The influence of nutrient loading, dissolved inorganic carbon and higher trophic levels on the interaction between submerged plants and periphyton

Abstract

Summary 1We studied the growth of a submerged aquatic plant in relation to periphytic and planktonic algae over a range of nutrient and dissolved inorganic carbon (DIC) availabilities. 2 In consecutive years two factorial experiments were conducted in 48 artificial ponds (each 3.14 m 3 ), comprising four concentrations of DIC (1.5, 2.5, 3.5 or 4.5 m  ) each crossed with three separate nutrient loadings (10 µ g L -1 P and 0.2 mg L N, 50 µ g L -1 P and 1 mg L N, or 200 µ g L -1 P and 4 mg L N). The second experiment differed by the inclusion of fish in the ponds. 3 In the first year DIC had no effect on plant growth, but nutrient loading did. Plants failed to grow in treatments where phytoplankton density was high (> 100 µ g L -1). Where phytoplankton was low, high numbers of invertebrates colonized the ponds, and periphyton abundance on the plants was low. In the second year, where phytoplankton never achieved the densities of the previous year, there was a significant effect of DIC concentration on plant growth but not of nutrients. Invertebrate abundance was lower and periphyton on the plants correspondingly higher. 4 In both years increased nutrient loading had no effect on the abundance of periphyton growing on the surface of the plants. Periphyton abundance was determined by the density of grazing invertebrates in the ponds. 5 There was a negative relationship between periphyton density and final plant density, which became significantly less steep with increasing DIC, indicating that periphyton and plants were competing for carbon. 6 DIC concentration has the potential to influence community structure in shallow lakes, altering competitive interactions between periphyton and plants and rendering low DIC lakes more prone to loss of plants when nutrient loading increases. However, the expression of this competition between periphyton and plants will depend on the density of grazing invertebrates present, which is itself influenced by the intensity of fish predation on those invertebrates.

The effect of periphyton on the light environment and production of Potamogeton perfoliatus L. in the mesotrophic basin of Lake Balaton

“…Biotic and abiotic light attenuation strongly influences the availability of light in the lower regions of the water column, and thus has a substantial impact on all autotrophic organisms and their community structure (Bécares et al 2008;Jones and Sayer 2003;Liboriussen and Jeppesen 2009). Periphyton, due to its high epiphytic algae content, is also influenced by changes in light attenuation (Jones et al 2002;Lalonde and Downing 1991;Müller 2006), while negatively 3 impacting both phytoplankton (Trochine et al 2011) and the plant substrate (Bécares et al 2008;Jones and Sayer 2003).…”

“…Since primary producers depend mainly on light availability, they are in constant competition for this resource (Becares et al 2008;Jones et al 2002;Jones and Sayer 2003;Roberts et al 2003;Weisner et al 1997). The reduction of available light associated with an increase of planktonic and epiphytic algal content could result in the decline of submerged macrophytes and thus a significant reduction in biodiversity (Blindow et al 1993;Scheffer et al 1993).…”

Responses of chlorophyll and MDA ofVallisneria natansto nitrogen and phosphorus availability and epiphytic algae

“…Some researchers hold that high N and P concentrations have a directly adverse effect on submerged macrophytes (Burkholder et al 1992;Chen et al 2002;Cao et al 2004, Nimptsch & Pflugmacher 2007. Others suggest that high N and P concentrations in shallow lakes have an indirect adverse effect on submerged macrophytes through stimulating overgrowth of the epiphytic algae and/or phytoplankton (Phillips et al 1978, Hough et al 1989, Havens et al 1999Jones et al 2002;Li , Zhang & Jeppesen 2008). Basically, plants are easily affected by the environment and have a series of mechanisms for responding to environmental changes ).…”

Sources and Dynamics of Dissolved Inorganic Carbon, Nitrogen, and Phosphorus in a Large Agricultural River Basin in Arid Northwestern China

“…Cation and anion concentrations: Cation concentrations including Ca 2+ and Mg 2+ were analyzed on an M410 flame photometer (Sherwood, UK). The concentrations of HCO 3 − and Cl − were measured using the methods of alkalinity titration and potentiometric titration [19], respectively. The duplicate samples were run on a regular basis, yielding RSDs less than 3%.…”

“…Dissolved inorganic carbon (DIC) is the most abundant carbon pool in many inland waterways and aquifers, being actively incorporated into aquatic food webs and playing an important part in regulating carbon fluxes between terrestrial, aquatic, and atmospheric reservoirs [1,2]. Inorganic N and P are important regulators of water and ecosystem integrity, controlling biomass abundance and biological community structures of aquatic environments [3]. Establishing a thorough understanding of nutrient fluxes linking terrestrial and aquatic systems is particularly important in large arid basins, where scarce water resources require managers to balance the needs of agricultural use versus ecosystem conservation [2,4,5].…”