Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 15, issue 4
Biogeosciences, 15, 1123-1147, 2018
https://doi.org/10.5194/bg-15-1123-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 15, 1123-1147, 2018
https://doi.org/10.5194/bg-15-1123-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 23 Feb 2018

Research article | 23 Feb 2018

Modelling potential production of macroalgae farms in UK and Dutch coastal waters

Johan van der Molen1,2, Piet Ruardij2, Karen Mooney4, Philip Kerrison5, Nessa E. O'Connor4, Emma Gorman4, Klaas Timmermans3, Serena Wright1, Maeve Kelly5, Adam D. Hughes5, and Elisa Capuzzo1,a Johan van der Molen et al.
  • 1The Centre for Environment, Fisheries and Aquaculture Science (Cefas), Lowestoft, NR33 0HT, UK
  • 2NIOZ Royal Netherlands Institute for Sea Research, Dept. of Coastal Systems and Utrecht University, Den Burg, 1797 SZ, the Netherlands
  • 3NIOZ Royal Netherlands Institute for Sea Research, Dept. of Estuarine and Delta Systems and Utrecht University, Yerseke, 4401 NT, the Netherlands
  • 4Queen's University, Belfast, BT7 1NN, UK
  • 5The Scottish Association for Marine Science (SAMS), Oban, PA37 1QA, UK
  • anow at: The Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth, DT4 8UB, UK

Abstract. There is increasing interest in macroalgae farming in European waters for a range of applications, including food, chemical extraction for biofuel production. This study uses a 3-D numerical model of hydrodynamics and biogeochemistry to investigate potential production and environmental effects of macroalgae farming in UK and Dutch coastal waters. The model included four experimental farms in different coastal settings in Strangford Lough (Northern Ireland), in Sound of Kerrera and Lynn of Lorne (north-west Scotland) and in the Rhine plume (the Netherlands), as well as a hypothetical large-scale farm off the UK north Norfolk coast. The model could not detect significant changes in biogeochemistry and plankton dynamics at any of the farm sites averaged over the farming season. The results showed a range of macroalgae growth behaviours in response to simulated environmental conditions. These were then compared with in situ observations where available, showing good correspondence for some farms and less good correspondence for others. At the most basic level, macroalgae production depended on prevailing nutrient concentrations and light conditions, with higher levels of both resulting in higher macroalgae production. It is shown that under non-elevated and interannually varying winter nutrient conditions, farming success was modulated by the timings of the onset of increasing nutrient concentrations in autumn and nutrient drawdown in spring. Macroalgae carbohydrate content also depended on nutrient concentrations, with higher nutrient concentrations leading to lower carbohydrate content at harvest. This will reduce the energy density of the crop and thus affect its suitability for conversion into biofuel. For the hypothetical large-scale macroalgae farm off the UK north Norfolk coast, the model suggested high, stable farm yields of macroalgae from year to year with substantial carbohydrate content and limited environmental effects.

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Macroalgae farming may provide biofuel. Modelled macroalgae production is given for four sites in UK and Dutch waters. Macroalgae growth depended on nutrient concentrations and light levels. Macroalgae carbohydrate content, important for biofuel use, was lower for high nutrient concentrations. The hypothetical large-scale farm off the UK north Norfolk coast gave high, stable yields of macroalgae from year to year with substantial carbohydrate content.
Macroalgae farming may provide biofuel. Modelled macroalgae production is given for four sites...
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