Overview of global <scp><i>Gracilaria</i></scp> production, the role of biosecurity policies and regulations in the sustainable development of this industry

Kim

et al. 2023

Plants

Part of the Indo-Chinese peninsula and located on the northwest edge of the Coral Triangle in the South China Sea, the Vietnamese coastal zone is home to a wealthy marine biodiversity associated with the regional geological setting and history, which supports a large number of marine ecosystems along a subtropical to tropical gradient. The diversity of coastal benthic marine primary producers is also a key biological factor supporting marine biological diversity. The present review provides: (1) an updated checklist of the Vietnamese marine flora, (2) a review of molecular-assisted alpha taxonomic efforts, (3) an analysis of marine floral biodiversity spatial distribution nationally and regionally (South China Sea), (4) a review of the impact of anthropogenic and environmental stressors on the Vietnamese marine flora, and (5) the efforts developed in the last decade for its conservation. Based on the studies conducted since 2013 and the nomenclatural changes that occurred during this period, an updated checklist of benthic marine algae and seagrasses consisted in a new total of 878 species, including 439 Rhodophyta, 156 Ochrophyta, 196 Chlorophyta, 87 Cyanobacteria, and 15 phanerogam seagrasses. This update contains 54 new records and 5 new species of macroalgae. The fairly poor number of new records and new species identified in the last 10 years in a “mega-diverse” country can be largely attributed to the limited efforts in exploring algal biodiversity and the limited use of genetic tools, with only 25.4% (15 species) of these new records and species made based on molecular-assisted alpha taxonomy. The South Central Coast supports the highest species diversity of marine algae, which coincides with the largest density of coral reefs along the Vietnamese coast. Vietnam holds in the South China Sea one of the richest marine floras, imputable to the country’s geographical, geological, and climatic settings. However, Vietnam marine floral biodiversity is under critical threats examined here, and current efforts are insufficient for its conservation. A methodical molecular-assisted re-examination of Vietnam marine floral biodiversity is urgently needed, complemented with in-depth investigations of the main threats targeting marine flora and vulnerable taxa, and finally, conservation measures should be urgently implemented.

Section: Species Namementioning

confidence: 99%

Marine Floral Biodiversity, Threats, and Conservation in Vietnam: An Updated Review

Kim

et al. 2023

Plants

“…fluorescence and antioxidant defense parameters. The objectives of this study were (1) to compare the temperature tolerance between the wild type and the green mutant and (2) to provide a research base for the selection of high-quality G. lemaneiformis germplasm resources.…”

Section: Molecular Phylogenetic Analysismentioning

confidence: 99%

“…Gracilariopsis lemaneiformis, an economically important seaweed, has been widely cultivated in China for over 20 years [1]. According to the National Bureau of Statistics [2], the annual yield of Gracilariales (mainly G. lemaneiformis) is the second largest in China.…”

Section: Introductionmentioning

confidence: 99%

“…In the present study, the physiological responses of a green-pigmented mutant and the wild type of G. lemaneiformis to heat and cold stresses were analyzed using chlorophyll fluorescence and antioxidant defense parameters. The objectives of this study were (1) to compare the temperature tolerance between the wild type and the green mutant and (2) to provide a research base for the selection of high-quality G. lemaneiformis germplasm resources.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Chlorophyll Fluorescence and Antioxidant Defense Parameters of Two Gracilariopsis lemaneiformis Strains under Different Temperatures

Meng

Yang

et al. 2023

Plants

In this study, two Gracilariopsis lemaneiformis strains—the wild type and a green-pigmented mutant—were cultured at three temperatures (8, 20, and 30 °C) for 7 days to explore their temperature tolerance using photosynthetic performance and antioxidant defense parameters. When the two strains of G. lemaneiformis were separately cultured at 30 °C, the fast chlorophyll fluorescence intensity of the wild type decreased, whereas the green mutant showed no significant change. The decrease in the performance index on absorption basis value under heat stress was lower in the green mutant than in the wild type. In addition, the green mutant had stronger antioxidant activity at 30 °C. Furthermore, a greater decrease in the values of maximum photochemical quantum yield and performance index on an absorption basis in the green mutant indicated that it had a greater degree of inhibition of photosynthetic performance under low temperatures. However, the green mutant produced less reactive oxygen species under low temperatures, suggesting that the antioxidant potential of the green mutant might be higher. In conclusion, the green mutant exhibited heat tolerance and could recover from low-temperature damage; therefore, it has the potential for large-scale cultivation.

Limnology & Oceanography

“…Gracilaria farming is one of the fastest‐growing aquaculture sectors, contributing to 11% of the global seaweed feed‐stock supply chain in 2019. Gracilaria species have been successfully farmed worldwide since the 1950s (Mantri et al 2022). Gracilaria lemaneiformis (Bory) E.Y.…”

mentioning

confidence: 99%

Nitrogen availability regulates the effects of a simulated marine heatwave on carbon sequestration and phycosphere bacteria of a marine crop

Jiang,

Hall‐Spencer,

Gao

et al. 2023

Great hope has been pinned on seaweed cultivation as being a potent way of removing CO2 to reduce rates of sea surface warming and acidification. Marine heatwaves and nitrogen pollution in coastal ecosystems are serious current issues that need to be better understood to inform decision making and policy. Here, we investigated the effects of a simulated heatwave and nitrogen pollution on carbon sequestration by an important seaweed crop species and its phycosphere bacteria. Gracilaria lemaneiformis was grown in ambient and high nitrogen conditions (14 and 200 μM L−1). Photosynthetic rate, seaweed biomass and particulate organic carbon accumulation were significantly increased in “high nitrogen‐no heatwave” conditions. In “ambient nitrogen heatwave” conditions, the expression of genes related to photosynthesis was down regulated and the seaweeds lost more dissolved organic carbon (DOC) to the surrounding water, resulting in more refractory dissolved organic carbon (RDOC). In “high nitrogen heatwave” conditions, photosynthetic gene expression was upregulated; bacterial abundance was also increased that can explain the reduced DOC and RDOC accumulation. The simulated heatwave reduced bacterial diversity while high nitrogen alleviated this effect. These findings suggest that the economically important alga G. lemaneiformis may lose more DOC and RDOC to nearshore waters during marine heatwave events, enhancing carbon sequestration, while nitrogen enrichment has a counteractive effect.