Zooplankton community structure in the presence of low levels of cyanotoxins: a case study in a high altitude tropical reservoir (Valle de Bravo, Mexico)

Valle de Bravo water reservoir in the State of Mexico is being intensively studied since it provides water to about 2,500,000 people living in Mexico City. Cyanobacterial blooms reduce the water quality in this reservoir and this poses health risks. We hypothesize that one of the reasons for these persistent blooms is the dominance of small sized zooplankton throughout the year. Zooplankton samples were collected monthly by filtering 50 L of water from the surface (10-20 cm) using a 50 µm mesh and the samples were fixed in 4% formalin in the field. We measured temperature, pH, conductivity, Secchi disk transparency, dissolved oxygen, nitrates and phosphates. The microcystin levels were also quantified. The Secchi depth ranged from 0.86 to 9 m, nitrate levels were low (0.28 to 2.06 mg L -1 ), while phosphates were in the range of 1 to 14 mg L -1 . The temperature varied from 14 to 25 °C. The zooplankton community was represented by 25 species of rotifers Keratella cochlearis had the highest density (840 ind L -1 , followed by Polyarthra vulgaris (750 ind L -1 ). As compared to previous studies where the genus Brachionus was practically absent, we found four brachionid species. Among cladocerans, Bosmina longirostris was the dominant taxa reaching up to 100 ind L -1 . Small sized zooplankton (<200 µm) dominated throughout the year. The zooplankton biomass in the winter months (December to February) was contributed by Daphnia laevis , copepodites and adult copepods. Unlike a decade ago when a dominance by cyanobacteria was recorded, in this study we found that the phytoplankton was dominated by diatoms and chlorophytes with an occasional presence of the cyanobacteria Anabaena spp . and Microcystis spp . The concentration of microcystins ranged from 0.5 to 0.7 µg L -1 and was within the parameters set by the WHO. Carlson’s Trophic State Index and Sladecek’s Brachionus/Trichocera ratio indicated that the reservoir was mesotrophic during the study period.

[1]  Ilia Ostrovsky,et al.  Ecological impacts of excessive water level fluctuations in stratified freshwater lakes , 2011 .

[2]  M. Vanni.  Effects of Food Availability and Fish Predation on a Zooplankton Community , 1987 .

[3]  J. Berry,et al.  First evidence of "paralytic shellfish toxins" and cylindrospermopsin in a Mexican freshwater system, Lago Catemaco, and apparent bioaccumulation of the toxins in "tegogolo" snails (Pomacea patula catemacensis). , 2010, Toxicon : official journal of the International Society on Toxinology.

[4]  Tom Andersen,et al.  Carbon, nitrogen, and phosphorus content of freshwater zooplankton , 1991 .

[5]  S. S. S. Sarma,et al.  Taxonomic studies of freshwater rotifers [Rotifera] from Mexico , 1997 .

[6]  S. Gkelis,et al.  Plankton food web structure in a eutrophic polymictic lake with a history of toxic cyanobacterial blooms , 2006 .

[7]  S. Joseph,et al.  Environmental status of a tropical lake system , 2011, Environmental monitoring and assessment.

[8]  S. Kinnear.  Cylindrospermopsin: A Decade of Progress on Bioaccumulation Research , 2010, Marine drugs.

[9]  J. J. Gilbert,et al.  Variation in Herbivore Response to Chemical Defenses: Zooplankton Foraging on Toxic Cyanobacteria , 1992 .

[10]  M. Beklioğlu,et al.  Danish and other European experiences in managing shallow lakes , 2007 .

[11]  E. Torres-Orozco,et al.  SPECIES COMPOSITION, ABUNDANCE AND DISTRIBUTION OF ZOOPLANKTON IN A TROPICAL EUTROPHIC LAKE : LAKE CATEMACO, MEXICO , 2015 .

[12]  K. Christoffersen.  Ecological implications of cyanobacterial toxins in aquatic food webs , 1996 .

[13]  M. Scheffer,et al.  Warmer climates boost cyanobacterial dominance in shallow lakes , 2012 .

[14]  W. Lampert,et al.  Food Thresholds in Daphnia Species in the Absence and Presence of Blue‐Green Filaments , 1990 .

[15]  S. Nandini,et al.  Seasonal changes in the rotifer (Rotifera) diversity from a tropical high altitude reservoir (Valle de Bravo, Mexico). , 2009, Journal of environmental biology.

[16]  Alan D. Lopez,et al.  First evidence of Ωc0→Ω−π+ , 1993 .

[17]  M. Manca,et al.  Response of rotifer functional groups to changing trophic state and crustacean community , 2011 .

[18]  Takehito Yoshida,et al.  Direct and indirect effects of zooplankton on algal composition in in situ grazing experiments , 2002, Oecologia.

[19]  J. Talling,et al.  Ecological Dynamics of Tropical Inland Waters , 1999 .

[20]  S. S. S. Sarma,et al.  Seasonal dynamics of zooplankton in Lake Huetzalin, Xochimilco (Mexico City, Mexico) , 2009 .

[21]  S. S. S. Sarma,et al.  Seasonal variations of zooplankton abundance in the freshwater reservoir Valle de Bravo (Mexico) , 2004, Hydrobiologia.

[22]  V. Sládeček.  Rotifers as indicators of water quality , 2004, Hydrobiologia.

[23]  J. Patočka,et al.  The toxins of Cyanobacteria. , 2001, Acta medica.

[24]  Wayne W. Carmichael,et al.  Health Effects of Toxin-Producing Cyanobacteria: “The CyanoHABs” , 2001 .

[25]  J. Alcocer,et al.  Limnology in Mexico , 2010, Hydrobiologia.

[26]  The temporal-spatial pattern of vertical migration by the freshwater copepod Skistodiaptomus oregonensis relative to predation risk , 1998 .

[27]  S. S. S. Sarma,et al.  Seasonal changes in the zooplankton abundances of the reservoir Valle de Bravo (State of Mexico, Mexico) , 2008 .

[28]  W. Carmichael.  The toxins of cyanobacteria. , 1994, Scientific American.

[29]  Erik Jeppesen,et al.  Horizontal dynamics of zooplankton in subtropical Lake Blanca (Uruguay) hosting multiple zooplankton predators and aquatic plant refuges , 2007, Hydrobiologia.

[30]  G. D. L. Lanza-Espino,et al.  Lagos y presas de México , 1995 .

[31]  Martha Leticia Gaytan-Herrera,et al.  Temporal variation of phytoplankton from the tropical reservoir Valle de Bravo, Mexico. , 2011, Journal of environmental biology.

[32]  G. Codd,et al.  Cyanobacterial toxins: risk management for health protection. , 2005, Toxicology and applied pharmacology.

[33]  M. Devetter.  Influence of environmental factors on the rotifer assemblage in an artificial lake , 2004, Hydrobiologia.

[34]  R. D. Gulati.  Structural and grazing responses of zooplankton community to biomanipulation of some Dutch water bodies , 1990, Hydrobiologia.

[35]  J. M. Elliott,et al.  Plankton Rotifers: Biology and Taxonomy , 1976 .

[36]  K. Izydorczyk,et al.  Diversity of planktonic cyanobacteria and microcystin occurrence in Polish water bodies investigated using a polyphasic approach , 2008 .

[37]  P. Ramírez-Garcia,et al.  Microcystin-LR equivalents and their correlation with Anabaena spp. in the main reservoir of a hydraulic system of Central Mexico , 2014 .

[38]  C. Burns.  Direct Observations of Mechanisms Regulating Feeding Behavior of Daphnia, in Lakewater , 1968 .

[39]  Alan E. Wilson,et al.  Bioaccumulation of microcystins by fish associated with a persistent cyanobacterial bloom in Lago de Patzcuaro (Michoacan, Mexico) , 2011, Environmental toxicology and chemistry.

[40]  J. Elser,et al.  Species‐Dependent Effects of Zooplankton on Planktonic Ecosystem Processes in Castle Lake, California , 1994 .

[41]  Henri J. Dumont,et al.  The dry weight estimate of biomass in a selection of Cladocera, Copepoda and Rotifera from the plankton, periphyton and benthos of continental waters , 1975, Oecologia.

[42]  A. Antunes,et al.  First report on the occurrence of microcystins in planktonic cyanobacteria from Central Mexico. , 2010, Toxicon : official journal of the International Society on Toxinology.

[43]  L. De Meester,et al.  Zooplankton community structure and environmental conditions in a set of interconnected ponds , 2004, Hydrobiologia.

[44]  Erik Jeppesen,et al.  High predation is of key importance for dominance of small-bodied zooplankton in warm shallow lakes: evidence from lakes, fish exclosures and surface sediments , 2011, Hydrobiologia.

[45]  M. Potts,et al.  The ecology of cyanobacteria: their diversity in time and space (reviewed by T. Bailey Watts) , 2001 .

[46]  M. Scholten.  Eutrophication management and ecotoxicology. , 2005 .

[47]  H. Bottrell.  A review of some problems in zooplankton production studies , 1976 .