Periphyton biomass accrual rate changes over the colonization process in a shallow mesotrophic reservoir

Abstract

Aim: We identified and analyzed the developmental phases (exponential and loss) of periphyton on artificial substrates based on biomass accrual rate in dry and rainy seasons in a shallow mesotrophic reservoir (Ninfeias Reservoir, Parque Estadual das Fontes do Ipiranga, São Paulo, Brazil). We evaluated the colonization time required for the developmental phase to change, as well as related limnological variables. Methods Samplings were carried out weekly, totaling 98 days of substrates exposure. We analyzed the limnological and periphyton variables (chlorophyll a, ash free dry mass, net and gross accrual rate). Results Maximum biomass occurred on the 42nd day in rainy season and on the 98th day in dry season. In the rainy season, the exponential phase of biomass accrual continued until the 28th day of colonization, followed by a fluctuation phase (35th to 77th day) and then a loss phase (84th to 98th days). In the dry season, the exponential phase continued until the 35th day, followed by a loss phase (42th to 63rd day) and then a fluctuation phase (70th and 77th day). In the same season, we observed the beginning of a new exponential phase (84th to 98th day). The biomass peak was recorded on the 42nd colonization day in the rainy season and on the 98th day in the dry season. Biomass and gross and net accrual were higher in the dry season than in the rainy season. Conclusions Periphyton biomass and net and gross accrual rates were higher during the dry season, which was characterized by high total nitrogen concentration, water transparency and low rainfall. We concluded that periphyton biomass accrual and the duration of the developmental phases (exponential, loss and fluctuation) changed with variations in limnological conditions in each climatic period in the tropical shallow reservoir studied.

Periphytic diatoms from an oligotrophic lentic system, Piraquara I reservoir, Paraná state, Brazil

“…Summer showed the highest accumulated rainfall (326.9 mm) during the sampling period and the lowest species number in both substrates. High rainfall lead to the detachment of the periphyton from the substrates (Casartelli et al 2016), which certainly contributed to the less number of species registered in Piraquara I. We registered nine diatom species (Spicaticribra kingstonii, Eunotia intermedia, Eunotia parasiolii, Eunotia pseudoimplicata, Encyonopsis subminuta, Cymbopleura naviculiformis, Planothidium incuriatum, Capartogramma crucicula and Nitzschia nana) that occurred in spring on both substrates, but were not recorded in summer.…”

The use of epilithic diatoms grown on artificial substrata to indicate water quality changes in the lower reaches of the St Lucia Estuary, South Africa

“…Although the exponential growth phase generally occurs within the accepted colonization time of 28−35 days, it is the availability of light and nutrients that controls the accrual phase pattern (Biggs, 1996). This was observed by Casartelli et al (2016) where higher chl-a concentrations on glass slides in a shallow mesotrophic reservoir during the dry season, in comparison to the wet season, due to high total nitrogen concentrations, water transparency and low rainfall was shown. Since the artificial structure holding the glass slides used during this study was suspended just below the water surface, light was not a limiting growth factor.…”

“…Slides were collected every week, at random positions, to assess the recruitment and colonisation by epilithic diatoms. The optimal colonisation time for maximum epilithic biomass development in freshwater systems is estimated at 2 to 4 weeks (Dalu et al, 2014;Casartelli et al, 2016), while in marine systems it is estimated at 5 weeks (Desrosiers et al, 2014). However, in a nutrient-enriched permanently open estuarine system the artificial substrata were found colonized by macroalgae before reaching the 30-day deployment period (Minne, 2003).…”

Relationship among carnivorous macrophyte Utricularia foliosa L. and species composition and life forms of periphytic algae community

“…The artificial substrate exposure time for periphyton colonization was 30 days at sampling sites. This exposure time was chosen because periphytic biomass accumulation is high at this colonization time in the studied reservoir (Casartelli et al, 2016), allowing a better comparison with the periphyton on artificial substrate and Utricularia. The stem and modified leaves of U. foliosa L were sampled.…”