Saturday, August 25th, 2018

DEMONSTRATION OF A NITROGEN BUDGET MODEL TO ASSESS WATER RENEWAL RATES AND NITROGEN LIMITATION IN COMMERCIAL SEAWEED FARMS

http://www.was.org/Meetings/ShowAbstract.aspx?Id=104070

Micro & Macro Algae Culture Session, AQUA 2018, 25-29th August, Montpelier, France. Oral Communication, abstract # 461

This work presents a simple nutrient mass balance model, developed for land-based seaweed farmers. The model provides the farmer, via a simple interface, the value of the water renewal rate that is necessary for a desired seaweed production (Figure 1), given a farm configuration and N input concentration in the inflow water.

The model was calibrated and evaluated for one of the main seaweed species in pond cultivation, Ulva spp.

The model application with published data illustrates the calculation of the water renewal required in a commercial seaweed farm with 2-ha area of Ulva production, a water depth of 0.5 m and a N input concentration averaging 50 μmol L−1. For that hypothetical case, the model advises the farmer to renew the water volume of the seaweed pond from 2 to 4 times per day at initial and harvesting seaweed densities, respectively. Those water renewal rates could be decreased to the range of 1.5 to 3 times per day during winter. The model is available online with the Ulva spp. calibration as a default, for widespread use, at http://seaplusplus4.com/algaeplanning.html. It can also be applied to other species by replacing the growth and N uptake kinetics.