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UV-absorbing compounds, such as mycosporine-like amino acids (MAAs), are a group of secondary metabolites present in many marine species, including red seaweeds. In these organisms, the content and proportion of the composition of MAAs vary, depending on the species and several environmental factors. Its high cosmetic interest calls for research on the content and composition of MAAs, as well as the dynamics of MAAs accumulation in seaweeds from different latitudes. Therefore, this study aimed to survey the content of UV-absorbing MAAs in three Subantarctic red seaweeds during a seasonal cycle. Using spectrophotometric and HPLC techniques, the content and composition of MAAs of intertidal Iridaea tuberculosa, Nothogenia fastigiate, and Corallina officinalis were assessed. Some samples were also analyzed using high-resolution mass spectrometry coupled with HPLC-ESI-MS in order to identify more precisely the MAA composition. I. tuberculosa exhibited the highest MAA values (above 1 mg g−1 of dried mass weight), while C. officinalis showed values not exceeding 0.4 mg g−1. Porphyra-334 was the main component in N. fastigiata, whereas I. tuberculosa and C. officinalis exhibited a high content of palythine. Both content and composition of MAAs varied seasonally, with high concentration recorded in different seasons, depending on the species, i.e., winter (I. tuberculosa), spring (N. fastigiata), and summer (C. officinalis). HPLC-ESI-MS allowed us to identify seven different MAAs. Two were recorded for the first time in seaweeds from Subantarctic areas (mycosporine-glutamic acid and palythine-serine), and we also recorded an eighth UV-absorbing compound which remains unidentified.

In the present work, Iridaea cordata (IC), a red marine macroalgae, was used as an efficient biosorbent for the removal of crystal violet (CV) and methylene blue (MB) dyes from aqueous solutions. The effects of pH (5, 7, and 9) and IC concentration (1, 3, and 5 g L−1) on the biosorption were studied through a 32 full factorial design. Under the optimal conditions (pH: 7, biosorbent concentration: 1 g L−1), biosorption kinetic studies were developed and the obtained experimental data were evaluated by pseudo-first order and pseudo-second order models. The results showed that the pseudo-second order model was in agreement with the experimental kinetic data for both dyes. Equilibrium studies were also carried out, and results exhibited good concordance with the Brunauer–Emmett–Teller isotherm. The biosorption capacities were 36.5 and 45.0 mg g−1 for CV and MB dyes, respectively. The dye removal percentages were around 75% for CV and 90% for MB. Thermodynamically, the biosorption process proved to be exothermic, spontaneous, and favorable. These results showed that IC biomass is a promising biosorbent for removal of CV and MB dyes from aqueous solutions. [ABSTRACT FROM AUTHOR]

This study aimed to isolate and characterize sulfated polysaccharides (SPs) from Iridaea cordata and evaluate their anticancer activity. SPs of the Antarctic red seaweed were obtained by CaCl2 (SP1) and ethanol precipitations (SP2) following diluted acid extraction at room temperature. Yields of SP1 and SP2 were approximately 14% and 23%, respectively, of the dry weight of red seaweed. The average molecular mass of the SP1 and SP2 was estimated about 1.84 × 103 and 1.42 × 103 kDa, respectively, by size-fractionation High-Performance Liquid Chromatography (HPLC). From the High-Performance Anion- Exchange Chromatography-Pulsed Amperometric Detection (HPAEC-PAD) analysis, the main monosaccharide was galactose with glucose and fucose as minor components. The sulfate content of SP2 (40.4%) was slightly higher than that of SP1 (33.8%). The FT-IR spectra also showed characteristic band of carrageenan-like sulfated polysaccharides. Taken together the SPs are thought to be carrageenan-like sulfated galactan. The polysaccharides (SPs) from I. cordata exhibited weak antitumor activity against PC- 3 (prostate cancer), HeLa (cervical cancer), and HT-29 (human colon adenocarcinoma). To our knowledge, this is the first data on biological activity of the Antarctic red seaweed I. cordata. [ABSTRACT FROM AUTHOR]

Studies on Antarctic intertidal fauna are comparatively scarce compared to those from the sublittoral and the deep sea. In order to contribute to filling this gap in knowledge, during the 2006 BENTART Spanish Antarctic Expedition, we conducted a quantitative and qualitative study on the fauna inhabiting the intertidal rocky platform of Fildes (=Maxwell) Bay, King George Island (South Shetlands Archipelago). This platform is dominated in its middle and lower area by the brown algae Adenocystis utricularis, which covers ca. 100 % of the rocky surface. Three quantitative samples of 20 × 20 cm were taken in the community of A. utricularis, and one additional sample of 20 × 20 cm in the tide pools community dominated by the gigartinacean rhodophyceae Iridaea cordata. In addition, qualitative samples of invertebrates that live under the boulders were also taken. Quantitative samples yielded a total of 9950 individuals belonging to 41 species. Mollusks were the most abundant group with a total of 9522 specimens belonging to 11 species, being the gastropod Eatoniella kerguelenensis regularis the most abundant with 6763 specimens. Crustaceans were represented by 295 specimens and 7 species and annelid polychaetes with 133 specimens and 20 taxa. The Shannon diversity indexes calculated for the quantitative samples of A. utricularis ranged between 0.803 and 1.030 with values of 1.577 for the I. cordata community. Our study confirms that the intertidal area of Fildes Bay hosts a surprisingly rich community in terms of abundance and biodiversity. [ABSTRACT FROM AUTHOR]

Endophytic organisms are known to have varied effects on their host organism in terrestrial and marine environments. In previous studies on marine algae, these symbioses range from innocuous to pathogenic depending on the host and endophyte species. The present study further assessed a pathogenic relationship between filamentous algal endophytes and a red algal host from the western Antarctic Peninsula. We analyzed endophyte presence (appearance of filamentous thalli) in the three life history stages of Iridaea cordata and potential impacts on fertility in the fertilized female gametophytes (carposporophytes) and tetrasporophytes. We found that endophytes proliferate throughout significantly more thallus area in tetrasporophyte and unfertilized gametophyte hosts than in carposporophyte hosts, but there was no correlation between endophyte cover and fertility in these individuals. This study also provides a demographic analysis of I. cordata populations surrounding Palmer Station, Antarctica, showing that these populations are haploid dominated (∼78% of individuals). The differential presence of filamentous algal endophytes indicates that endophyte pathogenicity indirectly has greater effect on tetrasporophytes and unfertilized gametophytes than on the carposporophytes, which house the products of sexual recombination. [ABSTRACT FROM AUTHOR]

Abstract: A high-resolution study of benthic foraminiferal assemblages was performed on a ca. eight metre long sediment core from Gullmar Fjord on the west coast of Sweden. The results of 210Pb- and AMS 14C-datings show that the record includes the two warmest climatic episodes of the last 1500years: the Medieval Warm Period (MWP) and the recent warming of the 20th century. Both periods are known to be anomalously warm and associated with positive NAO winter indices. Benthic foraminiferal successions of both periods are compared in order to find faunal similarities and common denominators corresponding to past climate changes. During the MWP, Adercotryma glomerata, Cassidulina laevigata and Nonionella iridea dominated the assemblages. Judging from dominance of species sensitive to hypoxia and the highest faunal diversity for the last ca. 2400years, the foraminiferal record of the MWP suggests an absence of severe low oxygen events. At the same time, faunas and δ13C values both point to high primary productivity and/or increased input of terrestrial organic carbon into the fjord system during the Medieval Warm Period. Comparison of the MWP and recent warming revealed different trends in the faunal record. The thin-shelled foraminifer N. iridea was characteristic of the MWP, but became absent during the second half of the 20th century. The recent Skagerrak–Kattegat fauna was rare or absent during the MWP but established in Gullmar Fjord at the end of the Little Ice Age or in the early 1900s. Also, there are striking differences in the faunal diversity and absolute abundances of foraminifera between both periods. Changes in primary productivity, higher precipitation resulting in intensified land runoff, different oxygen regimes or even changes in the fjord''s trophic status are discussed as possible causes of these faunal differences. [Copyright &y& Elsevier]

mphipods along the western Antarctic Peninsula appear to gain refuge from predators by associating with chemically defended macroalgae rather than palatable macroalgae. However, nothing is known about amphipod activity at night. If foraging on non-chemically defended macroalgae regularly occurs, then nocturnal foraging seems beneficial since visual predators are disadvantaged. To test this hypothesis, we collected three common macroalgal species and affiliated mesograzers, approximately 3 h before and after sunset. All associated mesofauna were counted and densities recorded. Amphipod densities were significantly decreased during the night on the chemically defended Desmarestia menziesii, while significantly increased on the palatable Iridaea cordata. Additionally, the amphipod Gondogeneia antarctica was found in significantly higher densities at night on Palmaria decipiens, a species shown to be readily eaten by G. antarctica and omnivorous fish. We believe that chemically defended macroalgae act as a refuge for mesograzers during the day, while more widespread foraging occurs at night. [ABSTRACT FROM AUTHOR]

Abstract: Iridaea cordata cultivated in the presence of UVB radiation (UVBR) was studied using transmission electron microscopy. Apical segments were cultivated in 0.97Wm−2 of UVBR for 40 days, 3h a day, and compared to a negative control (UVBR absent). UVBR caused modifications, mainly in the cortical cells, including an increased number of cell wall-producing vesicles, in addition to thicker and denser cellular walls, compared to the control. Additionally, cells were observed with an irregular contour and without defined organelles. The increase of cell-wall thickness could be interpreted as an acclimation to UVBR, which could lead to protection from this radiation. [ABSTRACT FROM AUTHOR]

The article presents a study which stressed the importance of analyzing the effects caused by different intensities of ultraviolet B rays (UVB) on the early development stages of the micro-algae Iridaea cordata or Rhodophyta, an algae that produces carageenan from Chile. It analyzed and evaluated the effects of different irradiances of UVB radiation on various development stages of the algae collected in Chile's Magellan Strait especially the morphology and growth of germling and young gamethophytes taken from a laboratory and young fronds taken from the field. Also noted is how exposure to UVB rays caused bleaching and decrease in the germlings' growth rates and as well as morphological alterations, and even necrosis, in young gametophytes.

Abstract: Lead (Pb) isotope ratios were measured in the marine macroalga Iridaea cordata collected from four locations in the Windmill Islands, East Antarctica. Based on the masses of thalli collected, samples analysed in this study were likely to be a mixture of one and two year old thalli. For a sample of thalli of various ages (<12 months to 2 years old) from the same site there was no apparent variation in Pb concentration or Pb isotope ratio with thallus mass/age, indicating that contaminant sources had been constant over the lifetime of the thalli sampled. I. cordata samples close to the Thala Valley waste disposal site (Brown Bay Inner) near the Australian Station, Casey, displayed isotopic signatures (208Pb/204Pb 35.99; 206Pb/207Pb 1.066; n =3; average values shown) trending towards that possessed by major Australian Pb sources (Broken Hill and Mt Isa, 208Pb/204Pb 35.60; 206Pb/207Pb 1.041) suggesting that these samples had been exposed to anthropogenic Pb originating from the Thala Valley waste disposal site. Material collected hundreds of metres from the tip location at Brown Bay Outer had isotopic values (208Pb/204Pb 36.32; 206Pb/207Pb 1.088; n =10) intermediate between Brown Bay Inner and sites further from the contaminant source at Sparkes Bay and Wilkes (208Pb/204Pb 36.46; 206Pb/207Pb 1.094; n =4) showing that contaminant transport was predominantly restricted to Brown Bay Inner. This study demonstrates that the isotope ratios of Pb in marine macroalgae can provide valuable information as to the origin and extent of heavy metal flux in a marine environment. [Copyright &y& Elsevier]

Molecular data obtained by a procedure for extracting PCR-amplifiable nuclear and chloroplast DNA from old and formalin-fixed red algal herbarium specimens were used to elucidate problems in the systematics of Pacific Gigartinaceae. Correspondence between nucleotide sequences of the internal transcribed spacer 1 region or the RUBISCO spacer from type specimens and modern collections supports the following conclusions. (1) The type of Fucus cordatus Turner, now Iridaea cordata (Turner) Bory, came from the southern hemisphere (probably from Isla de los Estados, Argentina) rather than from Banks Island, B.C., Canada. (2) The type of Iridaea heterocarpa P. et R. [Mazzaella heterocarpa (P. et R.) Fred.] represents the tetrasporangial phase of a species of Chondrus, possibly C. crispus Stackh. (3) The types of Iridaea lilacina P. et R., I. phyllocarpa P. et R., and Iridophycus furcatum S. et G. represent a single species from Alaska, Mazzaella phyllocarpa (P. et R.) Perest., currently but incorrectly called M. heterocarpa. (4) The type of Iridophycus oregonum Doty represents the tetrasporangial phase of the species from southern Alaska to southern California known incorrectly as M. heterocarpa. (5) Mazzaella splendens (S. et G.) Fred. is more closely related to M. linearis (S. et G.) Fred. than it is to M. flaccida (S. et G.) Fred. (6) Iridophycus coriaceum S. et G. is conspecific with M. splendens, whereas Rhodoglossum coriaceum E.Y. Dawson is an independent species: Mazzaella coriacea (E.Y. Dawson) Hughey. (7) Iridaea cornucopiae P. et R. is conspecific with Mazzaella laminarioides (Bory) Fred., and the type probably came from Chile rather than from the North Pacific. (8) Plants attributed to Iridaea cornucopiae in Pacific North America are referable to Mazzaella parksii (S. et G.) comb. nov. (9) Rhodoglossum parvum G. M. Smith et Hollenb. is an independent species: Mazzaella parva (G. M. Smith et Hollenb.) comb. nov. (10) Grateloupia squarrulosa S. et G., Grateloupia johnstonii S. et G., and Gigartina pectinata E.Y. Dawson represent a single species: Chondracanthus squarrulosus (S. et G.) comb. nov. [ABSTRACT FROM AUTHOR]

Examines the potential chemical defenses in Iridaea cordata Bory and Phyllophora antarctica A. et E.S. Gepp through the measurement of retention of test disks over the mouths of the common Antarctic sea urchin Sterechinus neumayeri Meissner. Retention of Thallus disks of both macroalgal species by the urchins for shorter times than inert filter paper disks; Results supporting the hypothesis that chemical defenses in I. cordata and P. antarctica play a role in deterring potential herbivores.

Evidence about the potential of mobile marine invertebrates to act as algal spore dispersai agents is presently circumstantial. Using a field correlational and experimental protocol, our study tested the hypothesis that amphipods can increase the spore recruitment of the red alga Iridaea laminarioides Bory. Iridaea laminarioides spore recruitment onto glass slides was measured at a site with high amphipod abundance and a site with low density of amphipods. To evaluate the effect of an Ulva canopy on recruitment, replicated glass slides with and without a surrounding Ulva canopy were installed at both sites. The number of I. laminarioides spores recruited on the glass slides was four to eight times higher at the high amphipod abundance site than at the low density site. However, the presence of an Ulva canopy covering the glass slides did not significantly increase the recruitment of I. laminarioides. Because the abundance of I. laminarioides, the proportion of cystocarpic plants, and the percentage of open cystocarps only differed slightly between the low and high abundance amphipod sites, we suggest that the variation in recruitment between the sites is due to the differences in amphipod abundance (and their movements) and not to differences in spore production. Moreover, the presence of I. laminarioides cystocarps showing amphipod grazing scars was significantly higher at the high amphipod density site than at the low density site. [ABSTRACT FROM AUTHOR]

The phenomenon of baxiphyte specificity in the settlement and growth of the red algal epiphytes Microcladia californica Farl and M. coulteri Harv, was examined by studying the interface with their respective basiphytes and by cross-inoculation experiments. Microcladia californica attaches only to the surface of its single basiphytes Egregia menziesii (Aresch.) Turn. Whereas M. coulteripenetrates the tissue of a wide range of basiphytes. The pattern of primary rhizoid development in both epiphytes determines the mode of attachment and may influence the range of basiphytes possible for each epiphyte. Cross-inoculation experiments show that Microcladia californica is not able to colonize the basiphtes of M. coulteri, Irideas and Prioniis, or Ulva. The mechanisms by which these algae restrict the growth of epiphytes include short life-span, "cuticle peeling" and chemical defense. Microcladia coulteri, which naturally colonizes iridaea and Prionitis, has evolved mechanismas to counteract the antifouling effects of those basiphytes. The question of why Egregia is the exclusive substratum for M. californica remains undermined. However, egregia may provide the appropriate ecological conditions and a surface topography conducive to M. californica spore settlement and growth. [ABSTRACT FROM AUTHOR]

Gametophytes are more abundant than sporophytes in wave exposed rocky intertidal populations of Iridaea laminarioides Bory in Central Chile. In this study we experimentally tested the differential effects of selected ecological factors on karyologically different life history phases. In the field, gametophytes dominated at higher elevations and during summer; tetrasporophytes were most abundant low in the intertidal and during the fall. Laboratory responses correlated with these patterns. Gametophytes exhibited greater desiccation tolerance than tetrasporophytes. Optimum growth of gametophytes occurred at higher temperatures (20°C) and longer photoperiods (16:8 h LD) than sporophytes (15°C) and (12:12 h LD). Grazing preferences changed with the developmental stage of the alga, but all herbivores tested had increased preference for diploid tissues as compared to haploid. Number of spores produced with respect to total plant surface, or total rocky surface, or settlement of spores and their germination rate did not show significant differences between phases hut showed great variability in space and time. Spontaneous store release, however, was always higher in cystocarpic than in letrasporangial thalli. Such a coin hi nation of results suggests that sonic real ecological differences exist between the two life history phases of I. laminarioides. Such ecological differences permit a prediction of vertical and lemporal patterns of distribution for both phases. Horizontal patterns of distribution cannot be explained because the several selection factors probably interact differently in various habitats. [ABSTRACT FROM AUTHOR]

This article focuses on the life history of Iridaes cordata and its distribution form British Columbia to California. The taxonomy of the Iridaea cordata complex in western North America is poorly understood. The bulk of the plants sampled in this study comply with concepts of I. cordata in most modern treatments. Gametophytic tissue of I. cordata showed a sharp increase in absorbance at 510 nanometer as the mass of tissue was increased from 0 to 3 mg. With greater mass there was little or no measurable increase in absorbance. Tetrasporophytic tissue showed an increase in absorbance over the entire 0 to 16 mg range used in the experiment.

An Iridaea cordata (Turner) Bory population made up of 83% gametophytes and 17% tetrasporophutes demonstrated little variation in these proportions over three years. These data contrast with an expectation that alternations of generations, as demonstrated by cultured studies. Analyses of reproductions and demographic attributes of alternation of generations in this populations. Growth and mortality rates in the summer could not account for the success of gametophytes, however, size class frequencies demonstrated that tetrasporophytes were smaller individuals. Sporelings recruited into this intertidal region and made up 20% of the spring population numbers. Even with this level of recruitment, gametophyte-to-tetrasporophyte ratios did not change. Perenating holdfasts regenerated 80% of the spring number and 90% of the total blade area. Consequently, perennation and differential survival of gametophyte spores or sporelings are proposed as mechanisms maintaining gametophyte dominance in this San Juan Island, Washinton population.] [ABSTRACT FROM AUTHOR]

Field experiments were used to examine the effects of biological interactions on the abundance of Iridaea flaccida (S. & G.) Silva within and below its normal range in the intertidal zone of central California. A combination of competitor removal, removal, grazer exclusion and transplant manipulations showed that within the I. Flaccida zone, this alga can be the first macroscopic plant to become re-established after clearing and that this can occur in less than two months. Grazing by molluscs within this zone retards, but does not prevant, re-establishment. Although absent prior to the experiments, both I. Flaccida and I. Cordata (Turn.) Bory settled, grew rapidly and reproduced in cleared areas below the I. Flaccida zone, regardless of the presence of grazers. These plants did not establish themselves if entire thalli or holdfasts of other algae normally occupying the lower zone were present. The results support the few other in situ experimental investigations of algal zonation by showing that, when bounded by other plants, the lower limits of intertidal algae are directly determined by competition. They also suggest that I. Flaccida and I. Cordata may be conspecific. [ABSTRACT FROM AUTHOR]

The in situ growth, maturation and senescence of central California Iridaea cordata (Turner) Bory was studied. This ontogenetic progression was quantified by measuring development and growth of: i) individually tagged blades, and ii) populations of blades within cumulative (1-yr duration) and seasonal experimental plots. Greatest growth and longest life span were exhibited by winter-spring initiated blades, and were correlated with a rapid increase in irradiance, but not with either seawater temperature or nutrients. Tagging studies showed that reproductive maturation and senescence of blades occurred throughout the year, irrespective of date tagged, growth rate or size. Moreover, the majority of blades continued to elongate following maturation, and some matured within 3 mo of initiation at all seasons but winter. At the population level maturation took place primarily during summer-autumn when 90 ±2% of the population was mature. The majority of the population senesces or "dies back" during autumn-winter. It is concluded that in situ, the blades are derived almost totally via vegetative means involving perennation. This indirectly suggests that sexual reproduction or the success of sporeling development are marginal. Additionally, the species is perennial with annually deciduous blades, characterized by both rapid growth and maturation. [ABSTRACT FROM AUTHOR]

Transmission electron microscopy of the iridescent algae Iridaea flaccida (S & G) Silva Iridaea cordata (Turn.) Bory var. cordata and I. cordata var, splendens (S & G) Abbott reveals a multilaminated cuticle covering the thallus. Experimental results show the cuticle: a) can be isolated intact by mechanical scraping or NaOH treatment; b) is iridescent by itself and the denuded thallus is not; and, c) is isolated without any subtending polysaccharide layer, cell walls or cells. This cuticle acts as a thin layer producing the constructive and destructive light interference which is seen as iridescence. It is formed of alternating electron opaque and translucent layers with a total thickness of 0.5-1.6 μm. Analysis of mechanically isolated cuticle shows that it is composed of protein (50%), carbohydrate (ca. 10%), inorganic salts (5%) and some fatty acids (less than 1.0%). The electron opaque layers may correspond to protein-rich regions and the electron translucent ones to regions rich in carbohydrates. The cuticle does not appear to affect photosynthesis or respiration, but rather, may protect the alga from physical factors such as desiccation and from predator injury. It is likely that the iridescence in other foliaccous red algae caused by a similar structure. [ABSTRACT FROM AUTHOR]

The population structure of 4 California Iridaeacordata (Turner) Bory populations was studied. Random sampling procedures were used to increasure seasonal variational variations in standing crops, density and size-class distribution of life history stages. The results describe aspects of the in situ life history: a prerequisite to realistically considering the distribution, ecology or life history expressions of an alga. Seasonal fluctuations in density occur only in the juvenile stage, which is initiated during the winter (November to January) predominantly from the basal perennial crusts. Both the gametangial and tetra-sporangial stages are present throughout the year. The tetrasporangial stage is dominant in relation to the sexual stages in both density and biomass during most of the year, except spring when the new crop is just maturing and all stages are abundant. Density is nearly constant and observable changes in the populations are due to biomass fluctuations. Seasonal lows in biomass occur during the winter with the majority of thalli in the smaller size-classes. Growth and maturation culminate in peak summer crops and dominance of the tetrasporangial stage, followed by autumnal senescence and die-back in winter. Carrageenans analyzed from immature thalli showed a predominance of lambda-type, previously determined as specific for tetrasporangial plants. This indirect evidence for the tetrasporangial nature of immature plants suggests that dominance of the diploid stage occurred prior to blade development and most likely at the spore level. Alternatively, field results indicate a major contribution and possible replacement of alternation of gametangial and tetrasporangial stages by thallus perennation and vegetative reproduction. [ABSTRACT FROM AUTHOR]

UV-absorbing compounds, such as mycosporine-like amino acids (MAAs), are a group of secondary metabolites present in many marine species, including red seaweeds. In these organisms, the content and proportion of the composition of MAAs vary, depending on the species and several environmental factors. Its high cosmetic interest calls for research on the content and composition of MAAs, as well as the dynamics of MAAs accumulation in seaweeds from different latitudes. Therefore, this study aimed to survey the content of UV-absorbing MAAs in three Subantarctic red seaweeds during a seasonal cycle. Using spectrophotometric and HPLC techniques, the content and composition of MAAs of intertidal Iridaea tuberculosa, Nothogenia fastigiate, and Corallina officinalis were assessed. Some samples were also analyzed using high-resolution mass spectrometry coupled with HPLC-ESI-MS in order to identify more precisely the MAA composition. I. tuberculosa exhibited the highest MAA values (above 1 mg g−1 of dried mass weight), while C. officinalis showed values not exceeding 0.4 mg g−1. Porphyra-334 was the main component in N.fastigiata, whereas I. tuberculosa and C.officinalis exhibited a high content of palythine. Both content and composition of MAAs varied seasonally, with high concentration recorded in different seasons, depending on the species, i.e., winter (I. tuberculosa), spring (N. fastigiata), and summer (C. officinalis). HPLC-ESI-MS allowed us to identify seven different MAAs. Two were recorded for the first time in seaweeds from Subantarctic areas (mycosporine-glutamic acid and palythine-serine), and we also recorded an eighth UV-absorbing compound which remains unidentified. [ABSTRACT FROM AUTHOR]

The influence of desiccation on the mechanical properties of the intertidal macroalga Iridaea cordata (Turner) Bory (Rhodophyta) was investigated over a range of water losses (0-83%) that bracketed in situ levels (26-67%). The tissue modulus (stiffness) remained constant for water losses up to about 70%, but increased sharply with losses between 70-83%. Tissue strength of desiccated samples did not fall below the range measured for undesiccated samples. There was a significant increase in breaking strain up to water losses of about 50%, after which breaking strain decreased. The relationship between toughness and desiccation resembled that for breaking strain. Overall, the mechanical properties of Iridaea cordata did not deteriorate when desiccated to levels consistent with those observed in the field. [ABSTRACT FROM AUTHOR]

Provides information on a research regarding the chemical feeding deterrent properties of the benthic algae Phyllopora antarctica and Iridea cordata from McMurdo Sound in Antarctica. Significance of P. antarctica and Iridea cordata to the sea urchin Sterechinus neumayeri in the area; Evaluation of the phagostimulatory responses of S. neumayeri to both fresh algae and algae that had been extracted to remove secondary metabolites; Findings of the study concerning the presence of bioactive secondary metabolites in P. antarctica.