Green tide algae integrated aquaculture for nitrogen bioremediation

140 Pages·2014·1.38 MB·English

ResearchOnline@JCU

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de Paula Silva, Pedro Henrique (2012) Green tide algae
integrated aquaculture for nitrogen bioremediation. PhD
thesis, James Cook University.

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Green tide algae integrated aquaculture for nitrogen bioremediation

Thesis submitted by
Pedro Henrique de Paula Silva
BSc (Biological Sciences)
in Jul 2012

for the research degree of Doctors of Philosophy
within the School of Marine and Tropical Biology
James Cook University
Statement of Access

I, the undersigned, author of this work, understand that James Cook University will make this
thesis available for use within the University Library and, via the Australian Digital Theses
network, for use elsewhere.

I understand that, as an unpublished work, a thesis has significant protection under the
Copyright Act and I do not wish to place any further restriction on access to this work.

20/02/2013
Signature Date

ii
Statement of Sources

DECLARATION

I declare that this thesis is my own work and has not been submitted in any form for another
degree or diploma at any university or other institution of tertiary education. Information
derived from the published or unpublished work or others has been acknowledged in the text
and a list of references is given. Every reasonable effort has been made to gain permission
and acknowledge the owners of copyright material. I would be pleased to hear from any
copyright owner who has been omitted or incorrectly acknowledged.

20/02/2013
Signature Date

iii
Electronic Copy Declaration

I, the undersigned, the author of this work, declare that the electronic copy of this thesis
provided to the James Cook University Library is an accurate copy of the print thesis
submitted within the limits of the technology available.

20/02/2013
Signature Date

iv
Statement of Contribution of Author

Research funding for this PhD was provided through the School of Tropical and Marine
Biology and Graduate School of James Cook University, the Advanced Manufacturing Co-
operative Research Centre (AMCRC) and MBD Energy. An AMCRC scholarship provided
stipend support.

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Acknowledgements

Firstly, I would like to thank my supervisor Rocky de Nys. He was always available to
discuss my work and provided endless motivation throughout this study. His enthusiasm has
often helped me to continue through this long journey. His guidance was essential to the
improvement of my scientific and writing skills. I am grateful for the opportunity to be one of
his students.
I am also grateful to my associate supervisor Nicholas Paul. His direction throughout this
study and his guidance with experiments and write up were also essential. The knowledge
and level of expertise I have achieved would not be possible without his help and patience.
I am also thankful to all the friends and colleagues who helped me in field trips and
everything else; Heidi Luter, Hugh McIntosh, Scott Seymour, Tine Carl, Sarah Castine, and
the support I received from the technical staff, present and past, at MARFU.
Finally, I would to thank my beautiful wife Lorenna Machado for the companionship
throughout this journey and the endless moments of joy that made me keep going even when
I thought this was not possible. Her understanding and encouragement helped me immensely.
Last, but not least, I would like to thank all my family. My parents, Cesar Antonio and Celia
Regina, are my role models and have always made me want to be a better person and live a
life of achievement. Without their unconditional support I would not have made it this far and
I dedicate this thesis to them.

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Abstract

Green tide algae bloom in eutrophic environments with fast growth rates, efficient nutrient
uptake and broad environmental resilience. These same characteristics are sought after for
algae in integrated aquaculture systems. To evaluate the potential use of naturally occurring
green tide algae in tropical integrated aquaculture the effects of key variables on resilience,
biomass productivity and bioremediation potential were quantified. Three locally abundant
green tide algal species (Cladophora coelothrix, Chaetomorpha indica and Ulva sp.)
demonstrated a high tolerance across the extremes of salinity (15 to 45‰) and total ammonia
nitrogen (TAN from 7 up to 700 µmols l-1) characteristic of tropical aquaculture
bioremediation ponds. In a preliminary in situ experiment Cladophora coelothrix
demonstrated high growth and survival rates, a high predicted productivity (4 t ha-1 for a 7-
day harvest cycles) and corresponding nitrogen removal (23 kg N harvest-1). Subsequently, it
was determined that large scale, in situ productivity of Cladophora coelothrix during four
winter months correlated primarily with nitrogen concentration, position in the pond and
stocking density, with a lesser influence of salinity, temperature and the ratio of nitrate-
nitrogen and total ammonium nitrogen. Growth and resilience were then determined in
factorial laboratory and mesocosm experiments, according to environmental fluctuations of
an entire growing season. Cladophora coelothrix growth was high irrespective of seasonal
fluctuations. Temperature was the key variable for seasonal growth, followed by nitrogen
concentration and salinity, and interestingly growth was limited by ~20% when nitrate-N and
TAN were available simultaneously. In addition to adequate nitrogen levels, seaweeds under
intensive culture require a high flux of dissolved inorganic carbon (Ci) to support
productivity. In this study, higher levels of inorganic carbon (Ci), in particular CO
2
significantly enhanced the productivity of Cladophora coelothrix (26%), Chaetomorpha
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linum (24%) and Cladophora patentiramea (11%), despite the demonstrated HCO -
3
utilization through high pH compensation points (9.7-9.9) and growth in pH levels up to 9.
Finally, classification and regression tree (CART) analysis in combination with logistic
equations, using relevant laboratory, mesocosm and field data from all previous data
chapters, were used to develop annual model simulations for large-scale algal culture for two
locally abundant green tide algae. The logistic model simulations demonstrate that
Cladophora coelothrix had a high environmental tolerance and the highest predicted annual
productivity of 24.3 T dry weight ha-1 year-1, equating to a nitrogen removal of 140 kg ha-1
year-1, whereas the lower environmental tolerance and overall growth of Cladophora
patentiramea resulted in a lower annual productivity of 10.8 T dry weight ha-1 year-1. In
conclusion, this study has demonstrated that green tide algae can be cultured in tropical land-
based ponds with high productivity and nitrogen bioremediation. Cladophora coelothrix, in
particular, demonstrated a broad environmental tolerance, high biomass productivity and
nitrogen bioremediation, and these results support the use of this green tide algal species in
integrated aquaculture.

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Table of Contents

Statement of Access…………………………………………………………………………...ii
Statement of Sources………………………………………………………………………….iii
Electronic Copy………………………………………………………………………….........iv
Contribution of Author………………………………………………………………………...v
Acknowledgements…………………………………………………………………………...vi
Abstract…………………………………………………………………………………........vii
Table of Contents…………………………………………………………………………......ix
List of Figures…………………………………………………………………………….......xi
List of tables……………………………………………………………………………........xiv

Chapter 1: General Introduction ........................................................................................... 1 

Chapter 2: Integrating filamentous green tide algae into tropical pond-based
aquaculture ............................................................................................................................. 13 
2.1 Introduction .................................................................................................................... 13 
2.2 Materials and Methods ................................................................................................... 15 
2.3 Results ............................................................................................................................ 21 
2.4 Discussion ...................................................................................................................... 28 

Chapter 3: Seasonal growth dynamics and resilience of the green tide alga Cladophora
coelothrix in high-nutrient tropical aquaculture ................................................................. 33 
3.1 Introduction .................................................................................................................... 33 
3.2 Materials and Methods ................................................................................................... 35 
3.3 Results ............................................................................................................................ 44 
3.4 Discussion ...................................................................................................................... 56 

Chapter 4: Enhanced production of green tide algal biomass through additional carbon
supply ...................................................................................................................................... 63 
4.1 Introduction .................................................................................................................... 63 
4.2 Materials and Methods ................................................................................................... 65 
4.3 Results ............................................................................................................................ 71 
4.4 Discussion ...................................................................................................................... 75 

Chapter 5: Developing a simple predictive model for large-scale biomass applications 82 
5.1 Introduction .................................................................................................................... 82 
5.2 Materials and Methods ................................................................................................... 83 
5.3 Results ............................................................................................................................ 90 
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