Volume 45, Issue 1

The polysaccharides from Chondria macrocarpa and Ceramium rubrum were examined by 13 C NMR spectroscopy and their spectra were analysed bymeans of set theory. The spectra of the polysaccharides from Chondria macrocarpa collected in autumn were in accord with previous chemical analysis but polysaccharides from seaweed collected in spring comprise a higher level of agar precursors, much lower levels of galactose 2-sulfate, and the polysaccharide is separable into two components, the predominant one of which is essentially free of anhydrogalactose. The signal subset due to the xylosyl unit substituted at the 3-position of 4-linked l-galactose could be assigned from the spectrum of desulfated polysaccharide from Chondria macrocarpa . The extract from Ceramium rubrum consisted of a backbone of 3-linked d-galactosyl units alternating with the 4-linked units 3, 6- anhydro-l-galactosyl and l-galactosyl in a ratio of 2:1 respectively, to which substitution by xylose occurred at approximately 8% of the total sugar units. The natural polymer had moderate levels of sulfate ester, with galactose-6-sulfate being the predominant unit, some of which survives alkaline treatment and was consistent with being 3-linked. There is also evidence of low levels of 3-linked galactose-2-sulfate.

Dried and ground material of the brown alga Ecklonia maxima and the waste product from the manufacture of Kelpak, a seaweed concentrate used in agriculture, have previously been shown to be effective biosorbents of heavy metals. The recovery of bound cadmium and the subsequent reuse of the biosorbents were investigated. Acids (HCl, HNO 3 and H 2 SO 4 ) and the chloride salts (NaCl and CaCl 2 ) were more effective at desorbing cadmium ions than the carbonate salts (NaHCO 3 and K 2 CO 3 ) and the chelator Na 2 EDTA. The optimum concentration of the acids for desorption was between 0.01M–0.1M. Depending on the acid and concentration used for desorption, optimum time for desorption ranged from 30 min to 2 h. The sorbent derived from ground Ecklonia maxima could be used for more than four adsorption-desorption cycles whereas the sorbent derived from the Kelpak Waste could only be used effectively for up to three adsorption-desorption cycles.

Nineteen species of marine macrophytic algae collected in Bodega Bay, California were investigated for their fatty acid composition. Red, brown and green algae have distinguishing fatty acid profiles, which have a chemotaxonomic significance for seaweeds. This does not depend on the geographical location of the algae. Algal habitat conditions affect quantitative characteristics of the fatty acids. The content of polyunsaturated fatty acids in algae from California was found to be noticeably higher formost of the algal species examined in comparison with the same or related species from other regions.

Fluctuations in nitrogen and carbon compounds were examined over an autumn growing season in the submersed marine angiosperm Zostera marina L. (eelgrass). The experimental design included replicated controls (ambient NO 3 − , typically < 2 μM), increased water-column nitrate (8 μMNO 3 − above ambient, pulsed daily), increased environmental temperature (3 to 4 °C above 20-year weekly means), and combined increased water-column nitrate and temperature. Above- and belowground tissues were collected weekly to biweekly and assayed for total soluble carbohydrates, non-reducing carbohydrates, starch, α-cellulose, lipids, free amino acids, total protein, tissue nitrate, tissue nitrite, and tissue ammonium. Tissue nitrate declined, and amino acids, proteins, lipids, and cellulose increased as the growing season progressed in both control and treated plants. In addition, there were seasonal quadratic responses for tissue ammonium, soluble carbohydrates, and non-reducing sugars, with maxima during periods of optimal plant growth (mid- to late September). Increased temperature promoted periodic increases in amino acids and soluble carbohydrates, but decreased accumulation of α-cellulose by the end of the experiment. Moreover, increases in water-column nitrate led to periodic increases in tissue ammonium and amino acids, as well as decreases in non-reducing sugars. Toward the end of the experiment, increases in soluble carbohydrates for plants grown under higher temperatures may have been associated with an extension of the growing season. In contrast, decreased non-reducing sugars in nitrate-enriched plants may have resulted from an increased carbon demand during nitrate assimilation/reduction, as well as a reallocation of carbon to enhance amino acid synthesis.

Nine species of sublittoral and deep-water red and brown algae are reported from the Canary Islands for the first time. The reports of the Western Atlantic species Gloiocladia atlantica (Searles) R.E.Norris and Rosenvingea antillarum (P. et H.Crouan) M. J.Wynne are the first from the Eastern Atlantic Ocean. The presence of Feldmannophycus rayssiae (J. et G. Feldmann) Augier et Boudouresque, Fauchea repens (C.Agardh)Montagne et Bory and Halichrysis depressa (J.Agardh) F. Schmitz, previously known from the Mediterranean Sea and the adjacent Atlantic coasts, place their southernmost known limit of distribution in the Canary Islands. Stypopodium schimperi (Buchinger ex Kützing) Verlaque et Boudouresque is reported for the first time in the Atlantic Ocean, although it is present in the Mediterranean Sea, probably as a Lessepsian species. The records of the widely distributed Stylonema cornu-cervi Reinsch, Acrochaetium infestans M. Howe et Hoyt and Spatoglossum schroederi (C. Agardh) Kützing were not unexpected. Data concerning morphology, habitat and geographical distribution of these species are presented. Observations on the scantly documented sublittoral species Schimmelmannia schousboei (J.Agardh) J.Agardh and Dictyopteris plagiogramma (Montagne)Vickers are also given. In the dioecious Schimmelmannia schousboei , which has been formerly accepted as a doubtful record for the Canary Islands, the reproductive morphology is described including the previously unreported spermatangia. Dictyopteris plagiogramma was recently included in a checklist of Canarian species of Dictyopteris and is discussed in detail here.

Six thraustochytrids ( Schizochytrium sp. KF-1, Schizochytrium mangrovei KF-2, KF-7, KF-12, Thraustochytrium striatum KF-9 and Ulkenia KF-13), isolated from fallen, senescent leaves of the mangrove tree Kandelia candel in Hong Kong, were identified and characterised in pine pollen seawater culture. Yeast extract peptone glucose seawater broth was used for growth studies. The pH range for growth was from 4 to 9 with optima from 4 to 7 for Schizochytrium species (KF-1, 2, 7, 12) and 5 to 6 for Thraustochytrium striatum KF-9 and Ulkenia sp. KF-13. Temperature and salinity optima for isolates KF-2 and KF-7 were at 25 °C and from 22.5–30% respectively while isolate KF-12 had a temperature optimum from 20–25 °C and salinity optima from 7.5–30%. Thraustochytrium striatum KF-9 and Ulkenia sp. KF-13 showed strong growth at 25 °C and 15–30%.

The lipid classes and fatty acid profiles of macrophytic algae from the Phaeophyta ( Egregia menziesii ), Rhodophyta ( Chondracanthus canaliculatus ) and Chlorophyta ( Ulva lobata ) were determined. Ulva lobata contained the highest amounts of lipids (20–29 mg g −1 dry mass), followed by Egregia menziesii (9–16 mg) and Chondracanthus canaliculatus (2–3 mg), with increased lipids in winter and spring. This was reflected in total fatty acid content (14–24, 6–13 and 1–2 mg g −1 dry mass, respectively).Major lipid classes were polar lipids (44–94 % of total lipids) and sterols (3–8%). Higher levels of triacylglycerols occurred in Egregia menziesii during spring (22%) and in Ulva lobata during summer (12%). Free fatty acids were also variable (0–26 %). Triacylglycerols were not detected in Chondracanthus canaliculatus . Low levels of wax esters and diacylglyceryl ethers were detected in Ulva lobata (0.1%). The major fatty acid common to all species was 16:0. Egregia menziesii and Chondracanthus canaliculatus contained 14:0, 18:1(n-9), 20:4(n-6) and 20:5(n-3) as major components. Egregia menziesii and Ulva lobata also contained 18:2(n-6), 18:3(n-3) and 18:4(n-3), and Chondracanthus canaliculatus and Ulva lobata contained 18:1(n-7). Large amounts ofC16 polyunsaturated fatty acids and the presence of 22:0 and C22 polyunsaturated fatty acids were unique to U. lobata . Knowledge gained regarding macroalgal lipid composition may prove useful in raising mariculture species.

Polysiphonia morrowii Harvey (Rhodophyta), native to Japan, Korea, China and Russia, is here reported for the first time from the Mediterranean Sea. Thalli were first found in 1999 off the Island of Chioggia, where imported clams and fish are handled; the following year, plants were also found near the Island of Venice itself. Polysiphonia morrowii is similar to Polysiphonia senticulosa Harvey, as reported from Japan and the north Pacific, and to Polysiphonia stricta (Dillwyn) Greville [= Polysiphonia urceolata (Dillwyn) Greville] from the Mediterranean basin. The specimens collected in the Lagoon of Venice are characterised by two of the most significant specific features of P.morrowii : endogenous axillary branchlets forming from the central axial cells, and tufts of axillary tetrasporangial branchlets on the axils of mature plants. The morphology and reproduction of P. morrowii are examined on the basis of the material collected at Venice.

In this study, we present the results of a 14-month field experiment on the effects of the introduced alga Caulerpa racemosa on two co-occurring native seagrasses, Cymodocea nodosa and Zostera noltii . The experiment was conducted in a mixed shallow seagrass bed along the Tuscan coast (Italy) that has been invaded by the alga since 1995. Treatment consisted of the manipulation of the presence of the alga (presence vs. removal). Response variables considered for Cymodocea nodosa were shoot and flower (both male and female) density and for Zostera noltii were vegetative and reproductive shoot density, the first species being dioecious and the latter monoecious. Results have indicated that the presence of the alga influences shoot density of both plants. With Cymodocea nodosa the shoot densitywas lowered andwith Zostera noltii it was increased in areas invaded by the alga. Both Cymodocea nodosa flower density and Zostera noltii reproductive shoot density were found to be significantly higher where Caulerpa racemosa was present relative to where it was removed. Hence, different effects, either positive or negative, of the alga were found depending on the species and response variable. Potential mechanisms of interaction are discussed.

Dipterocladia arabiensis sp. nov. is described on the basis of specimens collected from the Dhofar and Al Wusta regions of southern Oman. Observations are made on cystocarpic and tetrasporangiate specimens occurring from the shallow sublittoral to a depth of 17m. The new species differs from the two previously known species of Dipterocladia by themuchmore robust size of the thalli, the higher order of branching, and the relatively smaller sizes of both the pseudolaterals and the tetrasporangia. In the new species all of the polysiphonous sympodial axes are indeterminate, unlike D . pulchella , in which there is a distinction between determinate and indeterminate sympodial axes, whereas D . pinnatifolia is intermediate with respect to this feature. Prior collections of this alga from Oman have been cited as ‘ Rhodoptilum plumosum ?’.

Taxonomic uncertainty still exists in the Rhodophyta, and more suitable molecular markers for their phylogeny are required to establish conclusively their taxonomic relationship. In this paper, we describe sequencing, characterisation of partial nucleotide sequence of the TOP2 and phylogenetic analysis of the Top2, which is translated from the TOP2 in Porphyra yezoensis . The length of the partial nucleotide sequence of TOP2 was 1,208 bp and the predicted amino acid sequence was 402 amino acids. The present sequences matched to known TOP2 or Top2 sequences in the public databases and consensus sequences for the motifs [Top2 signature, ATP/GTPbinding site motif A (P-loop), etc.] are indicated in the amino acid sequences. In our phylogenetic trees, the Rhodophyta occupied an independent position within the crown eukaryotes. Thus, we can advocate that we succeeded in the determination of TOP2 and Top2 sequences of P. yezoensis andTop2may be a promising marker for phylogenetic analysis of the Rhodophyta. This is the first report to deal with Top2 from the Rhodophyta.