Zooplankton phosphorus excretion in Swarzędzkie Lake (Western Poland) and its influence on phytoplankton

Abstract

Zooplankton phosphorus excretion was studied in Swarzędzkie Lake in 2000-2002. Phosphorus excretion rates were high from spring through autumn, but low in winter. The highest value, 203.7 µgP l -1 d -1 (vertical profile mean), was recorded in June 2000. The mean rate was 26.6 µgP l -1 d -1 and was 10 times greater for rotifers than for both cladocerans and copepods. In most months, the calculated phosphorus excretion rate was greater than the sum of tributary external phosphorus loading and internal bottom sediment loading. Nevertheless, the influence of the zooplankton phosphorus excretion rate on yearly phytoplankton abundance, biomass and chlorophyll a was not statistically significant. Yearly variance in phytoplankton variables was best explained by a canonical variable composed of internal loading and zooplankton phosphorus excretion (total redundancy 32.8%).

Our current understanding of lake ecosystem response to climate change: What have we really learned from the north temperate deep lakes?

“…Evidence of the latter hypothesis is the relatively constant ambient nutrient levels between the two climatic scenarios (Table 5). Generally, the total amount and the relative importance of the phosphorus recycled depend on the trophic status of the lake, the water temperature as well as on the abundance and composition of the zooplankton community, with the smallest organisms being associated with higher rates of phosphorus excretion per unit of biomass (Gulati et al, 1989;Teubner et al, 2003;Ejsmont-Karabin et al, 2004;Kowalezewska-Madura et al, 2007). Thus, given the uncertainty associated with the competition patterns among coexisting zooplankton species under changing environmental conditions (Johnson and Havel, 2001), we hypothesize that the year-to-year variability of the zooplankton community composition and the succession patterns among groups with higher (rotifers) or lower (cladocerans, copepods) phosphorus excretion rates may become an important regulatory factor in phosphorus-depleted epilimnetic environments (Law et al, 2009).…”

Predicting the response of Hamilton Harbour to the nutrient loading reductions: A modeling analysis of the “ecological unknowns”

“…In particular, several studies have clearly demonstrated that nutrient regeneration by grazers might represent a significant source of inorganic nutrients for phytoplankton, with the smallest organisms (e.g., rotifers, protozoa) being associated with higher rates of phosphorus excretion per unit of biomass relative to the large ones, e.g., cladocerans, copepods (Gulati et al, 1989;Peduzzi and Herndl, 1992;Teubner et al, 2003;Ejsmont-Karabin et al, 2004;Kowalezewska-Madura et al, 2007). Further, it is an established pattern in limnology that plankton dynamics in resource-limited environments mostly depend on internal mechanisms which act to recycle the limiting nutrient many times over within the surface waters, but this dependence on nutrient regeneration decreases as the overall productivity increases (Legendre and Rassoulzadegan, 1995;Biddanda et al, 2001;Cotner and Biddanda, 2002).…”

Phosphorus release of metazoan zooplankton in two bays with different trophic status in Lake Taihu (China)

“…However, nutrient regeneration by zooplankton also is an important factor determining phytoplankton composition (Kowalczewska-Madura et al, 2007). Earlier studies revealed that most soluble P is released by zooplankton as PO −3 4 -P and, therefore, is available for phytoplankton growth (Lehman, 1980a).…”

“…Grazing by large zooplankton, particularly cladocerans, can regulate phytoplankton biomass and species composition (Carpenter et al, 1987;Reynolds, 1994;Sommer and Sommer, 2006). However, nutrient excretion by zooplankton may also affect the supply and stoichiometry of nutrients and thereby influence phytoplankton and lake trophic status (Lehman, 1980a;Elser et al, 1988;Sterner and Hessen, 1994;Kowalczewska-Madura et al, 2007). The role of zooplankton has been well studied in temperate lakes, but and less so in tropical and subtopical systems where zooplankton are smaller and likely to be less efficient in grazing phytoplankton (Jeppesen et al, 2010;Havens and Beaver, 2011).…”