Project Deliverables — SeaSoil Project

The thesis investigates the socio-economic profitability of cultivating S. latissima or wild harvesting A. nodosum in Norway, focusing on three types of plant- and soil amendments: liquid biostimulant, kelp meal, and biochar. Using a Cost-Benefit Analysis (CBA) over a 20-year period starting in 2024, the net present value (NPV) of each alternative was calculated. The study examined 10 hectares, contrasting with previous CBAs by incorporating ecosystem services (ES) into profitability assessments. The six project alternatives yielded the following NPVs: 1) Cultivation of S. latissima for liquid biostimulant: NPV = 174 million NOK (profitable); 2) Cultivation for kelp meal: NPV = -89 million NOK; 3) Cultivation for biochar: NPV = -106 million NOK; 4) Wild harvesting of A. nodosum for liquid biostimulant: NPV = -8 million NOK; 5) Wild harvesting for kelp meal: NPV = -284 million NOK; 6) Wild harvesting for biochar: NPV = -302 million NOK. The analysis concludes that only the liquid biostimulant production from S. latissima is socio-economically viable, with provisioning ES positively impacting the NPV. In contrast, the wild harvesting alternatives incur negative impacts due to environmental damage costs associated with the natural kelp forest's ES. Financial profitability in cultivation necessitates addressing external effects on ES via subsidies or compensation schemes.

Masters Thesis NMBU 2025

Cadmium and Arsenic Mobility in Soil Amended with Algae Fiber Fertilizer

Effects of Ascophyllum nodosum Residues on Trace Metal Dynamics Assessed Using DGT

Author: Elinor Evensen Smedstad

Abstract

Marine algae, particularly algae fiber (AF) from Ascophyllum nodosum, are evaluated as sustainable soil amendments due to their nutrient-rich properties. This study examined arsenic (As) and cadmium (Cd) mobility after adding AF at varying levels (1.05, 2.1, and 4.2 kg DM/m2) under simulated rainfall, measuring outcomes at Days 1 and 4. Results indicated that AF increased soil As and Cd concentrations slightly, with As rising from 4.1 mg/kg to 4.5 mg/kg, and Cd from 0.24 mg/kg to 0.258 mg/kg at the highest treatment. Organic matter content and pH also increased. The Diffusive Gradient in Thin films (DGT) method was used to assess labile metal fractions, confirming that As exhibited expected mobility patterns while Cd showed inconsistent behavior. The study found significant findings for As and Cd related to AF levels and highlighted the need for tailored management strategies to handle the contrasting mobilization of these metals, with As influenced mainly by dissolved organic carbon and Fe/Al (hydr)oxides, while Cd mobility was primarily affected by pH and organic matter.

Masters Thesis Nofima 2025

LINKING HYPERSPECTRAL IMAGING AND CHEMICAL ANALYSIS OF POTENTIAL TOXIC ELEMENTS (PTES) IN SUGAR KELP

Author: Magali Gendebien

Hyperspectral imaging (HSI) is explored as a non-destructive technique for trace metal quantification in sugar kelp (Saccharina latissima). This study evaluated HSI combined with chemometric modeling to predict concentrations of cadmium (Cd), arsenic (As), and iodine (I). The findings indicated weak to moderate predictive performance for arsenic and iodine, and ineffective predictions for cadmium due to limited variance in metal concentrations. Factors such as sample type (wet vs. dry) and imaging conditions affected spectral quality and outcomes, with better predictions for arsenic in wet samples and improved iodine predictions in dry samples. Although HSI did not yield reliable quantitative results, it highlights the importance of biological and technical factors influencing spectral signals and suggests avenues for future research to enhance detection capabilities in seaweed monitoring.

Location

Nofima, Ås, Oslo, Norway.

This project has received funding from the European Union’s Horizon 2020 research and innovation program (ERA-NET BlueBio cofund Grant No. 817992).

Acknowledgements
European Union’s Horizon 2020 research and innovation
program (ERA-NET BlueBio cofund) and
The Research Council of Norway (RCN),
Croatian Science Foundation (HRZZ),
Innovation Fund Denmark (IFD),
Marine Institute (MI), Ireland,
Ministry of Rural Affairs (MEM), Estonia.

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Contact

Project Coordinator: Dr Ingrid Olsen

Email: ingrid.olesen@nofima.no

Work Package 1

Work Package 5

Work Package 2

Work Package 3

Work Package 4

Cadmium and Arsenic Mobility in Soil Amended with Algae Fiber Fertilizer

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