사진

지식채널

• 논문정보

  검색결과 7건

  논문정보 목록 - 제목, 내용, 저자, 저널명/발행자, 상세보기

  제목	내용	저자	저널명/발행자	상세보기
  Organismal defenses versus environmentally mediated protection from herbivores: Unraveling the puzzling case of Desmarestia viridis (Phaeophyta)	Abstract The role of anti-herbivore organismal defenses in algae？herbivore interaction is frequently investigated without taking into account the potential role of environmental factors in mediating the interaction. Here we reexamine the interaction between the highly acidic, brown alga Desmarestia viridis and the green sea urchin, Strongylocentrotus droebachiensis, by incorporating a previously overlooked facet, the effect of changes in the wave environment on the ability of the urchin to establish contact with the alga. Factorial experiments in a wave tank (presence versus absence of waves; real versus mimic algae) showed that the aggregation of urchins on D. viridis was more than 2-fold greater in the absence than in the presence of waves. Similar numbers of urchins made contact with natural and mimic D. viridis plants, both with and without waves, indicating that any external release of chemicals (acid) from the alga had no perceptible repulsive effect on the urchin. The ability of the urchins to climb onto D. viridis increased markedly when urchin density attained a critical level. These results were consistent with field observations that urchins readily attack D. viridis under conditions of low wave action but do not under conditions of moderate wave action. We conclude (1) that the chemical makeup of D. viridis alone is neither necessary nor sufficient to limit contacts by the urchins and that (2) wave action is a major factor explaining the survival of D. viridis on urchin barrens, because waves limit the movements of the urchins towards the alga. We recommend that studies addressing marine algal defenses against herbivores be more comprehensive and examine interactions between algal traits, the physical environment, and the abundance and behavioral repertoire of herbivores.	Gagnon, Patrick,Louis Vincent St-Hilaire-Gravel, Patrick,Himmelman, John H.,Johnson, Ladd E.		상세보기
  Living within constraints: irreversible chemical build-up and seasonal temperature-mediated die-off in a highly acidic (H2SO4) annual seaweed (Desmarestia viridis)	Abstract Seaweeds exhibit a number of adaptations to cope with strong selective pressures imposed by shallow marine environments. The exceptional ability of the annual, brown seaweed Desmarestia viridis, to produce and store high concentrations of sulfuric acid (H2SO4) in intracellular vacuoles, makes it a particularly compelling model for studies of causes and consequences of acid production in seaweeds. We used two laboratory experiments, as well as measurements of intracellular pH of sporophytes and sea salinity and temperature over an entire growth season at one site in Newfoundland and Labrador (Canada), to test hypotheses about effects of salinity and temperature on acid production and die-off in D. viridis. We show that the acid is continuously and irreversibly accumulated (resulting in an intracellular pH as low as 0.53) as the seaweed grows from recruit to adult (March？June) and that this build-up inevitably culminates into dramatic mass releases of acid and die-offs. Progressive, synchronous death among individuals is under the predominant control of sea temperature (death systematically occurred around 12？°C in both laboratory and field), which suggests the evolution of a life-history strategy in which death occurs at a time when individuals reach a size that may correspond to reproductive maturity. The seaweed exhibits a low tolerance to changes in salinity (death was inevitable below 29？psu), which likely imposes severe limitations on its distribution range throughout its existence as a sporophyte. Our findings suggest that major phenological events and survival in D. viridis are intimately linked to synergistic effects of oceanographic controls, which either impair the ability of the seaweed to retain the acid in its tissues (seasonal sea warming), or contribute to dissipating the acid that is released to the environment (wave and current action). They also provide novel insights into the ecophysiological and evolutionary constraints within which marine organisms adapt.	Gagnon, Patrick,Blain, Caitlin,Vad, Johanne	Springer-Verlag	상세보기
  Yeast population increases during degradation of Desmarestia viridis (Phaeophyceae) in seawater model microecosystems	Abstract Desmarestia viridis,known to have an extremely low pH cell sap, supported rapidly increasing yeast populations in aquatic model systems. Population levels reached 108 yeasts ml-1 with an approximate doubling time of 1d. During incubation,pH declined in all systems except those receiving added carbon sources. Maximum yeast populations were not influenced by the initial experimental acidification of the medium or the presence of antibiotics added to suppress the growth of bacteria. In an unsupplemented system, Rhodotorula rubra and R. glutinis were the dominant yeasts. Systems with added organic material were dominated by a non-pigmented yeast. Examination of the algal filaments after 11 wk demonstrated little difference between experimental treatments, and that the filaments retained their original shape. Measurement of organic content in aquatic systems indicated little remaining soluble material. Similar population trends (i.e. yeast dominance and reduced bacterial populations) were observed in sand microcosms. Under these conditions, the algal filaments lost their original shape and were converted to a detritus-like substance.	Gunkel, W.,Crow, S.,Klings, K. W.	Springer-Verlag	상세보기
  Interactions between thermal and wave environments mediate intracellular acidity (H2SO4), growth, and mortality in the annual brown seaweed Desmarestia viridis	We used three laboratory experiments as well as measurements, throughout an entire growth season, of the length and survival of sporophytes, sea temperature, and wave height at two subtidal sites in Newfoundland (Canada), to investigate causal relationships between environmental variability, intracellular acidity, growth, and mortality in the highly acidic (H2SO4), annual brown seaweed Desmarestia viridis (O.F. Muller) J.V. Lamouroux. Light, grazing, and epibionts did not affect acidity. In the absence of waves, acid loss was threefold lower in cold (6.5oC) than warm (11oC) water, and threefold higher in the absence than presence of waves in warm (11 to 13oC) water. There were three phases of change in frond length at both sites: (1) increase [March to late June], (2) no change [July to mid-August], and (3) decrease [mid-August to late October]. Mortality rates and sea temperature in Phase 1 were low, whereas the onset of increasing mortality at the end of Phase 2 coincided well with the end of a 2-week period during which temperature increased rapidly, from 6 to 11oC. Results strongly suggested the more severe wave climate at the most wave-exposed site in September, when temperature was ~10oC, facilitated the dispersal of the acid being released, which delayed mortality by ~10days compared to the other site. All sporophytes had disappeared at both sites in late October. This is the first integrated analysis of seasonal variation in growth and mortality of D. viridis sporophytes. The strong connections between laboratory and field data attest to the critical role that thermal and hydrodynamic environments play in the life history of this unique seaweed.	Blain, C.,Gagnon, P.	North-Holland Pub. Co ; Elsevier Science Pub. Co	상세보기
  Novel observations of capelin (Mallotus villosus) spawning directly on a brown algae species (Desmarestia viridis) in coastal Newfoundland, Canada	Capelin (Mallotus villosus) is a key forage fish species within its circumpolar range. This species’ importance lies in its role in the typical marine ‘wasp-waist’ food web, where capelin acts as a conduit for energy flow from lower to higher trophic levels. Herein we describe a novel observation of capelin spawning subtidally on an annual brown algae species, Desmarestia viridis, during July？August 2019 in Placentia Bay, Newfoundland, Canada. Based on extensive video surveys of the seabed along with shoreline surveys and sediment sampling, we did not find other nearby sites with typical capelin subtidal and intertidal spawning habitat (i.e. medium sand to pebble gravel). Findings suggest that capelin spawned directly on this brown algae species, D. viridis. Eggs adhered to D. viridis developed normally and hatched successfully. As temperatures of intertidal areas are predicted to increase above temperatures suitable for capelin egg rearing (2？12°C) with climate change, D. viridis may become a high-quality subtidal spawning habitat for capelin and other fish species. In support, this algal species is adapted to colonize high disturbance areas, allowing protection from egg predators in a high flow environment while also being resistant to urchin grazing.	Bliss Laura,Davoren Gail		상세보기

• 특허정보

  검색결과 1건

  특허정보 목록 - 제목, 등록/출원번호, 출원인, 원문정보

  제목	등록/출원번호	출원인	원문정보
  쇠꼬리산말 추출물을 유효성분으로 함유하는 항염증용조성물	1020080061614	한국과학기술연구원	원문정보

• 유용한 해양생물 이야기

  검색결과 1건

  유용한 해양생물 이야기 목록 - 학명, 국명, 생리활성, 원료등록, 특징/이용

  학명	국명	생리활성	원료등록	특징/이용
  Desmarestia viridis	쇠꼬리산말	항산화, 항염증