Bosmina Species Research Articles

A new species of Bosmina (Liederobosmina) Brték, 1997 (Cladocera: Bosminidae) from high mountain lakes of Colombia.

Insufficient attention has been recently paid by the taxonomists to the family Bosminidae Baird (Crustacea: Cladocera). Here we describe a new species of Bosmina (Liederobosmina) Brték from high mountain water bodies of Colombia which is unique among all bosminids having heavily striated valves. Most probably, this taxon has a narrow distribution area in the Andean high mountains. It is obvious that the Andean highlands must be studied in detail, i.e. using molecular methods, and more new taxa might be detected in the future.

Miocene cladocera from Poland

The Bełchatów Lignite Mine of Poland is a treasure-cove for mid-to late Miocene plant and animal fossils, deposited in a slow-flowing river valley with swamps and oxbow lakes. Here, we report the finding of abundant fossil anomopod cladocerans. Some are three-dimensionally preserved, including the taxonomically important trunk limbs. They pertain to the families Chydoridae and Bosminidae, with species similar to but distinct from modern ones. All are members of the zooplankton, though some are littoral while others are pelagic in nature. Morphological stasis in these families is not outspoken as in the Daphniidae and the stasis hypothesis, based on ephippia only, is challenged. The absence of Daphnia is conspicuous and ascribed to a combination of fish predation and local water chemistry. Its place in the oxbow lakes is taken by at least two Bosmina species, one of which is undescribed. We consider this a case of paleo-competitive release. For Bosminidae, these are the first certified fossils predating the Pleistocene.

Cladocera remains and vegetation types to assess the state of oxbows

We assessed the usefulness of Cladocera remains for establishing the ecological status of oxbows and also tested the association of Cladocera species with various vegetation types. Cladocera remains were collected from the surface sediment of four habitat types (tangled vegetation, open water, reeds and tunnels) and 15 physical and chemical parameters of surface water were studied. In the surface sediment samples, we identified 32 Cladocera taxa. There was a significant difference in the number of species amongst habitat types as per ANOVA. The benthic and plant associated Cladocera communities of reeds, tangled vegetation, open water and tunnels were clearly separated from each other by NMDS ordination. CCA showed that habitat types had characteristic Cladocera species: Pleuroxus species were frequent in the tangled vegetation habitat, while Chydorus species were frequent in the open water. Remarkably, in reeds, Bosmina species were frequent, although these species are usually common in open water. Specimens of the Alona genus were found everywhere. Our findings suggest that the remains of Cladocera species may be useful indicators to assess and monitor the structure of freshwater lakes.

Dynamics of Cladocera Community in a Tropical Hypereutrophic Environment (Garças Reservoir, São Paulo, Brazil)

This study was performed at Garcas Reservoir, a hypereutrophic urban lake within Sao Paulo metropolitan area, Southeast Brazil. This reservoir underwent to a marked limnological change after the harvest of free floating macrophytes, shifting to a hypereutrophic state. Present purposes were to characterize the Cladocera community and verify its association with the water deterioration after the macrophytes removal period as well as to compare it to previous studies, before macrophytes harvesting. Samplings were collected from October 2007 until September 2008 and the results were compared to data obtained during pre-removal period (1997). Principal Component Analysis (PCA) showed that the highest values for water transparency were associated with the macrophytes pre-removal period while the highest values of electrical conductivity, chlorophyll a and total phosphorus were associated with the macrophytes post-removal period, indicating the degradation of the water quality. During this period, large cladocerans disappeared and the small sized species of Bosmina predominated. Male organisms of this genus were found as well as elevated densities of Bosmina huaroensis, suggesting overcrowding. Furthermore, it was detected a reduction of 82% in the number of species compared to data from 1997. The shifts to the hypereutrophic state led to aggressive alterations in Cladocera community, suggesting a strong stress on populations.

Palaeolimnological evidence of Bosmina morphotypes appearance in the late Holocene

Lacustrine sediments retain Cladocera (Crustacea) subfossils (carapaces, ephippia, head shields, and postabdomens) from the Holocene, which allows reconstructing past aquatic communities and environmental changes. In late Holocene (Subatlantic) fossils, among many Cladocera species, we noticed the appearance of several Bosmina ( Eubosmina) species in lakes surrounding the Baltic Sea. These species were never recorded in the early Holocene. The appearance of these species is a record of very recent speciation, which took place during the last millennium in lakes surrounding the Baltic Sea. Contemporary data show co-occurrence of several Bosmina ( Eubosmina) species ( longispina, kessleri, reflexa, ruehei, coregoni, gibbera, thersites). These species are not a product of invasion or introgressive hybridization, but in fact, they are probably a product of speciation. Here, we present the palaeolimnological evidence of this speciation from the only one species, Bosmina ( Eubosmina) longispina, found in lacustrine sediments from the last interglacial and glacial periods.

Competitor density and food concentration: an empirical approach to elucidate the mechanism of seasonal succession of two coexisting Bosmina

To examine the density effect and food concentration in the competitive output of two Bosmina species, the population growths of Bosmina fatalis were investigated by manipulating the density of B. longirostris and the concentration of algae. The B. fatalis density did not increase in conditions with abundant B. longirostris regardless of the food concentrations. The B. fatalis increased only at low densities of B. longirostris with high food concentrations. Based on the current results, a possible mechanism underlying the seasonal shift from B. longirostris to B. fatalis in Japanese eutrophic lakes will be explored below.

The late Holocene appearance of European Bosmina (Eubosmina) thersites (Crustacea, Cladocera) in lakes surrounding the Baltic Sea

This study shows the appearance of Bosmina (Eubosmina) thersites during the last millennium in two lakes in Northern Europe: Lake Charzykowskie (Poland) and Lake Lohja (Estonia). Cladocera remains collected from both lakes showed similar Bosmina species composition and changes during the late Holocene. Older sediment layers showed a prevalence of smaller Eubosmina species (B. (E.) longispina), indicating oligotrophic conditions of the lakes, while younger layers were dominated by larger species (B. (E.) coregoni and B. (E.) thersites), typically found in lakes with higher trophy. The presence of B. (E.) thersites has rarely been reported in paleolimnological research, and this is the first observance of its high abundance in lake sediments. More research is needed, however, to better understand the appearance, speciation driver, continental range, and ecological preferences of B. (E.) thersites.

Paleolimnological reconstruction of the trophic state in Lake Balaton (Hungary) using Cladocera remains

The sediment of Lake Balaton (Hungary) provides important information about the lake’s history, particularly with regard to eutrophication. In this study, we used fossil pigment analysis and subfossil Cladocera remains preserved in a dated sediment core to identify trophic stages from ~250 bc to present. Dates of the most recent eutrophic events are in good agreement with previously published data. In general, the abundance and diversity of the Cladocera community increased with eutrophication and decreased with oligotrophication. The sediments of Lake Balaton were characterised by Chydoridae remains, of which Alona species were the most abundant. Of these, Alona quadrangularis and Alona affinis accounted for 40 and 20% of the total Cladocera remains, respectively. The trophic state of Lake Balaton varied between mesotrophic and eutrophic regimes. Seven different trophic periods were identified in Lake Balaton on the basis of Sedimentary Pigment Degradation Unit (SPDU) content of the sediment. Eutrophic states were (1) from ~250 to ~30 bc, (3) between ~300 and ~590 ad, (5) between 1834 and 1944 and (7) from the 1960s until present. Mesotrophic states were (2) ~30 bc to ~300 ad, (4) 590–1834, (6) 1944–1960s. Discriminant analysis of the cladoceran data confirmed these historic events, except for the short mesotrophic episode between 1944 and 1960. The first stage of eutrophication of Lake Balaton (~250 to ~30 bc) was characterised by extensive macrophyte vegetation, as indicated by the increasing abundance of vegetation-associated Cladocera species (Eurycercus lamellatus, Sida crystallina, Pleuroxus sp.). Intensification of eutrophication was identified since the 1980s, reflected by a high abundance of Bosmina species. The most significant planktivorous fish of Lake Balaton was the Sabre carp (Pelecus cultratus), and when its number decreased, the abundance of Bosmina species increased. This study shows that Cladocera are responsive to trophic state changes, underlining their importance as a tool for the assessment of lake eutrophication.

Revision of the genusBosminaBaird, 1845 (Cladocera: Bosminidae), based on evidence from male morphological characters and molecular phylogenies

The systematics of the freshwater crustacean genus BosminaBaird, 1845 (Anomopoda: Bosminidae) is notoriously confused. Part of the problem stems from a lack of characters in this cyclic parthenogen. We aimed to remedy this problem by scoring male morphological characters (previously described in just a few species), and by estimating molecular phylogenies. More specifically, the goals of this investigation are: (1) a detailed description of the adult males of Bosmina species; (2) a study of the changes of male characters during the postembryonic development in different subgenera; (3) an analysis of the taxonomical value of male characters; and (4) the estimation of a phylogenetic tree based on male characters and genetic characters from mitochondrial 16S rDNA and nuclear rDNA-internal transcribed spacers (ITS) gene sequences. We redescribed males of ten species: Bosmina (Bosmina) longirostris (O. F. Müller, 1785); Bosmina (Bosmina) liederiDe Melo & Hebert, 1994; Bosmina (Sinobosmina) Burckhardt, 1924; Bosmina (Sinobosmina) cf. fatalis cyanopotamiaBurckhardt, 1924; Bosmina (Liederobosmina) meridionalisSars, 1904; Bosmina (Liederobosmina) cf. hagmanniStingelin, 1904; Bosmina (Lunobosmina) oriens (De Melo & Hebert, 1994); palaearctic Bosmina (Eubosmina) cf. coregoni Baird, 1857 (including the morphs ‘coregoni s.s.’, ‘coregoni kessleri’, ‘longispina’, and ‘crassicornis’); Beringian ‘Bosmina (Eubosmina) cf. longispina Leydig, 1860’; and Bosmina (Eubosmina) tanakai sp. nov. In addition, we fully redescribe B. (Lunobosmina) oriens and describe B.(E.)tanakai sp. nov. (an endemic Japanese lineage of the subgenus Eubosmina). A cladistic analysis of 24 morphological characters of males led to a single most parsimonious tree that agreed with phylogenies based on 16S mtDNA and nuclear genes. Both the male morphological and the genetic analyses indicated that the Japanese lineage containing B.(E.)tanakai sp. nov. is divergent and unique. Thus, these approaches resolved relationships that were unresolved with female morphology. Divergent life history evolution appears to have rendered male morphology more informative than female morphology for systematic biology. We provide a key for Bosmina species with adequately described males.

Cladoceran remains in lake sediments: a comparison between plankton counts and sediment records

To evaluate the comparability of neo- and paleo-limnology, we made year-to-year as well as seasonal comparisons of contemporary zooplankton data and cladoceran remains in thick (9–42 mm) annual laminations in sediment of Lake Vesijarvi, southern Finland. We calculated the expected annual exuviae production of nine planktonic taxa in the water column using contemporary zooplankton records, and compared the value to the observed net accumulation of their remains in deep sediment for 7 years. Although all of the species studied occur commonly in the lake pelagic zone, deposition of remains differed significantly among taxa. The observed accumulation of three Bosmina species and Chydorus sphaericus was similar to or exceeded expected values, suggesting good preservation of their remains as well as focusing of sediment into the deepest part of the lake. The accumulation of Limnosida and Leptodora remains exceeded expected values several fold, suggesting under-representation of these species in pelagic plankton samples, as well as efficient transportation and spatial averaging of their remains in the sediment. Daphnia, Diaphanosoma, and Ceriodaphnia were clearly under-represented in the sediment due to poor preservation of their remains and use of a 50-μm sieve in sediment processing. Thus, sieving should be taken into account as a possible source of bias. Correlation between relative abundances of all species in the sediment and in the plankton was weak (rs = 0.54, P < 0.001), but for well-preserved species, the correlation was strong (rs = 0.91, P < 0.001). Inter-annual variation in the deposition of remains suggested that resuspension and sediment focusing may vary between years, thus making it difficult to interpret absolute abundances, even though the deepest part of the basin shows clear varve formation and seasonality is well recorded. Detailed study of the uppermost lamination showed the seasonal succession of a cladoceran community within an annual varve as well as differences in the seasonality and intensity of ephippia production among the species. We recommend that results of cladoceran analyses be expressed in several ways (relative abundances, per unit dry weight, per unit organic matter, and as net accumulation values) before drawing final conclusions, as each approach may reveal a different aspect of the deposition process. In addition, sedimentation differences between epilimnetic and hypolimnetic species should be considered in stratified lakes.

Impact of an Insecticide on Persistence of Inherent Antipredator Morphology of a Small Cladoceran, Bosmina

Pesticides often modify predatory interactions by enhancing (or inhibiting) the development of antipredator morphologies of freshwater cladocerans. In the present study, we assessed the impacts of an insecticide, carbaryl, on the life-history parameters of a polymorphic cladoceran, Bosmina longirostris, and on Bosmina-copepod interaction. In this Bosmina species, all juvenile individuals have the defensive morphology irrespective of presence of predators in juvenile stages, and they lose or maintain such morph compliance with the presence/absence of the predators in adult stages. In the present study, individual somatic growth and population growth rate decreased due to applied carbaryl. Moreover, the animals lost the defensive morphology when their body size was smaller than with no-carbaryl treatment even in the presence of predators, indicating that the insecticide inhibited persistence of the inherent antipredator morphology. Such a chemical disturbance will increase the predation risk to individuals and, in turn, influence the population dynamics of the bosminids through increased mortality.

Impact of selective predation by Mesocyclops pehpeiensis on a zooplankton community: experimental analysis using mesocosms

AbstractPredation by cyclopoid copepods is an important factor affecting zooplankton communities in freshwater habitats. Experiments provide strong evidence of the role of selective predation by cyclopoid copepods in structuring zooplankton communities. To assess the predation impact of a cyclopoid copepod, Mesocyclopspehpeiensis, we conducted a mesocosm experiment using 20‐l polyethylene tanks in which the density of the predator and the food available to herbivorous zooplankton varied. M. pehpeiensis had a notable but selective effect on the zooplankton community. The population of a small cladoceran, Bosmina fatalis was affected negatively, but M. pehpeiensis did not have any apparent impact on the population dynamics of another Bosmina species, B. longirostris. On the other hand, the population of small rotifers responded positively to the presence of M. pehpeiensis, and their densities increased in mesocosms with a high density of M. pehpeiensis. It seems that suppression of B. fatalis by M. pehpeiensis predation indirectly affected rotifers by releasing them from competition with B. fatalis. The results suggest that copepod predation is a powerful factor regulating zooplankton communities directly and indirectly.

Abrupt Changes in Bosmina (Cladocera, Crustacea) Assemblages During the History of the Ostrowite Lake (Northern Poland)

During the 10000-year history of the Ostrowite Lake, there have been several episodes of change in dominance amongst species of the genus Bosmina. The dominants were alternately B.longirostris and Eubosmina spp. Amongst the subgenus Eubosmina, two species prevailed in different periods:Bosmina coregoni and Bosmina reflexa. The first species, Bosmina coregoni, is characterized by long antennae and short carapace mucrones, while the second one, Bosmina reflexa, by short antennae and very long mucrones. Bosmina reflexa was dominant at the beginning of the lake's history (Preboreal, 10000--9000 BP) and during the early Subboreal Period (5000–3500 BP). Only a small number of remains of Bosmina longispina(Eubosmina spp.) were present along the entire profile. Such strong changes in the domination of Bosmina species were observed for the first time in the sediments of Polish lakes. A similar transition from one species to another has been described in a few German lakes and was linked to climate changes. However, the changes in the Ostrowite Lake do not correlate with climate changes, but most probably, with changes in the lake's trophic level. This is suggested by the simultaneous increase of Bosmina reflexa and a good indicator of eutrophy, Bosmina longirostris.

Predation impact of Leptodora kindtii on population dynamics and morphology of Bosmina fatalis and B. longirostris in mesocosms

Summary1. We assessed the impact of predation by the invertebrate predator Leptodora kindtii on Bosmina longirostris and B. fatalis, which show seasonal and reciprocal succession patterns in Lake Suwa, in a mesocosm experiment using 20‐L tanks with or without the predator under different food conditions. We also analysed morphological responses of the two Bosmina species to the predator in the tanks.2. Bosmina fatalis dominated B. longirostris regardless of predator presence under high food density. However, the presence of Leptodora induced the dominance of B. fatalis more rapidly than its absence. On the contrary, no dominance of B. fatalis was observed in tanks with low food density, irrespective of the presence of the predator. Only B. fatalis showed morphological changes in response to the presence of Leptodora.3. Mucrone length and antennule shape (angle between body and antennule and angle between antennules) showed marked responses at both high and low food densities, but antennule length responded only at high food density. Mucrone length seems to be a more effective defence against Leptodora.4. The results suggest that B. fatalis is a superior competitor against B. longirostris and is more resistant to Leptodora predation, especially in good food conditions. The repeatedly observed seasonal succession of the two Bosmina species in the eutrophic Lake Suwa – the replacement of B. longirostris by B. fatalis following the occurrence of abundant Leptodora– seems to be caused by the selective predation of Leptodora on B. longirostris as well as the competitive ability of B. fatalis.

Seasonal and spatial distribution of two Bosmina species (B. longirostris and B. fatalis) in Lake Suwa, Japan: its relation to the predator Leptodora

In Lake Suwa, Japan, two Bosmina species, B. fatalis and B. longirostris, coexist and show different seasonal succession patterns. To determine the relative importance of factors affecting their succession, the seasonal and spatial distribution of the two Bosmina species and their relation to environmental variables were studied at six near-shore sites on Lake Suwa from May to October 2000, with measurements at each site made at 20 and 80 m from the shore. We analyzed the seasonal and spatial distribution patterns of Bosmina, rotifers, and the major invertebrate predators, cyclopoid copepods and Leptodora kindti. A range of variables (water temperature, dissolved oxygen concentration, and chlorophyll a concentration) was also measured. Multiple stepwise regression analysis was performed between Bosmina and the measured biotic and abiotic variables. Two species of Bosmina showed a marked pattern of seasonal succession, B. longirostris being dominant in May and October and B. fatalis exceeding B. longirostris in summer. However, the densities of both species and their density ratio differed between sites. The ratio of B. fatalis density to total Bosmina density, which indicates the dominance of B. fatalis, was correlated positively with water temperature and Leptodora density and negatively correlated with dissolved oxygen and cyclopoid copepod density. The results suggest that invertebrate predators play an important role in regulating the succession of Bosmina species in Lake Suwa.

Seasonal and reciprocal succession and cyclomorphosis of two Bosmina species (Cladocera, Crustacea) co-existing in a lake: their relationship with invertebrate predators

The seasonal succession and cyclomorphosis of Bosmina longirostris and Bosmina fatalis (also known as Sinobosmina fatalis) were investigated in the shallow eutrophic Lake Suwa from 1996 to 1999. Two different invertebrate predators, cyclopoid copepods and Leptodora kindtii, co-existed with Bosmina in the lake. A pattern of seasonal succession of the two species was apparent, with B. fatalis dominant in summer and B. longirostris in spring and fall. The two species also showed different seasonal changes in morphology. During summer, when the density of the invertebrate predator Leptodora was high, B. fatalis changed its morphology and maintained long features, with elongation of the antennules and mucrones. This species also maintained the protruding shape of the antennules by increasing the angles between the antennules and the body, and between two antennules, during the same period. The seasonal differences and magnitude of changes in morphology were more marked for larger individuals. However, such marked development of protruding structures was not observed in B. longirostris, which showed only slight changes in the antennule and mucrone lengths related to the density of copepods. The results suggest that the morphological traits of B. fatalis are a morphological defence against Leptodora, while those of B. longirostris are a response to copepods. In Lake Suwa, the predators show different patterns of seasonal changes in density. Different morphological traits and the resulting interactions with invertebrate predators seem to be important in determining the reciprocal succession of the two Bosmina species.

Can extreme morphology in Bosmina reduce predation risk from Leptodora ? An experimental test

Bosmina (Cladocera) populations, especially within the subgenus Eubosmina, show a variety of phenotypes that exhibit large differences in body size and shape and antennule length. In some populations, the morphological traits also vary during the season, with the most extreme forms occurring in periods with high densities of certain invertebrate predators. However, while temporal phenotypic variation in other cladocerans, as in the family Daphnidae, has been shown to be an adaptation to reduce the risk of predation by invertebrate predators, the reason for such changes in Bosmina is much less clear. We examined whether certain morphological traits in Bosmina species could act as a defence against invertebrate predators. We tested three Bosmina forms (subgenus Eubosmina), differing in morphology from each other, which are found in lakes together with the predator Leptodora kindtii (Cladocera). Bosmina (E.) longispina has a relatively low and elongated carapace with a caudal mucro, and short antennule, B. (E.) coregoni gibbera has a higher and more protruding carapace without caudal mucro, and a much longer antennule. Finally, B. (E.) coregoni retro extensa has a carapace like that of B. longispina but with no caudal mucro and a much longer antennule. In one experiment, B. longispina and B. gibbera were exposed for 12 h to Leptodora in Petri dishes. In a second experiment, we observed directly the escape efficiency of B. longispina, B. gibbera and B. retro extensa, and the handling time of Leptodora. The two Bosmina forms with more extreme morphological features had a lower death rate and higher escape efficiency than B. longispina. Prey that escaped did so, in most cases, within 5 min. Predator handling time was correlated to predator body length and antennule length of the prey. The results suggests that Bosmina species with extreme morphological traits may be less vulnerable to invertebrate predators.

Genetic characterization of an arctic zooplankter : insights into geographic polyploidy

Species of Bosmina from the temperate regions of North America and Europe are diploid and reproduce by cyclical parthenogenesis. By contrast, this study provides evidence that the dominant bosminid taxon in High Arctic lakes reproduces by obligate parthenogenesis and is a polyploid derived from interspecific hybridization. Sinobosmina liederi, a species common in temperate North America, is likely to have been one parent of these hybrids, but the other parent is unknown. As neither parent was detected in the Arctic, it seems unlikely that the hybrid clones that now occupy arctic lakes were synthesized locally. Most habitats contained only one or two clones, despite a total of 38 clones in the region, suggesting that priority effects have been important in restricting diversity within single lakes. The high regional diversity of arctic bosminids could reflect either repeated hybridization between the parent taxa or the genetic instability of newly formed polyploid lineages. These processes would produce hybrid polyploids that are considerably more diverse than their sexual parent taxa, and this difference in genetic diversity may confer an advantage to the polyploid biotype. As many zooplankton taxa from the arctic possess genetic characteristics similar to those of bosminids, these processes may provide a general explanation for the widespread occurrence of polyploids in the Arctic.

Clearance rates of Bosmina species in response to changes in trophy and food concentration

(1991). Clearance rates of Bosmina species in response to changes in trophy and food concentration. SIL Proceedings, 1922-2010: Vol. 24, No. 2, pp. 745-750.

Restoration by biomanipulation in a small hypertrophic lake: first-year results

Biomanipulation was carried out in order to improve the water quality of the small hypertrophic Lake Zwemlust (1.5 ha; mean depth 1.5 m). In March 1987 the lake was drained to facilitate the elimination of fish. Fish populations were dominated by planktivorous and benthivorous species (total stock c. 1500 kg) and were collected by seine- and electro-fishing. The lake was subsequently re-stocked with 1500 northern pike fingerlings (Esox lucius L.) and a low density of adult rudd (Scardinius erythrophthalmus). The offspring of the rudd served as food for the predator pike. Stacks of Salix twigs, roots of Nuphar lutea and plantlets of Chara globularis were brought in as refuge and spawning grounds for the pike, as well as shelter for the zooplankton. The impact of this biomanipulation on the light penetration, phytoplankton density, macrophytes, zooplankton and fish communities and on nutrient concentrations was monitored from March 1987 onwards. This paper presents the results in the first year after biomanipulation. The abundance of phytoplankton in the first summer (1987) after this biomanipulation was very low, and consequently accompanied by increase of Secchi-disc transparency and drastic decline of chlorophyll a concentration. The submerged vegetation remained scarce, with only 5 % of the bottom covered by macrophytes at the end of the season. Zooplankters became more abundant and there was a shift from rotifers to cladocerans, comprised mainly of Daphnia and Bosmina species, the former including at least 3 species. The offspring of the stocked rudd was present in the lake from the end of August 1987. Only 19% of the stocked pike survived the first year. Bioassays and experiments with zooplankton community grazing showed that the grazing pressure imposed by the zooplankton community was able to keep chlorophyll a concentrations and algal abundance to low levels, even in the presence of very high concentrations of inorganic N and P. The total nutrient level increased after biomanipulation, probably due to increased release from the sediment by bioturbation, the biomass of chironomids being high. At the end of 1987 Lake Zwemlust was still in an unstable stage. A new fish population dominated by piscivores, intended to control the planktivorous and benthivorous fish, and the submerged macrophytes did not yet stabilize.