Volume 50, Issue 2

The spatial and seasonal changes of total non-structural carbohydrate (TNC) reserves in above- and belowground tissues in eelgrass ( Zostera marina ) were assessed at four different sampling sites in Danish waters. The study consisted of annual field sampling, where sites differed in water depth and nutrient content in sediments. The TNC concentrations varied considerably in all tissues, and rhizomes generally represented the major storage organ. Sucrose was the main sugar contributing to TNC whilst starch represented the minor (<15%) reserves. Trehalose, which is reported in Z. marina here for the first time, due to the use of a recently developed HPLC method, was found in low concentrations (up to ∼2%) and showed a reverse seasonal variation compared to other sugars, with maximum concentrations in winter. Plants growing near depth limits (5.5 m) had significantly higher reserves, whereas no significant effect of sediment nutrient contents on the TNC concentrations was observed, reflecting the ability of Z. marina to tolerate a range of different growth conditions.

Diversity, abundance and distribution of intertidal macroalgae were investigated in relation to environmental conditions (site, shore level, salinity, temperature, NO 3- and ) in Sirinart Marine National Park, Phuket province, Thailand, from January to November 2004. The shores were divided into 3 categories by shore level: upper, mid and lower shores; and 3 sampling sites: sites 1, 2 and 3. A total of 52 species of macroalgae were recorded. Nine species are considered to be new records for the Thai marine flora. The average diversity index of macroalgae differed slightly among sites: 0.92±0.07 (mean±SE), 1.00±0.13 and 0.94±0.16 for site 1, site 2 and site 3, respectively. There was significant difference in abundance of macroalgae among sites and seasons. Lyngbya majuscula and Padina australis were the most abundant species. Their percentage covers were 31.66±7.21% and 27.77±4.67% in site 2 at mid shore level during March 2004 and in site 3 at mid shore level during November 2004, respectively.

Changes in spore abundance of the blade-forming Sarcothalia crispata and crustose coralline seaweeds were determined to relate height above the substratum at which propagules are liberated with their dispersal potential. Recruit density was quantified on artificial substrata at the surface of the water column, mid-water, and seafloor. Spore abundance was determined in water samples obtained at the same levels during periods of calm and rough seas. Spore density was also determined along a transect running perpendicularly to the shore. Density of recruits S. crispata increased with depth, whereas coralline recruits were abundant at the seafloor level. During calm seas, spore density of S. crispata and crustose corallines increased with depth, but the latter were more variable. During rough seas, spore density was very high; spores of S. crispata increased toward the surface, or were homogenous in the water column, whereas distribution of crustose coralline spores was more variable. Finally, density of crustose coralline spores decreased more abruptly with distance from the shore than that of the bladed species. These results strongly suggest that the height at which spores are released (a correlate of algal morphology) influences spore distribution in the water column and the dispersal potential.

Nitrate reductase (NR; EC 1.6.6.1) of the marine red macroalga Kappaphycus alvarezii was examined in algae maintained under L:D and constant light conditions. Undenaturated protein had a molecular mass of about 210 kD (±23 kD); based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting techniques, the enzyme appears to be composed of two possibly identical subunits of 100 kD. The NR of K. alvarezii was recognized by 10 out of 17 monoclonal antibodies raised against the NR from the red alga Porphyra yezoensis. Basal parts of the algal thallus had higher NR protein content, although the highest activity of NR has been located previously in the apical thallus parts, suggesting a post-translational regulation. The cellular expression of NR exhibits a daily rhythm. In extracts of algae grown under either constant light or a light:dark cycle, staining with antibodies NR 6 and NR 10 showed that the amount of protein varied by a factor of about 2, with the maximum occurring in the early day phase.

Filaments were induced from cut edges of segments of Gloiosiphonia capillaris, Gloiopeltis furcata, Chondrus ocellatus, Solieria tenuis, Ceramium kondoi, Chondria tenuissima, Laurencia okamurai and from the intact surfaces of Ceramium kondoi and Chondria tenuissima under unialgal culture conditions. The filaments of Gloiosiphonia capillaris can grow vegetatively under free-living conditions, while filaments of Gloiopeltis furcata tended to differentiate after excision from explants and grew autotrophically to the 10- to 20-cell stage. Filaments of other species usually survived attached to generating explants. Two distinct modes of filament regeneration were discerned among the species. In Gloiosiphonia capillaris, Gloiopeltis furcata, Chondrus ocellatus and Solieria tenuis , filaments initially developed into crust or crust-like compact tissue in suspension culture; upright thalli developed from the crusts. In Ceramium kondoi, Chondria tenuissima and Laurencia okamurai , thalli were generated from pseudoparenchyma that was developed from filaments, while creeping parts (rhizoids) formed a prostrate system.

Four species of marine algae are reported from the Canary Islands for the first time. Our report of the western Atlantic Gelidiella setacea (Gelidiales, Rhodophyta) is the first from the eastern Atlantic Ocean. Pseudotetraspora marina (Tetrasporales, Chlorophyta) previously known on the eastern side of the Atlantic Ocean from temperate saltmarshes only, is now reported growing in the shallow sublittoral zone, the habitat in which tropical western Atlantic populations also occur. The presence of Lomentaria chylocladiella (Rhodymeniales, Rhodophyta) represents the first report in the Atlantic Ocean of a species previously thought to be endemic to the Mediterranean Sea. The record of the widely distributed Acrochaetium hallandicum (Acrochaetiales, Rhodophyta) was not unexpected. Specimens of A. hallandicum have vegetative cells with a single lobate parietal chloroplast with a single pyrenoid, a feature that among acrochaetioid algae occurs exclusively in the genus Colaconema (Colaconematales), and consequently the species is transferred to this genus. Fertile sporophytes are described for Gelidiella setacea , a species previously known only in its vegetative condition. Cruciately to irregularly divided sporangia are regularly arranged in transverse rows in stichidia laterally formed on the axes. The species is transferred to the genus Parviphycus on the basis of the morphology of the stichidia and the distichous pattern of apical division exhibited by the axes, both exclusive features of this genus.

Griffithsia aestivana sp. nov. is described as an endemic from Bermuda. Vegetatively, it is most similar to G. capitata from the eastern Atlantic Ocean, but the two differ in overall size and in the tetrasporic state. Eleven other marine algal taxa are reported from Bermuda for the first time: Anadyomene howei, Struvea elegans, Cladophoropsis macromeres, Derbesia turbinata, Caulerpa racemosa var. lamourouxii, Halimeda discoidea, Chrysymenia nodulosa, Gloiocladia iyoensis, Dasya caraibica, Chondrophycus iridescens and Polysiphonia scopulorum . All except D. turbinata represent new northern limits of distribution in the North Atlantic Ocean. In addition, recent Bermuda collections of the alien Mediterranean Cystoseira compressa and the rarely found Womersleyella setacea are detailed.