Periphytic algal community adaptive strategies in N and P enriched experiments in a tropical oligotrophic reservoir

Abstract

This study aimed at evaluating periphytic algae adaptive strategies, including size class, growth, and adherence forms, and the CRS functional groups model under nitrogen and phosphorus artificial enrichment in a Brazilian tropical shallow and oligotrophic reservoir. Four treatments were designed using enclosures (n = 3) filled with 185 L of reservoir water: control (no nutrient addition), P? (isolated P addition, N-limiting condition); N? (isolated N addition, P-limiting condition); and NP? (combined addition, no limitation). N:P ratios were maintained throughout the experiment. Glass slides were used for periphyton growth, and sampling campaigns were carried out at short regular intervals (3-5 days) over a 31-day succession. Enrichment favored replacement of flagellates and loosely attached (mobile) forms by firmly attached mainly prostrate and entangled forms over succession. Isolated or combined P addition favored C-S-strategists green algae, whereas P limitation kept R-strategists over succession, promoting R-Cyanobacteria under high P limitation. Our results were supported by the species density and biovolume due to the dominance of small size classes (smallsized classes) in the community (nano and picoperiphyton). Overall, only the CRS strategies were more predictive of the experimental nutritional conditions.

Functional diversity and functional traits of periphytic algae during a short-term successional process in a Neotropical floodplain lake

“…A similar result for the dominant functional strategies was reported by Ferragut and Bicudo (2010). In a control condition, similar to our experiment without the flood pulse effect (low water period), R-strategist species dominated the entire succession process.…”

“…Among the size classes evaluated, nanoperiphyton species prevailed in the high water period with lower nutrient availability, and microperiphyton species predominated in the low water period. Studies have reported a reduction in nanoperiphyton species with increased enrichment of environments and a trend to increase the size of organisms in environments with higher nutrient availability (Cattaneo et al, 1997;Ferragut and Bicudo, 2010).…”

“…The establishment and development of certain species in the periphytic matrix may be favored by particular functional traits, such as morphology and cell size (Biggs, 1996;Biggs et al, 1998;Ferragut and Bicudo, 2010;Dunck et al, 2013b). In general, smaller and fast colonizing species with high dispersal capacity characterize early successional stages, and towards the climax or biomass peak of communities, species that better compete for resources and adapt to disturbances predominate (McCormick, 1996;Biggs, 1996;Biggs et al, 1998).…”

“…Biggs et al (1998) also related the functional strategies of species with the disturbance frequency and availability of resources in rivers and streams in a theoretical model. In recent studies, Ferragut & Bicudo (2010) evaluated periphytic algae adaptive strategies under nitrogen and phosphorus artificial enrichment in a tropical oligotrophic shallow reservoir. Larson & Passy (2012) analyzed the taxonomic and functional composition of the algal benthos during successional processes in response to nutrient supply and current velocity.…”

<b>Nile tilapia culture under feeding restriction in bioflocs and bioflocs plus periphyton tanks

“…Periphyton is capable to filter the water and reduce the concentrations of toxic compounds such as ammonia. It can also be ingested by the rearing animals as food (Ferragut & Campos, 2010;Richard et al, 2010). Aquaculture systems based on substrate, however, are most suited for semi-extensive culture, that one with minimal artificial feed allowances and low levels of fish production (Azim, Beveridge, Van Dam, & Verdegem, 2005;Liu et al, 2016).…”