method (30 min). It was also demonstrated that microwave irradiation increased the soluble organic matter content in the seed sludge. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved

Is subterranean lifestyle reversible? Independent and recent large-scale dispersal into surface waters by two species of the groundwater amphipod genus Niphargus

Abstract Groundwater is an extreme environment due to its absence of light, resource scarcity and highly fragmentary nature. Successful groundwater colonizers underwent major evolutionary changes and exhibit eye and pigment loss (troglomorphies). Consequently, their chances of dispersal and survival in the well-connected surface waters are greatly decreased, resulting in significant endemism. The West Palaearctic subterranean amphipod genus Niphargus comprises hundreds of narrowly endemic and troglomorphic species. Nevertheless, a few are known to occur in surface waters, two of which, N. hrabei and N. valachicus, have extremely large ranges that even exceed those of many surface-water amphipods. We tested if this pattern results from a secondary colonization of the relatively well-connected epigean environment, and whether this ecological shift promoted the large-scale dispersal of these species. Results showed that despite their ecological and zoogeographic similarities, N. hrabei and N. valachicus are not closely related and independently colonized surface waters. Their phylogeographic patterns indicate Middle to Late Pleistocene dispersal episodes throughout the Danube lowlands, and relatively modest yet significant genetic differentiation among populations. Clustering based on morphology revealed that the two species are phenotypically closer to each other than they are to most other epigean congeners. We presume that the ecological shift to surface environments was facilitated by their ability to thrive in hypoxic waters where rheophilic competitors from the family Gammaridae cannot survive. In conclusion, our results indicate that adaptation to groundwater is not a one-way evolutionary path and that troglomorphic species can occasionally recolonize and widely disperse in surface waters