Golden Algae bloom dynamics and thoughts on management strategies for reservoirs

Transcription

1 Golden Algae bloom dynamics and thoughts on management strategies for reservoirs Support from - Congressional earmark (Rep. Chet Edwards) - Texas Parks and Wildlife - Texas A&M University Leading Institutions Texas A&M University Baylor University University of Texas at Arlington Collaborators Texas Water Research Institute Brazos River Authority Texas Parks and Wildlife - Pat and Dan Loomis

2 Golden Algae bloom dynamics and thoughts on management strategies for reservoirs Co-PI s Dr. Daniel Roelke Dr. Bryan Brooks Dr. James Grover Researchers George Gable Leslie Schwierzke Reagan Errera Carrie Miller Courtney Franssen Jason Baker Ted Valenti Jr. Mieke Lahousse

3 Prymnesium parvum: life as a mixotroph sunlight bacteria organic nutrients (e.g., lipids, amino acids) inorganic nutrients (e.g., nitrate, ammonium, phosphate) life as a plant life as a animal

4 Lake Granbury, TX: Water quality questions What causes and terminates golden algae blooms? Are golden algae and E. coli problems linked? Granbury Might leaky septic systems play a role?

5 Research approach 1. In-lake monitoring fixed-station sampling high-resolution spatial mapping 2. Direct measurements of toxicity bioassays using a fish bioassays using a crustacean 3. Numerical modeling Box model (emphasis on food web interactions) One-dimensional model (emphasis on food web and hydrology)

6 In-lake monitoring: Fixed-stations Ten locations #1 Head of reservoir 1 #2, 3 #4, 5 #6, 7 #8, 9 Paired-stations (shallow and deep) 2,3 4,5 #10 Dam 6,7 8,9 10

7 1 2,3 4,5 6,7 10 8, River flow 10 6 m 3 d -1

8 1 2,3 4,5 6,7 10 8, Total bacteria (10 5 cells ml -1 ) River flow 10 6 m 3 d -1

9 1 2,3 4,5 6,7 10 8, P. parvum (10 6 cells liter -1 ) River flow 10 6 m 3 d -1

10 Scatter plots - DOC vs. Total bacteria Total bacteria (10 5 cells ml -1 ) Poor correlation using all data Weak correlation during period of bloom - when DOC high, total bacteria high

11 Scatter plots - Total bacteria vs. Golden algae Poor correlation using all data P. parvum (cells liter -1 ) Weak correlation during period of bloom - when P. parvum high, total bacteria high Total bacteria (10 5 cells ml -1 )

12 1 2,3 4,5 6,7 10 8, River flow 10 6 m 3 d -1

13 1 2,3 4,5 6,7 10 8, Fecal coliform (cfu 100 ml -1 ) River flow 10 6 m 3 d -1

14 1 2,3 4,5 6,7 10 8, E. coli (cfu 100 ml -1 ) River flow 10 6 m 3 d -1

15 Findings and future research 1. Fixed station sampling -weak relationships between P. parvum, bacteria and DOC - 10 additional sampling stations in coves

16 In-lake monitoring: Fixed-stations 10 additional stations 1 A B C 2,3 D E G 4,5 F I 6,7 H 8,9 10 J

17 In-lake monitoring: Mapping Dataflow On-board, flow through system with geo-referenced data collection

18 Lake Granbury 120 River flow (10 6 m 3 d -1 ) 0 Chlorophyll-a (µg liter -1 )

19 Lake Granbury 120 River flow (10 6 m 3 d -1 ) 0 Chlorophyll-a (µg liter -1 )

20 Findings and future research 1. Fixed station sampling - weak relationships between P. parvum, bacteria and DOC - 10 additional sampling stations in coves 2. Chlorophyll a mapping - pre-bloom (2006): patchy and high concentration at head - prior to bloom termination: near monospecific bloom but less concentration - are patch locations persistent?

21 Timing of P. parvum blooms in Texas What factors influence bloom formation? What factors influence bloom termination? Why is there no sizable population during the summer? P. parvum population density Blooms are a winter-time phenomenon Fall Winter Spring Summer Period for optimal growth (temperature)

22 Lake Whitney, TX In-lake experiments Three seasons: fall, spring, summer In each season, three experiments: each 1-week duration spanning 5 weeks Using 25-liter carboys and 3 to 6 replicates per treatment

23 In-lake methodology

24 Proportions experiments: L. Whitney and L. Waco 9 Fall experiments, 3 of 3 P. parvum P. parvum million (10 cells 6 per cells liter liter -1 ) 0 100% Whit. 75:25 50:50 25:75 100% Waco Filt. Whit. Filt. Waco

25 Proportions experiments: L. Whitney and L. Waco During the fall, some dissolved constituent from L. Waco had a deleterious effect on L. Whitney s P. parvum and total phytoplankton Nutrients? Salts? Pathogens? Pollutants? Allelopathy? No No No???? Initial and final nutrients not limiting; Nutrients accumulate in zooplankton (and detritus?) Salinity differed only by 2 psu; No significant effect Pathogens taxa specific Deleterious effect Waco water non-specific Pollutants from agriculture or industry? Blue-green algae observed in Waco sample

26 Proportions experiments: L. Whitney and L. Waco Allelopathy? known cyanotoxin producers

27 Findings and future research 1. Fixed station sampling - weak relationships between P. parvum, bacteria and DOC - 10 additional sampling stations in coves 2. Chlorophyll-a mapping - pre-bloom (2006): patchy and high concentration at head - prior to bloom termination: near monospecific bloom but less concentration, also patchy - are patch locations persistent? 3. Lakes Whitney and Waco mixing experiments - something dissolved in the water - antagonistic interaction between blue-greens and P. parvum?

28 Thoughts on management strategies Conditions unfavorable to P. parvum - inorganic nutrients non-limiting - established blue-green algae? Coves might be the key - limited nutrient additions (only in the coves and only during the period bloom initiation) to negate nutrient limitation and create conditions conducive for growth of blue-green algae - if coves are a source - circumvent golden algal blooms? - if coves are not a source - create a refuge for fish?