Wakame, getrocknet (roh?, bio?)

"Wakame blades are green when cooked and have a subtly sweet flavor and satiny texture. The blades are normally cut into small pieces as they tend to expand during cooking."

"In Japan and Europe, wakame is consumed either dried or salted. It is mainly used in soups (particularly miso soup) and salads (tofu salad), or simply used as a side dish. These dishes are typically dressed with soy sauce and vinegar/rice vinegar. In addition, Goma wakame, also known as seaweed salad, is a popular side dish at American and European sushi restaurants. Literally translated, it means “sesame seaweed”, as sesame seeds and oil are usually included in the recipe."

"Fucoidan is usually extracted from brown seaweeds, including Undaria pinnatifida. Fucoidan exhibits beneficial bio-activity and has antioxidant, anticancer, and anticoagulant properties."

"The brown seaweed species U. pinnatifida (Figure 2) is native to the cold temperate seas of China, Japan, and Korea, and has been introduced in many other places including the Europe Atlantic, French Mediterranean, Australia, and New Zealand (Figure 3). It is regarded as a highly invasive species with a high tolerance for light, temperature, and salinity [5,6]. It is also highly fertile with high growth rate and large reproductive output, releasing spores all year round [6,7]. It is farmed extensively in Japan, Korea, and Japan and as such, it is an abundant source from which fucoidan could be extracted and used."

Narratives Review

DOI: 10.3390/md16090321

Study: weak evidence

Website

"Extracts of U. pinnatifida possess exceptional bioactivities such as antioxidant, anticancer, anti-coagulant, anti-inflammatory, anti-diabetes and anti-microbial properties which are mainly exerted by polysaccharides, carotenoids, tocopherols, phycobilins, phycocyanins, vitamins, fatty acids and sterols (Wang et al. 2018), as well as amino acids, peptides and proteins (Zhang, Pang, and Han 2014)."

"According to the findings of a number of studies, excellent bioactivities possessed in proteins of U. pinnatifida may lead to the utilisationof these proteins in various nutraceutical applications, as antioxidant, antihypertensive, anticancer, anticoagulant, antidiabetic and antimicrobial agents. Similar studies done on nutraceutical applications of proteins of other seaweed species warrant these potential applications."

"It was first found in China, Japan and Korea and has spread to more than twelve countries comprising Spain, Australia, France, Italy, North and South America, Argentina and New Zealand (Mak et al. 2014)."

"The quantity of U. pinnatifida production in 2014 from China, the major producer in the world, was 203,099 tonnes dry weight from 7693 production sites. It corresponded to 2,030,990 tonnes of wet weight and the total global production was 2,359,000 tonnes of wet weight in the same year (FAO 2016). The total global productions of U. pinnatifida in past 50 years are illustrated in Figure 2. China, Japan and Republic of Korea mainly contribute to the global production of U. pinnatifida and the extensive commercial cultivations have been developed in these countries due to growing demand for U. pinnatifida as food and feed ingredient, especially after 2002."

"Though U. pinnatifida favors cold water (5–20
C), it shows greater tolerance to sunlight and temperature. It is capable of withstanding high wave exposure, salinity and other harsh environmental conditions (Hewitt et al. 2005). Generally, they are 60–120 cm long seaweeds which reach to 2–3 m length at maturity. Thallus of U. pinnatifida is fixed with fibrous holdfast which acts as the root of plant while the midrib of pant is attached to rolled wing-like blades at the end. Sporophyll is only present in mature plants and stipe extents sway from holdfast becoming the midrib (Figure 1)."

Narratives Review

DOI: 10.1080/10408398.2021.1898334

Study: weak evidence

"U. pinnatifida is edible seaweed and rich in carbohydrates, unsaturated fatty acids, protein composition, vitamins, and minerals, as well as natural bioactive compounds such as polyphenols, pigments, and phytosterols. Because of these components, U. pinnatifida possesses various bioactivities such as antioxidant, anti-inflammatory, anticancer, anti-obesity, anti-diabetes, and anti-hypertensive activity."

Narratives Review

DOI: 10.1016/j.aquaculture.2018.06.079

Study: weak evidence

"The water extraction and alcohol precipitation method are the most used method. More than 40 U. pinnatifida polysaccharides (UPPs) were successfully isolated and purified from U. pinnatifida, whereas only few of them were well characterized. Pharmacological studies have shown that UPPs have high-order structural features and multiple biological activities, including anti-tumor, antidiabetic, immunomodulatory, antiviral, anti-inflammatory, antioxidant, anticoagulating, antithrombosis, antihypertension, antibacterial, and renoprotection."

"Numerous studies have found that polysaccharides of U. pinnatifida play an indispensable role in the nutritional and medicinal value."

"Undaria pinnatifida, one of the most widespread seafood consumed in China and many other nations, has been traditionally utilized as an effective therapeutically active substance for edema, phlegm elimination and diuresis, and detumescence for more than 2000 years."

Narratives Review

DOI: 10.1016/j.ijbiomac.2022.02.138

Study: weak evidence

"Two other families belonging to the kelps are also of interest as food, namely, Alariaceae, with species A. esculenta and U. pinnatifida, and Lessoniaceae, with species Eisenia bicyclis. These species contain less iodine than the other kelps, with reported values typically ranging between 30 and 700 μg/g dw, although up to 1844 μg/g dw has been reported for A. esculenta."

"The recommended intake of iodine is 150 μg/day for adults (WHO & UNICEF, 2007), and the tolerable upper intake level set by the Scientific Committee on Food (SCF) is 600 μg/day (Scientific Committee on Food, 2002); thus, the window for the optimal consumption of iodine is narrow."
"The amount of brown algal biomass equaling a specific amount of iodine is highly variable. The maximum recommended intake of iodine for adults (600 μg) can be calculated by ingesting between 0.2—11 g processed, dry brown algae."
"Two other families belonging to the kelps are also of interest as food, namely, Alariaceae, with species A. esculenta and U. pinnatifida, and Lessoniaceae, with species Eisenia bicyclis. These species contain less iodine than the other kelps, with reported values typically ranging between 30 and 700 μg/g dw, although up to 1844 μg/g dw has been reported for A. esculenta."

Narratives Review

DOI: 10.1111/1541-4337.12918

Study: weak evidence

Website

"The kelp Undaria pinnatifida, or “Wakame,” has a global non‐native range and is considered one of the world's “worst” invasive species. Since its first recorded introduction in 1971, numerous studies have been conducted on its ecology, invasive characteristics, and impacts, yet a general consensus on the best approach to its management has not yet been reached."

"Native to cold‐temperate areas of the northwest Pacific (the coastlines of Japan, Korea, Russia, and China), the adventive kelp Undaria pinnatifida (Harvey) Suringar, 1873 (Phaecophycae, Laminariales), or “Wakame,” has a worldwide non‐native range (Figure 2). First identified as an invasive species on the Mediterranean coast of France in the 1970s (Perez, Lee, & Juge, 1981), Undaria pinnatifida (hereafter referred to as Undaria) is now established on the coastlines of 13 countries across four continents (James, Kibele, & Shears, 2015)."

"It is also a major species for seaweed mariculture in China, Japan, and Korea (Yamanaka & Akiyama, 1993), with total world yield in 2013 exceeding 2 million tonnes fresh weight (FAO FishStat)."

"In its native northeast Asia, Undaria is a winter annual species that inhabits rocky substrates from the low intertidal to 18 m depth, and is widespread at depths of 1–3 m (Koh & Shin, 1990; Saito, 1975; Skriptsova, Khomenko, & Isakov, 2004). ... Sporophytes can grow up to 1–1.7 cm per day, reach 1.3–2 m in length, and have a maximum life span of around 6–8 months (Castric‐Fey, Beaupoil, Bouchain, Pradier, & L'Hardy‐Halos, 1999; Choi, Kim, Lee, & Nam, 2007; Dean & Hurd, 2007)."

Narratives Review

DOI: 10.1002/ece3.3430

Study: weak evidence

Undaria is often considered to be one of the world's worst
invasive species. It is a species that, due to its large and conspicuous
sporophyte stage, can have a dramatic appearance at high population densities in heavily invaded locations. However, the Australasian situation shows that, while Undaria can be highly
successful at invading a wide range of coastal assemblages, evidence for direct adverse impacts is scant. This situation contrasts
certain other invasive macroalgae that can have dramatic ecological
effects (Ambrose and Nelson, 1982; Stæhr et al., 2000; Scheibling
and Gagnon, 2006; Bulleri et al., 2010), even when they are in
relatively low abundance (Bulleri et al., 2017)

Narratives Review

DOI: 10.1016/j.marenvres.2017.09.015

Study: weak evidence

Currently, seaweed cultivation is primarily concentrated in Asian countries, with minimal activity elsewhere. Cultivating seaweed in European Union (EU) waters could help the EU to achieve its ambitious environmental targets, as outlined in overarching policy initiatives, such as the Green Deal (COM(2019) 640 final), Carbon Neutrality, Farm to Fork (COM(2020) 381 final), and the upcoming Nature Restoration Law (COM(2022) 304 final).

Currently 99% of seaweed production in the EU depend on wild-stock harvesting while at global scale there is an opposite trend, with 99% of the production coming from cultivation.

However, fundamental knowledge about the potential of this activity in European waters is still lacking. In November 2022, the EC highlighted several challenges and recommended actions to foster the growth of the algae industry into a resilient, sustainable and regenerative sector capable of meeting the increasing EU demand (EU Algae Initiative COM (2022) 592 final). Among the key issues identified were the high production costs and low-scale production, which are hindered by the lack of scientific understanding of the potential for growth in EU marine regions.

Despite large areas of EU marine regions being unsuitable for seaweed cultivation, such as the Mediterranean and Black Seas, the potentially suitable area remains extensive, totalling over 1.5 million km² for intermediate species and over 1 million km² for cold water species. Identifying the Atlantic areas as the only suitable marine EU regions for seaweed cultivation aligns with previous global reports.

However, the large assimilation of elemental nutrients may also have possible deleterious consequences for the marine ecosystems, such as altering natural N:P ratios, obstructing phytoplankton growth, and disturbing marine food webs from the bottom to the top. These considerations and a proper environmental impact assessment should be fully considered before deciding on the locations of large cultivation sites. 

Another important aspect that was not tackled in this study, is the potential risk that a ‘large-scale’ seaweed cultivation might pose on the environment. Most notably the increase in competition (e.g., cultivated algae vs phytoplankton), noise (vessel traffic), sedimentary anoxia and hypoxia in bottom waters, seaweed pathogens (diseases), gene flow from cultivated seaweed species (e.g., altering natural population fitness)

Another revealing pattern is the significant limitation that wave height imposes on the potential growth of both types of seaweed in the north-western side of the Atlantic domains.

The Baltic Sea is typically a cold and brackish basin. Therefore, the main limiting factors are temperature for intermediate seaweed species and low salinity for cold-water species, as also described in previous works

Similarly, the assimilation of organic carbon into seaweed biomass has been proposed to represent a meaningful sink for atmospheric CO₂ if managed properly. 

However, these computed numbers are still lower than predicted demand in the coming decades showing the need for alternative solutions to enhance the potential for this activity. To optimize seaweed breeding, it is crucial to identify the most suitable species for cultivation, advance innovative nursery techniques for producing high-quality seeding material, and refine harvesting methods. 

Ökologische Modellierungsstudie

DOI: 10.1016/j.aquaculture.2024.741353

"Parental plants that are used for yearly sporeling production come from the farmed population. Parental plants are usually reserved on lone-lines until end of June after commercial harvest at the end of April. The plants are cultured under relatively deep water to elongate the time at sea until seeding process (hatchery) starts."

"At the end of June, when seawater temperature rises to 18–19 °C, well-matured sporophylls are cut off from the sporophytes, brought to land and dried in ambient temperature for 1–2 hours in a shaded place. Sporophylls are then put into filtered seawater for releasing spores, again at ambient temperature (16–18 °C). When the concentration of spores in the water reaches 100 000–150 000 per millilitre, the sporophylls are removed from the water, and collectors are inserted. Collectors are constructed by wrapping 2 mm thick nylon string around a plastic frame made of polyvinyl chloride (PVC) pipes. Collectors are removed from the seeding tank once the string are seeded with sufficient spores (50–100 spores within a 100× microscopic field), and are then transported in tanks of filtered seawater for the next step of the hatchery process. In the northern hemisphere, the hatchery starts in June when seeding spore onto collector is performed and ends in late of September when the seawater temperature drops to 22 °C, which is optimal for 200 µm long sporophytes to grow rapidly. The collectors are then transported to open sea and further grown at a water depth where the irradiance is about 200–300 µmol photons m^{-2 s-1}. The sporeling string is cut into 5 cm long pieces for insertion onto the main cultivation ropes when open sea cultivation starts."

"Cultivation of U. pinnatifida starts at sea by laying the longline horizontally and inserting sporeling strings at intervals of 35–40 cm. These strings will hang in the water, usually within 1 m of the surface. The interval between the horizontal longlines is 2 m. Each individual longline is 8 m in length. The initial sporeling is roughly 1 cm long. They will reach 2–3 m between outplanting in October and harvesting in April. Each individual longline can produce approximately 80–130 kg fresh Undaria biomass. The main variables to final production weight are the location, water current (strong current is favoured) and water depth where they are farmed."

"Harvesting starts in February when the sporophyte thalli reach approximately 1.5–2 m, and ends in late April. Plants are harvested manually by cutting the plants off the main cultivation rope. Sporophylls and thalli are packed separately and transported to the processing facility on the same day."

"Sporophylls are frozen immediately, while the remaining parts are bathed in hot water (85–95 °C) for approximately 20–60 seconds. The cooked plants are then thoroughly salted. The salted plants are packed in bags and pressed with heavy objects overnight to remove the excess salt water. Thereafter, the midribs and blades are separated manually by hand, packed into boxes and stored between -5 and -5 °C."

"In Japan, there are various kinds of commercial wakame products, including: dehydrated or dried, seasoned and instant wakame food. Most of the dehydrated products are of the traditional type, such as Suboshi and Haiboshi wakame. Compared with Suboshi wakame that is dried under the sun without ash treatment, Haiboshi wakame can keep its vivid green colour during storage at 35 °C for 50 days in the dark."

Website

"The tops and bottoms of the Undaria are trimmed at harvest, and the thallus is briefly blanched in sea water (rarely in fresh water); this changes its color from brown to bright green. The color change results from a change in chlorophyllrelated enzymes, and is regulated by time and temperature of blanching. The color change occurs above 65 C, but if the wakame is heated at too high a temperature for too long, chlorophyll is degraded to phaeophytin and the color changes to brown. Failure in the boiling process frequently leads to Undaria turning brown during storage. After blanching, Undaria is cooled, mixed with salt and preserved overnight in a highly-saturated salt water solution. The salted blades are then drained and allowed to dehydrate for several days, after which the mid-ribs are removed. The blade portions are further dehydrated before being checked for quality and packed into polyvinyl packages, which are stored at -20 C."

"In this process, the boiled and salted product is washed, chopped, desalted and dried at the factory. We use mechanical drying because the final product rehydrates quickly. However, large quantities of Undaria are processed through a rolling dryer, as this results in an end product comprised of small, easily-packed pieces (Iwasaki & Sato 1984). Less than 10% of the moisture is retained, which is good for product-stability during storage."

Narratives Review

DOI: 10.1007/BF00004026

Study: weak evidence

"Ocean farms are seemingly more sustainable compared to land-based agriculture because cultivation of seaweeds requires no fresh water, chemical fertilizer, or land, which are the significant negative factors to land-based cultivation."

DOI: 10.1016/B978-0-12-418697-2.00001-5

Book: weak evidence

A 2014 study found
that algae can annually produce 167 times more useful biomass
than corn when using the same amount of land (12). When
producing food for a large population, impressive production
figures such as these are key drivers of the overall efficiency and
effectiveness of algae as a human food source.
Compared to traditional crops, the percentages of lipids and
proteins can be much higher in algae, since they do not require
the use of non-edible cellulose for their structural components.
As a result, even low biomass production can generate high
levels of essential nutrients compared to terrestrial plants.

Narratives Review

DOI: 10.3389/fnut.2022.1029841

Study: weak evidence

Numerous studies have assessed the environmental impacts of full-scale algae cultivation in recent years (Richardson et al., 2012; Lardon et al., 2009; Gallagher, 2011). The impacts most commonly considered in these assessments include energy use, water consumption, land use, and greenhouse gases emissions: First, energy expenditure can be required for mixing to prevent biomass settling during cultivation for gas transfer to supply CO2 and remove excessive oxygen (Keymer et al., 2013) and for temperature control if overheating is a critical issue (B
echet et al., 2014). This energy consumption can generate indirect CO2 emissions depending on the source of energy ultimately used. Second, water is consumed during harvesting (efficient recycling can be challenging), leaks, and free-surface evaporation in open ponds, causing a level of water demand that can stress local water resources (Yang et al., 2011; Wigmosta et al., 2011; Guieysse et al., 2013b). Third, generating large quantities of algal biomass requires large land areas (B
echet et al., 2013b), which may cause a range of economic, social, and ecological impacts even if “marginal” land is used. Finally, microalgae were recently shown to produce significant amounts of nitrous oxide N2O (Alca´ntara et al., 2015; Guieysse et al., 2013a), which is a potent greenhouse gas and ozone-depleting pollutant (Myhre et al., 2013).

DOI: 10.1016/B978-0-08-101023-5.00021-2

Book: weak evidence

Production of S. latissima biomass The dried seaweed as raw material for alginate production had a climate impact of 6.12 kg CO2 equivalents (CO2 eq.) per kg dry seaweed at post-harvest drying. The high electricity consumption to dry the seaweed explains why the drying stood for 75% of the climate impact (Figs. 4, and 5). Algae in its wet form just after harvest had a considerably lower climate impact of 0.16 kg CO2 eq. per kg wet weight.

DOI: 10.1016/j.algal.2022.102725

Results reveal that the carbon sequestration during the seaweed cultivation stage of agar amounts to -7.21 kgCO2eq/kg,

During its growth, macroalgae absorbs aqueous solutions with carbon dioxide, nitrogen, phosphorus, etc. [8], thus contributing to climate change mitigation, ocean deacidification, eutrophication remediation, and bioremediation for fish and shrimp farming [9–11]. In addition, seaweed cultivation can reduce agricultural land demand [12]. Although macroalgae cultivation was recognized to be helpful in the transition to a low-carbon bio-economy, the manufacturing processes of agar using macroalgae can contribute to environmental impacts.

The results show the “cradle-to-gate” carbon emission of agar is -1.11 kg CO2eq/kg agar, indicating the carbon absorption by macroalgae can offset the carbon emissions of agar manufacturing. 

Gracilaria lemaneiformis

DOI: 10.1016/j.algal.2023.103384

"The genus Laminaria comprises the strongest accumulators of iodine currently known and are major emitters of both molecular iodine and iodinated organics into the atmosphere. These latter species are important contributors to the surface destruction of tropospheric ozone, contributing to coastal cloud formation and are an important link between ocean biology, atmospheric composition, and climate."

"It (Laminaria digita) is the strongest iodine accumulator among all living systems that is currently known, and its iodine emissions have an established impact on aerosol formation."

"Finally Laminaria digitata (Oarweed), is the major kelp species on North Atlantic rocky shores, including Maine and the Canadian Maritimes, Newfoundland and the European Atlantic coast from Brittany (France) to northern Norway."

Narratives Review

DOI: 10.1039/c8mt00327k

Study: weak evidence

"Die steigenden globalen Jod-Emissionen könnten demnach in der Arktis das Abschmelzen des Meereises weiter beschleunigen."

Website

Brown seaweeds are recognized sources of compounds with a wide range of properties and applications. Within these compounds, phlorotannins are known to possess several bioactivities (e.g., antioxidant, anti-inflammatory, and antimicrobial) with potential to improve wound healing. To obtain phlorotannins enriched extracts from Undaria pinnatifida, a biorefinery was set using low-cost industry-friendly methodologies, such as sequential solid–liquid extraction and liquid–liquid extraction. The obtained extracts were screened for their antioxidant and antimicrobial activity against five common wound pathogens and for their anti-inflammatory potential. The ethanolic wash fraction (wE100) had the highest antioxidant activity (114.61 ± 10.04 mmol·mg−1 extract by Diphenyl-1-picrylhydrazyl (DPPH) and 6.56 ± 1.13 mM eq. Fe II·mg−1 extract by and Ferric Reducing Antioxidant Power (FRAP)), acting efficiently against Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria, and showing a nitric oxide production inhibition over 47% when used at 0.01 µg·mL−1. NMR and FTIR chemical characterization suggested that phlorotannins are present. Obtained fraction wE100 proved to be a promising candidate for further inclusion as wound healing agents, while the remaining fractions analyzed are potential sources for other biotechnological applications, giving emphasis to a biorefinery and circular economy framework to add value to this seaweed and the industry.

In Vitro Laborstudie

DOI: 10.3390/biom11030461

Study: weak evidence

The alga Undaria pinnatifda is able to synthesize a great variety of bioactive metabolites of pharmaceutical and other industrial interest. However, this species has not yet been comprehensively studied in the Golfo San Jorge region (Chubut, Patagonia Argentina). Thus, in the present study, U. pinnatifda was collected at Golfo San Jorge, seasonally extracted and the chemical profle and biological activity evaluated by diferent techniques. The results showed that U. pinnatifda fundamentally biosynthesizes phenolic acids (cafeic and ferulic acids), favonols and favanol glycosides (quercetin, cacticin, quercitrin), carbohydrates, tannins, lipids, saponins, quinones, steroids, triterpenes and cardiotonic glycosides (of the k-strophanthoside, sciloriside, adynerin and convalatoxin types), with diferences according to the season. The extracts also showed moderate antioxidant activity by the DPPH method and outstanding cytotoxic activity by the Artemia salina test. Based on the results obtained, U. pinnatifda can be considered as a potential source of bioactive molecules. Variations in the metabolites were observed throughout the seasons; particularly in the winter season, favonoids were present in hexane and chloroform extracts, but not in methanol; tannins and other phenolic derivatives in the three winter extracts. This shows the importance of conducting seasonal studies to determine the best season for collection based on the metabolites to be studied.

In vitro Laborstudie

DOI: 10.1007/s10811-023-03058-0

Study: weak evidence

Website

Table 1.

Wakame Japan Whole Total iodine 42 (µg/g) 17 (SD)

Analytische Laborstudie

DOI: 10.1089/thy.2004.14.836

Study: weak evidence

Undaria pinnatifida (U. pinnatifida) is an edible brown seaweed with high health value. The objective of this study was to evaluate the effect of traditional cooking methods (i.e., blanching, steaming, boiling and baking) on the color, texture and bioactive nutrients of U. pinnatifida, so as to screen out the traditional cooking methods more suitable for U. pinnatifida. In this study, methods of blanching and boiling resulted in better reduction in total color difference (0.91 ± 0.58 and 0.79 ± 0.34, respectively) and retention of chlorophyll A (62.99 ± 1.27 µg/g FW and 51.35 ± 1.69 µg/g FW), along with better elevation of fucoxanthin content (increased by 11.05% and 18.32%, respectively). Baking method got the best retention of total phenol content (1.62 ± 0.11 mg GAE/g DW), followed by methods of boiling and blanching (1.51 ± 0.07 mg GAE/g DW and 1.43 ± 0.05 mg GAE/g DW). Among these cooking methods, blanching and boiling seemed to be the more suitable for U. pinnatifida compared to other methods. These results could help to determine the better cooking methods for U. pinnatifida products and provide a scientific and theoretical basis for improving human dietary health.

Experimentelle Laborstudie

DOI: 10.3390/foods11081078

Study: weak evidence

Metabolomics is often used to comprehensively elucidate the metabolites in organisms like seaweed. Amino acids hydrolysed from proteins and certain targeted metabolites in seaweed have been investigated. However, water-soluble metabolites like free amino acids, organic acids, and sugars have seldom been comprehensively analysed. Metabolomics are valuable tools for these studies, but they require optimisation of pre-treatment methodology. Here, we evaluated various pre-treatment drying and extraction methods for brown seaweed metabolomics. Three edible brown seaweeds (Cladosiphon okamuranus [Mozuku], Saccharina japonica [Kombu], and Undaria pinnatifida [Wakame]) were used. Freeze-drying and oven-drying at both 40 and 80 °C were investigated. Methanol-water extracts with and without chloroform were compared. Metabolites were evaluated and quantified using liquid chromatography-mass spectrometry and capillary electrophoresis-mass spectrometry. The results showed that metabolite profiling was determined mainly by seaweed species identity rather than pre-treatment method. Freeze-drying yielded higher metabolite concentrations than oven-drying at either 40 or 80 °C. The effects of extraction with and without chloroform on metabolite concentration varied with seaweed species.

Experimentelle Laborstudie

DOI: 10.1007/s10811-018-1614-z

Study: weak evidence