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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Seasonal and diel variation in greenhouse gas emissions from an urban pond and its major drivers
Bergen, Tamara van; Barros, Nathan O. ; Mendonça, Raquel ; Aben, Ralf ; Althuizen, Inge H.J. ; Moraes Huszar, Vera Lúcia de; Lamers, Leon P.M. ; Lurling, M.F.L.L.W. ; Roland, Fabio ; Kosten, Sarian - \ 2019
Limnology and Oceanography 64 (2019)5. - ISSN 0024-3590 - p. 2129 - 2139.
Small water systems are important hotspots of greenhouse gas (GHG) emission, but estimates are poorly constrained as data are scarce. Small ponds are often constructed in urban areas, where they receive large amounts
of nutrients and therefore tend to be highly productive. Here, we investigated GHG emissions, seasonal and diel
variation, and net ecosystem production (NEP) from an urban pond. In monthly 24-h field campaigns during
11 months, diffusive water–atmosphere methane (CH4) and carbon dioxide (CO2) fluxes and CH4 ebullition
and oxidation were quantified. With oxygen (O2) measurements, NEP was assessed. The pond was a net GHG
source the entire year, with an emission of 3.4 kg CO2 eq m−2 yr−1
. The dominant GHG emission pathway was
CH4 ebullition (bubble flux, 50%), followed by diffusive emissions of CO2 (38%) and CH4 (12%). Sediment CH4
release was primarily driven by temperature and especially ebullition increased exponentially above a temperature threshold of 15C. The pond’s atmospheric CO2 exchange was not related to NEP or temperature but likely
to a high allochthonous carbon (C) input via runoff and anaerobic mineralization of C. We expect urban ponds
to show a large increase in GHG emission with increasing temperature, which should be considered carefully
when constructing ponds in urban areas. Emissions may partly be counteracted by pond management focusing
on a reduction of nutrient and organic matter input.
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.

Effect of suspended clay on growth rates of the cyanobacterium Cylindrospermopsis raciborskii
Brasil, Jandeson ; Huszar, Vera L.M. ; Attayde, José L. ; Marinho, Marcelo M. ; Oosterhout, Frank Van; Lürling, Miquel - \ 2017
Fundamental and Applied Limnology 191 (2017)1. - ISSN 1863-9135 - p. 13 - 23.
Cyanobacteria - Inorganic turbidity - Light availability - Sedimentation - Suspended solids
Recent studies have shown that sediment resuspension may lead to the collapse of C. raciborskii dominance, which suggests that clay might have a negative effect on the growth of C. raciborskii. To test the hypothesis that suspended clay creates an unfavorable environment for growth of C. raciborskii, we exposed four different strains of this species to various concentrations of the clays kaolinite and bentonite, and monitored the biomass of each strain over the course of 1-week microcosm experiments. Contrary to our hypothesis, C. raciborskii was able to grow in suspensions of both clays. While kaolinite clay caused higher turbidity than bentonite, the growth rates of all four C. raciborskii strains were higher in kaolinite than in bentonite suspensions. C. raciborskii could still grow in clay concentrations that cause turbidity far above the levels found in natural lakes. Our study suggests that the reported collapse of C. raciborskii blooms with high concentrations of suspended sediments in tropical shallow lakes is probably not caused by the effects of suspended clay on light attenuation, but rather is a consequence of cell sinking or, possibly a response to disturbance events responsible for sediment suspension.
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.

Functional redundancy increases towards the tropics in lake phytoplankton
Kruk, Carla ; Segura, Angel M. ; Costa, Luciana S. ; Lacerot, Gissell ; Kosten, Sarian ; Peeters, Edwin T.H.M. ; Huszar, Vera L.M. ; Mazzeo, Nestor ; Scheffer, Marten - \ 2017
Journal of Plankton Research 39 (2017)3. - ISSN 0142-7873 - p. 518 - 530.
functional richness - latitudinal gradient - morphological traits - morphology-based functional groups

It has been suggested that the overwhelming number of species in tropical ecosystems consist largely of "neutral" and functionally equivalent species. In phytoplankton, differences in functionality have been shown to be clearly distinguishable from morphological traits. Here we examine whether the increase in species towards the tropics goes together with an increase in functional richness or not. We analyse the latitudinal distribution of phytoplankton morphology-based functional groups (MBFG), the within-group richness and community morphological traits in 83 shallow lakes across South America (5-55°S). We further looked into explaining environmental variables. Despite the increment in species richness towards the (sub)tropics, the average number of MBFG remained constant. Furthermore, size average and variance decreased towards warmer regions. In warm lakes, phytoplankton communities were species rich but redundant in terms of belonging to a MBFG. Increasing species richness only translated into increasing number of rare species in some of the MBFG. In contrast, cold lakes were species poor but less redundant (i.e. essential to maintain the number of MBFG) and had a higher morphological variability. Our results support the hypothesis of higher functional redundancy in warmer areas and the relevance of increasing herbivory in colder regions as a main driving process of latitudinal patterns.

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.

The efficiency of combined coagulant and ballast to remove harmful cyanobacterial blooms in a tropical shallow system
Miranda, Marcela ; Noyma, Natália ; Pacheco, Felipe S. ; Magalhães, Leonardo de; Pinto, Ernani ; Santos, Suzan ; Soares, Maria Fernanda A. ; Huszar, Vera L. ; Lurling, Miguel ; Marinho, Marcelo M. - \ 2017
Harmful Algae 65 (2017). - ISSN 1568-9883 - p. 27 - 39.
Chitosan - Cyanobacteria mitigation - Cylindrospermopsis - Eutrophication control - Microcystis

We tested the hypothesis that a combination of coagulant and ballast could be efficient for removal of positively buoyant harmful cyanobacteria in shallow tropical waterbodies, and will not promote the release of cyanotoxins. This laboratory study examined the efficacy of coagulants [polyaluminium chloride (PAC) and chitosan (made of shrimp shells)] alone, and combined with ballast (lanthanum modified bentonite, red soil or gravel) to remove the natural populations of cyanobacteria collected from a shallow eutrophic urban reservoir with alternating blooms of Cylindrospermopsis and Microcystis. PAC combined with ballast was effective in settling blooms dominated by Microcystis or Cylindrospermopsis. Contrary to our expectation, chitosan combined with ballast was only effective in settling Cylindrospermopsis-dominated blooms at low pH, whereas at pH ≥ 8 no effective flocculation and settling could be evoked. Chitosan also had a detrimental effect on Cylindrospermopsis causing the release of saxitoxins. In contrast, no detrimental effect on Microcystis was observed and all coagulant-ballast treatments were effective in not only settling the Microcystis dominated bloom, but also lowering dissolved microcystin concentrations. Our data show that the best procedure for biomass reduction also depends on the dominant species.

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.

High primary production contrasts with intense carbon emission in a eutrophic tropical reservoir
Almeida, Rafael M. ; Nóbrega, Gabriel N. ; Junger, Pedro C. ; Figueiredo, Aline V. ; Andrade, Anízio S. ; Moura, Caroline G.B. de; Tonetta, Denise ; Oliveira, Ernandes S. ; Araújo, Fabiana ; Rust, Felipe ; Piñeiro-Guerra, Juan M. ; Mendonça, Jurandir R. ; Medeiros, Leonardo R. ; Pinheiro, Lorena ; Miranda, Marcela ; Costa, Mariana R.A. ; Melo, Michaela L. ; Nobre, Regina L.G. ; Benevides, Thiago ; Roland, Fábio ; Klein, Jeroen de; Barros, Nathan O. ; Mendonça, Raquel ; Becker, Vanessa ; Huszar, Vera L.M. ; Kosten, Sarian - \ 2016
Frontiers in Microbiology 7 (2016)MAY. - ISSN 1664-302X
Caatinga - Carbon dioxide - Methane - Net ecosystem production - Organic carbon burial - Semiarid

Recent studies from temperate lakes indicate that eutrophic systems tend to emit less carbon dioxide (CO2) and bury more organic carbon (OC) than oligotrophic ones, rendering them CO2 sinks in some cases. However, the scarcity of data from tropical systems is critical for a complete understanding of the interplay between eutrophication and aquatic carbon (C) fluxes in warm waters. We test the hypothesis that a warm eutrophic system is a source of both CO2 and CH4 to the atmosphere, and that atmospheric emissions are larger than the burial of OC in sediments. This hypothesis was based on the following assumptions: (i) OC mineralization rates are high in warm water systems, so that water column CO2 production overrides the high C uptake by primary producers, and (ii) increasing trophic status creates favorable conditions for CH4 production. We measured water-air and sediment-water CO2 fluxes, CH4 diffusion, ebullition and oxidation, net ecosystem production (NEP) and sediment OC burial during the dry season in a eutrophic reservoir in the semiarid northeastern Brazil. The reservoir was stratified during daytime and mixed during nighttime. In spite of the high rates of primary production (4858 ± 934 mg C m-2 d-1), net heterotrophy was prevalent due to high ecosystem respiration (5209 ± 992 mg C m-2 d-1). Consequently, the reservoir was a source of atmospheric CO2 (518 ± 182 mg C m-2 d-1). In addition, the reservoir was a source of ebullitive (17 ± 10 mg C m-2 d-1) and diffusive CH4 (11 ± 6 mg C m-2 d-1). OC sedimentation was high (1162 mg C m-2 d-1), but our results suggest that the majority of it is mineralized to CO2 (722 ± 182 mg C m-2 d-1) rather than buried as OC (440 mg C m-2 d-1). Although temporally resolved data would render our findings more conclusive, our results suggest that despite being a primary production and OC burial hotspot, the tropical eutrophic system studied here was a stronger CO2 and CH4 source than a C sink, mainly because of high rates of OC mineralization in the water column and sediments.

Controlling cyanobacterial blooms through effective flocculation and sedimentation with combined use of flocculants and phosphorus adsorbing natural soil and modified clay
Pessoa Noyma, Natalia ; Magalhaes, L. de; Furtado, L.L. ; Nunes Teixeira Mucci, M. ; Oosterhout, M. van; Huszar, V.L.M. ; Marinho, M.M. ; Lurling, M.F.L.L.W. - \ 2016
Water Research 97 (2016). - ISSN 0043-1354 - p. 26 - 38.
Cyanobacteria bloom - Geo-engineering in lakes - Lake restoration - Local red soil - Phosphorus mitigation
Eutrophication often results in blooms of toxic cyanobacteria that hamper the use of lakes and reservoirs. In this paper, we experimentally evaluated the efficacy of a metal salt (poly-aluminium chloride, PAC) and chitosan, alone and combined with different doses of the lanthanum modified bentonite Phoslock® (LMB) or local red soil (LRS) to sediment positively buoyant cyanobacteria from Funil Reservoir, Brazil, (22°30’S, 44°45’W). We also tested the effect of calcium peroxide (CaO2) on suspended and settled cyanobacterial photosystem efficiency, and evaluated the soluble reactive P (SRP) adsorbing capacity of both LMB and LRS under oxic and anoxic conditions. Our data showed that buoyant cyanobacteria could be flocked and effectively precipitated using a combination of PAC or chitosan with LMB or LRS. The SRP sorption capacity of LMB was higher than that of LRS. The maximum P adsorption was lowered under anoxic conditions especially for LRS ballast. CaO2 addition impaired photosystem efficiency at 1 mg L-1 or higher and killed precipitated cyanobacteria at 4 mg L-1 or higher. A drawback was that oxygen production from the peroxide gave positive buoyancy again to the settled flocs. Therefore, further experimentations with slow release pellets are recommended.
Environmental rather than spatial factors structure bacterioplankton communities in shallow lakes along a >6000km latitudinal gradient in South America
Souffreau, Caroline ; Gucht, Katleen Van der; Gremberghe, Ineke van; Kosten, Sarian ; Lacerot, Gissell ; Lobão, Lúcia Meirelles ; Moraes Huszar, Vera Lúcia de; Roland, Fabio ; Jeppesen, Erik ; Vyverman, Wim ; Meester, Luc De - \ 2015
Environmental Microbiology 17 (2015)7. - ISSN 1462-2912 - p. 2336 - 2351.

Metacommunity studies on lake bacterioplankton indicate the importance of environmental factors in structuring communities. Yet most of these studies cover relatively small spatial scales. We assessed the relative importance of environmental and spatial factors in shaping bacterioplankton communities across a >6000km latitudinal range, studying 48 shallow lowland lakes in the tropical, tropicali (isothermal subzone of the tropics) and tundra climate regions of South America using denaturing gradient gel electrophoresis. Bacterioplankton community composition (BCC) differed significantly across regions. Although a large fraction of the variation in BCC remained unexplained, the results supported a consistent significant contribution of local environmental variables and to a lesser extent spatial variables, irrespective of spatial scale. Upon correction for space, mainly biotic environmental factors significantly explained the variation in BCC. The abundance of pelagic cladocerans remained particularly significant, suggesting grazer effects on bacterioplankton communities in the studied lakes. These results confirm that bacterioplankton communities are predominantly structured by environmental factors, even over a large-scale latitudinal gradient (6026km), and stress the importance of including biotic variables in studies that aim to understand patterns in BCC.

Growth and temperature-related phenotypic plasticity in the cyanobacterium Cylindrospermopsis raciborskii
Soares, M.C.S. ; Lurling, M. ; Huszar, V.L.M. - \ 2013
Phycological Research 61 (2013)1. - ISSN 1322-0829 - p. 61 - 67.
nitrogen limitation - nostocales - cyanoprokaryote - photosynthesis - chlorophyceae - cyanophyceae - morphology - tolerance - cultures - waters
Cylindrospermopsis raciborskii is an invasive and potentially toxic cyanobacterium, which has recently spread worldwide, mainly because of its tolerance to a wide range of climatic conditions. C. raciborskii is able to change several traits in response to environmental changes and its morphology is also affected by these changes (especially in nutrients). We also expected temperature to affect the morphology of this cyanobacterium. We examined the growth and morphology of C. raciborskii at different temperatures and compared laboratory results to the morphology of this cyanobacterium in situ. As expected, growth rates increased with temperature. In addition, a high carrying capacity at 32°C suggests that this cyanobacterium is able to form more dense blooms at high temperatures. Fragile trichomes and low growth rates were observed at 12°C. An increase in the growth rate related to temperature resulted in a decrease in trichome length, with shorter trichomes at 32°C. The same pattern was observed in wild populations of C. raciborskii in a tropical reservoir, where shorter trichomes were observed in warmer months, when biomass was highest. This species’ high ability to adapt to different environmental conditions throughout the year (i.e., nutrients, temperature) may have provided it with an additional advantage to increase its perennial blooms, mainly in tropical regions.
Plankton dynamics under different climate conditions in tropical freshwater systems (a reply to the comment by Sarmento, Amado & Descy, 2013)
Senerpont Domis, L.N. de; Elser, J.J. ; Gsell, A.S. ; Huszar, V.L.M. ; Jeppesen, E. ; Kosten, S. ; Roland, F. ; Sommer, U. ; Donk, E. van; Lurling, M. - \ 2013
Freshwater Biology 58 (2013)10. - ISSN 0046-5070 - p. 2211 - 2213.
amazonian floodplain lake - phytoplankton biomass - highland reservoirs - species composition - northern ethiopia - dry seasons - brazil - community - tigray - time
1.In our recent contribution to the special issue on plankton dynamics in a fast-changing world, we outlined some general predictions of plankton dynamics in different climate regions now and in future, building on the Plankton Ecology Group (PEG) model (de Senerpont Domis et al., 2013). 2.We proposed a stylised version of plankton dynamics in Fig. 3 of our article and stated that these patterns need to be further elaborated. Our figure displays annual plankton dynamics now and in future in oligotrophic, mesotrophic and eutrophic lakes in arctic, temperate and tropical climate zones. 3.We fully agree with Sarmento, Amado & Descy (2013) that more data on tropical regions are needed, and we are looking forward to the emergence of published data from tropical regions to extend our still-limited understanding of plankton dynamics in these regions. 4.Sarmento et al. (2013) did not agree with our predictions on plankton dynamics for hydrology-driven water systems in the tropics. Unfortunately, however, Sarmento et al. (2013) did not substantiate their statements with the much-needed data on plankton dynamics in the tropics. Moreover, they merely provide an overview of precipitation patterns in the tropics, not an alternative hypothesis for our predictions.
Plankton dynamics under different climatic conditions in space and time
Senerpont Domis, L.N. de; Elser, J.J. ; Huszar, V.L.M. ; Ibelings, B.W. ; Jeppesen, E. ; Kosten, S. ; Mooij, W.M. ; Roland, F. ; Sommer, U. ; Donk, E. van; Winder, M. ; Lurling, M. - \ 2013
Freshwater Biology 58 (2013)3. - ISSN 0046-5070 - p. 463 - 482.
north-atlantic oscillation - top-down control - amazonian floodplain lake - fresh-water cladocerans - central-european lake - driven regime shifts - high arctic lakes - shallow lakes - food webs - seasonal succession
1.Different components of the climate system have been shown to affect temporal dynamics in natural plankton communities on scales varying from days to years. The seasonal dynamics in temperate lake plankton communities, with emphasis on both physical and biological forcing factors, were captured in the 1980s in a conceptual framework, the Plankton Ecology Group (PEG) model. 2.Taking the PEG model as our starting point, we discuss anticipated changes in seasonal and long-term plankton dynamics and extend this model to other climate regions, particularly polar and tropical latitudes. Based on our improved post-PEG understanding of plankton dynamics, we also evaluate the role of microbial plankton, parasites and fish in governing plankton dynamics and distribution. 3.In polar lakes, there is usually just a single peak in plankton biomass in summer. Lengthening of the growing season under warmer conditions may lead to higher and more prolonged phytoplankton productivity. Climate-induced increases in nutrient loading in these oligotrophic waters may contribute to higher phytoplankton biomass and subsequent higher zooplankton and fish productivity. 4.In temperate lakes, a seasonal pattern with two plankton biomass peaks - in spring and summer - can shift to one with a single but longer and larger biomass peak as nutrient loading increases, with associated higher populations of zooplanktivorous fish. Climate change will exacerbate these trends by increasing nutrient loading through increased internal nutrient inputs (due to warming) and increased catchment inputs (in the case of more precipitation). 5.In tropical systems, temporal variability in precipitation can be an important driver of the seasonal development of plankton. Increases in precipitation intensity may reset the seasonal dynamics of plankton communities and favour species adapted to highly variable environments. The existing intense predation by fish on larger zooplankters may increase further, resulting in a perennially low zooplankton biomass. 6.Bacteria were not included in the original PEG model. Seasonally, bacteria vary less than the phytoplankton but often follow its patterns, particularly in colder lakes. In warmer lakes, and with future warming, a greater influx of allochthonous carbon may obscure this pattern. 7.Our analyses indicate that the consequences of climate change for plankton dynamics are, to a large extent, system specific, depending on characteristics such as food-web structure and nutrient loading. Indirect effects through nutrient loading may be more important than direct effects of temperature increase, especially for phytoplankton. However, with warming a general picture emerges of increases in bacterivory, greater cyanobacterial dominance and smaller-bodied zooplankton that are more heavily impacted by fish predation. © 2012 Blackwell Publishing Ltd.
Comparison of cyanobacterial and green algal growth rates at different temperatures
Lurling, M. ; Faassen, E.J. ; Kosten, S. ; Eshetu, Z. ; Huszar, V.M. - \ 2013
Freshwater Biology 58 (2013)3. - ISSN 0046-5070 - p. 552 - 559.
fresh-water zooplankton - climate-change - shallow lakes - community structure - microcystis-aeruginosa - phytoplankton - blooms - allelopathy - nutrient - daphnia
1.The hypothesis that cyanobacteria have higher optimum growth temperatures and higher growth rates at the optimum as compared to chlorophytes was tested by running a controlled experiment with eight cyanobacteria species and eight chlorophyte species at six different temperatures (20-35°C) and by performing a literature survey. 2.In the experiment, all organisms except the chlorophyte Monoraphidium minutum grew well up to 35°C. The chlorophyte Chlamydomonas reinhardtii was the fastest-growing organism over the entire temperature range (20-35°C). 3.Mean optimum growth temperatures were similar for cyanobacteria (29.2°C) and chlorophytes (29.2°C). These results are concordant with published data, yielding slightly higher mean optimum growth temperatures for cyanobacteria (27.2°C) than for chlorophytes (26.3°C). 4.Mean growth rates of cyanobacteria at 20°C (0.42day-1) were significantly lower than those of chlorophytes at 20°C (0.62day-1). However, at all other temperatures, there were no differences between mean growth rates of cyanobacteria and chlorophytes. 5.Mean growth rates at the optimum temperature were similar for cyanobacteria (0.92day-1) and chlorophytes (0.96day-1). However, analysis of published data revealed that growth rates of cyanobacteria (0.65day-1) were significantly lower than those of chlorophytes (0.93day-1) at their optimum temperatures. 6.Although climate warming will probably lead to an intensification of cyanobacterial blooms, our results indicate that this might not be as a result of higher growth rates of cyanobacteria compared with their chlorophyte competitors. The competitive advantage of cyanobacteria can more likely be attributed to their ability to migrate vertically and prevent sedimentation in warmer and more strongly stratified waters and to their resistance to grazing, especially when warming reduces zooplankton body size. © 2012 Blackwell Publishing Ltd.
What drives the distribution of the bloom-forming cyanobacteria Planktothrix agardhii and Cylindrospermopsis raciborskii?
Bonilla, S. ; Aubriot, L. ; Soares, M.C.S. ; Gonzalez-Piana, M. ; Fabre, A. ; Huszar, V.L.M. ; Lurling, M. ; Antoniades, D. ; Padisak, J. ; Kruk, C. - \ 2012
FEMS microbiology ecology 79 (2012)3. - ISSN 0168-6496 - p. 594 - 607.
oscillatoria-agardhii - phytoplankton communities - invasive cyanobacterium - northeast brazil - eutrophic lakes - shallow - light - temperature - reservoir - growth
The cyanobacteria Planktothrix agardhii and Cylindrospermopsis raciborskii are bloom-forming species common in eutrophic freshwaters. These filamentous species share certain physiological traits which imply that they might flourish under similar environmental conditions. We compared the distribution of the two species in a large database (940 samples) covering different climatic regions and the Northern and Southern hemispheres, and carried out laboratory experiments to compare their morphological and physiological responses. The environmental ranges of the two species overlapped with respect to temperature, light and total phosphorus (TP); however, they responded differently to environmental gradients; C. raciborskii biovolume changed gradually while P. agardhii shifted sharply from being highly dominated to a rare component of the phytoplankton. As expected, P. agardhii dominates the phytoplankton with high TP and low light availability conditions. Contrary to predictions, C. raciborskii succeeded in all climates and at temperatures as low as 11 degrees C. Cylindrospermopsis raciborskii had higher phenotypic plasticity than P. agardhii in terms of pigments, individual size and growth rates. We conclude that the phenotypic plasticity of C. raciborskii could explain its ongoing expansion to temperate latitudes and suggest its future predominance under predicted climate-change scenarios.
Phytoplankton species predictability increases towards warmer regions
Kruk, C. ; Segura, A.M. ; Peeters, E.T.H.M. ; Huszar, V.L.M. ; Costa, L.S. ; Kosten, S. ; Lacerot, G. ; Scheffer, M. - \ 2012
Limnology and Oceanography 57 (2012)4. - ISSN 0024-3590 - p. 1126 - 1135.
latitudinal diversity gradient - fresh-water phytoplankton - multispecies competition - community - plankton - classification - biodiversity - disturbance - limitation - dispersal
We explored systematic patterns in predictability of phytoplankton species from 83 lakes over a gradient ranging from subpolar to tropical regions in South America. We estimated the explained variance (proxy of predictability) of the presence and biomass (estimated as biovolume) of species using multiple regressions from commonly measured environmental variables such as nutrient levels, light, mixing depth, temperature, and zooplankton biomass. Both the presence and biomass of species occurring at least in 10 lakes were quite well predicted from the environmental variables, with average values of 35% and 58%, respectively. Predictability was not systematically related to phylogenetic affiliation or particular functional groups as defined by morphology. However, biomass predictability decreased with increasing occurrence, and improved with larger species size (maximum linear dimension). Species that were predictable in terms of biomass (R-2 >= 0.5, p
Warmer climates boost cyanobacterial dominance in shallow lakes
Kosten, S. ; Huszar, V.M. ; Bécares, E. ; Costa, S. ; Donk, E. van; Hansson, L. ; Lurling, M.F.L.L.W. - \ 2012
Global Change Biology 18 (2012)1. - ISSN 1354-1013 - p. 118 - 126.
fytoplankton - klimatologie - cyanobacteriën - temperatuur - meren - oppervlaktewaterkwaliteit - phytoplankton - climatology - cyanobacteria - temperature - lakes - surface water quality - fish community structure - trophic state - phytoplankton community - mesocosm experiments - blooms - nitrogen - nutrient - phosphorus - eutrophication
Dominance by cyanobacteria hampers human use of lakes and reservoirs worldwide. Previous studies indicate that excessive nutrient loading and warmer conditions promote dominance by cyanobacteria, but evidence from global scale field data has so far been scarce. Our analysis, based on a study of 143 lakes along a latitudinal transect ranging from subarctic Europe to southern South America, shows that although warmer climates do not result in higher overall phytoplankton biomass, the percentage of the total phytoplankton biovolume attributable to cyanobacteria increases steeply with temperature.
Phytoplankton community composition can be predicted best in terms of morphological groups
Kruk, C. ; Peeters, E.T.H.M. ; Nes, E.H. van; Huszar, V.M. ; Costa, L.S. ; Scheffer, M. - \ 2011
Limnology and Oceanography 56 (2011)1. - ISSN 0024-3590 - p. 110 - 118.
functional types - body-size - plankton - ecology - lake - diversity - classification - nutrient - evolution - patterns
We explored how well the aggregated biovolume of groups of species can be predicted from environmental variables using three different classification approaches: morphology-based functional groups, phylogenetic groups, and functional groups proposed by Reynolds. We assessed the relationships between biovolume of each group and environmental conditions using canonical correlation analyses as well as multiple linear regressions, using data from 211 lakes worldwide ranging from subpolar to tropical regions. We compared the results of these analyses with those obtained for single species following the same protocol. While some species appear relatively predictable, a vast majority of the species showed no clear relationship to the environmental conditions we had measured. However, both the multivariate and the regression analyses indicated that morphology-based groups can be predicted better from environmental conditions than groups based on the other classification methods. This suggests that morphology captures ecological function of phytoplankton well, and that functional groups based on morphology may be the most suitable focus for predicting the composition of communities
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