Volume 53, Issue 1

Marine species of Prasiola are most common on rocky shores of the North Atlantic and North Pacific Oceans. Prasiola linearis is a little-known member of this group, whose known distribution is restricted to coastal marshes of Pacific North America. The little information available on this species is mostly based on the original description; its life history has not been previously reported. Reproduction and life history were investigated in a series of experiments conducted in different combinations of culture medium, temperature, daylength and photon irradiance. The alga reproduced by aplanospores that were produced in the apical part of the blade. Upon release, each aplanospore reproduced a new thallus; sexual reproduction, which occurs in other marine species of Prasiola ( P. stipitata and P. meridionalis ) was not observed in P. linearis . No variation in reproductive patterns was observed between different combinations of factors tested; however, the alga showed very weak growth at 20°C. The life history of Prasiola linearis consists of a repetition of the same morphological phase reproducing by aplanospores. The diversity of life histories observed in marine species of Prasiola is illustrated and discussed.

There is confusion about the identity of laminar Ulva thalli in Italian and Mediterranean transitional systems and on the open coasts. Although some authors report the presence of both U. rigida and U. laetevirens , systematic revisions for the Adriatic and Mediterranean Seas recognise only the presence of U. laetevirens . This paper uses anatomical and environmental analyses to provide evidence for the presence of both species. The only diagnostic character that distinguishes the two is cell shape in cross section of rhizoidal and basal regions. Therefore, identification of floating thalli in these regions is not possible. The species grow and coexist in the same environments and on the same substrata, but analysis of environmental data suggests that U. rigida occurs preferentially in eutrophic environments, especially lagoon areas rich in phosphate, ammonium and phytoplankton, whereas U. laetevirens is more abundant in areas where nutrient levels are low.

The marine flora of Wake Atoll is phytogeographically interesting because the atoll is a small (6.5 km 2 ) isolated coral reef structure located in the central Pacific between the north-western Hawaiian Islands and the Marshall Islands. Eighty-one of the 103 species of subtidal marine benthic algae collected in October 2005 and April–May 2007 during two NOAA cruises to Wake Atoll represent new records for the atoll. Previously published collections include five species collected in December 1841 during the US Exploring Expedition, 35 additional species representing collections made in June 1998 by US Fish and Wildlife personnel, and incidental specimens collected by various biologists and deposited in the Herbarium Pacificum of the Bishop Museum, Honolulu. The 121 species of marine benthic algae now documented from Wake Atoll contain components from the Hawaiian Islands and Marshall Islands, but show a closer resemblance to those of the Hawaiian Archipelago.

Palisada flagellifera (Ceramiales, Rhodophyta) is recorded for the first time in the eastern Atlantic Ocean off Tenerife, La Gomera, La Palma and Fuerteventura, Canary Islands, Spain. The specimens were collected in 2006–2009 growing from the lower intertidal to subtidal zones to 2 m depth at sites exposed to wave action. The species possesses a palisade-like arrangement of cortical cells in cross section, lacks secondary pit connections between them, and has tetrasporangia produced by three fertile pericentral cells (the third and the fourth additional and the second that becomes fertile), and a right-angled arrangement of tetrasporangia. Gametangia were not observed. The phylogenetic relationships were inferred by analyses of the chloroplast-encoded rbc L gene sequences from 46 taxa. The Canarian and Brazilian P. flagellifera specimens formed a highly supported clade with a low level of genetic variation in the rbc L sequences (0.02–0.04%), confirming that they are the same taxonomic entity. This study expands the geographical distribution of P . flagellifera to the eastern Atlantic Ocean.

We studied crustose seaweeds associated with subtidal maërl beds and gravel bottoms in the Galician rías (NW Iberian Peninsula). Each species is described as well as its habitat and occurrence in maërl beds and gravel bottoms. We confirmed the great crustose species richness associated with European Atlantic maërl beds. We report a new species for the Atlantic Ocean ( Contarinia peyssonneliaeformis ) and six new records for the Iberian Peninsula ( Atractophora hypnoides stage “ Rhododiscus pulcherrimus ” , Peyssonnelia immersa , Scytosiphon lomentaria stage “ Microspongium gelatinosum ” , Petroderma maculiforme, Pseudolithoderma roscoffense and Phycocelis foecunda ). Peyssonnelia armorica is a new record for the Atlantic Iberian Peninsula and Peyssonnelia harveyana is a new record for the Galician coast. We provide for the first time observations on spermatangial structures in Cruoria cruoriaeformis occurring on the Atlantic Iberian Peninsula. The Galician crustose algal flora of subtidal maërl beds and gravel bottoms is increased up to 23 species (15 Rhodophyta and 8 Ochrophyta). Peyssonnelia rubra is excluded from the Galician flora.

The genome DNA required for molecular studies of Porphyra has generally been extracted from either blades or free-living “ Conchocelis ”. However, the main disadvantages are complicated procedures, high cost, and DNA contamination. In this study, we developed a strategy for pure DNA extraction from shell-boring “ Conchocelis ” and a single-step technique to prepare PCR templates. The results show that contamination of free-living “ Conchocelis ” with microalgae was eliminated after the filaments had bored into shells. The electrophoretic banding patterns and intensities were similar between materials obtained from free-living “ Conchocelis ” and shell-boring “ Conchocelis ”, suggesting that total DNA extraction from the latter was efficient. Molecular evidence demonstrated additional bands in PCR products of internal transcribed spacer (ITS) amplifications prepared from cultures of free-living “ Conchocelis ” contaminated with microalgae. The additional bands appeared in all three Porphyra yezoensis replicates and one out of three Porphyra haitanensis replicates, but were not detectable in preparations from shell-boring “ Conchocelis ”. The DNA extracted from shell-boring “ Conchocelis ” reduced the risk of microalgal contamination and the single-step technique reduced the time required for the preparation of DNA for molecular studies of Porphyra . The single-step method should be useful for PCR amplification of small amounts of materials, large sample sizes, or samples contaminated with microalgae. The technique may also be suitable for other genera of Bangiaceae, providing that shell-boring “ Conchocelis ” stages are present in their life cycles.

A new lectin from the red alga Tichocarpus crinitus (TCL) was purified and partially characterized. The purification procedure consisted of extracting soluble proteins with 0.025  m Tris-HCl buffer (pH 7.5), followed by ammonium sulphate precipitation (75% saturation), hydrophobic interaction chromatography on phenyl-Sepharose and gel filtration chromatography on Superdex 75 HR 10/30. TCL is a monomeric protein with a relative molecular weight of 41,000, as shown by gel filtration and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) in the presence and absence of β-mercaptoethanol. Isoelectric focusing showed that TCL is an acidic protein with an isoelectric point (pI) of 4.93, and analysis of its amino acid composition revealed high contents of acidic amino acids (aspartic and glutamic acids), serine, threonine, proline and alanine. Its activity was not inhibited by any of the monosaccharides tested, but was inhibited by the complex glycoproteins porcine stomach mucin (type VII) (PSM) and fetuin, and was independent of divalent cations. The carbohydrate content of 6.9% suggested that the lectin is a glycoprotein. TCL had a weak mitogenic effect on human lymphocytes and an ability to stimulate synthesis of pro-inflammatory cytokines TNF-α, IFN-γ, IL-6 by human whole-blood cells.

We studied mangrove vegetation at Tumpat to estimate different tree structural parameters (e.g., stem density and basal area) at selected sites (PCQ method). There were five dominant taxa in the vegetation, i.e., Sonneratia caseolaris , Nypa fruticans , Avicennia alba , Rhizophora mucronata , and Bruguiera gymnorrhiza in order of importance. Total tree density varied between 79 and 132 stems 0.1 ha -1 , and basal area from 0.14 to 4.9 m 2 0.1 ha -1 . Based on species composition and stem density, the mangrove sites were separable into two groups (Bray-Curtis similarity: 60%). While Group-1 (sites G9, J5, K4, N6 and O4), dominated by S. caseolaris and N . fruticans , was distributed throughout the forest, Group-2 (sites C6 and G6), represented largely by A. alba , was present close to the bay-mangrove boundary. Elevation measurements indicate that Group-1 species occupied low-lying to elevated grounds (0.87–2.23 m above mean sea level) with a (mean) salinity between 0.38 and 14.6 psu, whereas Group-2 occurred preferentially at low to medium elevations (0.86–1.29 m) and high salinity (14.6 psu). Discrete mangrove associations (=groupings) were discerned, wherein the distribution of species was governed by factors such as proximity of land or sea, freshwater input and elevation.

Worldwide, seagrasses face threats including climate change, disease and anthropogenic disturbance, with populations at the extremes of species’ distributions likely presaging future problems elsewhere in their geographical ranges. At the geographic limits of two marine macrophytes ( Zostera marina and Posidonia oceanica ) and under intense urbanization, seagrasses around Gibraltar are particularly vulnerable. However, the last published survey of Gibraltar seagrass meadows, in 1993, showed both species were abundant. We resurveyed this area and were unable to locate any seagrass in Gibraltar waters. Extensive coastal development and land reclamation make much former seagrass habitat in Gibraltar waters unsuitable, presenting substantial hurdles to any future restoration efforts.

Leaf reddening is well documented in terrestrial angiosperms, but has rarely been reported in seagrasses. In a survey of the world's six seagrass bioregions, we documented leaf reddening in 12 seagrass species from intertidal and shallow subtidal waters at 25 locations in the tropical Atlantic and tropical Indo-Pacific Oceans. Including additional observations of seagrasses with reddened leaves from Australia, the phenomenon is now documented in 15 seagrass species at 29 locations worldwide. Similar to terrestrial angiosperms, leaf reddening in seagrasses may relate to enhanced production of anthocyanins after exposure to one or more stressors.

We report here the effect of one form of disturbance, boat propeller scarring, on genetic variation in the subtropical seagrass Halodule wrightii . We developed an amplified fragment length polymorphism assay to measure genetic variation in plots representing four levels of scarring intensity: reference (0% scarring), low (1–5%), moderate (5–15%) and severe (>15%). Although we found severely scarred plots to have the lowest, and moderately scarred plots to have the highest, mean genetic diversity estimates ( H e , P ), differences among scarring levels were found to be non-significant (α=0.05). Analysis of molecular variance also showed no significant effect of scarring intensity. While propeller scarring can cause significant habitat loss, scarring intensities of up to 20% may not yet have seriously affected those factors (population size, flowering density, recruitment, gene flow) that strongly influence population genetic variation. The relatively recent occurrence of this type of disturbance, however, could mean that any long-term effects have yet to be detected.