The significance of new records of benthic red algae (Rhodophyta) for Hainan Island (and China) between 1990 and 2016

We present an annotated list of new finds of red algae from Hainan Island, Southern China, including those found in 1990 and 1992 during the German-Chinese expeditions to Hainan Island and in 2008–2016 by Titlyanova, Titlyanov, and Li. Between 1990 and 1992, a total of 64 taxa of red algae were newly recorded for Hainan Island. Of these 15 species were new records for China. During the period 2008–2016, a further 54 taxa were newly recorded for Hainan Island, of which 20 were new records for China. The full list of new taxa includes taxonomic forms, dates, and locales, together with known biogeographical distributions. During both periods, the apparent enrichment of red algal marine flora has occurred in a similar way—mainly at the expense of epiphytes with filamentous, thin-filamentous, and finely branched forms. We believe that the changes in the flora of Hainan Island have been influenced by both anthropogenic and natural factors including in particular exploitation of herbivores, nutrient pollution, and coral bleaching

NGUỒN LỢI, SỬ DỤNG VÀ NUÔI TRỒNG RONG Ở VIỆT NAM

Trong bài này, dựa trên dữ liệu của riêng các tác giả và tài liệu đã công bố, mô tả nguồn tài nguyên tự nhiên, sự sử dụng và trồng rong biển ở Việt Nam. Cho thấy rằng nguồn lợi của thực vật biển (đặc biệt là rong nâu) giảm đáng kể do việc khai thác rong tự nhiên bừa bãi. Ở Việt Nam, rong được sử dụng rộng rãi trong thực phẩm, trong y học dân gian, thu nhận các chất hữu ích như agar, alginat và Fucoidan, nhưng một lượng lớn thu được từ các nguồn tài nguyên tự nhiên và rong biển trồng đem xuất khẩu, chủ yếu là sang Trung Quốc. Công nghiệp trồng rong biển chủ yếu là việc trồng rong chứa agar giống Gracilaria và giống Kappaphycus chứa carrageenan. Bài viết cung cấp các khuyến nghị và thảo luận về cách trồng trọt các loài Sargassum phổ biến  nhất. Summary: Base on data of individual authors and documents published, the natural resources, use and seaweed cultivation in Vietnam aredescribed. It shows that the resources of marine plants (especially brown algae) significantly reduced due to the indiscriminate exploitation of natyral seaweed. In Vietnam, the seaweed is widely used in food and in folk medicine, obtain usedful substances such as agar, alginates and fucoidan, but a large amount of revenue from natural resources and seaweed mainly contains agar seaweed breeds Gracilaria and carrageenan seaweed breeds kappaphycus. Th review makers recommendation and disuss how to cultivate the most common species of Sargassum

Chemical and Physical Environmental Conditions Underneath Mat- and Canopy-Forming Macroalgae, and Their Effects on Understorey Corals

Disturbed coral reefs are often dominated by dense mat- or canopy-forming assemblages of macroalgae. This study investigated how such dense macroalgal assemblages change the chemical and physical microenvironment for understorey corals, and how the altered environmental conditions affect the physiological performance of corals. Field measurements were conducted on macroalgal-dominated inshore reefs in the Great Barrier Reef in quadrats with macroalgal biomass ranging from 235 to 1029 g DW m−2 dry weight. Underneath mat-forming assemblages, the mean concentration of dissolved oxygen was reduced by 26% and irradiance by 96% compared with conditions above the mat, while concentrations of dissolved organic carbon and soluble reactive phosphorous increased by 26% and 267%, respectively. The difference was significant but less pronounced under canopy-forming assemblages. Dissolved oxygen declined and dissolved inorganic carbon and alkalinity increased with increasing algal biomass underneath mat-forming but not under canopy-forming assemblages. The responses of corals to conditions similar to those found underneath algal assemblages were investigated in an aquarium experiment. Coral nubbins of the species Acropora millepora showed reduced photosynthetic yields and increased RNA/DNA ratios when exposed to conditions simulating those underneath assemblages (pre-incubating seawater with macroalgae, and shading). The magnitude of these stress responses increased with increasing proportion of pre-incubated algal water. Our study shows that mat-forming and, to a lesser extent, canopy-forming macroalgal assemblages alter the physical and chemical microenvironment sufficiently to directly and detrimentally affect the metabolism of corals, potentially impeding reef recovery from algal to coral-dominated states after disturbance. Macroalgal dominance on coral reefs therefore simultaneously represents a consequence and cause of coral reef degradation

The interaction between the proliferating macroalga Asparagopsis taxiformis and the coral Astroides calycularis induces changes in microbiome and metabolomic fingerprints

Mediterranean Sea ecosystems are considered as hotspots of biological introductions, exposed to possible negative effects of non-indigenous species. In such temperate marine ecosystems, macroalgae may be dominant, with a great percentage of their diversity represented by introduced species. Their interaction with temperate indigenous benthic organisms have been poorly investigated. To provide new insights, we performed an experimental study on the interaction between the introduced proliferative red alga Asparagopsis taxiformis and the indigenous Mediterranean coral Astroides calycularis. The biological response measurements included meta-barcoding of the associated microbial communities and metabolomic fingerprinting of both species. Significant changes were detected among both associated microbial communities, the interspecific differences decreasing with stronger host interaction. No short term effects of the macroalga on the coral health, neither on its polyp activity or its metabolism, were detected. In contrast, the contact interaction with the coral induced a change in the macroalgal metabolomic fingerprint with a significant increase of its bioactivity against the marine bacteria Aliivibrio fischeri. This induction was related to the expression of bioactive metabolites located on the macroalgal surface, a phenomenon which might represent an immediate defensive response of the macroalga or an allelopathic offense against coral.ERA-NET Biome project "SEAPROLIF"; CNRS; Provence Alpes Cote d'Azur Region; TOTAL Fundation; Fundacao para a Ciencia e a Tecnologia (FCT) [Netbiome/0002/2011]; FCT fellowships [SFRH/BPD/63703/2009, SFRH/BPD/107878/2015]info:eu-repo/semantics/publishedVersio

Heat-stress and light-stress induce different cellular pathologies in the symbiotic dinoflagellate during coral bleaching

Coral bleaching is a significant contributor to the worldwide degradation of coral reefs and is indicative of the termination of symbiosis between the coral host and its symbiotic algae (dinoflagellate; Symbiodinium sp. complex), usually by expulsion or xenophagy (symbiophagy) of its dinoflagellates. Herein, we provide evidence that during the earliest stages of environmentally induced bleaching, heat stress and light stress generate distinctly different pathomorphological changes in the chloroplasts, while a combined heat- and light-stress exposure induces both pathomorphologies; suggesting that these stressors act on the dinoflagellate by different mechanisms. Within the first 48 hours of a heat stress (32°C) under low-light conditions, heat stress induced decomposition of thylakoid structures before observation of extensive oxidative damage; thus it is the disorganization of the thylakoids that creates the conditions allowing photo-oxidative-stress. Conversely, during the first 48 hours of a light stress (2007 µmoles m−2 s−1 PAR) at 25°C, condensation or fusion of multiple thylakoid lamellae occurred coincidently with levels of oxidative damage products, implying that photo-oxidative stress causes the structural membrane damage within the chloroplasts. Exposure to combined heat- and light-stresses induced both pathomorphologies, confirming that these stressors acted on the dinoflagellate via different mechanisms. Within 72 hours of exposure to heat and/or light stresses, homeostatic processes (e.g., heat-shock protein and anti-oxidant enzyme response) were evident in the remaining intact dinoflagellates, regardless of the initiating stressor. Understanding the sequence of events during bleaching when triggered by different environmental stressors is important for predicting both severity and consequences of coral bleachin

Retrospective analysis of diversity and species composition of marine macroalgae of Hainan Island (China)

Retrospective analysis of diversity and species composition of marine macroalgae of Hainan Island in the period 1933−1992 is presented in this paper. There are two extensive sample collection periods of benthic macroalgae: the early collection (EC) covers a period between the early 1930s and the 1980s before considerable urbanization and reef degradation took place and a late collection (LC) was performed in 1990/1992 during a phase of rapid urbanization. Analysis of data also including an earlier published inventory of green algae covering the same collection sites (Titlyanov et al. 2011a) revealed that the marine flora of the island comprises 426 taxa in total, with 59% red algae, 18% brown algae and 23% green algae. In total 59 species of red algae, 11 species of brown algae and 37 species of green algae sampled during the LC are new records for Hainan Island. Considerable floristic changes between EC and LC became evident. In the LC there were significantly more filamentous, tubular or fine blade-like, and often epiphytic, green and red algae with a high surface-to-volume ratio. Additionally a reduction of green, brown and red algal species with larger fleshy or foliose thalli and a low surface-to-volume ratio was observed. It is assumed that the changes reflect the degradation of the coral reef ecosystem around Hainan, which was damaged by human activities especially in the 1950s–1970s

New records of benthic marine green algae (Chlorophyta) for the island of Hainan (China)

The island of Hainan (China) is located on the northern periphery of the subtropical Pacific Ocean in the South China Sea and possesses one of the most prominent fringing coral reefs of China. The marine algal flora of the island was described for the first time after several early expeditions in the 1930’s (and around 1960) mentioning 68 species of marine green algae (Chlorophyta) in total. Sixty years later, the island was revisited in autumn 1990 and spring 1992 within in the framework of two extensive expeditions in order to scrutinise the algal biodiversity of the coral reef habitats. Again 20 years later, three more surveys were performed in 2008, 2009 and 2010 focusing only on the southern shores of Hainan Island near Sanya city. The analysis of this material revealed the existence of 31 new records of marine green algae for Hainan Island, including 17 species which also constitute new records for China. The new records are described and characteristic details are depicted. Collection sites around Hainan Island and world-wide distributions are given. Thirteen newly recorded species were only sampled once and therefore seem to be rare. Thirteen other species are pre-dominantly epiphytic or endophytic. The new records for China are fairly typical for tropical to subtropical locations of south-western to south-eastern Asia, except Chlorochytrium cohnii (distribution hitherto restricted to Europe), Chaetomorpha minima (distribution hitherto restricted to North and Central America, Africa, Indian Ocean islands) and Cladophora perpusilla (distribution hitherto restricted to Central and South America, Australia, New Zealand, Pacific islands). None of the new records are considered to represent an invasive species

New records of benthic brown algae (Ochrophyta) from Hainan Island (1990-2016)

This study reports on the intertidal and shallow subtidal brown algal flora from Hainan Island in the South China Sea, based on extensive sample collection conducted in 1990, 1992, and 2008-2016. The analyiss revealed 27 new records of brown algae for Hainan Island including 5 species which also constitute new records for China. 21 of these species are described with photographs and an annotated list of all species with information on life forms, habitat (localities and tidal zones) and their geographical distribution is provided