The Stream Inlet to a Shallow Bay of a Drinking Water Reservoir, a ‘Hot‐Spot’ for Microcystis Blooms Initiation

Abstract

Stream inlets into shallow bays of reservoirs and lakes may be 'hot-spots' for toxic cyanobacterial bloom initiation. These 'hot-spots' may be connected with the permanent inflow of high nutrient concentrations from the catchment, optimal physical conditions (wind protected areas) that occur in shallow areas and/or ineffective top-down control. Four sampling sites along a transect from stream to reservoir in a shallow bay of Sulejow Reservoir (Poland) were studied to test the above hypothesis, comprising a transition zone between lotic and pelagic habitats. Investigations showed that stream inlet into shallow bay acted as incubator for Microcystis blooms. The nutrient level, especially phosphorus, was identified as the major cause of cyanobacterial bloom growth. The increase of Microcystis biomass strongly correlated with increasing microcystin concentrations, however, a relationship with microcystin content was not observed. Toxicity of bloom demonstrated seasonal variability, reaching its maximum at the initial phase of bloom.

Do fish and blue-green algae blooms coexist in space and time?

“…It is a typical lowland shallow reservoir, with an area of approximately 2700 ha, an average depth of 3.3 m and a max depth of 11 m. The reservoir is eutrophic, and the chlorophyll a concentration during growth seasons reaches a mean value of 30 g dm −3 and can exceed 150 g dm −3 during phytoplankton blooms. The dominant species of cyanobacteria in the area is Microcystis aeruginosa (Wagner and Zalewski 2000;Izydorczyk et al, 2008b). The analysis of cyanobacterial bloom samples confirmed their highly hepatotoxic character (Tarczyńska et al, 2001;Jurczak et al, 2004;Mankiewicz-Boczek et al, 2006a,b;Izydorczyk et al, 2008a;Gągała et al, 2013).…”

“…In the past decades, increasing eutrophication has led to frequent outbreaks of cyanobacterial blooms in many lakes and reservoirs all over the world (Dokulil and Teubner 2000;Tarczyńska et al, 2001;Anderson et al, 2002;Briand et al, 2003;Chorus 2005;Mankiewicz-Boczek et al, 2006a;Xie et al, 2007;Izydorczyk et al, 2008aIzydorczyk et al, , 2008bGągała et al, 2010). The probability of cyanobacterial toxic blooms will likely increase in the next several decades due to the consequences of climate change on freshwater ecosystems, which will pose potential risks to fish ecology and ecosystem sustainability (Paerl and Huisman 2008;Jöhnk et al, 2008;Wagner and Adrian 2009;Huber et al, 2012;Kosten et al, 2012).…”

Do human activities affect phytoplankton biomass and composition in embayments on Lake Diefenbaker?

“…This is partly because embayments are usually shallow and sheltered from the main channel of lakes or reservoirs. Hence, embayments often experience low flushing or longer water residence time (Mitrovic et al 2001;Hall et al 2003;Izydorczyk et al 2008). Consequently, the combined effects of nutrients released from anthropogenic activities in embayments and their longer residence time may encourage rapid algal growth and nuisance algal blooms (Izydorczyk et al 2008;Poste et al 2012;Mbonde et al 2015).…”

“…Hence, embayments often experience low flushing or longer water residence time (Mitrovic et al 2001;Hall et al 2003;Izydorczyk et al 2008). Consequently, the combined effects of nutrients released from anthropogenic activities in embayments and their longer residence time may encourage rapid algal growth and nuisance algal blooms (Izydorczyk et al 2008;Poste et al 2012;Mbonde et al 2015). For instance, Hall et al (2003) found that higher total phosphorus (TP) concentrations were associated with greater chlorophyll a concentrations in three embayments (Sodus Bay, Sandy Pond and Chaumont Bay) compared to offshore locations in Lake Ontario, Canada.…”

Relationships among cyanobacteria, zooplankton and fish in sub-bloom conditions in the Sulejow Reservoir

“…This area is characterized by stable hydrological conditions, with retention times of up to 60 days, and a high supply of nutrients from the catchment area, which favors cyanobacterial growth, mainly Microcystis aeruginosa Kütz. and Aphanizomenon flos-aquae (L.) (Izydorczyk et al, 2008). The dominant species of bloom-forming cyanobacteria is M. aeruginosa, which produces microcystin-LR (MC-LR), microcystin-YR (MC-YR) and MC-RR (Jurczak et al, 2005;Gągała et al, 2014 (Frankiewicz et al, 1999;Frankiewicz and Świerzowski, 2004).…”