The effects of nutrients and zooplankton community structure on phytoplankton growth in a subtropical Australian reservoir: An enclosure study

Abstract

Patterns of zooplankton-phytoplankton interactions in subtropical lakes of the Southern Hemisphere may deviate from those established for north-temperate lakes. We tested the responses of phytoplankton growth to different community structures of zooplankton and nutrient enrichment in a subtropical Australian reservoir for the prediction of potential outcomes of lake biomanipulation. Two zooplankton communities were created in lake enclosures over 4 weeks: a rotifer-dominated community developed in the presence of planktivorous fish (Hypseleotris spp.) and a Ceriodaphnia-dominated community developed in the absence of fish. Biomass gradients of both communities were established in 20 L containers and several separate containers received no additions (controls) or were enriched with nitrogen and/or phosphorus. The growth rate of total phytoplankton significantly increased in response to nutrient enrichment, indicating nutrient limitation. Most phytoplankton taxa were not markedly affected by grazing of either zooplankton community. However, both communities had significant stimulatory effects on the growth of inedible chlorophytes. The ability of zooplankton grazing to negatively affect phytoplankton growth during the summer was counteracted regardless of zooplankton community structure, possibly by nutrients regenerated by zooplankton. We hypothesise that in the subtropical system studied, changes in food web nutrient recycling may be more important for the outcome of biomanipulation than grazing impacts.

<b>Impact of Brazilian fish species at early developmental stages on plankton communities and water chemical parameters

“…This result corroborates whith argued that juvenile fish affect plankton, reducing the densities of some organisms and consequently, enabling the population growth of other species, altering the zooplankton structure (Gerking, 1994, Qin et al, 1995Keefe et al, 1998;Böing et al, 1998;SASS et al, 2014). An association between consumption of larger sized zooplankton organisms with reduced grazing on phytoplankton and consequent increase in biovolume of this community has been described by several authors (Matheus & Barbiere, 1999;Pegano et al, 1999;Hunt & Matveevb, 2005 The effect of the larvae of different fish species on the assemblage of copepods was not observed by Guest et al (1990), which differs from the results obtained here in, which may be related to larval diet in both studies. On the other hand, these authors observed effects of larvae of different fish species on cladocerans, different from that found in the present study, in which the density and biovolume of cladocerans was not different between tanks with different species and even the control tank.…”

“…Shifts in the dominant zooplankton species lead to changes in the phytoplankton (Watson, Bayne, Devries, & Williams, 2003;Hunt & Matveevb, 2005;Soares & Hayashi, 2005). Lower biomass of phytoplankton in environments with high biomass of Daphnia galeata were observed by Urabe (1990), and Böing et al (1998) reported lower biovolume of phytoplankton with increasing clearance rate by D. galeata.…”

Asynchrony of spring phytoplankton response to temperature driver within a spatial heterogeneity bay of Three-Gorges Reservoir, China

“…Iriarte and Purdie, 2004;Jasprica and Hafner, 2005;Henson et al, 2006;Miller and Harding, 2007;Peeters et al, 2007a) or on the effect of nutrient on phytoplankton biomass (e.g. Hunt and Matveev, 2005;Beamud et al, 2007;Ç elik and Ongun, 2008;Kasprzak et al, 2008;Katano et al, 2008 Tirok and Gaedke (2007) investigated the individual and combined effects of three physical variables (irradiance, temperature and water stability) on algal dynamics using descriptive statistics, multiple regression models and a process-oriented dynamic simulation model, few studies has tried to reveal the relative importance of local (e.g. spatial heterogeneity) and regional (e.g.…”

Can nearby eutrophic reservoirs sustain a differentiated biodiversity of planktonic microcrustaceans in a tropical semiarid basin?

“…Due to the different usages, the reservoirs showed different nitrogen sources (Boyer et al 2002), resulting in probable distinct responses in the composition of the main food (phytoplankton) and, consequently, zooplankton (Burford and Pearson 1998, Hunt and Matveev 2005, Bozelli et al 2009). Ammonia, for example, which is predominant in the highly altered reservoirs (Borborema and Saco I), is easily assimilated by phytoplankton.…”

“…However, the different sources of pollution and the deterioration of water quality can lead to a differentiated composition of the community (Burford and Pearson 1998, Hunt and Matveev 2005, Bozelli et al 2009), even in systems located close to each other. And, this can be used as a tool to indicate the environment condition and help in management.…”