Periphyton Populations Research Articles

Combined effects of surface area of periphyton substrates and stocking density on growth performance, health status, and immune response of Nile tilapia (Oreochromis niloticus) produced in cages

A 4-month feeding trial was conducted to investigate the effect of surface area of periphyton substrates (PS) and stocking density (SD) of juvenile Nile tilapia, Oreochromis niloticus, on growth, major blood constituents, and some immunity biomarkers. Six treatments (T1–T6) were established in 18 floating cages (1 m3 water each) fixed in an earthen pond for growing tilapia (1.12 ± 0.10 g), in a 2 × 3 factorial design experiment (2 SD × 3 PS). For T1, T2, and T3, fish were stocked at a rate of 70 m−3 with 1, 2, or 3 PS units (area: 0.7, 1.4, and 2.0 m2, respectively). For T4–T6, fish were stocked at 90 m−3, also with 1, 2, or 3 PS units. All fish were fed a 20% crude protein supplemental diet. The best growth rates, feed efficiency, body composition, immune response, and overall health status were attained for T2 group with 70 fish m−3 in the presence of 2 PS units (1.4 m2) followed by T5 with 90 fish m−3 plus 2 PS. Stocking density affected albumin while periphyton substrates impacted cholesterol, triglycerides, and alanine aminotransferase levels in fish serum. Meanwhile, total proteins and glucose-6-phosphate dehydrogenase were not significantly affected. Serum immunoglobulin (IgM and IgG) values were relatively higher in fish reared at 70 m−3 than at 90 fish m−3 indicating better immunity response. Periphyton biomass (dry matter, DM and ash-free DM) was lower in T2, than in other treatments, whereas periphyton populations belonged mainly to Chlorophyta (52–75%), Cyanobacteria (17–23%), and Charophyta (4–21%). Accordingly, the present study suggests that 70 fish m−3 and 2 PS units (surface area of 1.4 m2) would be an optimal combination for the best growth, health status, and immunity response of juvenile Nile tilapia reared in periphyton-based cage system.

The Mass-Dimension Relationships in the Mussels Mytilus Galloprovincialis (Mollusca, Bivalvia) from Different Phenotypical Groups in Periphyton Populations near Odessa Coast, the North-Western Part of Black Sea

Abstract The data of the size-mass indices in the mussels Mytilus galloprovincialis (Lamarck, 1819) from three phenotypic groups - brown, dark violet (black) and “zebra” (brown with radial black stripes) shells in the periphyton settlements on the concrete traverses near Odessa coast, the North-western part of Black Sea (Ukraine), in March-November 2014-2015 are presented. A comparative evaluation has been made on the relationships of total mass of the mollusks, wet and dry mass of their soft body and mass of the shells on the one hand, and the size of animals (length of its shells) on the other hand, in the each of phenotypical groups from the five marine beach areas. It is shown, that in the marine areas with different degrees of isolation from the open sea by coast-protection engineering constructions, the mussels from different phenotypes have almost the same size-mass characteristics. Only the dry weight of soft animal body, which indicated to fatness of mollusk and therefore demonstrated his biological prosperity in specific hydrological conditions, can serve as a reliable criterion which can mark the shellfish habitats with different gradients of environmental factors.

THE SCALE TRANSITION: SCALING UP POPULATION DYNAMICS WITH FIELD DATA

Applying the recent developments of scale transition theory, we demonstrate a systematic approach to the problem of scaling up local scale interactions to regional scale dynamics with field data. Dynamics on larger spatial scales differ from the predictions of local dynamics alone because of an interaction between nonlinearity in population dynamics at the local scale and spatial variation in density and environmental factors over the regional population. Our systematic approach to scaling up involves the following five steps. First, define a model for dynamics on the local spatial scale. Second, apply scale transition theory to identify key interactions between nonlinearity and spatial variation that translate local dynamics to the regional scale. Third, measure local-scale model parameters to determine nonlinearities at local scales. Fourth, measure spatial variation. Finally, combine nonlinearity and variation measures to obtain the scale transition. Using field data for the dynamics of grazers and periphyton in a freshwater stream, we show that scale transition terms greatly reduce the growth and equilibrium density of the periphyton population at the stream scale compared to rock scale populations, confirming the importance of spatial mechanisms to stream-scale dynamics.

Effect of periphyton on growth performance of grey mullet, Mugil cephalus (Linn.), in inland saline groundwater ponds

Summary The present study attempts to assess the potential of artificial substrates to enhance fish production in inland saline groundwater ponds through periphyton production. Grey mullet, Mugil cephalus, was cultured for 100 days in ponds with substrate (treatment ponds) and without substrate (control ponds). To enhance the surface area, bamboo poles were used as substrate. The periphyton population, pigment concentration and hydrobiological characteristics of pond water were monitored. The studies revealed little difference in most of the water quality parameters observed in the two treatments. However, turbidity (27.0 ± 0.1–35.0 ± 0.1 Nephalo Turbidity Unit (NTU)), chlorophyll ‘a’ (6.6 ± 0.6–7.6 ± 0.6 μg L−1), plankton population (phytoplankton 8.4 × 103–9.4 ×103 numbers L−1; zooplankton 4.0 × 103–5.1 × 103 numbers L−1) and NH4–N (2.0 ± 0.2–2.3 ± 0.1 mg L−1) were high in the treatment with no additional substrate; however, in the treatment with substrate the total Kjeldahl nitrogen (9.8 ± 0.8–10.8 ± 0.7 mg L−1) and o-PO4 (0.1 ± 0.01–0.1 mg L−1) remained significantly (P < 0.05) higher. Highest periphyton biomass in terms of dry matter (DM) (0.8 ± 0.01–1.4 ±0.01 mg cm−2), ash free DM (0.4 ± 0.0–0.6 ± 0.01 mg cm−2), chlorophyll ‘a’ (3.1 ± 0.2–8.1 ± 0.8 μg cm−2) and pheophytin ‘a’ (1.9 ± 0.4–3.9 ± 0.5 μg cm−2) was observed at 50 cm depth in ponds provided with additional substrate. Fifteen plankton genera showing periphytic affinity colonized the bamboo substrates. Fish growth (mean fish weight 524.3 ± 8.7 g and SGR 2.5 ± 0.1) was significantly (P < 0.05) higher in ponds provided with additional substrate compared with control ponds (387.2 ± 6.0). Length–weight relationship (LWR) (W = cLn) also showed that the exponential value (‘n’) of length was high in substrate-supported ponds (n = 2.36) in comparison with controls (n = 1.09). These studies suggest that a periphyton-supported aquaculture system can be used successfully for the culture of herbivorous brackishwater fish species like M. cephalus in inland saline groundwaters and thus could contribute to the development of sound and sustainable aquaculture technology.

A pulse-amplitude modulated fluorescence-based method for assessing the effects of photosystem II herbicides on freshwater periphyton

A test was developed that measures in vivo chlorophyll afluorescence variables to assess the apparent sensitivity of freshwaterperiphytic algae to photosystem II inhibitors. Natural periphyticcommunities from rivers were collected on artificial substrata, and theeffects of short-term exposures to two PSII herbicides (atrazine andisoproturon) on the fluorescence parameters were measured with apulse-amplitude modulated fluorometer. The EC50 for each herbicide werecalculated from fluorescence yield indices, and these results were comparedto 14C-based primary production measurements on the samecommunities. The fluorescence-based method appears to give very reliableestimations of EC50 for each pesticide we tested, ranging from 0.46 to5.18 μM and 0.07 to 6.77 μM for atrazine and isoproturon,respectively. This method could be used in ecotoxicology monitoringprograms, to detect changes in natural periphyton populations sensitivity,following photosystem II herbicide contamination in rivers or lakes.

98/02850 Gas hydrate and free gas volumes in marine sediments: Example from the Niger Delta front: Hovland, M. et al. Marine and Petroleum Geology, 1997, 14 (3), 245–255

Periphyton diversity and biomass were studied for wet and dry seasons (between 1994 and 1995), selected stations at the upper New Calabar river. The periphyton species assemblage were dominated by diatoms species (45 species) except for areas with crude oil tainting on the substrates. The periphyton standing crop and biomass were higher in concentrations for the crude oil impacted environment (Stations 4 and 5). Also the values for the upper limits area (stations 1, 2 and 3) of the river were lower than that obtained for the lower limit area (station 7, 8, 9 and 10). In comparison using student t-test, there were no significant differences in values between seasons for the periphyton standing crop and biomass (P>0.05).The assemblage structure for all the stations, showed that diatoms dominated the population and constituted over 70% of the entire periphyton community except for stations 4 and 5 where the Cyanophyta (blue greens) predominated the periphyton population. The species diversity for the stations were above 2.50 except for Stations 4 and 5 (impacted by crude oil), that had diversity values <2.0.Some of the physicochemical parameters such as pH and the nutrient parameters (NH4+ -N, NO3 -N, and PO4+3) showed strong co-linearity with periphyton standing crop and biomass.It is concluded that the activities of industries in the upper New Calabar river had impacted on the periphyton community, but such impact was localised and not on the entire stretch of the study area.

The effect of industrial activities on the periphyton community at the upper reaches of New Calabar river, Niger delta, Nigeria

Periphyton diversity and biomass were studied for wet and dry seasons (between 1994 and 1995), selected stations at the upper New Calabar river. The periphyton species assemblage were dominated by diatoms species (45 species) except for areas with crude oil tainting on the substrates. The periphyton standing crop and biomass were higher in concentrations for the crude oil impacted environment (Stations 4 and 5). Also the values for the upper limits area (stations 1, 2 and 3) of the river were lower than that obtained for the lower limit area (station 7, 8, 9 and 10). In comparison using student t-test, there were no significant differences in values between seasons for the periphyton standing crop and biomass ( P>0.05). The assemblage structure for all the stations, showed that diatoms dominated the population and constituted over 70% of the entire periphyton community except for stations 4 and 5 where the Cyanophyta (blue greens) predominated the periphyton population. The species diversity for the stations were above 2.50 except for Stations 4 and 5 (impacted by crude oil), that had diversity values <2.0. Some of the physicochemical parameters such as pH and the nutrient parameters (NH4+ -N, NO 3 -N, and PO 4 +3) showed strong co-linearity with periphyton standing crop and biomass. It is concluded that the activities of industries in the upper New Calabar river had impacted on the periphyton community, but such impact was localised and not on the entire stretch of the study area.

The composition and ecology of periphyton communities in freshwaters. II. Inter-relationships between water chemistry, phytoplankton populations and periphyton populations in a shallow lake and associated experimental reservoirs (‘Lund tubes’)

Water chemistry, phytoplankton populations and periphyton populations on Potamogeton pectinatus, have been compared in a shallow, brackish lake, Hickling Broad, and in two enclosed, 20 m diameter butyl rubber reservoirs, placed in it. The seasonal changes of periphyton on Hippuris vulgaris and Myriophyllum spicatum in the lake have also been examined. The lake has been made more eutrophic by agricultural land drainage and roosting gull populations, the tubes to a greater extent by gulls perching on their rims. The water in the tubes became persistently dominated by colonial blue-green algae, a spring diatom pulse was absent, and severe nitrogen limitation was found. Periphyton on P. pectinatus in the tubes was scanty. In the lake, however, though phytoplankton chlorophyll a levels were lower, an alternation of spring diatom and summer colonial blue-green algae was recorded. Nitrogen limitation was less severe in the lake and abundant periphyton crops, mainly of diatoms, developed on P. pectinatus and to a...

A standardized method for identifying and counting the vagile and sessile periphyton.

A technique adapting the traditional "slide method" for quantitative study of periphyton populations is described. A substrate of known area and composition (a microscope slide) is exposed to colonization by periphyton in a body of water. At the end of the exposure time the periphyton is fixed while still on the slide and (as suggested by Bodian) impregnated with protargol. This impregnation reveals clearly all the autotrophic and heterotrophic forms in the periphyton population. The entire population is thus permanently preserved for study.

Site Variation in Littoral Periphyton Populations: Correlation and Regression with Environmental Factors

AbstractOver a six month period, littoral periphyton communities on vertically oriented glass slides were quantitatively sampled from four stations in Elk Lake, British Columbia. Correlation and multiple regression analyses were employed to assess the temporal interrelationships between 15 environmental variables, concurrently measured, and the periphyton populations, expressed as total cell counts and species diversity, for the complete data set of each station. At all stations there was a statistically significant increase in total cell populations with increasing length of slide exposure; positive correlations also occurred with pH, temperature, nitrite, nitrate and copper, while negative ones occurred with oxygen, orthophosphate and hardness (magnesium and total). At all but one station there was a significant decrease in species diversity with increasing slide exposure duration, a decrease attributed to the simultaneous increase in standing crop resulting in intensified competition for diminishing substrate area suitable for cell colonization. Multiple stepwise regression analyses demonstrated that greater than 80% of the variation in periphyton total cells at all four stations could be reliably predicted or described in terms of length of slide exposure, phosphate (ortho and total), and hardness (calcium and total). On the other hand, exposure duration and total cell populations were the most important variables associated with changes in species diversity at three of the four stations. In general, correlations and regressions between standing crop and environmental variables were more statistically reliable and consistent between stations than comparable analyses with species diversity. Use of multiple regression and correlation disclosed the importance of small, non statistically significant variation in ecologically relevant variables and permitted objective comparison of stations.