Saprobic Conditions Research Articles

Temporal changes of biodiversity in urban running waters – Results of a twelve-year monitoring study

Freshwater biodiversity underlies severe threats, mainly suffering from habitat degradation by anthropogenic land use, in particular by urbanisation. However, recent long-term studies indicate recovery of stream macroinvertebrate diversity due to improved water quality at least in North America and Europe. We monitored macroinverbrates at 56 urban stream sites over a 12-year period (2009–2020) in Braunschweig, a German urban district. We utilised these data to investigate spatio-temporal changes in taxon richness and assemblage structure as well as factors potentially affecting the resulting patterns. Overall taxon richness was increasing over the study period, comprising both all taxa and taxa being indicators for healthy stream conditions. 53.6% of the sites had significant positive trends becoming most eminent since 2014, despite decelerating since 2018, the beginning of an extra-ordinary dry period. Only 10.7% of the study sites had negative trends. Assemblage structure was shaped by environmental factors like stream width and water quality. Over-average taxon richness including positive trends and higher numbers of indicator taxa of healthy stream conditions was found in streams with higher flow velocity, good saprobic conditions and more natural streambed structure. In contrast, low taxon richness and predominance of tolerant taxa were found in streams with more degraded conditions. Most of the environmental conditions having positive effects on taxon richness were improved by various programs set up by the environmental authorities. We therefore conclude, if urban stressors like organic pollution and structural degradation can be mitigated by revitalisation and water quality improvement, urban streams can have good potential for increasing biodiversity and improving ecological functioning.

Evaluating the mycostimulation potential of select carbon amendments for the degradation of a model PAH by an ascomycete strain enriched from a superfund site.

Although ecological flexibility has been well documented in fungi, it remains unclear how this flexibility can be exploited for pollutant degradation, especially in the Ascomycota phylum. In this work, we assess three mycostimulation amendments for their ability to induce degradation in Trichoderma harzanium, a model fungus previously isolated from a Superfund site contaminated with polycyclic aromatic hydrocarbons. The amendments used in the present study were selected based on the documented ecological roles of ascomycetes. Chitin was selected to simulate the parasitic ecological role while cellulose and wood were selected to mimic bulk soil and wood saprobic conditions, respectively. Each amendment was tested in liquid basal medium in 0.1 and 1% (w/v) suspensions. Both chitin and cellulose amendments were shown to promote anthracene degradation in T. harzanium with the 0.1% chitin amendment resulting in over 90% removal of anthracene. None of the targets monitored for gene expression were found to be upregulated suggesting alternate pathways may be used in T. harzanium. Overall, our data suggest that mycostimulation amendments can be improved by understanding the ecological roles of indigenous fungi. However, further research is needed to better estimate specific amendment requirements for a broader group of target fungi and follow up studies are needed to determine whether the trends observed herein translate to more realistic soil systems.

Cilioprotists as biological indicators for estimating the efficiency of using Gravel Bed Hydroponics System in domestic wastewater treatment

Interest has increased over the last several years in using different methods for treating sewage. The rapid population growth in developing countries (Egypt, for example, with a population of more than 87 millions) has created significant sewage disposal problems. There is therefore a growing need for sewage treatment solutions with low energy requirements and using indigenous materials and skills. Gravel Bed Hydroponics (GBH) as a constructed wetland system for sewage treatment has been proved effective for sewage treatment in several Egyptian villages. The system provided an excellent environment for a wide range of species of ciliates (23 species) and these organisms were potentially very useful as biological indicators for various saprobic conditions. Moreover, the ciliates provided excellent means for estimating the efficiency of the system for sewage purification. Results affirmed the ability of this system to produce high quality effluent with sufficient microbial reduction to enable the production of irrigation quality water.

Successions of zooperiphyton in a small river

In the small Latka River, which is characterized by a high heterogeneity of abiotic characteristics and a rich fauna composition, a high diversity of developing zooperiphyton structures was recorded consisting of invertebrates with short life cycles: the larvae of chironomids, caddisflies, mayflies, oligochaetes, nematodes, and other animals. One distinctive feature of seasonal and interannual zooperiphyton succession is the annual prevalence in abundance of spreading chironomid larvae of age I, which belong to the most representative dominating group of amphibiotic invertebrates, including species adapted to different saprobic conditions. The taxonomic and quantitative domination of chironomids make it possible to consider the family Chironomidae a key group in the formation of the zoocenosis structure. Under disturbed habitat conditions (pollution, rainfall floods, and the press of omnivorous invertebrates), the restoration of typical structures occurs rather quickly due to the particular features of biology in species short life cycles. However, no relative stabilization in communities was observed. This is the main difference between the sequence of succession processes in the Latka River and that observed in large water bodies (lakes and water reservoirs), where there are no strict limitations on living-space volume or food availability and abiotic conditions are more stable, thus allowing filter-feeding sessile animals (sponges, bryozoans, and zebra mussels) to develop on solid substrates. These species are able to develop multispecies consortia and form relatively stable long-term communities.

A new cell primo-culture method for freshwater benthic diatom communities

A new cell primo-culture method was developed for the benthic diatom community isolated from biofilm sampled in rivers. The approach comprised three steps: (1) scraping biofilm from river pebbles, (2) diatom isolation from biofilm, and (3) diatom community culture. With a view to designing a method able to stimulate the growth of diatoms, to limit the development of other microorganisms, and to maintain in culture a community similar to the original natural one, different factors were tested in step 3: cell culture medium (Chu No 10 vs Freshwater “WC” medium modified), cell culture vessel, and time of culture. The results showed that using Chu No 10 medium in an Erlenmeyer flask for cell culture was the optimal method, producing enough biomass for ecotoxicological tests as well as minimising development of other microorganisms. After 96 h of culture, communities differed from the original communities sampled in the two rivers studied. Species tolerant of eutrophic or saprobic conditions were favoured during culture. This method of diatom community culture affords the opportunity to assess, in vitro, the effects of different chemicals or effluents (water samples and industrial effluents) on diatom communities, as well as on diatom cells, from a wide range of perspectives.

Restoration of channelized streams — a benthological study

In the course of data analysis, calculation of Saprobic Index on the base of absolute numbers, SIabs was helpful to characterize saprobic conditions. Among statistical methods of data analysis, Ren...

Water Quality of the Danube in Hungary and its Major Determining Factors

Three District Water Authorities cover the whole Hungarian stretch of the Danube. Since the formation of the monitoring network fifteen years ago, the water quality has been observed at fifteen sampling points. Throughout this time, sampling has been performed under different hydrometeorological conditions. Based on these investigations, it was found that the quality of the river was influenced equally by the local and the hydrometeorological conditions. Major pollution sources are: the sewage from Bratislava, Györ and Budapest; the paper pulp, chemical, and sugar beet factories in the Slovakian catchment; the Hungarian chemical, petro-chemical, and food industries; and non-point source pollution from agriculture. The effects of these sources depend on the degree of wastewater treatment, and on the mixing rate. The waste loads provide a continuous source of nutrients, giving rise to bacterial proliferation. The organic nitrate and phosphorus loads are increasing, which is compensated for by biodegradation. In the winter, when the water temperature falls below 10°C and solar radiation is low, saprobic conditions characterize the water quality. In the summer, when solar radiation and temperature increase, trophic conditions determine the water quality. Thus, in winter the ammonia content increases, but in the spring, nitrification starts to improve and, especially in the lower reaches, algal overproduction can be detected. This situation changes during flood periods, when the concentration of polluting material is decreased by dilution, and at the same time, the high level of suspended solids inhibits the growth of organisms needing solar radiation. The most unfavourable water quality conditions occur in the winter low-flow period, when problems may occur in drinking water supply if the water is chlorinated.

Ciliated Colonization of Artificial Substrates in Different Saprobic Conditions in a Running Water

AbstractThis work investigates the effect of water current velocity and organic load on the colonization rate of ciliated Protozoa in periphyton communities. Artificial substrates (glass slides) were placed at three stations in a small mountain stream which runs through urban and industrial areas. The first station was located in an oligosaprobic to beta‐mesosaprobic zone, the second in an alfa‐mesosaprobic zone, and the third station in an alfa‐mesosaprobic to polysaprobic zone. At each station three substrates were placed in biotopes of different current velocity values (5… 20 cm/ sec., 20… 40 cm/sec. and 50… 70 cm/sec.). With such a distribution of artificial substrates it was possible to study the effect of the water current velocity on the colonization dynamics of ciliates in particular saprobic zones.

Indicator value of the genus Opercularia (Ciliata)

From the rich genus of Ciliata Peritrichida, comprising about 100 species, 8 taxa were selected, described, figured and classified saprobiologically (Table 1): Opercularia coarctata, O. confusa, O. minima, O. microdiscum, O. nutans, O. allensii, O. curvicaula and O. phryganeae. These species are considered as common and serving as best indicators of the saprobic conditions of their environment.

Observações hidrobiológicas sobre a poluição do rio Capibaribe-Mirim, Pernambuco, Brasil

Foi estudada, do ponto de vista ecológico, a poluição da água do rio Capibaribe-Mirim. Foram feitas cerca de 40 coletas de material de janeiro a dezembro de 1974, compreendendo os períodos seco e chuvoso, em 6 estações distribuídas desde o alto curso do rio (perto de Macaparana) até o médio curso (imediações de Goiana). Observaram-se 96 taxa entre espécies e variedades, sendo as mais frequëntes e dominantes as seguintes: Biddulphia laevis (Ehr.) Hustedt, Synedra ulna (Nitzsch) Ehr., Eunotia pectinalis (Kutz) Rabenhost, Nitzschia sigma (Kutz) W. Smith, Navicula cuspidata var. ambigua (Ehr.) Cleve, Eunotia didyma Grunow, Amphora ovalis Kutz., Amphora coffeaeformis Agard, Hantzschia amphioxys (Ehr.) Grunow, Nitzschia triblionella var. victoriae (H.) Grunow, Pinnularia acrospheria Breb., Pinnularia mesolepta (Ehr.) W. Smith, Rhopalodia gibberula (Ehr.) O. Müller, Surirella ovata kutz. É dada especial atenção ás algas Bacillariophyceae e Chlorophyceae. São apresentados, em forma tabular, o inventário ecológico, os índices halóbicos e sapróbicos das espécies, e a freqüência e distribuição das diatomáceas nas diversas estações de coleta.

Diatomáceas de tanques do cactário do Jardim Botânico, Guanabara, Brasil

O autor analisou a microflora de três tanques situados no Cactário do Jardim Botânico, Rio de Janeiro, Guanabara. Tanque nº 1. Apresentou desenvolvimento muito intenso da microfibra nos mseses mais frios. As diatomáceas foram muito freqüentes. As espécies indicadoras de saprobidade foram as seguintes: Gomphonema gracile Ehr., pinnularia maior. (kutz) Cleve, Gomphonema parvulum (kutz) Grunow, Navicula mutica Kutz., Pinnularia borealis Ehr., Pinnularia microstauron (Ehr) Cleve, Pinnularia acrospheria Breb., Hantzschia amphioxys (Ehr) Grunow, Nitzschia palea Kutz., Eutonia pectinalis (Kutz) Rabenh. Tanque nº 2. As diatomáceas indicadoras de águas contaminadas, anotamos como segue: Eutonia pectinalis (Kutz) Rabenh., Gomphonema parvulum (kutz) Grunow, Hanstzschia amphioxys (Ehr) Grunow, Navicula mutica Kutz, Pinnularia borealis Ehr., Pinnularia maior (Kutz) Cleve, Pinnularia microstauron (Ehr) Cleve. Tanque nº 3. Foi bastante reduzida a freqüência da microflora. Comparando-o com os tanques nº 1 e 2, as diatomáceas e clorofícias observadas, mostraram-se diminuídas nos meses mais quentes. Encontramos as seguintes espécies oligosaprobias: Eunotia pectinalis (Kutz) Rabenh., Gomphonema gracile ehr., Gomphonema parvulum (Kutz) Grunow Hantzschia amphioxys (Ehr) Grunow, Pinnularia borealis Ehr., Pinnularia maior (Kutz) Cleve. Foram consideradas também as clorofíceas quanto ao regime de saprobidade do material estudado. Eutonia augusta f. crenulata Cleve-Euler e Eutonia veneris var. exsecta Clever-Euler encontradas em nossas amostras, são novas para o Brasil. Um total de 71 espécies foram determinadas de 21 coletas realizadas durante o período de 36 meses.

The effects of saprobic conditions on some ciliated Protozoa in the benthos and hypolimnion of a eutrophic pond

SummarySeasonal fluctuations in numbers of some mesosaprobic ciliated Protozoa were followed from May 1969 to December 1970 in a eutrophic pond in north‐west England. The most common species were Loxodes magnus and Loxodcs striatus; some counts of Frontonia leucas, Spirostomum teres, Stentor coeruleus and Paramecium caudatum were also made.From about October to May, when the pond was mixed and the bottom water was well oxygenated, dense benthic populations of these ciliates were found (maxima 221 L. magnus and 293 L. striatus in 0·1 ml of sediment). They were absent from the plankton.In summer, stratification occurred, conditions in the hypolimnion became saprobic (i.e. low oxygen and high levels of potentially toxic substances such as sulphide, ammonia, and carbon dioxide), and very few benthic ciliates were present. Some planktonic Loxodes (up to 34 L. magnus and 137 L. striatus/ml) were, however, found in the hypolimnion. Possibly conditions in the water column were less severe than in the sediment, or perhaps the planktonic ciliates migrated vertically, from time to time, to an oxygen supply at the boundary with the epilimnion.Experimental exposure of the Loxodes species (also S. teres) to saprobic conditions in closed bottles caused the death of most ciliates within 50–150 h of closing the bottles.Deoxygenation of Loxodes was also carried out in a stream of argon, when there was no build‐up of the potential toxins associated with anoxia. Almost all Loxodes were lost between 20 and 70 h, hence, oxygen deficiency alone is probably sufficient to explain the low populations in the summer benthos.