Control of Lacustrine Phytoplankton by Nutrients: Erosion of the Phosphorus Paradigm

Lewis, William M.; Wurtsbaugh, Wayne A.

doi:10.1002/iroh.200811065

Cited by 334 publications

(262 citation statements)

References 76 publications

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“…Therefore, some research argue that P is the ultimate limiting nutrient overtime since N 2 fixation helps satisfy N requirements (Schindler et al 2008). In fact, N limitation has been observed in whole-lake experiments and many studies have indicated that N 2 fixation by phytoplankton cannot fully compensate for nitrogen deficiency (Kolzau et al 2014;Lewis and Wurtsbaugh 2008;Paerl 2009;Scott and McCarthy 2010). This is mainly because the process is controlled by lots of physical-chemical factors except for N/P ratio (Paerl 2009).…”

Section: Environmental Implicationsmentioning

confidence: 99%

Critical nutrient thresholds needed to control eutrophication and synergistic interactions between phosphorus and different nitrogen sources

Zeng

Qin

Bao

et al. 2016

Environ Sci Pollut Res

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Eutrophication is one of the greatest threats to global freshwater ecosystems. The phytoplankton responses to nutrient inputs vary in different water bodies, so it is particularly important to determine the nutrient thresholds and synergistic interactions between nutrients in different freshwater ecosystems. Field sampling and bioassay experiments were conducted to determine the thresholds of soluble reactive phosphorus (SRP), nitrate-nitrogen (NO 3 -N), and ammonium-nitrogen (NH 4 -N) in Miyun Reservoir. A separate nutrient addition bioassay was designed to assess the synergistic interactions between these nutrients. Chlorophyll a (Chl a) concentrations were used to estimate phytoplankton biomass. The results showed the following: (1) nutrient threshold bioassay indicated that eutrophication thresholds of SRP, NO 3 -N, and NH 4 -N should be targeted at below 0.04 mg P L −1 , 0.5 mg N L −1 , and 0.3 mg N L −1 , respectively, to limit the growth of phytoplankton. (2) The stimulatory effect of BNH 4 -N plus P^on phytoplankton biomass was greater than (4) Ammonium was an important factor for the growth of phytoplankton and inputs of both NH 4 -N and NO 3 -N should be reduced to control bloom formation. Our findings imply that although P load reduction is important, appropriate reductions of all forms of N in watershed is recommended in the nutrient management strategy for Miyun Reservoir.

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Section: Environmental Implicationsmentioning

confidence: 99%

Critical nutrient thresholds needed to control eutrophication and synergistic interactions between phosphorus and different nitrogen sources

Zeng

Qin

Bao

et al. 2016

Environ Sci Pollut Res

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“…Paterson et al (2011) misinterpret the increase in heterocyte abundance as a signal that the phytoplankton have overcome N deficiency. The mere presence of heterocystous cyanobacteria does not indicate that N fixation is meeting phytoplankton N demand (Lewis and Wurtsbaugh 2008). If N-fixing cyanobacteria were supplying N at a rate proportional to P fertilization, TN concentrations would remain constant or increase relative to TP.…”

mentioning

confidence: 99%

Response to Comment: Nitrogen fixation has not offset declines in the Lake 227 nitrogen pool and shows that nitrogen control deserves consideration in aquatic ecosystems

Scott¹,

McCarthy²

2011

Limnology & Oceanography

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We thank Paterson et al. (2011) for their comment on Scott and McCarthy (2010). As stated in our original paper, we agree that Lake 227 has remained eutrophic in response to phosphorus (P) fertilization alone. However, the effect of halting nitrogen (N) fertilization cannot be fully evaluated until the N pool in Lake 227 has reached steady state. The relatively high chlorophyll a (Chl a) and phytoplankton biomasses reported for 2007and 2009(Paterson et al. 2011 were not surprising considering the tremendous variability in these measurements over the entire experimental period. However, these new data do not nullify the decreases in total N (TN) and Chl a from 1990 to 2005, determined from data in Schindler et al. (2008). Additional years of P fertilization at the current rate are needed to determine if decreasing N, but stable P, results in measurable decreases in Chl a or phytoplankton biomass.TN concentrations in Lake 227 have continued to decline, but total P (TP) concentrations have not changed since N fertilization was suspended in 1990. Furthermore, dissolved inorganic N (DIN) : total dissolved P (TDP) and total dissolved N (TDN) : TDP ratios have decreased, and heterocyte abundances have increased since 1990 (Paterson et al. 2011). Paterson et al. (2011 misinterpret the increase in heterocyte abundance as a signal that the phytoplankton have overcome N deficiency. The mere presence of heterocystous cyanobacteria does not indicate that N fixation is meeting phytoplankton N demand (Lewis and Wurtsbaugh 2008). If N-fixing cyanobacteria were supplying N at a rate proportional to P fertilization, TN concentrations would remain constant or increase relative to TP. Instead, N losses from denitrification, burial, or washout have been greater than ecosystem N gains from N fixation, which confirms that fixed N has not accumulated in Lake 227 over a multi-annual timescale (Scott and McCarthy 2010).The energetic costs of N fixation limit phytoplankton primary production and biomass accumulation. Many studies have shown that cyanobacteria differentiating heterocytes and fixing N have lower growth efficiencies and accumulate less biomass per unit N than those assimilating DIN (Rhee and Lederman 1983;Attridge and Rowell 1997;De Nobel et al. 1997). Therefore, the tradeoff associated with the high energetic costs of N fixation, compared with the relatively low energetic costs of DIN assimilation, will yield less biomass when cyanobacteria are fixing N, even at the ecosystem scale.Using a meta-analysis of almost 900 studies on freshwater and marine environments, Elser et al. (2007) showed that the combination of N + P enrichment always yielded more biomass than N or P enrichment alone. The tremendous temporal variability in Chl a and phytoplankton biomasses over the 41-yr experiment in Lake 227 masks this effect. However, when data were grouped by the seven unique combinations in P and N fertilization rates (Schindler et al. 2008;Paterson et al. 2011), average annual Chl a concentrations were strongly proportional to annua...

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“…From a 37-year whole-ecosystem experiment, Schindler et al (2008) asserted that nitrogen demand of a lake can be met by its nitrogen fixers (e.g., cyanobacteria) and, therefore, eutrophication cannot be controlled by reducing nitrogen input. This assertion has been questioned, however, and multiple nutrient management strategies have been proposed by other scientists (Lewis & Wurtsbaugh 2008;Paerl et al 2011). The challenge, then, is to determine how phytoplankton growth is limited by different nutrients (i.e., N, P, or trace metals) in various ecosystems (Hecky & Kilham 1988;Martin & Fitzwater 1988;Beardall et al 2001;Elser et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Nitrogen and phosphorus limitation of phytoplankton growth in different areas of Lake Taihu, China

Wang

Bin

et al. 2014

Journal of Freshwater Ecology

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Lake Taihu has attracted attention worldwide because of its extensive cyanobacterial blooms in the warm season. A better understanding of nutrient controls over phytoplankton is critical if the blooms are to be controlled. In the present study, we investigated the effects of nutrient addition on the growth of phytoplankton collected from Meiliang Bay (Station 1), Lake Center (Station 2), and Xukou Bay (Station 3) in July and September 2011. Cyanophyta was dominant in all water samples. Nevertheless, we observed higher proportions of other phyla and lower concentrations of microcystin-LR in September than in July. Further, Station 3 possessed many fewer Cyanophyta, but disproportionately higher concentrations of microcystin-LR than the other two stations. The overall phytoplankton biomass decreased in the order Station 1 > Station 2 > Station 3 and July > September. More interestingly, phosphorus-induced phytoplankton growth coincided with a distinct drop in particulate organic carbon (or nitrogen) to phosphorus ratio at Stations 2 and 3. By contrast, nitrogen, applied either alone or together with phosphorus, had negligible effect on phytoplankton growth. These results suggest that phytoplankton at Stations 2 and 3 were limited by phosphorus and no nutrient limitation occurred at Station 1. Therefore, nutrient limitation in Lake Taihu may be more dynamic and sporadic than previously thought and has implications for management of phytoplankton blooms.

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Control of Lacustrine Phytoplankton by Nutrients: Erosion of the Phosphorus Paradigm

Cited by 334 publications

References 76 publications

Critical nutrient thresholds needed to control eutrophication and synergistic interactions between phosphorus and different nitrogen sources

Critical nutrient thresholds needed to control eutrophication and synergistic interactions between phosphorus and different nitrogen sources

Response to Comment: Nitrogen fixation has not offset declines in the Lake 227 nitrogen pool and shows that nitrogen control deserves consideration in aquatic ecosystems

Nitrogen and phosphorus limitation of phytoplankton growth in different areas of Lake Taihu, China

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