Internationale Revue der gesamten Hydrobiologie und Hydrographie

Published by Wiley-VCH Verlag
Online ISSN: 1522-2632
Print ISSN: 1434-2944
Publications
It has been two decades since 1993 when research on the biology of rotifer aging was last reviewed by Enesco. Much has transpired during this time as rotifer biologists have adapted to the "omics" revolution and incorporated these techniques into the experimental analysis of rotifers. Rotifers are amenable to many of these approaches and getting adequate quantities of DNA, RNA, and protein from rotifers is not difficult. Analysis of rotifer genomes, transcriptomes, and proteomes is rapidly yielding candidate genes that likely regulate a variety of features of rotifer biology. Parallel developments in aging biology have recognized the limitations of standard animal models like worms and flies and that comparative aging research has essentially ignored a large fraction of animal phylogeny in the lophotrochozoans. As experimentally tractable members of this group, rotifers have attracted interest as models of aging. In this paper, I review advances over the past 20 years in the biology of aging in rotifers, with emphasis on the unique contributions of rotifer models for understanding aging. The majority of experimental work has manipulated rotifer diet and followed changes in survival and reproductive dynamics like mean lifespan, maximum lifespan, reproductive lifespan, and mortality rate doubling time. The main dietary manipulation has been some form of caloric restriction, withholding food for some period or feeding continuously at low levels. There have been comparative studies of several rotifer species, with some species responding to caloric restriction with life extension, but others not, at least under the tested food regimens. Other aspects of diet are less explored, like nutritional properties of different algae species and their capacity to extend rotifer lifespan. Several descriptive studies have reported many genes involved in rotifer aging by comparing gene expression in young and old individuals. Classes of genes up or down-regulated during aging have become prime targets for rotifer aging investigations. Alterations of gene expression by exposure to specific inhibitors or RNAi knockdown will probably yield valuable insights into the cellular mechanisms of rotifer life extension. I highlight major experimental contributions in each of these areas and indicate opportunities where I believe additional investigation is likely to be profitable.
 
Repeated measures linear mixed models analyzed with restricted maximum likelihood analysis of square root transformed lifespan and total lifetime fecundity, reporting F statistics and p-values for fixed effects
Here we report one of the first investigations of evolvability of lifespan and reproduction in metazoans, examining both extrinsic and intrinsic factors. We tested effects on senescence of an environmental variable (simulated lake hydroperiod, the length of time an aquatic habitat is inundated), female reproductive physiology (asexual females that reproduce by ameiosis, versus sexual females reproducing by meiosis), and time in a benign culture environment (minimal, if any, external mortality factors). To do this we established chemostat cultures of the rotifer Brachionus plicatilis s.s., and maintained the cultures for 385 d. Hydroperiod alone or in interaction with the effects of time in the benign environment (season) or reproductive physiology had no significant effect on the net reproductive rate, generation time, or rate of aging. Yet combining animals from both ephemeral and permanent hydroperiods revealed a 26% increase in asexual female lifespan across seasons (23% decrease in the rate of aging) and a 56% increase in asexual fecundity, suggesting that maintenance in benign laboratory conditions leads to slower aging. The relative stasis of traits for sexual females implies an impact of reproductive physiology on evolvability. In addition we found a positive correlation between fecundity and lifespan, suggesting an absence of trade-offs in life history traits in the benign laboratory environment.
 
Alpine stream systems are known to be affected by the prevailing water sources (glacial, non-glacial), regional climate and the vegetation of the watershed. Especially at higher altitudes, these conditions influence and shape abiotic factors and the biology of stream reaches, there usually resulting in harsh environmental settings for the biota. Little is known about nutrients, food availability and food utilization in these systems. We investigated the physico-chemical conditions, food resources (DOM, CPOM, FPOM, seston, Aufwuchs) and the bottom fauna in nine reaches of different stream types (glacial, non-glacial systems) above and below the treeline in two seasons. Gut content and stable isotope (δ 15N, δ 13C) analysis were used to estimate food consumption and assimilation for dominant species. Although most of the taxa were detritivores, some species showed a preference for specific food items. Both, the principal dietary component as well as stable isotope analyses confirmed the placement of taxa into functional feeding guilds. In addition the results of stable isotope analysis suggested opportunistic feeding of several species. Autochthony appeared to play an important role even in glacial streams, where long snow cover, frequent flooding and high turbidity limit Aufwuchs development for most months of the year.
 
Eight New Zealand lakes were surveyed for 14C uptake by phytoplankton as a function of light intensity. The results support the view that the photosynthetic picoplankton is an important contributor to primary productivity in oligotrophic lakes but is relatively unimportant in more eutrophic lakes. A comparison of carbon uptake vs. light intensity characteristics (P vs. I) of the picoplankton size class vs. that of the total phytoplankton community supports the view that the picoplankton size class may be adapted to utilization of dimmer light.
 
Tubifex tubifex (Müller, 1774) was found in the profundal of 23 Estonian lakes out of the 187 lakes where oligochaetes were met in the deeper zone: in 4 cases as the single tubificid species but usually together with Potamothrix hammoniensis (Michaelsen) dominating in almost all lakes. T. tubifex was abundant and large in size in the profundal of a few lakes with mesotrophic features but scarce and dwarfish (if not lacking) in the common eutrophic ones. Observations in aquaria demonstrate that its occurrence in eutrophic lakes is not limited by the bacterial food. Some kind of competition with P. hammoniensis can be supposed but no direct evidence exists. Recent colonization of the profundal of an eutrophic lake by T. tubifex, probably from the littoral of the same lake, was observed.
 
The assemblage of Anemonia viridis which is an important component of the photophilic soft algae biocoenosis, has not been adequately studied up to date. The A. viridis assemblage studied, was poor in species number compared to other photophilic soft algae assemblages, possibly because of its peculiar physiology and competition for space. Three age groups of A. viridis were distinguished, two of which (the first and the third) showed significant seasonal variations. The reasons for this are still unclear and may depend on recruitment, competition among small-sized individuals, predation or other mortality factors, and migration of larger individuals.
 
This study aims to evaluate the suitability of non-linear geostatistics and indicator kriging (IK) as a tool in environmental impact assessment and nature conservation, in particular to search for potential Special Areas of Conservation (SAC) for the endangered fish species twaite shad, Alosa fallax(Lacepède, 1803) within the German Exclusive Economical Zone (EEZ) of the North Sea. To analyse the spatial distribution of this fish species, data on standardised biomass index (catch per unit effort, c.p.u.e., kg × 30 min–1) from 1996 to 2001 were used, regarding the third and fourth quarters of each year, respectively. Thereby we assume that the spatial distribution can be described as a time-invariant process. This assumption is supported by information on annual sampling effort, allocation of hauls and spatial distribution of the positive catches. All indicator variograms obtained for different c.p.u.e. cut-off values displayed distinct spatial structures, clearly indicating that the indicator variables were spatially autocorrelated. Gaussian models were fitted by least-squares methods and were evaluated with a goodness-of-fit statistic. Subsequently, IK was employed to estimate the probability of exceeding the c.p.u.e. cut-off values for the twaite shad in the investigation area. These were highest in the Weser- and Elbe-estuary, probably because of migrations of twaite shad to and from estuaries at the time of investigation due to spawning, while within the German EEZ of the North Sea no such areas with increased probabilities could be discerned. Thus, although available data did not allow to identify and implement any SAC in the German EEZ, the methods employed here can be regarded as a promising management tool in biological conservation issues. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
 
Pseudohaplocaulus infravacuolatus nov. spec. and Vorticella chlorellata Stiller, 1940. two peritrich ciliates attached to planktonic coenobia of Anabaena sp. (Cyanophyta). were investigated using live observation, silver impregnation, and scanning electron microscopy. Pseudohaplocaulus infravacuolatus differs from its nearest relative, P. anabaenae (Stiller, 1940). mainly by the location of the anterior contractile vacuole. Vorticella chlorellata has symbiotic green algae. a J-shaped macronucleus. and a single, ventral contractile vacuole. The number of silverlines is very close to that of V. picta, but distinctly different from that of V. chlorostigma (Ehrenberg, 1931), an other green Vorticella, redescribed for the first time. Vorticella rhabdostyloides Kellicott, 1885 is recognized as a distinct species, but transferred to Haplocaulus: H. rhabdostyloides (Kellicott, 1885) nov. comb. Likewise, Vorticella fasciculuta Müller, 1773 is considered a distinct species and transferred to Pseudovorticella: P.fasciculata (Müller, 1773) nov. comb.
 
Some aspects of the biology and ecology (life cycle, feeding and production) of a population of Isoptena serricornis in the Rudava River (Slovakia) are studied, reported and discussed. The life cycle is annual, with slow growth in autumn-winter and fast growth in late summer and spring. The growth decreased two weeks before the Fall Equinox and increased two weeks after the Spring Equinox. The flight period spans from the end of May to the beginning of July. The presence of large sand particles in the gut of all studied nymphs is of note, and indicates that I. serricornis acts as a deposit-collector species. Nymphal food is principally composed of detritus, unicellular organisms and, in nymphs of intermediate or large size, Chironomidae larvae. Adult food is composed fundamentally of different types of pollen grains. Males usually have lower food content than females. Annual production of this species (∼694–750 mg · m−2) is very high in relation to other previously studied Chloroperlidae. This is probably largely responsible for I. serricornis being one of the most abundant components of the macroinvertebrate community in its habitat in the Rudava River. A negative correlation between production and temperature was observed.
 
The genus Bosmina can be differentiated into four subgenera: 1. Bosmina s. str. BAIRD, 1845, 2. EubosminaSELIGO, 1900, 3. NeobosminaLIEDER, 1957, and 4. SinobosminaLIEDER, 1957. Subgeneric discrimination is based upon several features of the females (postabdominal claw, serration of the mucro, patterns of the lateral head pores) and, mainly, upon certain differences in the morphology of the male (postabdomen and, according to LILLJEBORG 1900, BURCKHARDT 1924 and KOŘINEK 1971, the first leg). The distribution of the Bosmina subgenera throughout the world varies: Bosmina s. str. is distributed worldwide (except for Australia?), Eubosmina is holarctic, Neobosmina has been found in Africa, the neotropical zone, Australia and Oceania, and Sinobosmina occurs in East and South-East Asia.
 
The morphology of mandibles of Holopedium gibberum was studied using scanning electron microscopy. They are strongly asymmetric and differ with that of Anemia and Podonidae and similar with that of Branchinecta and Daphniiformes especially Penilia.
 
Two new species of the genus Diaphanosoma,D. oligosetum and D. dorotheae, from Louisiana and North Carolina respectively, are described. The former species has large head with protruding dorsal part, large lanceolate spine on the basipodite's distal outer end, an extremely reduced number of antennal setae, up to six in adult specimens, and unique armament of valve margin. On the whole, it shows the pronounced combination of primitive and specialized morphological traits. D. dorotheae is a member of D. brachyurum species group differing from its other known representatives in presence of a small but very conspicuous spine on the end of proximal segment of antennal exopodite and a variable number of setae (seven or eight) on the distal segment of the branch. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
 
Fine Structure of the Club Cells (Alarm Substance Cells) in the Epidermis of Astyanax mexicanus Filippi 1853 (Characinidae, Pisces) and its Cave Forms “Anoptichthys” The club cells in the epidermis of Astyanax mexicanus are of the same ultrastructure as those in other Ostariophysan fish. There are also no essential differences to be found between the club cells of epigean Astyanax mexicanus and its cave forms “Anoptichthys”. Our findings correspond to former statements in that the function of the club cells producing and releasing alarm substances has been maintained in the cave forms.
 
Kotov and Štifter (2006) revised the taxonomy of the genus Ilyocryptus Sars, 1862 (Branchiopoda: Anomopoda: Ilyocryptidae) and concluded that 28 species can be recognized as valid for the world fauna. In order to test phylogenetic relationships between the species and to contribute to a better understanding of the genus, a cladistic (using branch-and-bound search) analysis was conducted for 25 Ilyocryptus species (two of them with two subspecies). In total, 32 morphological characters were used. An evolutionary-morphological interpretation of the results was also made. Phylogenetic analysis revealed that Ilyocryptus elegans is an earlier derived member of the genus, while other species are separated into two main branches: agilis - and sordidus -lines (without reference to type of moulting). Species with incomplete moulting and species with complete moulting do not form separate clusters, suggesting an independent origin of incomplete moulting within different species groups. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
 
The cyclopoid copepod Metacyclops minutus, a typical species of temporary pools, shows an unusual life cycle in a small pond in South Germany. The species is present from April/May to December during which period it forms at least 8 generations. Winter and early spring, when the pond is frozen to the bottom, are spent in the bottom mud as C4 or C5 instars. M. minutus shows an extraordinarily low degree of sex size dimorphism (female: male body length ratio) and no significant differences in. copepodite development time between the two sexes. This, together with the exceptionally short durations of embryonic- and postembryonic development enables reproduction to start without delay and rapid population growth after harsh conditions. By these means M. minutus is the first species to reproduce after periods of extremely low water level; later, when conditions in the pond become more stable, M. minutus is surpassed in numbers by a coexisting, filterfeeding and parthenogenetically reproducing cladoceran Moina brachiata.
 
Analyses were made of subfossil Eubosmina remains from the Lake Neuendorfer See, a lake in the middle part of the river Spree in the “Urstromtal” of Baruth situated in the eastern part of Germany. In addition to Bosmina (Bosmina) longirostris (O. F. M., 1785) Bosmina (Eub.) longicornis longicornis Schoedler, 1866 occured in the lake from the Boreal (sediment depth 15.85 m) to the recent surface layers of the core. Other eubosminids did not occur during the history of the Lake Neuendorfer See with the exception of few remains of B. (Eub.) longispina, which were detected in the lowermost layers of the core during the late Pleistocene. In the present-day plankton, Bosmina (Eub.) l. longicornis was the only eubosminid found in the Lake Neuendorfer See. During the long period between colonization during the Boreal to the present, no changes were detected in typical morphological features of B. (Eub.) l. longicornis. All remains of Eubosmina in the layers above 15.85 m belong undoubtedly to the same taxon. No signs of any morphological instability (other then ontogenetic and cyclomorphic formchanges) or “morphological transition” (Hofmann, 1977) to other taxa could be found. By using paleolimnological analyses, the named taxon has proven to be a “good” entity within the group of long-spined taxa of the subgenus Eubosmina.
 
The autecology of Monhystera paludicola (n = 3766 individuals), a dominant nematode of Lake Königssee, was studied throughout the year 1986. The species comprised 2341% of all nematodes in the littoriprofundal and profundal. Mean yearly biomass was highest at 10 m depth (149 pg/lOO cm2, fresh weight). Abundance peaked twice a year in the littoral (winter and summer) and once in deeper regions (winter). The main reproductive period is the winter. Morphometric data (n = 658) revealed sexual dimorphism in size, body shape and weight. There was considerable water depth and time dependent variation in sex ratios. The proportion of individuals in the top sediment layer increased with water depth. Juveniles and adults were partially segregated in the sediment column. M. paludicola appears to undergo vertical migrations.
 
Field observations, laboratory experiments and a literature survey were conducted to evaluate the habitat characteristics of Eurytemoralacustris (Poppe 1887), a freshwater calanoid copepod species. Combined effects of temperature and oxygen concentration in the deep water of thermally stratifying lakes seem to be the ultimate factors governing the occurrence of the species throughout its home-territory. E. lacustris is largely restricted to relatively deep lakes (>30 m) providing a hypolimnetic refuge characterised by low temperatures (<∼10 °C) and oxygenated water during summer. Therefore, although the species is spread over much of Europe it was only found in a small number of lakes. Long-term records in different lakes revealed E. lacustris to be perennial with relatively high biomasses occurring from May to September. During thermal stratification on average 87% of the nauplii and 72% of the copepodite biomass was found in hypolimnetic waters colder than 10 °C. Diurnal vertical migration was observed for the copepodid stages, but the migration amplitude clearly decreased from May to September. The migration amplitude was significantly related to light intensity. According to its special habitat requirements, E. lacustris might be considered a glacial relict sensitive to temperature increase and oxygen depletion. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
 
A search of the literature on rotifers recorded from China, includes today 477 valid species names and 42 subspecies or infrasubspecific variants in 84 genera and 28 families recorded since 1893. Chinese rotifera research is reviewed, and all recorded species are listed with current taxonomic status and their first localities in China. Most of the named taxa are widely distributed or cosmopolitan, with only a small number (about 3%) possibly restricted to China. This fauna exhibits 15 endemic taxa. The composition and distribution of Chinese Rotifera are briefly analyzed. It is likely that considerably more rotifers remain to be described from China as further study to be carried on and taxonomic resolution improves.
 
The genus Cypretta VAVRA, 1895 from Malaysia, Indonesia and the Philippines is reviewed. Currently, eleven species are known from these areas. Two new species are described and two species are redescribed. Remarks and diagnostic illustrations are given for the known species.
 
The decline in recruitment of glass eels, elvers and young yellow eels to the Skagerrak-Kattegat area in Sweden was demonstrated by catch data from trawl hauls at sea (IKMWT) and from eel ladders in two rivers emptying in the Kattegat. A long term decline since the 1940's was indicated and the same short term decrease as observed in other European countries during the 1980's was proved.
 
This is the first report of parasite infestation of Tipulidae by water mite larvae in the middle reaches of a river in Japan. Forty-four species of adult crane flies were identified. The most abundant species was Antocha (Antocha) bifidaAlexander 1924 with 22204 individuals (76.5% were male). Some 2113 individuals (9.5%) were parasitized by water mites, viz., SperchonplumiferThor 1902 (maximum: 40/host, mean value: 3.5 ± 2.5/host). 73.1% of S. plumifer larvae were attached to the abdomen. Many S. plumifer larvae parasitized A. bifida adults from late May to early July, but after a small flood, few S. plumifer larvae were collected. Floods have a major impact on both the A. bifida population and on its parasite, the S. plumifer larval population. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
 
Size-frequency distribution (total length) of P. intricata nymphs. Box width is proportional to the total number of nymphs.
Annual and cohort mean density and biomass, production, P/B ratio and CPI (cohort production interval) of P. intricata at the sampling site.
Changes in density, biomass and mean biomass of individual of P. intricata at the sampling site.
Nymphal gut contents of P. intricata at the sampling site.
The nymphal biology (life cycle, secondary production and feeding) of a population of Protonemura intricata was studied in a calcareous stream with almost constant temperature (7–8 °C) through the year at Prosiek valley (Chočské Vrchy Mts., West Carpathians, Slovakia). The results were compared with those previously known for this species in other areas. According to our data, the species has a complicated life cycle consisting of two cohorts with different duration (probably a cohort splitting). This life cycle seems to be uncommon among the Plecoptera, which usually has simple univoltine or semivoltine life cycles, and could be probably attributed to the constant temperature regime similar to that of tropical environments. One factor, the photoperiod length, was positively correlated with monthly growth rates. The nymphal growth varied throughout the year, but the highest growth was in late spring and summer, and the lowest was in winter. The annual secondary production was very high (909.4 mg · m–2) despite not being the most frequent taxon in the stream. The highest monthly production values were observed in the autumnal-winter period (November–December) due to massive hatching of nymphs. The lowest production values were observed in late summer and early autumn. Analyses of gut contents showed that this species behaves mainly as gatherer-collector, but also as shredder and, occasionally, as scraper. Changes in the gut content composition were detected in relation to the size. Comparing our results with those of the literature, it can be inferred that different populations of P. intricata can show notable differences in their life history when inhabiting places with different thermal conditions. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
 
The leech Dina punctata Johanson, 1927 inhabits various types of running waters. This species appeared in Slovakia probably after the first Rhine-Main-Danube canal was built. Because little is known about its ecology, the aim of our study was to analyze the life cycle, individual growth rate, reproduction parameters and food composition of D. punctata in the Vydrica Stream. Samples of leeches were taken mainly each month from April 2003 to November 2004. The leech D. punctata had maximal 2-year life cycle there. Mature leeches, which were recognized by the presence of clitella, were present from April to the end of August. The most individuals mature at the age of 1 year. The breeding season of D. punctata peaks in June. The number of eggs per one cocoon is from 3 to 12. The mean successfulness of development of egg to embryo is 58%. Larvae from the family Chironomidae (28%), Gammarus fossarum (20%) and oligochaetes from the subfamily Naidinae (17%) are the dominant components of the feeding niche. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
 
A new species of AcanthocyclopsKiefer is described from central Mexico. It differs from its congeners by a combination of characters including mainly: 11–13 antennular segments, a spine formula of 3444 and modified setae on legs 2–4. The presence of a compound distal antennular segment is aberrant within the Cyclopoida. The new species seems to be related to Nearctic forms of the vernalis –robustus clade. Ancestors of this lineage probably reached central Mexico as a result of glaciation events and the new species is a remain of stranded postglacial populations; some of these forms were succesful in colonizing tropical lands. A key for the identification of the species of Acanthocyclops recorded in Mexico is included. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
 
Data on quantities of glasseels and elvers caught at 11 stations on the western and northern coast of Europe together with abundance indices for glass eels at Den Oever, Netherlands and for larvae in the Bay of Biscay are presented covering the period 1924 to 1988. Large catches were made in the 1960's and 1970's followed by a sudden and widespread, but not universal, decline in the 1980's. Catches within years between stations showed significant correlations in some cases but not in all.
 
Bryceella perpusilla n. sp. A. Habitus in dorsal view. B. Habitus in lateral view. C. Mastax hard parts (trophi) in dorsal view.
Light microscopic images of Bryceella perpusilla n. sp. A. Adult specimen in ventral view. B. Specimen with currently deposited egg. C. Foot with retracted toes. D. Inner organization. E. Mastax hard parts (trophi). br brain, eg egg, fo foot, fu fulcrum, gg gastric gland, ma manubrium, ra ramus, st stomach, un uncus, gv germovitellarium. 
SEM images of the Bryceella perpusilla n. sp. A. Specimen in dorsal view. B. Specimen in lateral view. C. Head with rostrum. D. Corona in ventrolateral view. E. Foot in dorsal view. F. Head with dorsal antenna. ca caudal antenna, da dorsal antenna, fo foot, lps lumbar pseudosegment, ne neck, pps preanal pseudosegment, sty stylus Arrow head (epidermal projection covering dorsal antenna). 
SEM images of the trophi of Bryceella perpusilla n. sp. A. Dorsal view. B. Ventral view. C. Dorsolateral view. D. Dorsofrontal view. E. Dorsal view. F. Hypopharynx in dorsal view. al alulae, dmc dorsal manubrial chamber, ds distal subuncus, fu fulcrum, hyp hypopharynx, ma manubrium, ra ramus, rfsb ramus foramen subbasalis, rfb ramus foramen basalis, un uncus, vmc ventral manubrial chamber. 
We here describe the new proalid rotifer species Bryceella perpusilla n. sp. on the basis of light and electron microscopy. The species, certainly representing one of the smallest rotifer and even metazoan species at all, was obtained in January 2008 from terrestrial mosses of North-west Germany. Bryceella perpusilla n. sp. is distinguished from other species of the genus by the very small size, the slender body outline, the short apical styli, the triangular rostrum, the outward curving, blunt and rod-shaped toes, the four-nucleated vitellogermarium, the slender manubria and the caudally directed alulae. With our observations, that can be used for future cladistic analyses of the Proalidae, we are able to define the generic diagnosis of Bryceella more precisely and to give an adapted species key. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
 
Top-cited authors
Manuel Graça
  • MARE Marine & Environmental Research center University of Coimbra
Michael Hupfer
  • Leibniz-Institute of Freshwater Ecology and Inland Fisheries
Alex David Rogers
Jörg Lewandowski
  • Leibniz-Institute of Freshwater Ecology and Inland Fisheries
Charles Heckman