Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Intraspecific variability in response to phosphorus depleted conditions in the cyanobacteria Microcystis aeruginosa and Raphidiopsis raciborskii
Guedes, Iame Alves ; Pacheco, Ana Beatriz F. ; Vilar, Mauro C.P. ; Mello, Mariana M. ; Marinho, Marcelo Manzi ; Lurling, Miquel ; Azevedo, Sandra M.F.O. - \ 2019
Harmful Algae 86 (2019). - ISSN 1568-9883 - p. 96 - 105.
Cylindrospermopsis - Ecotypes - Phosphorus uptake - Strain variability

Phosphorus loading plays an important role in the occurrence of cyanobacterial blooms and understanding how this nutrient affects the physiology of cyanobacteria is imperative to manage these phenomena. Microcystis aeruginosa and Raphidiopsis raciborskii are cyanobacterial species that form potentially toxic blooms in freshwater ecosystems worldwide. Blooms comprise numerous strains with high trait variability, which can contribute to the widespread distribution of these species. Here, we explored the intraspecific variability in response to phosphorus depleted conditions (P-)testing five strains of each species. Strains could be differentiated by cell volume or genetic profiles except for those of the same species, sampling location and date, though these presented differences in their response to (P-). Although differently affected by (P-)over 10 days, all strains were able to grow and maintain photosynthetic activity. For most M. aeruginosa and R. raciborskii strains growth rates were not significantly different comparing (P+)and (P-)conditions. After ten days in (P-), only one M. aeruginosa strain and two R. raciborskii strains showed reduction in biovolume yield as compared to (P+)but in most strains chlorophyll-a concentrations were lower in (P-)than in (P+). Reduced photosystem II efficiency was found for only one R. raciborskii strain while all M. aeruginosa strains were affected. Only two M. aeruginosa and one R. raciborskii strain increased alkaline phosphatase activity under (P-)as compared to (P+). Variation in P-uptake was also observed but comparison among strains yielded homogeneous groups comprised of representatives of both species. Comparing the response of each species as a whole, the (P-)condition affected growth rate, biovolume yield and chlorophyll yield. However, these parameters revealed variation among strains of the same species to the extent that differences between M. aeruginosa and R. raciborskii were not significant. Taken together, these results do not support the idea that R. raciborskii, as a species, can withstand phosphorus limitation better than M. aeruginosa and also point that the level of intraspecific variation may preclude generalizations based on studies that use only one or few strains.

Managing Eutrophication in a Tropical Brackish Water Lagoon : Testing Lanthanum-Modified Clay and Coagulant for Internal Load Reduction and Cyanobacteria Bloom Removal
Magalhães, Leonardo de; Noyma, Natalia Pessoa ; Furtado, Luciana Lima ; Drummond, Erick ; Leite, Vivian Balthazar Gonçalves ; Mucci, Maíra ; Oosterhout, Frank van; Moraes Huszar, Vera Lúcia de; Lürling, Miquel ; Marinho, Marcelo Manzi - \ 2019
Estuaries and coasts 42 (2019)2. - ISSN 1559-2723 - p. 390 - 402.
Geo-engineering - Lake restoration - PAC - Phoslock - Phosphorus control - Sediment release

The release of phosphorus (P) stored in the sediment may cause long-term delay in the recovery of lakes, ponds, and lagoons from eutrophication. In this paper, we tested on a laboratory scale the efficacy of the flocculant polyaluminium chloride (PAC) and a strong P-binding agent (lanthanum-modified bentonite, LMB) on their ability to flocculate a cyanobacterial bloom and hamper P release from a hypertrophic, brackish lagoon sediment. In addition, critical P loading was estimated through PCLake. We showed that cyanobacteria could be effectively settled using a PAC dose of 2 mg Al L−1 combined with 400-mg L−1 LMB; PAC 8 mg Al L−1 alone could also remove cyanobacteria, although its performance was improved adding low concentrations of LMB. The efficacy of LMB to bind P released from the sediment was tested based on potentially available sediment P. A dose of 400 g LMB m−2 significantly reduced the P release from sediment to over-standing water (either deionized water or water from the lagoon with and without cyanobacteria). In sediment cores, LMB + PAC reduced sediment P flux from 9.9 (± 3.3) to − 4.6 (± 0.3) mg P m−2 day−1 for the experimental period of 3 months. The internal P load was 14 times higher than the estimated P critical load (0.7 mg P m−2 day−1), thus even if all the external P sources would be ceased, the water quality will not improve promptly. Hence, the combined LMB + PAC treatment seems a promising in-lake intervention to diminish internal P load bellow the critical load. Such intervention is able to speed up recovery in the brackish lagoon once external loading has been tackled and at a cost of less than 5% of the estimated dredging costs.

Cyanobacteria dominance drives zooplankton functional dispersion
Josué, Iollanda I.P. ; Cardoso, Simone J. ; Miranda, Marcela ; Mucci, Maíra ; Ger, Kemal Ali ; Roland, Fabio ; Marinho, Marcelo Manzi - \ 2019
Hydrobiologia 831 (2019)1. - ISSN 0018-8158 - p. 149 - 161.
Biodiversity - Eutrophication - Freshwater - Microbial food quality - Plankton

Accelerated eutrophication reduces water quality and shifts plankton communities. However, its effects on the aquatic food web and ecosystem functions remain poorly understood. Within this context, functional ecology can provide valuable links relating community traits to ecosystem functioning. In this study, we assessed the effects of eutrophication and cyanobacteria blooms on zooplankton functional diversity in a tropical hypereutrophic lake. Phytoplankton and zooplankton communities and limnological characteristics of a tropical Brazilian Lake (Southeast, Brazil) were monitored monthly from April 2013 to October 2014. Lake eutrophication indicators were total phosphorus, total chlorophyll-a, and chlorophyll-a per group (blue, green, and brown). The variation of major phytoplankton taxonomic group biomass was calculated and used as a proxy for changes in phytoplankton composition. Zooplankton functional diversity was assessed through functional dispersion and the community-weighted mean trait value. Regressions were performed between the lake eutrophication indicators, the phytoplankton biomass variation, and zooplankton functional dispersion. Our results suggest that eutrophication and cyanobacterial dominance change the composition of zooplankton traits and reduce functional dispersion, leading to zooplankton niche overlap. These findings are important because they provide a meaningful view of phytoplankton-zooplankton trophic interactions and contribute to an improved understanding their functional effects on aquatic ecosystems.

Assessment of possible solid-phase phosphate sorbents to mitigate eutrophication : Influence of pH and anoxia
Mucci, Maíra ; Maliaka, Valentini ; Noyma, Natalia Pessoa ; Marinho, Marcelo Manzi ; Lürling, Miquel - \ 2018
Science of the Total Environment 619-620 (2018). - ISSN 0048-9697 - p. 1431 - 1440.
Geo-engineering - Phosphate adsorption - Phosphorus control

Managing eutrophication remains a challenge to water managers. Currently, the manipulation of biogeochemical processes (i.e., geo-engineering) by using phosphorus-adsorptive techniques has been recognized as an appropriate tool to manage the problem. The first step in finding potential mitigating materials is conducting a sequence of upscaling studies that commence with controlled laboratory experiments. Here, the abilities of 10 possible solid–phase-sorbents (SPS) to adsorb P were examined. Four materials adsorbed P, and two of these materials were modified, i.e., a lanthanum-modified-bentonite (LMB) and an aluminum-modified-zeolite (AMZ), and had the highest adsorption capacities of 11.4 and 8.9 mg P g− 1, respectively. Two natural materials, a red soil (RS) and a bauxite (BAU), were less efficient with adsorption capacities of 2.9 and 3.4 mg P g− 1, respectively. Elemental composition was not related to P adsorption. Since SPS might be affected by pH and redox status, we also tested these materials at pH values of 6, 7, 8 and 9 and under anoxic condition. All tested materials experienced decreased adsorption capacities under anoxic condition, with maximum adsorptions of 5.3 mg P g− 1 for LMB, 5.9 mg P g− 1 for AMZ, 0.2 mg P g− 1 for RS and 0.2 mg P g− 1 for BAU. All materials were able to adsorb P across the range of pH values that were tested. The maximum adsorption capacities of LMB and RS were highest at pH 6, AMZ was higher at a pH of 9 and BAU at a pH of 8. Thus, pH influenced P adsorption differently. Given the effects of pH and anoxia, other abiotic variables should also be considered. Considering the criteria that classify a useful SPS (i.e., effective, easy to produce, cheap and safe), only the two modified materials that were tested seem to be suitable for upscaling to enclosure studies with anoxic sediments.

Coagulant plus ballast technique provides a rapid mitigation of cyanobacterial nuisance
Noyma, Natalia Pessoa ; Magalhães, Leonardo De; Miranda, Marcela ; Nunes Teixeira Mucci, Maira ; Oosterhout, Frank van; Moraes Huszar, Vera Lúcia de; Marinho, Marcelo Manzi ; Lima, Eduardo R.A. ; Lurling, Miquel - \ 2017
PLoS ONE 12 (2017)6. - ISSN 1932-6203 - 16 p.

Cyanobacteria blooms are a risk to environmental health and public safety due to the potent toxins certain cyanobacteria can produce. These nuisance organisms can be removed from water bodies by biomass flocculation and sedimentation. Here, we studied the efficacy of combinations of a low dose coagulant (poly-aluminium chloride-PAC-or chitosan) with different ballast compounds (red soil, bauxite, gravel, aluminium modified zeolite and lanthanum modified bentonite) to remove cyanobacterial biomass from water collected in Funil Reservoir (Brazil). We tested the effect of different cyanobacterial biomass concentrations on removal efficiency. We also examined if zeta potential was altered by treatments. Addition of low doses of PAC and chitosan (1±8 mg Al L-1) to the cyanobacterial suspensions caused flock formation, but did not settle the cyanobacteria. When those low dose coagulants were combined with ballast, effective settling in a dose-dependent way up to 99.7% removal of the flocks could be achieved without any effect on the zeta potential and thus without potential membrane damage. Removal efficacy was influenced by the cyanobacterial biomass and at higher biomass more ballast was needed to achieve good removal. The combined coagulant-ballast technique provides a promising alternative to algaecides in lakes, ponds and reservoirs.

Critical assessment of chitosan as coagulant to remove cyanobacteria
Lurling, Miguel ; Noyma, Natalia Pessoa ; Magalhães, Leonardo de; Miranda, Marcela ; Mucci, Maíra ; Oosterhout, F. van; Huszar, Vera L.M. ; Marinho, Marcelo Manzi - \ 2017
Harmful Algae 66 (2017). - ISSN 1568-9883 - p. 1 - 12.
Cyanobacterial blooms - Eutrophication - Flock and sink - Mitigation - Nuisance control

Removal of cyanobacteria from the water column using a coagulant and a ballast compound is a promising technique to mitigate nuisance. As coagulant the organic, biodegradable polymer chitosan has been promoted. Results in this study show that elevated pH, as may be common during cyanobacterial blooms, as well as high alkalinity may hamper the coagulation of chitosan and thus impair its ability to effectively remove positively buoyant cyanobacteria from the water column. The underlying mechanism is likely a shielding of the protonated groups by anions. Inasmuch as there are many chitosan formulations, thorough testing of each chitosan prior to its application is essential. Results obtained in glass tubes were similar to those from standard jar tests demonstrating that glass tube tests can be used for testing effects of coagulants and ballasts in cyanobacteria removal whilst allowing far more replicates. There was no relation between zeta potential and precipitated cyanobacteria. Given the well-known antibacterial activity of chitosan and recent findings of anti-cyanobacterial effects, pre-application tests are needed to decipher if chitosan may cause cell leakage of cyanotoxins. Efficiency- and side-effect testing are crucial for water managers to determine if the selected approach can be used in tailor-made interventions to control cyanobacterial blooms and to mitigate eutrophication.

Chitosan as coagulant on cyanobacteria in lake restoration management may cause rapid cell lysis
Nunes Teixeira Mucci, Maira ; Noyma, Natalia Pessoa ; Magalhães, Leonardo de; Miranda, Marcela ; Oosterhout, Frank van; Guedes, Iamê Alves ; Huszar, Vera L.M. ; Marinho, Marcelo Manzi ; Lürling, Miquel - \ 2017
Water Research 118 (2017). - ISSN 0043-1354 - p. 121 - 130.
Cell lysis - Cell viability - Cyanobacterial blooms - Eutrophication - Lake restoration - Photosystem II efficiency

Combining coagulant and ballast to remove cyanobacteria from the water column is a promising restoration technique to mitigate cyanobacterial nuisance in surface waters. The organic, biodegradable polymer chitosan has been promoted as a coagulant and is viewed as non-toxic. In this study, we show that chitosan may rapidly compromise membrane integrity and kill certain cyanobacteria leading to release of cell contents in the water. A strain of Cylindrospermopsis raciborskii and one strain of Planktothrix agardhii were most sensitive. A 1.3 h exposure to a low dose of 0.5 mg l−1 chitosan already almost completely killed these cultures resulting in release of cell contents. After 24 h, reductions in PSII efficiencies of all cyanobacteria tested were observed. EC50 values varied from around 0.5 mg l−1 chitosan for the two sensitive strains, via about 5 mg l−1 chitosan for an Aphanizomenon flos-aquae strain, a toxic P. agardhii strain and two Anabaena cylindrica cultures, to more than 8 mg l−1 chitosan for a Microcystis aeruginosa strain and another A. flos-aquae strain. Differences in sensitivity to chitosan might be related to polymeric substances that surround cyanobacteria. Rapid lysis of toxic strains is likely and when chitosan flocking and sinking of cyanobacteria is considered in lake restoration, flocculation efficacy studies should be complemented with investigation on the effects of chitosan on the cyanobacteria assemblage being targeted.

Efficacy of Coagulants and Ballast Compounds in Removal of Cyanobacteria (Microcystis) from Water of the Tropical Lagoon Jacarepaguá (Rio de Janeiro, Brazil)
Magalhães, Leonardo de; Noyma, Natália Pessoa ; Furtado, Luciana Lima ; Nunes Teixeira Mucci, Maira ; Oosterhout, Frank van; Huszar, Vera L.M. ; Marinho, Marcelo Manzi ; Lurling, Miguel - \ 2017
Estuaries and coasts 40 (2017)1. - ISSN 1559-2723 - p. 121 - 133.
Bloom control - Chitosan - Cyanobacteria - Eutrophication - Mitigation - PAC

Eutrophication is considered the most important water quality problem in freshwaters and coastal waters worldwide promoting frequent occurrence of blooms of potentially toxic cyanobacteria. Removal of cyanobacteria from the water column using a combination of coagulant and ballast is a promising technique for mitigation and an alternative to the use of algaecides. In laboratory, we tested experimentally the efficiency of two coagulants, polyaluminium chloride (PAC) and chitosan (made of shrimp shells), alone and combined with two ballasts: red soil (RS) and the own lagoon sediment, to remove natural populations of cyanobacteria, from an urban brackish coastal lagoon. PAC was a very effective coagulant when applied at low doses (≤8 mg Al L−1) and settled the cyanobacteria, while at high doses (≥16 mg Al L−1) large flocks aggregated in the top of test tubes. In contrast, chitosan was not able to form flocks, even in high doses (>16 mg L−1) and did not efficiently settle down cyanobacteria when combined with ballast. The RS itself removed 33–47 % of the cyanobacteria. This removal was strongly enhanced when combined with PAC in a dose-dependent matter; 8 mg Al L−1 was considered the best dose to be applied. The lagoon sediment alone did not promote any settling of cyanobacteria but removal was high when combined with PAC. Combined coagulant and ballast seems a very efficient, cheap, fast and safe curative measure to lessen the harmful cyanobacteria bloom nuisance in periods when particularly needed, such as around the 2016 Olympics in Jacarepaguá Lagoon.

Assessment of the Effects of Light Availability on Growth and Competition Between Strains of Planktothrix agardhii and Microcystis aeruginosa
Araujo Torres, C. de; Lurling, M.F.L.L.W. ; Manzi Marinho, M. - \ 2016
Microbial Ecology 71 (2016)4. - ISSN 0095-3628 - p. 802 - 813.
In this study, we tested the hypothesis that Planktothrix agardhii strains isolated from a tropical water body were better competitors for light than Microcystis aeruginosa strains. These cyanobacteria are common in eutrophic systems, where light is one of the main drivers of phytoplankton, and Planktothrix is considered more shade-adapted and Microcystis more high-light tolerant. First, the effect of light intensities on growth was studied in batch cultures. Next, the minimum requirement of light (I*) and the effect of light limitation on the outcome of competition was investigated in chemostats. All strains showed similar growth at 10 μmol photons m−2 s−1, demonstrating the ability of the two species to grow in low light. The optimum light intensity was lower for P. agardhii, but at the highest light intensity, Microcystis strains reached higher biovolume, confirming that P. agardhii has higher sensitivity to high light. Nonetheless, P. agardhii grew in light intensities considered high (500 μmol photons m−2 s−1) for this species. M. aeruginosa showed a higher carrying capacity in light-limited condition, but I* was similar between all the strains. Under light competition, Microcystis strains displaced P. agardhii and dominated. In two cases, there was competitive exclusion and in the other two P. agardhii managed to remain in the system with a low biovolume (≈15 %). Our findings not only show that strains of P. agardhii can grow under higher light intensities than generally assumed but also that strains of M. aeruginosa are better competitors for light than supposed. These results help to understand the co-occurrence of these species in tropical environments and the dominance of M. aeruginosa even in low-light conditions.
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