• ALGAE
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• v.37 no.1
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• pp.63-74
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• 2022

Perennial stipitate kelps are globally distributed and individual species can inhabit broad latitudinal ranges, expressing notably longevous persistence. Despite the foundational role kelps provide to their communities, little is known about the variability in persistence of the stipitate kelps at local spatial scales. We studied the population persistence of Eisenia arborea, a heat- and wave force-tolerant perennial stipitate kelp with a distributional range extending from British Columbia to south of the range limit of all other northeast Pacific kelps, in Baja California Sur, Mexico. Persistence characteristics for E. arborea among sites were compared and used to test the hypothesis that stand persistence varied at local spatial scales around Isla Natividad, a Pacific island off the Baja California peninsula with documented spatiotemporal environmental heterogeneity. Collected individuals around the island were "aged" using the previously validated age estimation technique of counting annual cortical dark rings. After detecting no significant differences among sites in the covariation between estimated ages for collected individuals and stipe length, we utilized in-situ population-level stipe length measurements to more rapidly predict age structures within six stands around the island. Predicted age structures, and associated stand densities, revealed persistence characteristics and density varied at local scales and a strong positive relationship existed between stand density and stand mean and maximum ages. We speculate that stands responded differently to deterministic influences (e.g., the 2014-2016 marine heatwave and / or competition with Macrocystis) resulting in heterogenous local persistence of this foundation species.

• ALGAE
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• v.27 no.1
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• pp.9-19
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• 2012

Phlorotannins are common metabolites produced in kelps that can have deterrent functions against grazers. The factors dictating seasonal patterns of phlorotannin content in northeastern Pacific kelps are not well understood. This study assessed density and grazing of the gastropod Lacuna vincta on the annual canopy-forming kelp Nereocystis luetkeana and the perennial understory species Agarum clathratum, Saccharina latissima and S. groenlandica in Kachemak Bay, Alaska. In addition, we assessed seasonal patterns of environmental variables as possible drivers of phlorotannin concentrations. Phlorotannins occurred in all species, with overall lowest levels in N. luetkeana, and with different seasonal patterns among the four species. Lacuna vincta was most dense on N. luetkeana thalli in the summer and had highest grazing rates on this low-phlorotannin species. However, correlations between L. vincta density and phlorotannin content of each kelp species were not significant. Except for N. luetkeana, there were no correlations between phlorotannin levels and environmental variables. We suggest that kelp life history traits may be more important for phlorotannin patterns in these kelp species than grazers or environmental drivers.

• ALGAE
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• v.37 no.2
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• pp.85-103
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• 2022

Korea is one of the most advanced countries in kelp aquaculture. The brown algae, Undaria pinnatifida and Saccharina japonica are major aquaculture species and have been principally utilized for human food and abalone feed in Korea. This review discusses the diversity, population structure and genomics of kelps. In addition, we have introduced new cultivar development efforts considering climate change, and potential carbon sequestration of kelp aquaculture in Korea. U. pinnatifida showed high diversity within the natural populations but reduced genetic diversity in cultivars. However, very few studies of S. japonica have been conducted in terms of population structure. Since studies on cultivar development began in early 2000s, five U. pinnatifida and one S. japonica varieties have been registered to the International Union for the Protection of New Varieties of Plants (UPOV). To meet the demands for seaweed biomass in various industries, more cultivars should be developed with specific traits to meet application demands. Additionally, cultivation technologies should be diversified, such as integrated multi-trophic aquaculture (IMTA) and offshore aquaculture, to achieve environmental and economic sustainability. These kelps are anticipated to be important sources of blue carbon in Korea.

• ALGAE
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• v.23 no.4
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• pp.289-294
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• 2008

To estimate seaweed biomass or standing crop, a nondestructive sampling can be beneficial because of not much destroying living plants and saving time in field works. We suggest a methodological procedure to estimate seaweed biomass per unit area in marine benthic habitats by using species-specific regression equations. Percent cover data are required from the field samplings for most species to convert them to weight data. However, for tall macroalgae such as kelps we need density data and their size (e.g., size class for subtidal kelps) of individuals. We propose that the field sampling should be done with 5 replicates of 50 cm x 50 cm quadrat at three zones of intertidals (upper, middle, lower) and three depth points (1, 5, 10 m) in subtidals. To obtain a reliable regression equation for a species, a substantial number of replicate is necessary from destructive samplings. The regression equation of a species can be further specified by different locality and different season, especially for the species with variable morphology temporally and spatially. Example estimation carried out in Onpyung, Jeju Island, Korea is provided to compare estimated values with real weight data.

• ALGAE
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• v.35 no.3
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• pp.237-252
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• 2020

Temperate rocky reefs dominated by the giant kelp, Macrocystis pyrifera, support diverse assemblages of benthic macroalgae that provide a suite of ecosystem services, including high rates of primary production in aquatic ecosystems. These forests and the benthic macroalgae that inhabit them are facing both short-term losses and long-term declines throughout much of their range in the eastern Pacific Ocean. Here, we quantified patterns of benthic macroalgal biomass and irradiance on rocky reefs that had intact kelp forests and nearby reefs where the benthic macroalgae had been lost due to deforestation at three sites along the California, USA and Baja California, MEX coasts during the springs and summers of 2017 and 2018. We then modeled how the loss of macroalgae from these reefs impacted net benthic productivity using species-specific, mass-dependent rates of photosynthesis and respiration that we measured in the laboratory. Our results show that the macroalgal assemblages at these sites were dominated by a few species of stipitate kelps and fleshy red algae whose relative abundances were spatially and temporally variable, and which exhibited variable rates of photosynthesis and respiration. Together, our model estimates that the dominant macroalgae on these reefs contribute 15 to 4,300 mg C m^-2 d^-1 to net benthic primary production, and that this is driven primarily by a few dominant taxa that have large biomasses and high rates of photosynthesis and / or respiration. Consequently, we propose that the loss of these macroalgae results in the loss of an important contribution to primary production and overall ecosystem function.

• ALGAE
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• v.27 no.2
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• pp.115-123
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• 2012

The establishment of algal spores plays an essential role in adult kelp distribution and abundance patterns. Sedimentation is a key variable regulating algal spore settlement and success, possibly controlling species-specific dominance $in$ $situ$. Laboratory experiments were used to determine spore attachment and survival rates of two Alaskan canopy-forming kelps, $Nereocystis$ $luetkeana$ (K. Mertens) Postels & Ruprecht and $Eualaria$ $fistulosa$ (Postels & Ruprecht) M. J. Wynne, to various types of sediment loading. Spore attachment for both species was significantly and similarly affected by three sediment treatments: suspended particles; settled sediment covering the substratum; and smothering of attached spores by settling sediment. Spore attachment decreased by approximately 90% at 420 mg sediment $L^{-1}$, the highest sediment load tested here, under all three treatments for both species. These results suggest that increases in sedimentation may constrain the success of the spore stages, but sediment does not seem to be a likely factor explaining species-specific distribution patterns. However, while sedimentation affected spores of both species similarly, timing of spore release in relation to times of maximum sediment load in the water might differ for different species, possibly explaining kelp species distribution patterns.

• Fisheries and Aquatic Sciences
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• v.15 no.2
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• pp.163-168
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• 2012

The non-utilized biomass of the aquacultured seaweed Undaria pinnatifida, particularly the rhizoid, is an alternative source of arachidonic acid (AA). Of the five aquacultured kelps that were tested, U. pinnatifida yielded the highest amount of AA, which was isolated from the rhizoids. Its identity (C20:4 n-6) was confirmed from gas chromatography-mass spectrometry spectral data. The optimal conditions for post-harvest storage or pretreatment of the rhizoids in Provasoli's enriched seawater for AA extraction were determined to be pH 7.8, 2% $CO_2$-enriched air, 20 ${\mu}mol\;m^{-2}\;s^{-1}$ light, and $10^{\circ}C$. Under these conditions, the AA content after 1 day of storage was enhanced by up to 127%. In the absence of light under ambient aeration, the AA content after 1 day of storage diminished to 90%. Rhizoids collected late in the season (April and May) contained the highest amounts of AA (approximately 2.5 mg/g tissue).

• ALGAE
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• v.27 no.3
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• pp.139-153
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• 2012

The re-examination of morphological and anatomical characters of Laminaria appressirhiza and L. inclinatorhiza collected from different localities in the Sea of Okhotsk was performed. Despite their commercial and ecological importance to the region they have not been comprehensively reviewed since their first description in 1970. Our results show that some original diagnostic key characters (e.g., shape of holdfast, shape of sporangial sori, and dissection of blade) are not stable and have deviations from the type morphology when plants grow in different environments. In L. inclinatorhiza, the sporangial sori development occurred differently to the pattern indicated in original species description as they did not develop simultaneously on both sides of the blade. Instead, the sporangial sori outlines on both sides of the blade did not coincide at first and only became coincident later. Also, a deep-water population of L. inclinatorhiza with an unusual and interesting morphology, growing at depths of 15-25 m on opened rocky coasts in Taujskaya Bay (northern part of the Sea of Okhotsk) was found. The stable diagnostic key characters to distinguish these two species are the cone-like, multilayered, very thick and massive holdfast (in L. inclinatorhiza) and rolled margins of blades, lamellar rosette-like part of thallus, and sporangial sori developing only on one side of the blade (in L. appressirhiza). The ecological characteristics, distribution, and abundance of both species in the Sea of Okhotsk are discussed. Both species are perennial and widely distributed in the region. L. appressirhiza is more often found as a subdominant species among other kelps, forming maximum biomass and density of 7-9 kg and 8-25 plants per $1m^2$, respectively. L. inclinatorhiza sometimes forms local mono-species communities with maximum biomass and density of 10-12 kg and 10-15 plants per $1m^2$, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.2
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• pp.155-166
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• 1990

There have been many problems like plasmolysis in the ultrastructural studies with kelps. The present study was conducted with series of different fixatives and buffer solutions and several resins to solve the plasmolysis phenomena. The fixative of 1470 mosmol($3\%$ glutaraldehyde, $2.4\%$ paraformaldehyde in 0.05M cacodylate buffer with 0.2M sucrose and $0.5\%$ caffeine at pH of 7.2) showed the least frequency of plasmolysis. The relationship between the concentration of primary fixatives and the frequency of plasmolysis was not found. With above fixative the possibility of plasmolysis during infiltration period was not identified using ultra-low viscosity resin. Generally, the kelp(Laminaria religiosa) contains a lot of mucilage, which interupts the infiltration of fixative. The possible physiological mechanisms related with mucilage secretion may be unable to fix the region of plasmalemma properly.

• Herbal Formula Science
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• v.17 no.2
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• pp.133-142
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• 2009

Objective : Recently, obesity has increased at an alarming rate and is now a worldwide health problem. Natural dietary supplement, $CharmSlim^{(R)}$(C), is mixed pills, which consists of beans, black sesames, kelps, onions, adlay seeds, anchovies, pyogo mushrooms, green tea. Our study was performed to determine the weight-loss effects of natural dietary supplement, based on natural ingredients, in mice fed high-fat diet with an abundance of carbohydrates. Methods : Four groups of male ICR mice were fed different diets during 6 weeks: normal diet(NOR), high-fat (15%, w/w) diet(HF), high-fat supplemented with natural dietary supplement powdered 5%(C5) and 10%(C10) groups. We measured the changes of food intake, body weight and adipose tissues weights. Also we examined levels of lipid profiles in serum. Results : Body weight, liver weight and food efficiency ratio were significantly higher in the HF group than in NOR group. After 6 weeks of treatment, body weight, liver weight and adipose tissues weights (epididymal, perinephric, visceral and BAT) were significantly decreased in the C10 group when compared to the control HF group. The C10 group had markedly lower serum levels of total cholesterol and triglyceride when compared with HF group. Conclusion : These results demonstrate that this dietary supplement can suppress the increased lipid profiles, body weight and fat gains, thus could be considered as an effective adjunct in the treatment of obesity.