Gigartina Stellata Research Articles

Carotenoids in red algae

The carotenoid composition of the following 8 species of red algae has been studied quantitatively and qualitatively: Bangia fuscopurpurea, Nemalion helminthoides, Bonnemaisonia hamifera (tetrasporophyte), Gigartina stellata, Rhodymenia palmata, Ceramium rubrum, Polysiphonia brodiaei, and Polysiphonia urceolata. Naturally occurring material of G. stellata, R. palmata, and P. brodiaei was investigated, while monoalgally cultured material was obtained from the remaining 5 species. α- and β-carotene, lutein, zeaxanthin, and small amounts of α- or β-cryptoxanthin were commonly present, but the two species P. brodiaei and P. urceolata were devoid of carotenoids containing α-ionone rings. Fucoxanthin was detected in naturally occurring material of B. fuscopurpurea, N. helminthoides, C. rubrum, and P. brodiaei, but could not be found in cultured material of the 3 first-mentioned species. The possible origin of the fucoxanthin is discussed as well as the biochemical and phylogenetic implications of the results obtained. As judged from the electronic spectrum of the total extracts, chlorophyll d was not present in any of the algae investigated. The total amounts of carotenoids and the ratio carotenoids: chlorophyll a were similar to those reported in previous work.

Carrageenan ecology of Gigartina stellata (Stackhouse) Batters

Seasonal variations of carrageenan and other biochemical properties in estuarine and open coastal populations of Gigartina stellata (Stackhouse) Batters were recorded monthly during 1972–1973. Protein and viscosity values were highest during late winter—early spring when nitrogen nutrient levels were highest. The levels of carbohydrate and carrageenan exhibited erratic and minimal seasonal variations, even so the lowest values were found during the spring periods of maximum protein levels. Estuarine populations of Gigartina exhibited lower protein and greater carrageenan contents than open coastal populations; earlier studies with the closely related red alga, Chondrus crispus Stackhouse, showed the opposite situation. Differential physiologies and tolerances of Chondrus and Gigartina may explain their contrasting biochemical properties.

The production of antimicrobial compounds by British marine algae I. Antibiotic-producing marine algae

Using five species of bacteria as the test organisms, 151 species of British marine algae have been screened for the production of antibiotics. Of these, Asparagopsis armata, Bonnemaisonia asparagoides, Bonnemaisonia hamifera, Chondrus crispus, Dilsea carnosa, Gloiosiphonia capillaris, Sphondylothamnion multifidum, Desmarestia aculeata, Desmarestia ligulata, Laminaria digitata, Dictyopteris membranacea, Dictyota dichotoma, Halidrys siliquosa and most members of the family Rhodomelaceae appear to possess outstanding antibacterial properties. Although the production of antibiotics would appear to be a characteristic of several families, it has not been possible to establish any major correlation between taxonomy and antibiotic production. In the case of two closely related and morphologically similar species, Chondrus crispus and Gigartina stellata, the former possesses considerable degrees of antimicrobial activity whilst the latter exhibits no such activity. The results also indicate that the production of antibiotics by the algae is affected by the season of the year.

The life history of Gigartina stellata (Stackh.) Batt. (Rhodophyceae, Gigartinales) in culture

The life history of Gigartina stellata has been completed in culture. Starting from carpospores produced by plants in nature, the alga was taken through two generations within a 3-year period. In all cases carpospores gave rise directly to gametophytic plants without intervention of a tetrasporophyte. Male plants with spermatia were absent in culture, and were not noted in the field. A complete apomictic life history is indicated, and since the gametophyte contains κ-carrageenan this phase can be considered haploid.

North Carolina marine algae. II. New records and observations of the benthic offshore flora

Abstract Twenty new records from North Carolina are reported including four species of green algae, two species of brown algae, and fourteen species of red algae. Nineteen of these collections constitute the northernmost records of these species, though most are found in the Bermudian flora. The other new record, that of Gigartina stellata (Stackhouse) Batters, represents a new southern extension for this northern species. Two previously questionable records and one species known only from shallow water in North Carolina are verified as members of the deep water offshore flora. A clarification of the records of Agardhiella tenera (J. Agardh) Schmitz in this area is given.

The ratio of kappa- to lambda-carrageenan in nuclear phases of the rhodophycean algae, chondrus crispus and Gigartina stellata

The ratio of the concentrations of κ- to λ-carrageenan is shown to be related to the nuclear phase in Chondrus crispus both in culture and in nature. This ratio is low in tetrasporic plants and relatively high in the gametophytes. It was found to vary somewhat amongst samples analysed, but was always less than unity in tetrasporophytes and greater than unity in gametophytic plants. The κ/λ ratio in Gigartina stellata was high in gametophytes as in C. crispus; the tetrasporophytic phase of this species is unknown. It is suggested that the commercial quality of carrageenan can be correlated with the biological status of the harvested plants.

Ecological studies of economic red algae. II. Culture studies of Chondrus crispus Stackhouse and Gigartina stellata (Stackhouse) batters

The carpospores of Chondrus crispus Stackhouse and Gigartina stellata (Stackhouse) Batters were grown under a variety of light intensities, temperatures, and salinities. Chondrus exhibited a rapid increase in growth concurrent with increasing intensities up to 440 ft-c and tended to level off above this intensity. Gigartina exhibited a less rapid, but more consistent, increase in cell production coincident with increasing light intensity through 770 ft-c. The growth of both species was accelerated with increasing temperatures to 19 °C. Spores of C. crispus germinated and grew relatively rapidly over a broad range of salinities (15–45‰ at 19°C). Gigartina exhibited a more restricted tolerance to reduced salinity (20 ‰ at 19°C). The local distribution and abundance of both species are correlated with their responses in culture as well as with previous observations on their photosynthesis and respiration.

Ecological studies of economic red algae. III. Growth and reproduction of natural and harvested populations of Gigartina stellata (Stackhouse) batters in New Hampshire

The growth in situ of populations of Gigartina stellata (Stackhouse) Batters has been recorded at three New Hampshire locations and correlated with seasonal and spatial variations of surface salinity, temperature, and nutrients. Annual growth began between February and May, depending upon the location and its hydrographic regime. Gigartina populations reached maximum biomass and size in August and September, and a general decrease in both occurred during the reproductive period from October to February. The period of fastest growth coincided with increasing summer temperatures, while maximum carpospore release occurred during the period of decreasing (coldest) temperatures. The largest plants and maximum biomass of Gigartina were found on the open coast (at a semi-exposed site) while smaller plants and reduced biomass were evident within the Great Bay Estuary System. Salinity is a dominant factor influencing both the local distribution and growth of the plant. Gigartina is primarily restricted to the littoral zone, and its maximum length and biomass occur between +0.45 and +1.0 m above M.L.W.Experimental plots were established to determine the effects of differential levels and seasons of harvesting on G. stellata. Summer (August) harvesting allowed control levels of biomass and population structure to be reached after one year, while winter (December) harvests attained control levels after 19 months. Denuded and sterilized quadrats required more than three years to re-establish themselves. Harvesting in December gave control levels of reproduction in the careful and moderately harvested plots after 9 and 12 months respectively. An August harvest deprived all the plots of reproductive potential until the following reproductive season.

Ecological studies of economic red algae. I. Photosynthesis and respiration of Chondrus crispus Stackhouse and Gigartina stellata (Stackhouse) Batters

The photosynthesis and respiration of Chondrus crispus Stackhouse and Gigartina stellata (Stackhouse) Batters are recorded under a variety of light intensities, temperatures, salinities, and degrees of desiccation. The apparent photosynthesis (uncorrected for plant respiration) of C. crispus is light-saturated at ~ 1000 ft-c, that of G. stellata at ~2100 ft-c. The optimal temperature for photosynthesis in both species is ~20 °C, but they have a high photosynthetic capacity over a wide range of temperatures. The respiration of C. crispus and G. stellata is relatively uniform from 8–20 °C. Both species have maximum photosynthesis/respiration ratios at 20 °C. C. crispus showed its maximum photosynthesis and minimum respiration at a salinity of 24‰; G. stellata exhibited maximum photosynthetic and reduced respiration rates at 40%.. The apparent photosynthesis and respiration of C. crispus are adversely affected by a high degree of dehydration, while G. stellata is more flexible. The local abundance and distribution of C. crispus and G. stellata are correlated with their photosynthetic responses.

The evaluation of some red marine algae as a source of carrageenan and of its k- and lambda-components.

AbstractThe red seaweeds, Chondrus crispus, Gigartina stellata, G. radula, G. acicularis, G. pistillata, Eucheuma spinosum, and Polyides rotundus, have been evaluated as a source of carrageenan and of its k‐ and λ‐components. The fractionation of carrageenan from C. crispus with potassium ions does not always give a sharp separation into ‘pure’ k‐ and λ‐components and is dependent on habitat. Seasonal variations in total yield, k/λ ratio, optical rotation and chemical composition were observed.G. stellata and G. radula give poor separations but G. acicularis and G. pistillata give sharp fractionations and the proportion of λ‐polysaccharide in these two species is much higher than that in C. crispus. Approximately 30% of the dry weight of these seaweeds is λ‐carrageenan.Carrageenan from E. spinosum cannot be fractionated with potassium ions. This polysaccharide, which accounts for ˜55% of the dry weight of the seaweed, is structurally related to k‐carrageenan but has a higher sulphate ester content. The extract of P. rotundus is also insensitive to potassium ions but differs from that of E. spinosum in having a negligible content of 3,6‐anhydrogalactose.Different carrageenans have been depolymerised to give products of low viscosity and high sulphate content. This was achieved in the case of k‐carrageenan and carrageenan from E. spinosum by mild treatment with acid. Two methods are described for λ‐carrageenan; the first involves oxidation with periodate, reduction with borohydride, and mild acid hydrolysis. The second method, which is cheaper and more effective, employs hypochlorite as oxidant. A series of degraded products is listed.

Répartition des Phéophycées dans l'Archipel de Molène (Finistère). I. Cartes de Molène et de Quéménès

Abstract The Archipelago of Molene, situated between the Channel and the Atlantic Ocean, has never been studied by phycologists. In the course of a study on Chondrus crispus and Gigartina stellata, the width of the belts of Phaeophyceae was measured. The distribution of the Phaeophyceae on the islands of Molene and Quemenes is shown on charts.

Marine algal zonation and substratum in Beer Bay, south-east Devon

The intertidal zonation of the dominant algal species in Beer Bay, south-east Devon, was examined in relation to substratum by means of plane-table maps and transects. The dominance of Ulva lactuca on colonies of the reef-building worms Sabellaria alveolata was noted, but the distributions of Fucus vesiculosus, F. serratus, Gigartina stellata and Enteromorpha spp. showed no correlation with substratum.

Browsing of Patella

DURING a recent investigation of Gigartina stellata which has been carried out at Millport, Isle of Cumbrae, I have been struck with the relationship between the limpet (Patella vulgata) and the seaweed, and have observed effects very comparable with those described by Mr. N. S. Jones1. This work is being described in more detail elsewhere, and will, I think, confirm the observations of Jones, Orton, Eslich and others that Patella is able to browse on young algal growths, and, by the glades that it forms in an algal community, may considerably lessen the algal covering on that part of the shore.

A Polysaccharide from Gigartina stellata: the Isolation of Crystalline 2: 6-Dimethyl-β-d-Galactopyranose from the Methylated Polysaccharide

THROUGH the kindness of Dr. A. P. Orr of the Marine Station, Millport, in supplying a quantity of Gigartina stellata which is used in the preparation of 'British Agar'1, we have been able to investigate a polysaccharide isolated from this material.