Total Number Of Heterotrophic Bacteria Research Articles

Sustainable Restoration of Soil Functionality in PTE-Affected Environments: Biochar Impact on Soil Chemistry, Microbiology, Biochemistry, and Plant Growth

Biochar can be useful for the functional recovery of soils contaminated with potentially toxic elements (PTEs), even if its effectiveness is variable and sometimes limited, and conflicting results have been recently reported. To shed some light on this regard, softwood-derived biochar was added at 2.5 (2.5-Bio) and 5.0% w/w (5.0-Bio) rates to an acidic (pH 5.74) soil contaminated by Cd (28 mg kg−1), Pb (10,625 mg kg−1), and Zn (3407 mg kg−1). Biochar addition increased soil pH, available P and CEC, and reduced labile Cd, Pb, and Zn (e.g., by 27, 37, and 46% in 5.0-Bio vs. the unamended soil). The addition of biochar did not change the number of total heterotrophic bacteria, actinomycetes, and fungi, while it reduced the number of Pseudomonas spp. and soil microbial biomass. Dehydrogenase activity was reduced in amended soils (e.g., by ~60 and 75% in 2.5- and 5.0-Bio, respectively), while in the same soils, urease increased by 48 and 78%. Approximately 16S rRNA gene amplicon sequencing and the Biolog community-level physiological profile highlighted a significant biochar impact (especially at a 5% rate) on soil bacterial diversity. Tomato (but not triticale) yield increased in the amended soils, especially in 2.5-Bio. This biochar rate was also the most effective at reducing Cd and Pb concentrations in shoots. Overall, these results demonstrate that 2.5% (but not 5.0%) biochar can be useful to restore the soil chemical fertility of PTE-polluted soils with limited (or null) impact on soil microbial and biochemical parameters.

HYDROCARBON CONTAMINATION IMPACT ON SANDY SOILS WITHIN THE DZUNBAYAN OIL FIELD (EASTERN MONGOLIA)

The data are presented on the particle-size distribution, content of hydrocarbons, n-alkanes in their composition and the number of microorganisms in the soils of Dzunbayan oil production area (Mongolia, the Eastern Gobi desert steppe). The soils studied are characterized by the dominance of sand and fluid fraction (99.50–99.8%) with particles of 2–20 μm. The soils show alkaline reaction (pH 8.2–8.7), they are slightly saline in the control areas and highly saline (water extract salinity 0.13–2.34‰) near the production well. The content of petroleum hydrocarbons (HC) in soils of the study area varied from 9 to 60 mg/kg, with a maximum near the well. The study of the molecular composition of n-alkanes revealed the dominance of long-chain homologues (66.3–79.2% of the total n-alkanes), occurring at various stages of physicochemical and microbiological weathering. According to a number of features, the microbial community of soils is characterized by a high degree of adaptation to the conditions of the arid zone, salinity, and high pH values; at the same time, these conditions limit the development of typical representatives of soil microbiocenoses, i.e., actinomycetes and, to a greater extent, microscopic fungi. The total number of heterotrophic bacteria (HBGs) in the studied soil samples varied within 1.22–3.49 million CFU/g of soil. The proportion of oil-oxidizing bacteria (NOB) was 12.6–18.9% OBA, which corresponded to the high adaptive capacity of the community to hydrocarbons. Specific climatic conditions, features of soil composition, as well as oil with a predominance of heavy paraffin fractions of the Dzunbayan deposit, characterize the low potential ability of soils to self-purify under the oil pollution.

Biogeochemical Features of the Formation of the Holocene Sediments in Lake Dukhovoe at the Stage of Early Diagenesis in Eastern Baikalia

Abstract —A 6-meter core of the Holocene sediments in Lake Dukhovoe is studied. The material composition of the core is heterogeneous and has clear bedding. Lacustrine sediments are represented by the upper 293 cm. Each bed of the sediments is subjected to microbiological analysis. A high total number of heterotrophic bacteria is revealed in the upper (0–15 cm) and deeper (110–150 cm) sapropel intervals. Sulfate-reducing bacteria are identified only in Chrysophyceae cysts. The CaO/Fe2O3 ratio shows the degree of “carbonate content” of bottom sediments. It is low in the lake sapropel (0.2), which indicates the geochemical specificity (carbonate-free sapropel). Na, Mg, Al, Si, Al, Ca, Fe, Mn, Zr, and Cr concentrations in sapropel are within the average concentrations for the Earth’s crust, shale, and oceanic pelagic clays, while U and Mo concentrations exceed them. Phytoplankton is enriched in phosphorus (biogenic element) and chalcophile elements (Zn, Cd, Sn, Sb, Hg, Pb, and Cu), which characterize the pollution of the modern atmosphere of the Baikal region. Diagenetic processes result in the transformation of the pore waters, namely an increase in mineralization as compared to lake water, an increase in the concentrations of biogenic components (HCO3-, NH4+, NO3-, and PO43-) and a decrease in SO42-. Pyrite framboid accumulations are revealed in organomineral sediments below the horizon of 200 cm, and iron phosphates represented by vivianite are identified in sapropel.

МИКРОБИОЛОГИЧЕСКАЯ ХАРАКТЕРИСТИКА ГИДРОТЕХНИЧЕСКИХ СООРУЖЕНИЙ НЕКОТОРЫХ БУХТ Г. СЕВАСТОПОЛЯ

Hydraulic structures, which are constantly present in bays, are one of the factors affecting the condition of coastal waters. Microperiphyton, which is formed on hydraulic structures in coastal zones with varying degrees of anthropogenic and recreational pressure, has the greatest indicative value. Microbiological studies of periphyton significantly complement the characterization of the ecological state of the coast. This study presents data on the quantitative distribution of heterotrophic and hydrocarbon-oxidizing bacteria in the microperiphyton of silt deposits of the southern breakwater of Sevastopol Bay and the eastern breakwater of Kamyshovaya Bay. The total number of heterotrophic bacteria in the silt deposits of the southern breakwater generally ranged from 103 to 104 cells/ml, while that of the eastern breakwater mainly varied within 103–105 cells/ml. The results obtained indicate that the silty deposits in the considered water areas to the development of the analyzed groups of bacteria participating in the processes of self-purification of water areas, and their number does not depend on the depth. Data analysis showed that the number of heterotrophic bacteria in the eastern breakwater was higher than in the southern breakwater. Seasonal differences in the number of studied groups of bacteria were not revealed. It was found that the processes of self-purification of the marine environment from oil and petroleum products are more active on the outer side of the breakwater, and these processes are more pronounced on the southern breakwater.

High-Frequency Variability of Bacterioplankton in Response to Environmental Drivers in Red Sea Coastal Waters.

Autotrophic and heterotrophic bacterioplankton are essential to the biogeochemistry of tropical ecosystems. However, the processes that govern their dynamics are not well known. We provide here a high-frequency assessment of bacterial community dynamics and concurrent environmental factors in Red Sea coastal waters. Weekly sampling of surface samples during a full annual cycle at an enclosed station revealed high variability in ecological conditions, which reflected in changes of major bacterioplankton communities. Temperature varied between 23 and 34°C during the sampling period. Autotrophic (Synechococcus, 1.7–16.2 × 104 cells mL−1) and heterotrophic bacteria (1.6–4.3 × 105 cells mL−1) showed two maxima in abundance in spring and summer, while minima were found in winter and autumn. Heterotrophic cells with high nucleic acid content (HNA) peaked in July, but their contribution to the total cell counts (35–60%) did not show a clear seasonal pattern. Actively respiring cells (CTC+) contributed between 4 and 51% of the total number of heterotrophic bacteria, while live cells (with intact membrane) consistently accounted for over 90%. Sequenced 16S rRNA amplicons revealed a predominance of Proteobacteria in summer and autumn (>40%) and a smaller contribution in winter (21–24%), with members of the Alphaproteobacteria class dominating throughout the year. The contribution of the Flavobacteriaceae family was highest in winter (21%), while the Rhodobacteraceae contribution was lowest (6%). Temperature, chlorophyll-a, and dissolved organic carbon concentration were the environmental variables with the greatest effects on bacterial abundance and diversity patterns.

Effects of estuarine oyster, Crassostrea cuttackensis as the extractive species at varied densities on productivity and culture environment in brackishwater integrated multi-trophic aquaculture (BIMTA) system

Integrated multi-trophic aquaculture (IMTA) involves incorporation of species from different trophic or nutritional levels in the same system to get better production based on mutual gain to the co-cultured species and improved ecosystem health. However, in brackishwater, very few trials on IMTA have been conducted so far with scarce information on the optimum density of extractive species like oyster and seaweed. Edible estuarine oyster, Crassostrea cuttackensis is abundantly available in the Sundarban. Being a filter-feeder, it can be used as an extractive species for organic matter removal in IMTA. Therefore, an experimental trial was conducted to assess the effect of different stocking densities of C. cuttackensis on performances of milkfish (Chanos chanos) and Pacific white-leg shrimp (Penaeus vannamei), and environmental remediation in an IMTA system. There were three densities of oyster, 0.6 (T1), 1.2 (T2), and 1.8 (T3) kg m−3 distributed to 1000 L FRP circular tanks containing milkfish (4.51 ± 0.05 g) and white-leg shrimp (4.50 ± 0.03 g) at 25 and 50 no. m−3, respectively. Control tanks contained the same number of milkfish and shrimp with no oyster. All the three treatments and control had triplicate tanks. During the 60-day trial period, fish and shrimp were fed with a common diet containing 30% crude protein at 5% of biomass. Results showed that the highest growth of milkfish (24.66 ± 0.31 g) and shrimp (15.20 ± 0.17 g) was obtained in T3 (P < 0.05) compared to that of the control [13.97 ± 0.08 g (milkfish), 11.83 ± 0.13 g (shrimp)]. Apparent feed conversion ratio (AFCR) was the lowest in T3 (0.92 ± 0.01) (P < 0.05). Although, survival of milkfish did not vary, shrimp survival was the highest in T3. The inorganic nutrients (nitrogenous and phosphorus compounds) and particulate organic matter (POM) of water improved in all the IMTA treatments compared to the control. The number of total heterotrophic bacteria and Vibrio counts in tank water was significantly low in T3 (P < 0.05). The benefit-cost ratio in T3 was found to be 1.6 times higher than that of the control. This trial suggested that oyster, C. cuttackensis can act as an effective extractive species in IMTA system when stocked at a density of 1.8 kg m−3. Therefore, treatment T3 IMTA model proved to be more productive and had a successful bio-remediation effect on the environment.

Distribution of Heterotrophic and Nitrogen fixing Rhizobacteria in Irrigation Sites of Lake Alau Borno State Northeastern Nigeria

This study was conducted to know the population of rhizobacteria in both irrigation and non-irrigation sites of the dam. The dense population of these organism indirectly promote plant growth and development. Five sites (A, B, C, D and E) were used to collect soil samples randomly and transported to the laboratory for analysis. Total heterotrophic bacterial count was done using nutrient agar (NA) and nitrogen fixing bacteria was counted using Ashbey’s media (AM). The result shows that highest number of total heterotrophic bacteria in site C (46.0×106) cfu/g in irrigation site whereas higher count in non-irrigation site was (13.0×106) site D, the nitrogen fixing bacterial count in irrigation site was higher at site E with (12.0×106) and for the non-irrigation site was higher at site D with (14.0×106) The total heterotrophic bacteria isolated in the soil sample are the species of Bacillus alvei, Bacillus alvei, Bacillus cereus, Bacillus cereus, Pseudomonas putida, Klebsiella aeruginosa and Enterobacter aeruginosa. Likewise, the Nitrogen fixing bacteria isolated are the species of Rhizobium leguminosarum, Klebsiella pneumonia, Bacillus lentus, Azotobacter nigricans, Azotobacter tropicalis, Azotobacter spp, and Azotobacter tropicalis. The long history of agricultural activities in the lake area has directly influenced the diversity of microbial population in the area.

Effect of organic carbon source and stocking densities on growth indices, water microflora, and immune-related genes expression of Litopenaeus vannamei Larvae in intensive culture

The study conducted to evaluate the effect of different stocking densities in a biofloc (BF) system, with sugarcane bagasse as an organic carbon source on growth performance, immune response-related genes, and microbial biomass of shrimp larvae in a 90-days. Litopenaeus vannamei larvae (0.002 ± 0.01 g) were cultured in 12-tanks with different stocking densities (12 or 16 larvae/l), including two controls without a carbon source (12C and 16C) and two BF treatments without a commercial diet (12BF and 16BF) in triplicates. Based on the results, the total number of heterotrophic bacteria (THB) and Vibrio spp. counts (TVC) were positively affected by BF treatment. The highest THB value was recorded in treatment 12BF, whereas the lowest TVC value was recorded in 16BF. The highest (9.85 ± 1.60 g) and lowest (7.96 ± 2.72 g) weight gains were observed in 16BF and its control.Overall, the highest growth indices, survival rate and crude protein content were recorded in BF treatments. Furthermore, the expression of immunity-related genes were positively affected by BF treatment. However, the addition of agricultural by-product sugarcane bagasse as a carbon source in BF-tanks with zero-water exchange facilitated water recycling and increased the number of THB communities which could replace the commercial diet in BF-tanks and improve the growth and health of shrimp.

IMPACT OF WINDTHROWS DISTURBANCE ON CHEMICAL AND BIOLOGICAL PROPERTIES OF THE FOREST SOILS FROM ROMANIA

The present study investigates the influence of windthrows on the chemical and biological characteristics and respiration processes of forest soils from Romania. Three pure Norway spruce, common beech, and sessile oak stands were chosen together with control plots, where the forest and soils were not affected by windthrows. Soil samples were taken from two soil layers: 0 10 cm and 10 20 cm. Soil carbon dioxide fluxes or soil respiration was monitored at 20 randomly selected points for each sample surface. Soil temperature and soil water content were also measured at these points. Furthermore, the total number of heterotrophic bacteria and the total number of fungi were also measured. We found that abiotic factors lead to the modification of the chemical and biological properties of forest soils: soil pH was higher in the areas affected by windthrows, while humus and nitrogen quantities were lower in these areas. However, these changes were observed only in the first 10 cm of the soil profile. Underground microclimatic conditions were found to influence soil respiration, with higher respiration values observed in the surfaces affected by windthrows. In the Norway spruce and common beech stands, aerobe heterotroph bacteria and fungus were more abundant in soils that were not affected by windthrows because the uprooted trees remove top horizons of soils and the creation of leaf litter, roots and fungal hyphae, stops. In this situation, organic matter, in the soil, begins to decay.

MICROBIAL INDICATION OF POLLUTION FOR THE SURFACE WATERS IN THE NOVIK BAY (RUSSKY ISLAND, PETER THE GREAT BAY, JAPAN SEA)

The Novik Bay is the largest one among the inlets of Russky Island in Peter the Great Bay. This water area is actively used for aquaculture and commercial and recreational fishery and attracts many tourists, so permanent monitoring of its water quality is necessary. Current environmental situation in the Novik Bay is assessed using microbiological indicators. The following parameters are used: total number of heterotropic bacteria, number of coliform bacteria, and number of metal-resistant microorganisms as indicators of oil and phenolic pollution. The water samples were collected in spring and autumn of 2017 and in spring and summer of 2018, following the standards GOST 31862 and GOST 31861. The number of microorganisms was determined by standard microbiological methods of sowing. The total number of heterotrophic bacteria corresponds to the requirements for oligo- or mesosaprobic waters. The number of metal-resistant microorganisms indicates that the waters of the bay are not subjected to industrial effluents and other man-made effects, its pollution by oil products is noticeable in some local areas only but the major part of the bay is low-polluted. In comparison with the data of previous chemical-ecological and microbiological tests, these assessments show better condition of the Novik Bay waters.

Effects of anEnterococcus faecium‐based probiotic on growth performance and health of Pirarucu,Arapaima gigas

Intensive fish farming has resulted in an increased concern for disease outbreaks. Probiotic use is one of the strategies being developed to improve fish health and productivity. Measures of probiotic colonization, growth performance, haematological characteristics and parasite load were used to evaluate the effect of diets supplemented with Enterococcus faecium on growth and health of Arapaima gigas juveniles. A completely randomized design with four treatments (diet with E. faecium at 1 × 106 CFU/g and 1 × 108 CFU/g, control diet and diet with the culture medium MRS) and three replicates was used. Ninety-six Arapaima juveniles were distributed in 12 cages fed with the specified diet for 68 days. Colonization of the intestinal tract by lactic acid bacteria reduced the total number of heterotrophic bacteria in fish fed with probiotics compared to controls. Fish fed a supplemented diet containing 1 × 108 CFU/g presented higher values of weight gain, survival and fish growth uniformity, and lower values of feed conversion ratio. The prevalence of Trichodina sp. could have affected the survival of fish in the control group. Reduction in parasite load and an increase in haematocrit, the number of erythrocytes, thrombocytes, neutrophils and monocytes were also observed in fish fed the diet containing 1 × 108 CFU/g. Enterococcus faecium presented a probiotic effect in A. gigas juveniles and can be recommended for use at a concentration of 1 × 108 CFU/g to modify the gut microbiota, improve growth performance and haematology and reduce parasitic load.

Utjecaj kišnih glista Lubricus rubellus na brojnost mikroorganizama u zemljištu tretiranom pendimetalinom

This paper examines the modus in which earthworm Lumbricus rubellus with its activity affects the total count of different physiological groups of microorganisms in soil treated with herbicide pendimethalin.The experiment was carried out in ten glass containers with a soil substrate, whereby one of them was the control one, and each group of three containers was treated with different concentration of pendimethalin. A concentration of pesticide of 5 μl/kg, which is recommended by the declaration, one lower concentration of 3 μl/kg and one higher of 7 μl/kg were used. The number of physiological groups of microorganisms is determined from the three containers treated with different concentrations of pendimethalin 48 hours after the treatment, and from the other three containers 21 days after the treatment. Two days after the application of different concentration of pesticide, a significant statistical decrease was found in the number of fungi and cellulotical microorganisms in soil, while the total number of heterotrophic bacteria as well as microorganisms which participate in different stages of nitrogen metabolism increased. However, 21 days after the treatment a significant decrease in the total number of heterotrophic bacteria in all treated containers comparing to the control one was noticed, where earthworms with their activities partially attenuated the negative effect of pendimethalin on soil bacterial flora. They also had a positive effect on the number of fungi, actinomycetes and cellulolytic microorganisms while the presence of earthworms had no significant influence on the number of aminoautotrophs, oligonitrophils and free-living diazotrophs. It was shown that earthworms with their activities attenuate the negative effect of pendimethalin on bacterial flora, actinomycetes and fungi, which points out to their possible use in processes of bioremediation.

Soil diagnosis of an urban settlement with low levels of anthropogenic pollution (Stepnoe, Saratov region)

A soil diagnosis of an urban territory Stepnoe (Saratov region) was conducted within the framework of soil research monitoring of inhabited localities with low levels of anthropogenic impact using chemical and microbiological analysis. Excess over maximum permissible concentration (MPC) of mobile forms of Cr, Zn and Cd were not observed within the researched territory. A universal excess over MPC of mobile forms of Ni, Cu and Pb was established which is most likely connected with anthropogenic contamination. It was discovered that, at the territory of the Stepnoe settlement, mobile forms of heavy metals compounds (HM) in most cases formed paragenetic associations with high correlation coefficient and despite this, an excess over MPC was not significant. This point to a common mineralogical origin of the elements inherited from the parent rock. The values of the total index of chemical contamination were not above 16, which puts the researched samples in a category with permissible contamination. The indices of the total number of heterotrophic bacteria, iron-oxidizing and hydrocarbon-oxidizing bacteria in most samples corresponded to normal indices for chestnut solonetsous and saline soils. In some samples, a deviation from the normal indices was observed justifying the impact of specific contaminants on the soil.

Impact of untreated urban waste on the prevalence and antibiotic resistance profiles of human opportunistic pathogens in agricultural soils from Burkina Faso

This study examined the long-term effects of the landfill disposal of untreated urban waste for soil fertilization on the prevalence and antibiotic resistance profiles of various human opportunistic pathogens in soils from Burkina Faso. Samples were collected at three sites in the periphery of Ouagadougou during two campaigns in 2008 and 2011. At each site, amendment led to changes in physico-chemical characteristics as shown by the increase in pH, CEC, total C, total N, and metal contents. Similarly, the numbers of total heterotrophic bacteria were higher in the amended fields than in the control ones. No sanitation indicators, i.e., coliforms, Staphylococci, and Enterococci, were detected. Pseudomonas aeruginosa and Burkholderia cepacia complex (Bcc) were detected at a low level in one amended field. Stenotrophomonas maltophilia was detected from both campaigns at the three sites in the amended fields and only once in an unamended field. Diversity analysis showed some opportunistic pathogen isolates to be closely related to reference clinical strains responsible for nosocomial- or community-acquired infections in Northern countries. Antibiotic resistance tests showed that P. aeruginosa and Bcc isolates had a wild-type phenotype and that most S. maltophilia isolates had a multi-drug resistance profile with resistance to 7 to 15 antibiotics. Then we were able to show that amendment led to an increase of some human opportunistic pathogens including multi-drug resistant isolates. Although the application of untreated urban waste increases both soil organic matter content and therefore soil fertility, the consequences of this practice on human health should be considered.

EFFECTIVENESS OF THE SANDPITS SECURITY SYSTEM AGAINST MICROORGANISMS AND INTESTINAL PARASITES SAND CONTAMINATION

Playgrounds and sandpits (small architecture objects according to the Construction Law) are subject to meticulous supervision, both at the design stage and subsequent status checks of the objects. One of the requirements arising from the need to protect playgrounds from animals is the necessity for fencing the object (Regulation of 31 December 2002 On Safety and Hygiene in Public and Private Schools and Institutions; Polish Standard PN-EN 1176 Playground equipment and surfacing). Does fencing playgrounds really reduce contamination of sand? To verify this hypothesis, the studies have been conducted on the residential areas’ sandpits, both fence secured and unsecured, located in close proximity to one another. The aim of the study was to evaluate the effectiveness of fences and nets as protection from microbial and parasite contamination of sandpits, mainly due to the access of animals to them. For several seasons of spring and summer the sand was examined in terms of the total number of heterotrophic bacteria and fungi (organic matter contamination of sand indicators) and for the presence of coliform bacteria (including Escherichia coli), bacteria of the Salmonella genus and the eggs of intestinal parasites. It can be concluded that fencing playgrounds affects sand pollution less with waste and plant material (as a consequence, it has been reported statistically significantly less heterotrophic bacteria and fungi in the fenced sandpits’ sand). Unfortunately, the fence does not eliminate the risks associated with sand pollution of coliform bacteria. Cats and birds, but also dogs, still have a continuous access to sand. Due to the repeatedly stated carelessness of children and their caregivers, gates left open to the playground do not constitute an obstacle for domestic and stray animals. Another source of sand pollution with intestinal pathogens can be a manner of carriage of new sand, as there is no legislation governing the issue of transport. It has been visually found that the sand has been transported in a vehicle used for waste disposal.

ASSESSMENT BIOREMEDIATION OF CONTAMINATED SOILS TO PETROLEUM COMPOUNDS AND ROLE OF CHEMICAL FERTILIZERS IN THE DECOMPOSITION PROCESS

Today oil removal from contaminated soil by new methods such as bioremediation is necessary. In this paper, the effect of chemical fertilizers and aeration on bioremediation of oil-contaminated soil has been investigated. Also the control group, (bioremediation of petroleum hydrocarbons in contaminated soil without treatment by chemical fertilizers and aeration treatment was examined. The condition of experiment is as following: those were treated 70 days in glass columns (30×30×30cm dimensions), ambient temperature (25-30 0 C), relative humidity 70%, aeration operation with flow 0.7 lit/min. The total number of heterotrophic bacteria of break down oil and the total of petroleum hydrocarbons were analyzed using gas chromatography analysis. all experiments were replicated three times. The microbial population results for control soil, treated soil by aeration and treated soil by aeration and chemical fertilizers columns are 2.3×10 5 , 1.04×10 10 , and 1.14×10 11 CFU/gr, respectively. The concentrations of total petroleum hydrocarbons of remaining are 46965, 38124, and 22187 mg kg -1 respectively. The obtained results show that the aeration operation and chemical fertilizers have effective role on degradation of petroleum hydrocarbon by oil degrading bacteria from soil.

Effects of probiotic forms, compositions of and mode of probiotic administration on rearing of Pacific white shrimp (Litopenaeus vannamei) larvae and postlarvae

Development of probiotics for replacement of antibiotics is one of the key factors for management in sustainable aquaculture. This study examined the effects of probiotic forms (microencapsulated and freeze-dried cells), compositions of probiotics (bacteria, yeast and microalgae) and mode of probiotic administration (probiotic supplementation in either water additives or through probiotic-enriched artemia) on the growth, survival rate and microbial number of Litopenaeus vannamei at various stages in two separate experiments: (1) larval stages from zoea 3 to mysis 3 and (2) postlarval (PL) stages from PL 1 to PL 21. The treatments of both experiments included addition of: (T1) artemia enriched with mixed microencapsulated Bacillus (MB), (T2) artemia enriched with mixed MB and microencapsulated yeast (MY), (T3) artemia enriched with mixed MB, MY and microencapsulated Chaetoceros (MC), (T4) mixed MB, (T5) mixed MB and MY, (T6) mixed MB, MY and MC, (T7) mixed freeze-dried Bacillus (FB), (T8) mixed FB and freeze-dried yeast (FY), (T9) mixed FB, FY and freeze-dried Chaetoceros (FC) and (T10) control (no addition of probiotics). Results demonstrated that two probiotics forms and modes of probiotic administration did not affect (P>0.05) growth and survival of zoea 3 to PL 21. The compositions of probiotics did not affect (P>0.05) growth and survival of zoea 3 to mysis 3. However, PL 1 to PL 21 treated with either bacteria and yeasts or bacteria, yeasts and Chaetoceros exhibited increases (P<0.05) in growth and survival as compared to controls. Numbers of total heterotrophic bacteria (THB), Bacillus and yeasts in shrimp from zoea 3 to PL 21 or culture water of all treatments were higher (P<0.05) than in controls. This investigation suggested that incorporation of bacteria and yeasts or bacteria, yeasts and Chaetoceros as microencapsulated or freeze-dried forms in water additives or probiotic-enriched artemia possessed as effective probiotics for rearing of L. vannamei based on the enhancement of survival and growth rate and concomitant increase in the beneficial microbial probiotics in shrimp larvae and postlarvae as well as in culture water.

The abundance of some pathogenic bacteria in mangrove habitats of Paraiba do Norte estuary and crabmeat contamination of mangrove crab Ucides cordatus

Study on mangrove water and sediment of Paraiba do Norte river (Northeastern Brazil) and crabmeat of Ucides cordatus was carried to investigate the relation between the abundance of bacteria in the mangrove habitat and in the crabmeat. Simultaneous collection of samples of water, sediment and crabs (U. cordatus) was done during the rainy and dry seasons at two areas of mangroves that differed in influence of tide and sewage discharge. The numbers of total heterotrophic bacteria in the mangrove water were between 0.04 and 6 log CFU 100mL-1, and in the sediment between 5 and 6 log CFU g-1. The location closer to waste discharge showed higher incidence of total heterotrophic bacteria, coliforms, Staphylococcus aureus and Salmonella spp. The counts of total heterotrophic bacteria in the crabmeat varied from 1.3 to 4.4 log CFU g-1, and did not differ significantly between the locations analysed. No crabmeat sample showed the presence of coliforms, S. aureus and Salmonella spp.

The occurrence of lipolytic bacteria and the activity of extracellular lipases in a riverine ecosystem

Abstract This study determined the numbers and distribution of heterotophic and lipolytic bacteria and the activity of lipases in the water of the Słupia River, in the section of the river that flows through the city of Słupsk. From spring to fall the mean number of heterotrophic bacteria remained at a relatively constant level (158.3 × 103 cells cm-3-169.4 × 103 cells cm-3), whereas in winter a sudden drop to only 18.3 × 103 cells cm-3 was found. The numbers of heterotrophic bacteria in the whole studied section of the river were similar. The mean number of lipolytic bacteria reached a maximum in spring (12.9 × 103 cells cm-3), was high in summer (10.5 × 103 cells cm-3), and reached a minimum (1.3 × 103 cells cm-3) in winter. Lipolytic bacteria accounted for only 5 to 8% of the total number of heterotrophic bacteria. No marked differences in the numbers of lipolytic bacteria were determined within the section of the river studied. The highest levels of lipase activity were determined in spring (18.9 nM MUF dm-3 h-1) and fall (19.9 nM MUF dm-3 h-1), while the lowest (11.0 nM MUF dm-3 h-1) were noted in winter. There were no differences in the level of activity of lipolytic enzymes among the sites studied.

In situ phytoremediation of PAH- and PCB-contaminated marine sediments with eelgrass ( Zostera marina)

In view of the fact that there are presently no cost-effective in situ treatment technologies for contaminated sediments, a 60-week-long phytoremediation feasibility study was conducted in seawater-supplied outdoor ponds to determine whether eelgrass ( Zostera marina) is capable of removing polynuclear aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) from submerged marine sediments. It was determined that all PAHs and PCBs, independent of the number of aromatic rings and degree of chlorination, respectively, were removed to a much larger extent in planted sediments compared to unplanted controls. After 60 weeks of treatment, the concentration of total PAHs decreased by 73% in planted sediments but only 25% in unplanted controls. Similarly, total PCBs declined by 60% in the presence of plants while none were removed in the unplanted sediment. Overall, the apparent PAH and PCB biodegradation was greatest in the sediment layer that contained most of the eelgrass roots. Abiotic desorption tests conducted at week 32 confirmed that the phytoremediation process was not controlled by mass-transfer or bioavailability limitations since all PAHs and PCBs desorbed rapidly and to a large extent from the sediment. PAHs were detected in both roots and shoots, with root and shoot bioaccumulation factors for total PAHs amounting to approximately 3 and 1, respectively, after 60 weeks of phytoremediation treatment. Similarly, the root bioaccumulation factor for total PCBs was around 4, while no PCBs were detected in the eelgrass leaves at the end of the experiment. The total mass fraction of PAHs and PCBs absorbed and translocated by plant biomass during the 60-week period was insignificant, amounting to less than 0.5% of the total mass of PAHs and PCBs which was initially present in the sediment. Finally, the number of total heterotrophic bacteria and hydrocarbon degraders was slightly but not statistically significantly greater in planted sediments than in unplanted controls. After ruling out contaminant loss to the water column or absorption and transformation within plant cells, it is most likely that the presence of eelgrass stimulated the microbial biodegradation of PAHs and PCBs in the rhizosphere by releasing root exudates, plant enzymes, or even oxygen. Additional research is needed to further elucidate these potential phytoremediation mechanisms.