Freshwater Biology Research Papers - Academia.edu (original) (raw)

1. We studied the effects of increased water temperatures (0–4.5 °C) and nutrient enrichment on the stoichiometric composition of different primary producers (macrophytes, epiphytes, seston and sediment biofilm) and invertebrate consumers... more

1. We studied the effects of increased water temperatures (0–4.5 °C) and nutrient enrichment on the stoichiometric composition of different primary producers (macrophytes, epiphytes, seston and sediment biofilm) and invertebrate consumers in 24 mesocosm ecosystems created to mimic shallow pond environments. The nutrient ratios of primary producers were used as indicative of relative nitrogen (N) or phosphorus (P) limitation. We further used carbon stable isotopic composition (δ13C) of the different primary producers to elucidate differences in the degree of CO2 limitation.2. Epiphytes were the only primary producer with significantly higher δ13C in the enriched mesocosms. No temperature effects were observed in δ13C composition of any primary producer. Independently of the treatment effects, the four primary producers had different δ13C signatures indicative of differences in CO2 limitation. Seston had signatures indicating negligible or low CO2 limitation, followed by epiphytes and sediment biofilm, with moderate CO2 limitation, while macrophytes showed the strongest CO2 limitation. CO2 together with biomass of epiphytes were the key variables explaining between 50 and 70% of the variability in δ13C of the different primary producers, suggesting that epiphytes play an important role in carbon flow of temperate shallow lakes.3. The ratio of carbon to chlorophyll a decreased with increasing temperature and enrichment in both epiphytes and seston. The effects of temperature were mainly attributed to changes in algal Chl a content, while the decrease with enrichment was probably a result of a higher proportion of algae in the seston and epiphytes.4. Macrophytes, epiphytes and seston decreased their C : N with enrichment, probably as an adaptation to the different N availability levels. The C : N of epiphytes and Elodea canadensis decreased with increasing temperature in the control mesocosms. Sediment biofilm was the only primary producer with lower C : P and N : P with enrichment, probably as a result of higher P accumulation in the sediment.5. Independently of nutrient level and increased temperature effects the four primary producers had significantly different stoichiometric compositions. Macrophytes had higher C : N and C : P and, together with epiphytes, also the highest N : P. Seston had no N or P limitation, while macrophytes and epiphytes may have been P limited in a few mesocosms. Sediment biofilm indicated strong N deficiency.6. Consumers had strongly homeostatic stoichiometric compositions in comparison to primary producers, with weak or no significant treatment effects in any of the groups (insects, leeches, molluscs and crustaceans). Among consumers, predators had significantly higher N content and lower C : N than grazers.

1. We investigated the effect of moderate eutrophication on leaf litter decomposition and associated invertebrates in five reference and five eutrophied streams in central Portugal. Fungal parameters and litter N and P dynamics were... more

1. We investigated the effect of moderate eutrophication on leaf litter decomposition and associated invertebrates in five reference and five eutrophied streams in central Portugal. Fungal parameters and litter N and P dynamics were followed in one pair of streams. Benthic invertebrate parameters that are considered useful in bioassessment were estimated in all streams. Finally, we evaluated the utility of decomposition as a tool to assess stream ecosystem functional integrity.2. Decomposition of alder and oak leaves in coarse mesh bags was on average 2.3–2.7× faster in eutrophied than in reference streams. This was attributed to stimulation of fungal activity (fungal biomass accrual and sporulation of aquatic hyphomycetes) by dissolved nutrients. These effects were more pronounced for oak litter (lower quality substrate) than alder. N content of leaf litter did not differ between stream types, while P accrual was higher in the eutrophied than in the reference stream. Total invertebrate abundances and richness associated with oak litter, but not with alder, were higher in eutrophied streams.3. We found only positive correlations between stream nutrients (DIN and SRP) and leaf litter decomposition rates in both fine and coarse mesh bags, associated sporulation rates of aquatic hyphomycetes and, in some cases, total invertebrate abundances and richness.4. Some metrics based on benthic invertebrate community data (e.g. % shredders, % shredder taxa) were significantly lower in eutrophied than in reference streams, whereas the IBMWP index that is specifically designed for the Iberian peninsula classified all 10 streams in the highest possible class as having ‘very good’ ecological conditions.5. Leaf litter decomposition was sufficiently sensitive to respond to low levels of eutrophication and could be a useful functional measure to complement assessment programmes based on structural parameters.

The aim of this study was a combined and multifaceted characterization (morphological, molecular, lipid, pigment, and ecological data) of a Lemanea (freshwater red alga) population from the south–eastern Alps, exploring its adaptive... more

The aim of this study was a combined and multifaceted characterization (morphological, molecular, lipid, pigment, and ecological data) of a Lemanea (freshwater red alga) population from the south–eastern Alps, exploring its adaptive strategies to the montane habitat, (turbulent, very–cold glacial stream with extremely low–conductivity). Although the thalli were small (only up to 1 cm), the morphology was within the current circumscription of Lemanea fluviatilis. The molecular data placed this population within a clade of specimens identified as L. fluviatilis and L. fucina. This L. fluviatilis population was determined to possess lipid classes, especially phosphatidylcholine and monogalactosyldiacylglycerol with high unsaturation index (UI) and long acyl chains, which are typical adaptations for maintaining adequate membrane fluidity and consequently all the metabolic processes associated to the plasma membrane. The carotenoids profile revealed that, besides α /β– carotene, there are significant amounts of zeaxanthin and lutein. This study further demonstrated that red algae are a rich source of important food web w–3 fatty acids and may play an important role in the diets of grazers. L. fluviatilis is reported from one of the highest elevations (2,170 m a.s.l.) known for the genus Lemanea and this species. This study confirms the presence of L. fluviatilis in a cold, unpolluted, turbulent stream and this type of stream may be its preferred habitat.

1. Waterbirds are considered to import large quantities of nutrients to freshwater bodies but quantification of these loadings remains problematic. We developed two general models to calculate such allochthonous nutrient inputs... more

1. Waterbirds are considered to import large quantities of nutrients to freshwater bodies but quantification of these loadings remains problematic. We developed two general models to calculate such allochthonous nutrient inputs considering food intake, foraging behaviour and digestive performance of waterbirds feeding in terrestrial habitats: an intake model (IM), mainly based on an allometric relationship for energy requirements and a dropping model (DM), based on allometric relationships for defaecation.2. Reviewed data of nitrogen (N) and phosphorus (P) content of herbivorous food varied according to diet type (foliage, seeds and roots), season and fertilization. For model parameterization average foliage diet contained 38.20 mg N g−1 and 3.21 mg P g−1 (dry weight), whereas mean faeces composition was 45.02 mg N g−1 and 6.18 mg P g−1.3. Daily allochthonous nutrient input increased with body mass ranging from 0.29 g N and 0.03 g P in teals Anas crecca to 5.69 g N and 0.57 g P in mute swans Cygnus olor. Results from IM differed from those of DM from ducks to swans by 63–108% for N and by −4 to 23% for P. Model uncertainty was lowest for the IM and mainly caused by variation in estimates of food retention time (RT). In DM food RT and dropping mass determined model uncertainty in similar extent.4. Exemplarily applying the models to Dutch wetlands resulted in mean annual contribution of herbivorous waterbirds to allochthonous nutrient loading of 382.8 ± 167.1 tonnes N a−1and 34.7 ± 2.3 tonnes P a−1, respectively, which corresponds to annual surface-water loadings of 1.07 kg N ha−1 and 0.10 kg P ha−1.5. There was a distinct seasonal pattern with peak loadings in January, when bird abundances were highest. Lowest inputs were in August, when bird abundance and nutrient content in food was low and birds foraged less in terrestrial habitats. Three-quarters of all nutrient input was contributed by greater white-fronted goose Anser albifrons, greylag goose Anser anser, wigeon Anas penelope and barnacle goose Branta leucopsis alone.6. We provide general, easy to use calculation methods for the estimation of allochthonous nutrient inputs by waterbirds, which are applicable to a range of waterbird species, a variety of potential diets and feeding behaviours, and across spatial scales. Such tools may greatly assist in the planning and execution of management actions for wetland nutrient budgets.

1. The importance of a long-term ecological perspective is well documented, yet the availability of long-term data remains limited. This paper highlights the value of long-term ecological studies of freshwater macroinvertebrates by... more

1. The importance of a long-term ecological perspective is well documented, yet the availability of long-term data remains limited. This paper highlights the value of long-term ecological studies of freshwater macroinvertebrates by reviewing both the availability of long-term data and recent ecological contributions based on them.2. A survey of recent literature on stream macroinvertebrates identified 46 papers published between 1987 and 2004 that included long-term (i.e. ≥5 years) data. Most recently published long-term studies of stream macroinvertebrates began collecting data in the 1970s and 1980s and their duration (time between first and last year sampled) was relatively brief (median = 9 years, maximum = 96 years). Most studies did not expand their temporal perspective by incorporating older data collected by other researchers.3. Recent long-term studies of macroinvertebrates have made major contributions to our understanding of interannual variation and cycles, complex abiotic and biotic interactions, and natural and anthropogenic disturbance and recovery. Without these studies, we would know much less about the magnitude of natural temporal variation, the importance of physical and biological disturbance and interactions, the role of pathogens and introduced species, the overall impact of pollution and the effectiveness of protection and remediation efforts.4. If we are to encourage long-term perspectives in our science, we need to facilitate the transfer of individual studies, as well as knowledge and data, among scientists. This includes efforts to archive and annotate data more effectively, so that they can be more easily incorporated into future research.

this article is about all Ultimate Guide to Marimo Moss Balls. In this article talks all about keeping, cultivating, carrying and tips of marimo moss balls in the freshwater tank. Please visit our site aquascaper.org for more information... more

this article is about all Ultimate Guide to Marimo Moss Balls. In this article talks all about keeping, cultivating, carrying and tips of marimo moss balls in the freshwater tank. Please visit our site aquascaper.org for more information about aquarium moss plants

BACKGROUND: In spite of its indusrial usefulness and varied daily uses, lead (Pb) pollution is a widespread ecological problem that faces the humans in the 21th century. Pb was found to produces a wide range of toxic effects including... more

BACKGROUND:
In spite of its indusrial usefulness and varied daily uses, lead (Pb) pollution is a widespread ecological problem that faces the humans in the 21th century. Pb was found to produces a wide range of toxic effects including neurotoxicity especially to the developing and young offspring. Recently, the utilization of herbal plants has received a significant attention where there has been rising awareness in their therapeutic use; among these is the garlic.
AIM OF THE WORK:
In light of the above, the current study is designed experimentally in female pregnant rats in order to investigate the beneficial role of garlic extract in the protection from the maternal and fetal cerebellar damage that produced by administration of different doses of Pb during pregnancy.
MATERIALS AND METHODS:
Positively pregnant female rats were divided into five groups; one control group, two Pb-treated groups (exposed to 160 and 320 mg/kg b.wt. of Pb, respectively) and two groups treated with both Pb and garlic (exposed to Pb as previous groups together with 250 mg/ kg b.wt. /day of garlic extract). Treatments started from day 1 till day 20 of pregnancy, where the mother rats of different experimental groups were sacrified to obtain the fetuses. Pb level in the maternal nd fetal blood and cerebellum was estimated by spectrophotometry. Specimens of the cerebellum of different mother and fetal groups were processed to histological and immunohistochemical staining for microscopic examination.
RESULTS:
The results showed that administration of Pb to pregnant rats resulted in a dose-dependent toxicity for both mothers and fetuses in the form of decrease of maternal weight gain, placental and fetal weights, brain weight and diminished fetal growth parameters, which were prominent in rat's group treated with larger dose of Pb. In Pb-treated rats, Pb level in blood and cerebellum was high when compared to the control. The histopathological examination of the cerebellum of treated dams and fetuses showed marked alterations mainly in the form of Purkinje cell degeneration and lack of deveopmet of fetal cerebellum. Co-treatment of garlic extract along with Pb resulted in a significant decrease in Pb levels as compared with those treated with Pb alone with improvement of the histopathological changes.
CONCLUSIONS:
This study was useful in evaluating the hazardous effects of uncontrolled use of Pb in general and in assessing the developmental and neurotoxicity of fetuses due to exposure during pregnancy in particular. Co-administration of garlic has beneficial effects in amelioration of Pb-induced neurotoxicity and reversing the histopathological changes of the cerebellum of mother rats and fetuses.
KEYWORDS:
garlic; glial fibrillary acidic protein; lead; purkinje cells

Indonesia merupakan satu negara dengan kekayaan biodiversitasnya, salah satunya adalah keanekaragaman krustasea yang meliputi kepiting, udang, dan lobster. Jenis krustasea tersebut tersebar di berbagai wilayah, dari mulai di darat, air... more

Indonesia merupakan satu negara dengan kekayaan biodiversitasnya, salah satunya adalah keanekaragaman krustasea yang meliputi kepiting, udang, dan lobster. Jenis krustasea tersebut tersebar di berbagai wilayah, dari mulai di darat, air tawar sampai air laut, serta memiliki ukuran yang beragam dari mulai berukuran mikro sampai makro. Krustasea dapat digunakan objek untuk studi sistem respirasi dan pencernaan, sehingga dapat diketahui perbedaan sistem antar spesies satu dengan yang lain. Hasil dari studi tersebut dapat diaplikasikan untuk budidaya atau pemanfaatan lain dari krustasea. Praktikum ini dilakukan untuk mempelajari sistem respirasi dan pencernaan krustasea dengan menggunakan spesimen Macrobrachium rosenbergii, Penaeus monodon, dan Scylla serrata.

Papua dikenal sebagai pulau yang alamnya relatif belum banyak dijamah manusia. Pulau ini menjadi rumah bagi banyak fauna termasuk ikan. Salah satu ikan yang hidup di sini adalah ikan pelangi arfak dan dalam beberapa literatur berbahasa... more

Papua dikenal sebagai pulau yang alamnya relatif belum banyak dijamah manusia. Pulau ini menjadi rumah bagi banyak fauna termasuk ikan. Salah satu ikan yang hidup di sini adalah ikan pelangi arfak dan dalam beberapa literatur berbahasa Inggris dikenal sebagai arfak rainbowfish. Di daerah asalnya, yaitu di sekitar daerah Prafi, ikan ini disebut “Anggicak” dalam Bahasa Suku Arfak (Hatam) dan di daerah Kebar dikenal sebagai “Wadjen”. Berdasarkan hasil penelusuran dalam daftar merah IUCN (The International Union for Conservation of Nature) semenjak tahun 1996 sampai dengan tahun 2018, status konservasi ikan ini sudah termasuk dalam kategori rawan punah (vulnerable).

1. We investigated the distribution of chironomid taxa in urban wetlands in the greater Melbourne area, Australia, to test if their distribution was influenced by sediment pollution and other environmental variables.2. For identification... more

1. We investigated the distribution of chironomid taxa in urban wetlands in the greater Melbourne area, Australia, to test if their distribution was influenced by sediment pollution and other environmental variables.2. For identification of the Chironomidae, DNA markers generated via polymerase chain reaction–restriction fragment length polymorphism of cytochrome c oxidase sub unit I (COI) were validated against morphology and reference specimens for more than 5000 chironomids representing over 80 species. DNA-based identification generally concurred with morphological separation, but also indicated the existence of cryptic diversity in some genera.3. Non-metric multidimensional scaling (NMS) and canonical correspondence analysis (CCA) showed chironomid assemblages were structured among wetlands and could be linked to several habitat characteristics. However, Chironomidae assemblages were only weakly linked to sediment pollution.4. Logistic regressions identified potential bioindicators of sediment pollution. Riethia stictoptera, Tanytarsus inextentus, Coelopynia and Chironomus ‘februarius’ were negatively associated and Chironomus duplex was positively associated with sediment pollution. Thresholds for the pollution sensitivities of specific species were mostly similar to those established with previous microcosm tests.5. Several other environmental factors influenced the distribution of specific chironomid taxa. Salinity, substratum type and submerged and riparian vegetation were particularly important.6. We conclude that specific chironomid taxa rather than assemblages have potential as bioindicators of sediment pollution provided their ecological preferences are considered and their pollution sensitivities are characterized using multiple methods. The integration of DNA-based techniques should facilitate accurate and rapid identification of bioindicators species.

Bu çalışmada Karadeniz havzasında seçilen 14 lokasyondan toplanan Alburnoides bipunctatus (Bloch, 1782)'un popülasyon içi ve popülasyonlar arası varyasyonları, tür içindeki farklılıkların açıklanması amacıyla morfometrik karakterler... more

Bu çalışmada Karadeniz havzasında seçilen 14 lokasyondan toplanan Alburnoides bipunctatus (Bloch, 1782)'un popülasyon içi ve popülasyonlar arası varyasyonları, tür içindeki farklılıkların açıklanması amacıyla morfometrik karakterler kullanılarak çalışılmıştır. Metrik karakterler üzerine uygulanan ayırma fonksiyonu analizi (DFA) ve kümeleme analizi (CA), Karadeniz havzasının Batı, Doğu ve Orta bölgelerindeki örnekleri morfolojik açıdan farklı üç popülasyon olarak sınıflandırmıştır. Morfometrik karakterler ve çok değişkenli analizler, Doğu Karadeniz havzasındaki popülasyonların Alburnoides fasciatus'a yakın olduğunu göstermiştir. Ayrıca Orta Karadeniz Bölgesi'ni temsil eden Bafra bölgesindeki popülasyonun diğer bölgelerden farklılık gösterdiği belirlenmiştir. /
In this study, inter and intra-population variations of cyprinid fish Alburnoides bipunctatus (Bloch, 1782) collected from selected 14 localities in Black Sea basin, Turkey, were studied by using morphometric characters for explaining differentiation within the species. Discriminant function analysis (DFA) and cluster analysis (CA) applied on metric characters, indicated that samples from Western, Eastern and Middle regions of Black Sea basin were classified into three morphologically distinct populations. Morphometric characters and multivariate analyses showed that the Eastern Black Sea basin populations are similar to Alburnoides fasciatus. Also population from Bafra region that represents Middle Black Sea region is well differentiated from other regions.