Mitigating Cyanobacterial Harmful Algae Blooms

89 Pages·2015·2.01 MB·English

by  Theis, Susan

AN ABSTRACT OF THE THESIS OF

Susan A.F. Theis for the degree of Master of Science in Botany and Plant Pathology
presented on December 8, 2014.

Title: Mitigating Cyanobacterial Harmful Algae Blooms: The Role of Plant Humics

Abstract approved:

____________________________________________
Allen J Milligan

Abstract: Cyanobacterial harmful algae blooms (cyanoHABs) are a growing concern
worldwide due to damage of ecosystems and threats to human health. Previous research
indicates that plant humics from aquatic and wetland vascular plants are effective
inhibitors of cyanobacterial metabolism and growth and may be useful as control agents
for mitigating cyanoHABs. Using lake-side incubations, we exposed natural
phytoplankton assemblages to plant humics. Three plant species, Hordeum vulgare
(barley straw), Typha latifolia (cattail), and the submerged, aquatic invasive
Myriophyllum spicatum (Eurasian watermilfoil) were tested for inhibitory effects against
cyanobacteria in mesocosm experiments. Trials were conducted on a eutrophied
Northern Michigan lake against five cyanobacterial genera (Microcystis, Anabaena,
Lyngbya, Oscillatoria, and Arthrospira) and one Chlorophyta (Ulothrix). Lakeside
mesocosm experiments were conducted in 3.4L jars containing lake water at continuous
oxygen saturation. Treatment effectiveness was assessed via microscopic analysis of
cyanobacterial and Chlorophyte biomass. Total phosphorus, soluble reactive phosphorus,
and total nitrogen changes were analyzed with each treatment. All treatments
significantly inhibited Microcystis growth rates. Anabaena was significantly inhibited by
M. spicatum at all doses. Lyngbya was significantly inhibited in over 65% of all
treatments. Oscillatoria growth rates were unaffected in all but two treatments, and
Ulothrix was unaffected in all but one treatment. Results indicate that plant humic
substances are effective in suppressing cyanobacterial growth and that local aquatic
plants introduce less phosphorus while exhibiting similar inhibition rates as barley straw.
This work suggest that fringing wetlands and submerged aquatic plants may play an
important role in regulating harmful cyanobacterial blooms by providing inhibitory
humics and that this role should be considered when determining wetland value.
©Copyright by Susan A.F. Theis
December 8, 2014
All Rights Reserved
Mitigating Cyanobacterial Harmful Algae Blooms:
The Role of Plant Humics

by
Susan A.F. Theis

A THESIS

submitted to

Oregon State University

in partial fulfillment of
the requirement for the
degree of

Master of Science

Presented December 8, 2014
Commencement June 2015
Master of Science thesis of Susan A.F. Theis presented on
December 8, 2014.

APPROVED:

________________________________________________
Major Professor, representing Botany and Plant Pathology

________________________________________________
Head of the Department of Botany and Plant Pathology

________________________________________________
Dean of the Graduate School

I understand that my thesis will become part of the permanent collection
of Oregon State University libraries. My signature below authorizes
release of my thesis to any reader upon request.

_________________________________________________
Susan A.F. Theis, Author
TABLE OF CONTENTS

Page
1. Mitigating Cyanobacterial Harmful Algae Blooms ................................................... 1
1.1 Introduction .......................................................................................................... 3
1.2 Study Site ............................................................................................................. 8
1.3 Materials and Methods ......................................................................................... 8
1.3.1 Plant material ............................................................................................... 9
1.3.2 Mesocosms .................................................................................................. 9
1.3.3 Algal composition ..................................................................................... 10
1.3.4 Time and Dosage ....................................................................................... 10
1.3.5 Data Analysis ............................................................................................ 11
1.3.6 Statistics .................................................................................................... 12
1.4 Results ................................................................................................................ 14
1.4.1 Hordeum vulgare ....................................................................................... 14
1.4.2 Myriophyllum spicatum ............................................................................. 15
1.4.3 Typha latifolia ........................................................................................... 16
1.4.4 Community Results ................................................................................... 18
1.5 Discussion .......................................................................................................... 21
1.5.1 Mechanisms ............................................................................................... 21
1.5.1.1 Reactive Oxygen Species .................................................................... 21
1.5.1.2 HS Components and direct toxicity ................................................... 23
TABLE OF CONTENTS (Continued)
Page
1.5.2 Mesocosm Conditions ............................................................................... 24
1.5.2.1 Light Attenuation ............................................................................. 25
1.5.2.2 Microbial Role ..................................................................................... 26
1.5.3 Experimental Effectiveness ....................................................................... 26
1.5.3.1 Nutrient Dynamics ............................................................................. 27
1.5.3.2 Hordeum vulgare ................................................................................ 28
1.5.3.3 Myriophyllum spicatum ...................................................................... 29
1.5.3.4 Typha latifolia .................................................................................... 30
1.5.4 General Phytoplankton Trends .................................................................. 33
1.5.5 Management Implications ..................................................................... …35
1.5.5.1 Wetland Valuation .............................................................................. 37
1.5.5.2 Active Management Strategies ........................................................... 39
1.6 Conclusion ........................................................................................................ 40

Bibliography ................................................................................................................. 65
LIST OF FIGURES

Figure Page

1. H. vulgare (barley straw) treatment effects on the growth rates of
Microcystis, Ulothrix, Lyngbya, Oscillatoria, and Arthrospira ……………………...41

2. Linear correlation of H. vulgare treatment doses (g/L) and growth
rates (µ/d) of Microcystis.........................……………………….………………....42

3. Linear correlation of H. vulgare treatment doses (g/L) and growth
rates (µ/d) of Lyngbya……………………………………………………………………...42

4. Linear correlation of H. vulgare treatment doses (g/L) and growth
rates (µ/d) of Oscillatoria………………………………………………………………….43

5. Linear correlation of H. vulgare treatment doses (g/L) and growth
rates (µ/d) of Arthrospira…………………………………………………………..43

6. Linear correlation of H. vulgare treatment doses (g/L) and growth
rates (µ/d) of Microcystis, Lyngbya, Oscillatoria, and Arthrospira………………….44

7. H. vulgare (barley straw) treatments on (A) total phosphorus, (B) soluble
reactive phosphorus, and (C) total nitrogen………………………………………..45

8. Myriophyllum spicatum treatment effects on the growth rates of
Microcystis, Anabaena, Ulothrix, Lyngbya, Oscillatoria, and Arthrospira…………46

9. Linear correlation of M. spicatum treatment doses (g/L) and growth
rates (µ/d) of Microcystis ……………………………………………….................47

10. Linear correlation of M. spicatum treatment doses (g/L) and growth
rates (µ/d) of Ulothrix……………………………………………………………………..47

11. Linear correlation of M. spicatum treatment doses (g/L) and growth
rates (µ/d) of Lyngbya……………………………………………………………..48

12. Linear correlation of M. spicatum treatment doses (g/L) and growth
rates (µ/d) of Arthrospira………………………………………………………….48

13. Linear correlation of M. spicatum treatment doses (g/L) and growth
rates (µ/d) of Microcystis, Lyngbya, Oscillatoria, and Arthrospira………………..49
LIST OF FIGURES (Continued)

Page
14. M. spicatum treatments on (A) total phosphorus, (B) soluble reactive
phosphorus, and (C) total nitrogen ………………………………………………..50

15. Typha latifolia (cattail) green shoot treatments effect on the growth
rates of Microcystis, Ulothrix, Lyngbya, Oscillatoria, and Arthrospira….………..51

16. T. latifolia green shoot treatment impacts on (A) total phosphorus,
(B) soluble reactive phosphorus, and (C) total nitrogen…..……………..………..52

17. Typha latifolia (cattail) brown shoot treatment effects on the growth
rates of Microcystis, Ulothrix, Lyngbya, Oscillatoria, and Arthrospira….….........53

18. Linear correlation of T. latifolia brown shoot treatment doses (g/L)
and growth rates (µ/d) of Microcystis ……………..………………………….......54

19. Linear correlation of T. latifolia brown shoot treatment doses (g/L)
and growth rates (µ/d) of Lyngbya…………………………………………………54

20. Linear correlation of T. latifolia brown shoot treatment doses (g/L)
and growth rates (µ/d) of Microcystis, Lyngbya, Oscillatoria, and
Arthrospira………………………………………………………………………...55

21. T. latifolia brown shoot treatments on (A) total phosphorus, (B) soluble
reactive phosphorus, and (C) total nitrogen…….…………….…………………...56

22. Typha latifolia (cattail) root treatments effects on the growth rates
of Microcystis, Ulothrix, Lyngbya, Oscillatoria, and Arthrospira………….……..57

23. T. latifolia root treatments on (A) total phosphorus, (B) soluble reactive
phosphorus, and (C) total nitrogen………………………………………………..58

24. Increases in total phosphorus (µg/L) from controls in treatments
significantly inhibiting Microcystis………………………………………….......59

25. Increases in total phosphorus (µg/L) from controls in treatments
significantly inhibiting Lyngbya………………………………………………60

26. Increases in total phosphorus (µg/L) from controls in treatments
inhibiting Oscillatoria………………………………..……………………….61