Band 66, Heft 6

Marine prairies play various crucial roles in marine ecosystems. The seagrasses that compose them are one of the most important components engineering the marine coastal system, providing significant spatial niches. Some of the seagrasses found in marine prairies are protected, and it is not recommended to sample them with destructive methods. Non-destructive methods such as remote sensing have been proposed as important means of studying these protected species. In the present study, the acoustic scattering properties of Cymodocea nodosa were studied with two different in / ex situ experiments conducted on a Turkish Mediterranean coast using a scientific echosounder (206 kHz split beam transducer) in different months over the years 2011 and 2012. After a series of acoustic processes, correlations and regression equations were established between different acoustic parameters of the Elementary Distance Sampling Units and biometric traits of below/above ground parts of the seagrass. The relationships were logarithmically established producing first a Rayleigh zone, followed by a geometrical zone that occurred with increased biometrics. No seasonal difference occurred in the relationships for the above-ground parts. Unlike the leaves, seagrass sheaths demonstrated unstable echo energy, inconsistent relationships, and unexplained acoustic responses over the span of several months. Regarding leaf density changing in time, significant relationships were explained as a function of the acoustic zones. Four points were highlighted to explain the differences in the estimations between the two experiments; i) the backscattering strengths depended on strength of biomass and its fractions (leaf area, shoot density and volume) between the two experiments, ii) the first experiment measured backscattering strength from individual specimens, but the second experiment was performed on the total biomass of seagrass per unit area, iii) different frequency response to the biometrics occurred in the two experiments, and iv) the non-linear effect of the sheath could not be separated from that of the leaf during the second experiment. The present study was the first attempt to characterize relationships between the biometric and acoustic backscattering properties of C. nodosa , and will guide researchers in future use of non-destructive methods.

The identification of macroalgal species within the Laurencia complex is challenging, due to the presence of inconspicuous morphological characters, extensive variation in these traits and a diverse biogeography. Moreover, for a number of these species, no DNA sequence data are available in online databases. For this study, five algal specimens, tentatively assigned to Laurencia , were collected from Malta in the central Mediterranean Sea and studied using an integrative systematics approach. An analysis of the data resulted in the description of a new species, Laurencia mediterranea using combined morphological and molecular criteria, including COI-5P and rbc L. Morphologically L. mediterranea sp. nov. was distinct from other Laurencia spp. in the type of holdfast, the colour and shape of the thallus, the presence of secondary pit connections, lenticular thickenings and ‘corps en cerise’ . Moreover, a new genetic species cluster indicated a separate taxon at the species level. Our study demonstrates that genetic sequences having clear links to sample metadata and digital herbaria are indispensable for macroalgal biodiversity research. This approach could offer a solution for algal taxonomy in cases where biogeography is important and limited sequence data exist in online DNA libraries.

Gelidiella acerosa is a widely distributed species, with type locality in Yemen, whose morphology has been characterized by decumbent axes from which numerous abundantly branched erect axes emerge, pectinate, alternate or radial. Recent phylogenetic studies have revealed the presence of genetically independent groups throughout its distribution range. However, these groups cannot be described as independent since there are no sequences from the type locality that allow us to establish the genetic group to which the true G. acerosa belongs, generating a complex of cryptic species. In the present study, from COI-5P and rbc L sequence data, we detected six genetically differentiated groups, one of which is represented only by specimens from the Western Atlantic region. Given the allopatric pattern, it is possible to describe the Atlantic group as an independent species of the cryptic complex in the Indo-Pacific. Gelidiella papillosa sp. nov. shares several morphological features with other specimens previously identified as G. acerosa in other countries, like the appearance of the thallus, branching patterns, the presence of multiple superficial hairs on the branches or cell measurements. However, these characters have not been evaluated in detail among the different genetic groups within Gelidiella acerosa , consequently, G. papillosa can be supported only by its genetic independence and allopatric distribution.

The records of the unarmored dinoflagellate Gynogonadinium aequatoriale have been restricted to the western equatorial and the eastern tropical Pacific Ocean. The genus is reported for the first time in the Mediterranean Sea from the coast of Taranto, Ionian Sea. This is a distinctive taxon that can only be confused with the cosmopolitan Pseliodinium fusus (= Ceratoperidinium falcatum ). A comparison of these two species is provided.

Species of the dinoflagellate genus Alexandrium are marine and planktonic forms, widely distributed, and some are recognized to form harmful algal blooms and to produce saxitoxins causing Paralytic Shellfish Poisoning in humans, and other toxins. We studied the species composition of Alexandrium in tropical and subtropical coastal areas of the Mexican Pacific: from the southern Gulf of California to the Gulf of Tehuantepec. Eleven Alexandrium species were identified, described, and illustrated using light microscopy, and occasionally scanning electron microscopy for certain species. Additionally, the genetic characterization of seven strains and four species, was performed, using sequences of the D1/D2 LSU rDNA and ITS regions. We identified the species (morphospecies): Alexandrium affine , A . gaarderae , A . globosum , A . leei , A . margalefii , A . minutum , A . monilatum , A. pseudogonyaulax , A . tamarense , A . tamiyavanichii , and A . tropicale . Of these, A. affine , A . leei , A . minutum , A . monilatum , A. pseudogonyaulax , A . tamarense and A . tamiyavanichii have been widely recognized as harmful algae. Alexandrium gaarderae , A . globosum and A .  tropicale are new records for the Mexican Pacific. This is the first morphological documentation of A. pseudogonyaulax . Future studies of the genus might increase its species richness if more cultures are established and metabarcoding approach is used.

Unialgal stock cultures for seeding the tank water can be used for the mass cultivation of seaweeds in artificial seawater, as in microalgal mass cultivation. High costs for artificial sea salt mixtures and distilled water would be required, however, to use artificial seawater in big tanks for commercial purposes, but frequent medium changes may not be required, since the major ions contained in artificial seawater, such as sodium, will barely be utilised by the cultured algae during long periods of time, even over years. Similar growth rates were obtained at the start and end of an experiment conducted with Ulva pseudocurvata cultivated unialgally for two years without water change, at a low algal density and with weekly addition of Provasoli Enrichment. Growth in this experiment was increasingly impeded due to gamete swarming events causing dark greenish water every few weeks. The experimental water had then to be boiled in order to kill the gametes. In a second experiment, this time performed at a high algal density, maximum yield values were 20–30 g fresh weight m −2  d −1 , both for 2-year-old and newly prepared artificial seawater. These results verified the hypothesis that long-term Ulva cultivation in artificial seawater is possible without frequent medium changes.

Crypthecodinium cohnii strains can accumulate significant amounts of lipids with a high fraction of docosahexaenoic acid that is used in pharmaceutical and nutraceutical applications. In this study, macroalgal hydrolysate was used as a low-cost carbon source for the growth of the oleaginous strain Crypthecodinium sp. AL–05 to reduce the cost of its growth and lipid production. The Saudi strain was placed in the genus Crypthecodinium with high statistical support based on the sequences of three concatenated genes (SSU, ITS, and LSU rDNA). Crypthecodinium sp. AL-05 was grown on four different glucose concentrations and three different macroalgal hydrolysate concentrations: 20, 40, and 80 g  l −1 . We also used the same concentrations of macroalgal hydrolysate with 10 g  l −1 of four carbon sources: acetic acid, glycerol, glucose, and sugarcane molasses. Glucose (40 g  l −1 ) gave the best results, followed by 80 g  l −1 macroalgae alone and with glucose or molasses. One-way ANOVA followed by a Bonferroni correction post-hoc test showed that the dry weight of Crypthecodinium sp. AL–05 produced using the following carbon sources: the four concentrations of the pure glucose, 80 g  l −1 macroalgae alone, 40 and 80 g  l −1 macroalgae + glucose, 40 and 80 g  l 1 macroalgae + molasses were significantly higher than the other 10 carbon sources tested. Three carbon sources (20 g  l −1 macroalgae with glucose, molasses and acetic acid) produced percentages of lipids that were significantly lower than the other 16 carbon sources. For the first time, our research shows that the dinoflagellate Crypthecodinium AL–05 can be successfully grown on macroalgal hydrolysate, which can be used in industrial processes. Importantly, Crypthecodinium sp. AL–05 grown on 80 g  l −1 macroalgae produced only saturated fatty acids, of which caprylic acid represented 43.45 % of the total fatty acids. Caprylic acid is widely used in industry and pharmaceuticals and the Saudi isolate can be used for its commercial production using macroalgae as a carbon source.

The present review documents the diversity of marine fungi collected in Portuguese marine environments (sandy beaches, salt marshes and marinas) from studies over the past 30 years and results from new data. One hundred and ninety fungal species are reported (mainly identified by morphology, with 63 species at the same time identified by molecular approaches), of which 156 are currently listed as marine fungi in www.marinefungi.org. Twenty-two new species are exclusive to Portugal. Substratum specificity was observed in Portugal for 77 marine species but reduced to 26 considering the occurrence on multiple substrata for some of these species reported in other parts of the world. Worldwide data also confirmed a core group of more than 20 generalist marine fungi, which colonized the different categories of substrata (woody, herbaceous, and other marine sources). Most marine species are exclusively saprobes (100) or saprobe/parasite/pathogen (27). Temperate (85) and cosmopolitan (45) species are dominant, but some species were also found in tropical or tropical/subtropical regions (7 and 4, respectively). Ascomycota species were the dominant group (184), mostly as asexual morphs (120); with few Basidiomycota (5 species) and Mucoromycota (1 species). Acrostalagmus luteoalbus , Cladosporium tenuissimum , Nigrospora sphaerica , Scedosporium boydii , Stemphylium vesicarium , and Trichoderma lixii are new records for Portugal. Other species were isolated in Portugal for the first time on new substrata: Stachybotrys chartarum (from seawater), Corollospora maritima and Zalerion maritima (from sand), and Lulworthia cf. purpurea (from a drift culm).

Although many novel marine fungi have been described from Indian mangroves, a significant number of mangroves in India have not been thoroughly investigated for marine fungi. This study highlights the diversity of marine fungi inhabiting dead and decaying wood of Avicennia marina and Rhizophora mucronata, collected from Thengaithittu and Veerampattinam mangroves of Pondicherry, Puducherry State, India. Through microscopic examination, a total of 52 species (in 48 genera) of marine fungi were identified, with 50 species (in 46 genera) belonging to the Ascomycota and 2 species (in 2 genera) belonging to the Basidiomycota. Previous studies recorded 69 marine fungi from Ariyankuppam and Mahé mangroves of Puducherry, and this study contributes 22 new records of marine fungi to this region. In this study, the phylogenetic placement of Rhizophila marina was determined, and this fungus was found to belong to the family Diatrypaceae.