Removing constraints on the biomass production of freshwater macroalgae by manipulating water exchange to manage nutrient flux

Cole, Andrew J., de Nys, Rocky, and Paul, Nicholas A. (2014) Removing constraints on the biomass production of freshwater macroalgae by manipulating water exchange to manage nutrient flux. PLoS ONE, 9 (7). e101284. pp. 1-9.

[img]
Preview
PDF (Published Version) - Published Version
Available under License Creative Commons Attribution.

Download (541kB) | Preview
View at Publisher Website: http://dx.doi.org/10.1371/journal.pone.0...
 
27
196


Abstract

Freshwater macroalgae represent a largely overlooked group of phototrophic organisms that could play an important role within an industrial ecology context in both utilising waste nutrients and water and supplying biomass for animal feeds and renewable chemicals and fuels. This study used water from the intensive aquaculture of freshwater fish (Barramundi) to examine how the biomass production rate and protein content of the freshwater macroalga Oedogonium responds to increasing the flux of nutrients and carbon, by either increasing water exchange rates or through the addition of supplementary nitrogen and CO2. Biomass production rates were highest at low flow rates (0.1–1 vol.day21) using raw pond water. The addition of CO2 to cultures increased biomass production rates by between 2 and 25% with this effect strongest at low water exchange rates. Paradoxically, the addition of nitrogen to cultures decreased productivity, especially at low water exchange rates. The optimal culture of Oedogonium occurred at flow rates of between 0.5–1 vol.day21, where uptake rates peaked at 1.09 g.m22.day21 for nitrogen and 0.13 g.m22.day21 for phosphorous. At these flow rates Oedogonium biomass had uptake efficiencies of 75.2% for nitrogen and 22.1% for phosphorous. In this study a nitrogen flux of 1.45 g.m22.day21 and a phosphorous flux of 0.6 g.m22.day21 was the minimum required to maintain the growth of Oedogonium at 16–17 g DW.m22.day21 and a crude protein content of 25%. A simple model of minimum inputs shows that for every gram of dry weight biomass production (g DW.m22.day21), Oedogonium requires 0.09 g.m22.day21 of nitrogen and 0.04 g.m22.day21 of phosphorous to maintain growth without nutrient limitation whilst simultaneously maintaining a high-nutrient uptake rate and efficiency. As such the integrated culture of freshwater macroalgae with aquaculture for the purposes of nutrient recovery is a feasible solution for the bioremediation of wastewater and the supply of a protein resource.

Item ID: 34200
Item Type: Article (Research - C1)
ISSN: 1932-6203
Additional Information:

© 2014 Cole et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funders: Australian Renewable Energy Agency (ARENA), Advanced Manufacturing Cooperative Research Centre (AMCRC)
Date Deposited: 24 Jul 2014 04:16
FoR Codes: 07 AGRICULTURAL AND VETERINARY SCIENCES > 0704 Fisheries Sciences > 070401 Aquaculture @ 50%
10 TECHNOLOGY > 1002 Environmental Biotechnology > 100203 Bioremediation @ 50%
SEO Codes: 96 ENVIRONMENT > 9609 Land and Water Management > 960912 Urban and Industrial Water Management @ 100%
Downloads: Total: 196
Last 12 Months: 15
More Statistics

Actions (Repository Staff Only)

Item Control Page Item Control Page