Search results for " Algae"
showing 10 items of 95 documents
Using growth and geochemical composition of Clathromorphum compactum to track multiscale North Atlantic hydro-climate variability
2020
International audience; Records of ocean/atmosphere dynamics over the past centuries are essential to understand processes driving climate variability. This is particularly true for the Northwest Atlantic which is a key region with an essential role in global climate regulation. Over the past two decades, coralline red algae have been increasingly used as environmental and climatic archives for the marine realm and hold the potential to extend long-term instrumental measurements. Here, we investigate the possibility to extract climate and environmental information from annual growth patterns and geochemical composition of the coralline red algae, Clathromorphum compactum, from Saint-Pierre …
Prospects of in vivo 31P NMR method in glyphosate degradation studies in whole cell system
2009
Abstract The degradation of the phosphonate herbicide glyphosate ( N -phosphonomethylglycine) by four taxonomically distinct microorganisms was studied in vivo in whole cell system using phosphorus nuclear magnetic spectroscopy ( 31 P NMR). The time-course of glyphosate metabolization in dense cell cultures was followed by means of 31 P NMR up to 21 days after the addition. The results obtained by this non-invasive way confirmed that the cells of Spirulina platensis and Streptomyces lusitanus biodegrade herbicide. Moreover, phosphorus starvation influenced the rate of glyphosate degradation by S. platensis . On the other hand, the results of similar measurements in the cultures of green alg…
Interspecific variation in total phenolic content in temperate brown algae
2017
Marine algae synthesize secondary metabolites such as polyphenols that function as defense and protection mechanisms. Among brown algae, Fucales and Dictyotales (Phaeophyceae) contain the highest levels of phenolic compounds, mainly phlorotannins, that play multiple roles. Four temperate brown algae (Cystoseira amentacea, Cystoseira compressa, Dictyopteris polypodioides and Padina pavonica) were studied for total phenolic contents. Total phenolic content was determined colorimetrically with the Folin-Ciocalteu reagent. Significant differences in total phenolic content were observed between leathery and sheetlike algae and also within each morphological group. Among the four species, the she…
Influence of variable feeding on mesophilic and thermophilic co-digestion of Laminaria digitata and cattle manure
2014
Abstract In this study the effect of various feeding ratios on mesophilic (∼35 °C) and thermophilic (∼50 °C) co-digestion of brown algae Laminaria digitata and cattle manure was investigated. Algae input of 15% VS caused no influence on specific methane yield from mesophilic co-digester while deteriorated the process parameters such as the development of propionic acid in total volatile fatty acids (tVFA) pattern of the thermophilic co-digester. The accumulation of tVFA continued for the latter reactor as the feeding ratio of algae enhanced to 24% VS, but the specific methane yield improved dramatically. Same rise in feeding once again showed no improvement in specific methane yield from me…
DO INVASIVE MACROALGAE INFLUENCE ASSOCIATED MOLLUSC DIVERSITY IN THE MEDITERRANEAN SEA ?
2013
The benthic molluscs associated to the non-indigenous red algae Asparagopsis taxiformis invading the Mediterranean rocky subtidal were compared with those associated to a native brown alga. The results showed a marked difference in species richness and abundance between native and non-native algal species.
Antibacterial activity and HPLC analysis of extracts from Mediterranean brown algae
2020
The antibacterial activity of methanolic extracts of eight Mediterranean brown algae belonging to the genera Cystoseira sensu lato, Dictyopteris and Padina was investigated. Extracts from Sargassaceae showed antibacterial activity. Specifically, Carpodesmia crinita and Carpodesmia brachycarpa extracts inhibited the growth of the Gram-positive strain Kocuria rhizophila whereas Cystoseira compressa and Carpodesmia amentacea extracts showed antibacterial activity against the Gram-positive strains, Kocuria rhizophila and Staphylococcus aureus. None of them inhibited the growth of the Gram-negative bacterium Escherichia coli. The extracts of Cystoseira sp. pl. and Treptacantha ballesterosii did …
Freshening of the Alaska Coastal Current recorded by coralline algal Ba/Ca ratios
2011
Arctic Ocean freshening can exert a controlling influence on global climate, triggering strong feedbacks on ocean‐atmospheric processes and affecting the global cycling of the world’s oceans. Glacier‐fed ocean currents such as the Alaska Coastal Current are important sources of freshwater for the Bering Sea shelf, and may also influence the Arctic Ocean freshwater budget. Instrumental data indicate a multiyear freshening episode of the Alaska Coastal Current in the early 21st century. It is uncertain whether this freshening is part of natural multidecadal climate variability or a unique feature of anthropogenically induced warming. In order to answer this, a better understanding of past var…
INTERSPECIFIC VARIATION IN TOTAL PHENOLIC CONTENT IN TEMPERATE BROWN ALGAE
2015
The aim of this study was to focus on interspecific variation of total phenolic contents (TPC) in temperate brown algae also considering their relationship with environmental conditions. In particular, we compared the TPC of four species characterized by different thallus morphology, growth cycle and bathymetric level: Cystoseira amentacea (C. Agardh) Bory, Cystoseira compressa (Esper) Gerloff & Nizamuddin, Dictyopteris polypodioides (A.P. De Candolle) J.V. Lamouroux and Padina pavonica (Linnaeus) Thivy, collected in summer 2011 from the north-western coast of Sicily.
Botanical names in Southern Hemisphere Veronica (Plantaginaceae ): sect. Detzneria , sect. Hebe , and sect. Labiatoides
2007
The classification of the Southern Hemisphere Veronica complex is discussed in the light of recent findings that these segregate genera are nested within the hitherto northern Veronica clade. In order to render Veronica monophyletic, we transfer Chionohehe, Derwentia, Detzneria, Hebe, Hebejeebie, Heliohebe, Leonohebe, and Parahebe to Veronica subgen. Pseudoveronica. Correct names are listed for all species in Veronica subgen. Pseudoveronica, according to the International Code of Botanical Nomenclature. Those species previously included in Derwentia together with other Australian species of Veronica are now classified in Veronica sect. Labiatoides, that in Detzneria is now classified in Ver…
Typification of the marine siphonous green algae Caulerpa prolifera (Bryopsidales, Chlorophyta)
2015
The typification of the marine siphonous green algae Caulerpa prolifera (Forsskål) J.V. Lamouroux (≡ Fucus prolifer Forsskål) (Caulerpaceae), including f. obovata (J. Agardh) Weber-van Bosse and f. zosterifolia Børgesen, is discussed. Original material conserved in the Natural History Museum of Denmark (Copenhagen) at C (Herbarium Forsskålii) and in the Botanical Museum of Lund University at LD are designated as the corresponding lectotypes.