Seaweed Cultivation Research Articles

Global potential for seaweed aquaculture on existing offshore infrastructure.

Seaweed aquaculture is growing 8.9% annually to a forecast US$ 22.13 billion in 2024 and has several environmental, economic and social co-benefits. A proposed approach to expanding seaweed aquaculture is to develop offshore aquaculture. However, the costs of the infrastructure remain a key barrier. Reducing costs by growing seaweed on obsolete oil and gas infrastructure and offshore wind farms may make offshore seaweed cultivation economically viable, but the scale of opportunity needs to be clarified. We estimate an area of 53,387-106,774ha is currently available to cultivate seaweed on offshore wind farms, which could yield 736,831-4,441,116 tonnes of dry seaweed annually. Existing offshore oil and gas infrastructure could create 1,357,530-5,430,120ha for growing seaweed. Using 2019 seaweed prices, seaweed production on offshore wind farms and oil and gas infrastructure could return USD $3356 - $50,320 Million, sequester 687,784-8,616,449 tonnes of CO₂, and subsequent low carbon seaweed products could displace 987,642-33,221,364 tonnes of CO₂ emissions. While the scale of opportunity is significant, we caution that the regulatory and engineering costs of 'keeping the lights on' for decommissioned oil and gas infrastructure may make costs prohibitively high for seaweed cultivation. Even with existing infrastructure, the cost of cultivating seaweed offshore remains the largest barrier to implementation. A significant increase in market value for seaweed products is required to make offshore infrastructure economically viable. Similarly, many ecological and regulatory risks to offshore seaweed cultivation need to be further understood and minimised.

WATER SUITABILITY FOR SEAWEED Kappaphycus alvarezii CULTURE USING SENTINEL-2A IN AENG BATU-BATU VILLAGE, TAKALAR REGENCY

Certain individuals residing in Aeng Batu-Batu Village are engaged in the cultivation of seaweed (Kappaphycus alvaezii). However, the community encounters a challenge in identifying suitable areas for seaweed farming. The objective of this study is to assess the appropriateness of the waters for cultivating seaweed. The present study was carried out in June 2023. The exploration method utilized in this study seeks to ascertain the degree of suitability exhibited by the waters for seaweed cultivation. An Aeng Batu-Batu Village sampling procedure was implemented, consisting of three repetitions. A unique set of water quality parameters was acquired at each sampling point. In descending order, the values of each parameter are presented. Current velocity (23.62-11.47 cm/s), depth (5-2 meters), water clarity (3.35-2.3 meters), pH (7.91-7.73), salinity (27-23 ppt), temperature (30-28 °C), phosphate (0.0362-0.0122 mg/L), and nitrate (0.069-0.014 mg/L). The water suitability matrix indicates that 185.06 ha of the valley's water is suitable for seaweed cultivation in Aeng Batu-Batu Village, while 0.3 hectare of the valley's water is unsuitable for seaweed cultivation.

Implementasi Horisontal Net Untuk Meningkatkan Peran Perempuan Dalam Pengelolaan Kebun Bibit Rumput Laut

Seaweed cultivation currently uses the longline method. In practice, the longline method demands significant effort, leading to a greater male dominance in the cultivation process. This community service activity offers the most effective approach to enhancing the involvement of women in seaweed cultivation. We carried out this community service activity in one of the cultivation areas in North Buton Regency, Southeast Sulawesi Province. Seaweed farmers received training and assistance to implement horizontal nets. Twenty female seaweed farmers and 20 male farmers participated in the training. During the training activities, women play a significant role by performing practical tasks such as creating, cultivating, and maintaining horizontal net tools used in seaweed cultivation. At the field implementation level, women play a greater role in operating and maintaining horizontal nets. This community service activity has instilled new hope in expanding the availability of seaweed seed gardens and enhancing the role of women, thereby potentially increasing the income of female seaweed farmers.

Plant Spacing Variations on Cell Number and Agar Content in Gracilaria verrucosa

The primary issue at the Gracilaria verrucosa seaweed cultivator is the low productivity associated with current cultivation methods. Analyzing cell number and agar content provides valuable insights into seaweed cultivation productivity, growth activity, nutrient absorption, and chemical composition. This research aims to examine how variations in planting distance affect the cell number and agar content of Gracilaria verrucosa. The research was conducted at the Maranak Experimental Pond Installation, Brackish Water Aquaculture Fisheries Research Institute, located in Marannu Village, Lau District, Maros Regency. Analysis of cell numbers and agar content was performed at the Fisheries Research Institute Laboratory of the Brackish Water Aquaculture Center from June to July 2024. Utilizing a completely randomized quantitative experimental design with four treatments and three repetitions, the research included: Treatment A (planting distance 20 cm), Treatment B (30 cm), Treatment C (40 cm), and Treatment D (50 cm). The results indicated that planting distance significantly impacts cell number, with the 50 cm distance yielding the highest average cell count of 213.00 ± 9.64. Similarly, planting distance affects agar content, with the 50 cm distance producing the highest agar content of 27.31%. Therefore, a planting distance of 50 cm is identified as the most effective, resulting in both the highest number of cells and agar content.

Unlocking synergies: Enhancing bioremediation, growth, and physiological responses of Penaeus vannamei co-cultured with seaweed

Seaweeds, an inorganic extractive species in the Integrated multi-trophic aquaculture (IMTA) system, offer the potential for mitigating coastal pollution and a source of nutrition aligning with Sustainable Development Goals. A co-culture strategy was hypothesized to address rising concerns over intensive shrimp farming, limited suitable seaweed cultivation areas, and production optimization. Initially, locally available seaweeds along the Maharashtra coast were screened, followed by co-culture with P. vannamei with selected seaweed to evaluate production performance and physiological responses in zero-water exchange system. The first four-week study was conducted in shrimp wastewater with six different seaweeds, where Gracilaria foliifera performed best with significant (p < 0.05) improvement in nutrient uptake efficiency (Total ammoniacal nitrogen- 64 %, Phosphate- 99.87 %, Nitrite-32 %, Nitrate-13 %) and yield (4.56 kg m−3), enhanced elemental profile, biochemical composition, and pigments. A further optimization study of G. foliifera in shrimp wastewater for 96 h identified the optimal stocking density of 1–3.5 gL−1, based on nutrient uptake efficiency (TAN- 61 %, PO4–72 %, NO2–48 %, NO3–27 %). In the second experiment, considering the highest uptake, G. foliifera stocking density was maintained at 3.5 gL−1, and different stocking densities of P. vannamei (20, 40, 60, 80, 100 nos. m−2) were assessed with two controls, shrimp monoculture and Gracilaria monoculture. Results showed that co-culturing P. vannamei at 20 nos.m−2 followed by 60 nos.m−2 with G. foliifera at 3.5 gL−1 yielded the highest mean weight gain, specific growth rate, and production with low feed conversion ratio, while also improving water quality. The co-culture system also led to lower stress enzyme levels, reduced serum glucose and cholesterol, and normal histological observations in the hepatopancreas compared to monoculture. This study suggests that the co-culture of P. vannamei at 60 nos.m−2 with G. foliifera at 1–3.5 gL−1 proved superior without compromising productivity and physiological responses over monoculture in a sustainable manner.

Advancing Seaweed Cultivation: Integrating Physics Constraint in Machine Learning for Enhanced Biomass Forecasting in IMTA Systems

Monitoring seaweed growth rates and biomass is crucial for optimizing harvest strategies in aquaculture systems. While such a task can be managed manually on a small farm with a few seaweed tanks, it is not feasible on a commercial farm with 1000s of tanks. To this end, an Internet of Things (IoT) based seaweed growth monitoring system is being developed at Harbor Branch Oceanographic Institute (HBOI) at Florida Atlantic University (FAU). Using the Integrated Multi-Trophic Aquaculture (IMTA) system at HBOI as the test site, the project aims to develop a solution that allows farm managers to monitor seaweed growth remotely using automated sensors. An important component of this IoT solution is the machine learning-based prediction model. This study introduces an advanced Long Short-Term Memory (LSTM)-based approach for forecasting seaweed growth and biomass. In particular, an algae growth mathematical model driven by readily available environmental and aquaculture conditions has been integrated as a physical constraint in the LSTM model. This design addresses a principal challenge in this study—the lack of continuous ground truth measurements, as the biomass is recorded only at discrete intervals (e.g., initial, weekly partial harvests, and final harvest). The LSTM models are trained and evaluated for their predictive performance using experimental and synthetic data. Compared with the LSTM models with MSE loss function alone, the results showed that the model with a loss function under physics constraint achieved a significantly lower error in predicting seaweed growth. The rationale behind choosing LSTM over other state-of-the-art models is presented in the paper. This study highlights the potential of integrating machine learning with physical models to optimize seaweed cultivation and support sustainable aquaculture practices. The proposed methodology can seamlessly extend to the remote sensing data in other aquaculture settings.

Pengembangan Ekonomi Lokal melalui Budidaya Rumput Laut dalam Meningkatkan Perekonomian Masyarakat Pesisir

Pontap Village in Palopo City is one of the seaweed cultivation locations. The focus of developing this cultivation is to overcome the unemployment rate and increase community income. This study aims to provide an overview of the development of seaweed cultivation in improving the economy of coastal communities, especially around Pontap Village, Palopo City. The technical aspects of seaweed cultivation businesses make seaweed cultivation activities very popular with coastal communities, which are relatively easy with a short maintenance time. In contrast, from an economic aspect, this business is not just profitable but highly lucrative because the investment and production costs are relatively cheap. The type of seaweed that has economic value that is developed in Palopo City is the Gracilaria sp. type. So it can be concluded from the results of this study that seaweed cultivation efforts positively impact local communities' welfare. However, challenges related to the management of natural resources and environmental impacts need to be considered to maintain the sustainability of seaweed cultivation. This can be seen from the community's behavior in managing seaweed, which still ignores environmental factors. This certainly contradicts the concept of integrated coastal area conservation. These findings provide important insights for local stakeholders, government, and development practitioners.

Role of intensive mariculture on CO2 absorption and carbon burial, and the carbon sink potential of Sanggou Bay, China

Suspended-raft cultivation of bivalves and seaweed significantly influences carbon transport and transformation pathways in bay ecosystems, ultimately affecting air–sea CO2 flux (FCO2) and sedimentary carbon burial. Previous studies focused on whether bivalve and seaweed individuals are a carbon source or sink, but have not discussed the effects of their large-scale cultivation on carbon dynamics from the perspective of a bay ecosystem. In this study, we compared seasonal and spatial variations in air–sea FCO2 and sedimentary carbon burial flux in seaweed culture, bivalve culture, bivalve–seaweed polyculture, and non-culture areas in Sanggou Bay, China, a bay with a long history of mariculture practices. We found that in spring and summer, the air–sea FCO2 was lowest in the seaweed area; it was lowest in the bivalve area in autumn and winter. Despite this, the seaweed area annually absorbed twice the amount of atmospheric CO2 compared to the bivalve area. The bivalve area had the highest sedimentary carbon burial flux and the non-culture area had the lowest. More inorganic carbon than organic carbon was buried in sediment. Atmospheric CO2 absorption was positively correlated with sedimentary carbon burial. Seaweed culture was the main contributor, absorbing around half of the atmospheric CO2 of the bay, whereas bivalve culture exhibited the highest carbon burial, contributing about 40 % to the bay's sediment. We constructed an annual carbon budget model, and the estimated values for atmospheric absorption, seawater dissolution, and sedimentary burial were 2.09 × 104, 1.02 × 104, and 0.78 × 104 t C a−1, respectively. Taken together, our results indicate that the large-scale mariculture of bivalves and seaweed affect both atmospheric CO2 absorption and sedimentary carbon burial, as well as their relationship. Seawater dissolution is also a substantial carbon sequestration reservoir that cannot be overlooked when assessing the biogeochemical carbon cycle of bay ecosystems.

Implementasi Blue Economy terhadap Budi Daya Rumput Laut sebagai Keberlanjutan Ekonomi Masyarakat Pesisir Desa Tokorondo, Kabupaten Poso, Sulawesi Tengah

This study aims to assess the implementation of the blue economy concept in developing seaweed cultivation in Tokorondo Village, Poso Regency, Central Sulawesi. This study uses a descriptive research method with a qualitative approach, with data sources being primary data and secondary data. The study results indicate that the seaweed farming community has implemented all principles and indicators of the blue economy well and following the concept. Furthermore, the study results indicate that public awareness of implementing the blue economy concept significantly affects the sustainability of the community's economy in Tokorondo Village.

Spectral-Spatial Deep Learning model for seaweed cultivation mapping using PlanetScope imagery in Pangkajene and Islands Regency

Spectral-Spatial Deep Learning model for seaweed cultivation mapping using PlanetScope imagery in Pangkajene and Islands Regency

Life-cycle environmental burdens of cultivated seaweed as blue food: The case study of Wakame and Kelp in Dalian, China

Cultivated seaweed, known as typical blue food, benefits environmental sustainability like climate change mitigation when replacing land-based food with carbon-intensive fertilizer input. However, seaweed cultivation still generates environmental burdens that remain unclear, especially in China, where approximately 60 % of global seaweed is cultured. Here, we developed life cycle assessment (LCA) models to quantitatively compare the environmental performance of two seaweed species of wakame (Undaria pinnatifida) and kelp (Saccharina japonica) cultivated by floating rafts. We also developed scenarios to examine the environmental performance by controlling the seedling density and cultivation line inputs. Results show that the environmental loads of wakame are 10–40 % higher than those of kelp, with carbon footprints of 44–59 kgCO2e and 37–58 kgCO2e per ton wet weight, respectively. Seaweed cultivation at sea produces the most environmental burdens. The polyethylene cultivation lines are the crucial input influencing environmental performance. Extending the service time of cultivation lines by 10 % reduces the environmental load by ∼5 % on average. Lower seedling density with fewer cultivation line inputs slightly decreases the environmental burden but with less seaweed yield. Nitrogen and phosphorus removed by seaweed harvest are two orders of magnitude lower than fertilizers applied in land cropping systems of coastal provinces but are four orders higher than the life-cycle emissions of seaweed cultivation. We reviewed the carbon footprint of previous investigations on seaweed farming to compare with ours. Our study adds new knowledge to quantitatively understand the environmental burdens of cultured seaweed (especially for wakame Undaria pinnatifida) as a blue food alternative to land-based foods.

Perceived constraints and suggestions of marine fisherwomen towards seaweed culture in Ramanathapuram district of Tamil Nadu

Perceived constraints and suggestions of marine fisherwomen towards seaweed culture in Ramanathapuram district of Tamil Nadu

Analysis of Human Resources Quality in Seaweed Production Development in Sumenep

This research highlights the need for an integrated approach to enhance human resource quality for the sustainable development of seaweed production in Sumenep Regency. By focusing on Pagar Batu Village, Saronggi District, a significant seaweed-producing area, this study aims to support community welfare, particularly for coastal communities. Using a descriptive qualitative method with a case study approach, the research explores the dynamics of local seaweed cultivation, focusing on conditions as they naturally occur. Data collection involved observations, interviews, and documentation to capture a comprehensive view of seaweed production. Findings reveal both supporting factors, such as cooperative teamwork and adequate equipment, and obstacles like unpredictable weather, poor water quality, and fluctuating prices. Training programs organized by local authorities show potential in increasing technical knowledge, though outreach is still limited. This research underscores the importance of capacity building and technical training to address these challenges, fostering sustainable productivity and economic growth in Sumenep's seaweed sector.

Analisis Potensi Budidaya Rumput Laut dan Strategi Ekowisata Pantai Mutiara, Kabupaten Trenggalek, Provinsi Jawa Timur

Sustainable ecotourism management can affect the state of the community around the area. A total of approximately 15 beaches are managed in Trenggalek Regency. This study aims to analyze the suitability of the water parameters of Prigi Bay, Trenggalek as a seaweed cultivation location and get the right strategy in the development of Mutiara Beach ecotourism, Trenggalek Regency. The data collection method carried out is by combining questionnaire dissemination techniques, direct interviews with resource persons, and field observation. The questionnaire procedure was carried out using the slovin method to determine the number of respondents by applying accidental sampling. Field observation procedures were carried out to measure water quality parameters at 4 observation stations. The research was conducted in May 2024. The parameters measured for seaweed cultivation include temperature, brightness, current velocity, pH, salinity, dissolved oxygen, and water depth. The research analysis uses quantitative descriptive with the Inverse Distance Weighted (IDW) Interpolation technique to analyze data on the suitability of seaweed cultivation locations and supply demand analysis which will later be used as a SWOT analysis to analyze ecotourism strategies. The results of the study on the potential of seaweed cultivation showed that the water temperature ranged from 30⁰ C-31.4⁰ C, brightness 50-142 cm, current velocity 0.08-0.013 m/s, pH 7.22-7.76, salinity 30-32 ppt, dissolved oxygen 9.4 mg/l, and water depth 9-15 m. So based on the thematic map of land suitability, stations 1 &amp; 2 are not suitable for seaweed cultivation while stations 3 &amp; 4 are very suitable for cultivation. Meanwhile, in the ecotourism strategy, the development results are obtained in accordance with the SO strategy. Visitors and managers prioritize advantages and opportunities as an alternative to development.

Heavy Metal Contamination Suspected Cause of Mass Deaths in Seaweed Cultivation in Waters Affected by Mine Waste

Since 2012 until this year, there has been a decrease and a mass death of seaweed, especially in centers where mining exploitation is located. The need for technology on seaweed that is almost extinct is eroded due to environmental damage caused by mining industry waste. One technology that can be used in genome editing is mapping and selecting potential superior genes in several seaweeds cultivated in Morowali waters. This research uses experimental research methods. The data collection technique in this study is observation—water measurement and sampling at 16 stations. The collected data were then analyzed by the International Modification Association of Official Analytical Chemists (AOAC) method 2005: 999.10, using Flame Atomic Absorption Spectrophotometer (FAAS) and Graphite Furnace Atomic Absorption Spectroscopy (GFAAS). The results showed that the heavy metal content in mercury/mercury, arsenic, nickel, and lead exceeded the aquatic biota threshold. In addition, the highest heavy metal content in Fatufia and Lalampu waters is accompanied by reddish and muddy watercolor.

Prospective LCA of brown seaweed-based bioplastic: Upscaling from pilot to industrial scale

Seaweed-based bioplastics are considered a possible alternative to conventional fossil-based plastics due to their potential environmental advantages. The cultivation of seaweed is a fast-growing practice that requires no arable land, freshwater, or fertilizers, perceiving it as an advantageous option for bioresource production. However, research on the environmental impacts of seaweed-based bioplastics is still limited, highlighting the need for a life cycle assessment (LCA) to evaluate their potential. In this article, a prospective LCA is conducted to assess the environmental impacts of brown seaweed-based bioplastic production, from pilot to industrial scale. Upscaling techniques are combined for each life-cycle stage, using interviews to upscale seaweed production and process simulation for the biorefinery and film fabrication steps, and the end-of-life scenario is modelled as composting. All the processes were upscaled to 4000 tonnes (t) per year in 2030 and 2 million tonnes (Mt) per year in 2035, including marginal suppliers of brown seaweed. The results show that the production of 1 kg of brown seaweed-based bioplastic resulted in approximately 1.37 kg CO2-eq. in the best-performing scenario, producing 2 Mt per year in 2035 accounting for the carbon uptake, which is lower than low-density polyethylene (LDPE) with an impact of 3.6 kg CO2-eq. The impact in marine eutrophication in the 2 Mt scenario is −0.009 kg N-eq., and −0.002 kg P-eq. in freshwater eutrophication. This study provides for the first time estimates of prospective industrial-scale impacts of the emerging seaweed-based bioplastic and shows how different upscaling techniques can be successfully combined, i.e., interviews and process simulation, to conduct a prospective LCA of seaweed-based bioplastics. The results demonstrate the potential of seaweed-based bioplastics as a sustainable alternative to conventional plastics.

Seaweed farming households and their livelihood strategies in North Buton, Indonesia

Abstract There is limited information on the livelihood strategies practiced by seaweed farmers in Southeast (SE) Sulawesi. This study aims to describe the livelihood strategies of seaweed farmers in Langere village, North Buton district, SE Sulawesi, Indonesia as they cope with poverty by cultivating and producing seaweed. A three-stage approach was applied to determine the impact of seaweed culture on the livelihood strategies of seaweed farmers. This was followed by in-depth interviews with formal and informal community leaders in the village, officials from government agencies, and selected households. The data were then analyzed descriptively. The results of the study suggested that farmers used various strategies, such as common culture practices, fishing, and non-fishery activities. Furthermore, to prioritize seaweed culture in Langere as a regional priority in the fisheries sector, certain constraints and opportunities must be addressed, particularly production, fluctuating prices, market instability, institutionalization, and policy-making. These challenges must be discussed thoroughly to ensure the continuous the seaweed culture development.

Growth and quality of the seaweeds (Kappaphycus alvarezii and Eucheuma denticulatum) in different inter croppings and planting distances using the longline method

Abstract Seaweed cultivation is currently being extensively practiced to boost productivity. This research aimed to determine the optimal Daily Growth Rate (DGR) and planting distance for enhancing the growth and quality of K. alvarezii (KA) and E. denticulatum (ED), specifically the dry weight (DW) to wet weight (WW) ratio and Clean Anhydrous Weed (CAW) content. The 45-day experiment used a 2-factorial Randomized Block Design (RBD) with planting distance (J) and intercropping planting pattern (R) as the two factors. The results showed that ED (R3) at planting distances of 7 and 14 cm achieved the highest DGR, ranging from 3.46%/day (J2, R3) to 4.55%/day (J1, R3) and 9.92%/day (J1, R3) to 10.91%/day (J2, R3). The intercropping between KA and ED had the second highest DGR, ranging from 3.81%/day (J3, R1) to 8.21%/day (J2, R1). The highest DW: WW ratio was observed in ED (1:4.59; J2, R3). The highest CAW levels were found in the KA treatment (53.63 %; J1, R2). The intercropping treatment showed CAW levels from 48.70 (J2, R1) to 50.56 (J1, R1). In conclusion, ED planted at a distance of 7-14 cm had the most favorable effect on daily growth rate, dry weight to wet weight ratio, and CAW. Additionally, the intercropping method used for the first time in this research between KA and ED can also be employed to increase seaweed production.

Understanding and estimating the role of large-scale seaweed cultivation for carbon sequestration on a global scale over the past two decades

Seaweeds, as marine photosynthetic organisms, are harvested by humans from the wild or through cultivation for various production purposes and to provide a range of marine ecosystem services, including nutrient removal, oxygen production, and carbon sequestration. The potential use of cultivated seaweed in mitigating carbon dioxide (CO2) has been extensively proposed in conjunction with commercial seaweed production worldwide. This study aims to assess the annual potential and benefits of cultivated seaweed in reducing and fixing anthropogenic CO2. Over the past two decades (2000–2019), global seaweed production has seen significant growth. The total output of cultivated seaweed reached 407.4 × 107 tons (t), with coastal mariculture removing 4.26 × 107 t of carbon annually and wild capture removing 2.24 × 106 t. The recalcitrant dissolved organic carbon (RDOC, 549.88–621.60 × 104 t) plays a significant role in the carbon sinks of seaweed cultivation. The substantial benefits of carbon sink resulting from the formation of RDOC from seaweed make up a considerable proportion in the calculation of carbon sequestration and sink enhancement benefits in large-scale seaweed cultivation. The sizable carbon sink base of seaweed cultivation (8631.90–9567.37 × 104 t) results in significant carbon fixation benefits. The total economic value of carbon sequestration and oxygen production was estimated at $70.36 ± 1.52 billion, with an annual average benefit of $3.52 ± 1.70 billion. Increasing the area and yield available for cultivated seaweed has the potential to enhance biomass production, carbon accumulation, and CO2 drawdown. It is crucial to emphasize the need for improved communication regarding the essential criteria for the feasibility of CO2 removal (CDR), with a focus on conducting life cycle assessments (LCA) when utilizing marine processes in the present and future work. The sustainable development of the seaweed cultivation industry not only ensures that Asian-Pacific countries remain leaders in this field but also provides an effective yet overlooked solution to excessive CO2 emissions worldwide.

Beyond the Win–Win Discourse: Designing Seaweed Farming for Long‐Term Success

ABSTRACTCommunication about seaweed aquaculture has so far been dominated by its many socio‐economic and ecological advantages. A key risk of this ‘hype’ is the potential loss of support from communities affected by seaweed cultivation if reality fails to live up to expectations. This could have justice and equity implications for impacted communities, and undermine potential benefits for those communities, as well as affecting the long‐term success of emerging industries. This paper highlights experiences from other marine sectors in which a similar emphasis on benefits has drowned out discussion of potential costs, often leading to initial success but long‐term failure. We highlight the importance of clearly communicating possible negative impacts, and meaningfully engaging stakeholders to shape marine interventions. Finally, we recommend further research into the social dimensions of seaweed farming in geographies where this practice is nascent, and increased attention to the potential trade‐offs of scaling up seaweed cultivation.