Volume 61, Issue 2

Extensive offshore meadows of Halimeda incrassata are documented for the first time in sandy bottoms of La Palma, Canary Islands. Halimeda incrassata forms dense sublittoral assemblages between 20 and 55 m, but isolated populations occur down to 65 m depth. This species currently spreads over an area of 9.14 ha. Population coverage varies with depth, with the highest values at 35–40 m and an average cover of 62.34%. The calcified segments of H. incrassata act as a stable substratum in these soft bottoms for the growth of other macroalgae, such as the rhodophytes Lophocladia trichoclados and Cottoniella filamentosa . Specimens reach lengths of up to 10 cm, shorter than individuals from the Caribbean. Although it is difficult to ascertain whether this species is a recent introduction, there is evidence of a correlation between the increase in population coverage and recent ocean warming, constituting another example of the tropicalization of the marine flora of this region.

Gelidium canariense and Gelidium arbusculum coexist in the upper sublittoral zone in the Canary Islands and are the only Gelidiales registered as vulnerable species. Spore germination and the formation of rhizoids are vital steps for the successful growth of new plants. We investigated the initial germination stages of tetraspores and the growth of the primary rhizoid in these two vulnerable species. Both Gelidiales exhibited Gelidium -type germination. However, liberated tetraspores of G. canariense and G. arbusculum germinated earlier than those of other species of the Gelidiales. The growth curves of primary rhizoids were similar in both species.

Although the genus Gracilaria is well represented on the Mexican coasts, there are few studies focused on the taxonomic aspects and the clarification of the relationships between species. The high morphological plasticity exhibited by several of its representatives could underestimate the true species richness. In the present study, a group of cylindrical specimens of Gracilaria from the southeastern Gulf of Mexico, previously identified as G. cornea , was collected. Based on COI-5P and rbc L sequences, these samples formed an independent group closely related to G. ferox , a flat species. Morphologically, our specimens differed from G. ferox and the other species of Gracilaria by the presence of very small cystocarps and a thick pericarp composed of many layers of cells. We propose Gracilaria microcarpa sp. nov. as the name for this group of cylindrical specimens from the Yucatan Peninsula of Mexico.

Multiple-marker (COI-5P, UPA, psb A and rbc L-3P) and two algorithmic approaches [automatic barcode gap discovery (ABGD) and Poisson tree process (PTP)] were used for species delimitation of Lithophylloideae in Brazil. The integrative approach was mostly congruent between markers and algorithmic methods of species delimitation, suggesting the occurrence of 24 species. Based on morphology and molecular data, Amphiroa rigida , Amphiroa vanbosseae , Lithophyllum atlanticum , Lithophyllum kaiseri , Lithophyllum margaritae , Titanoderma pustulatum , Titanoderma prototypum and Paulsilvella huveorum , which were previously reported for Brazil, are confirmed in this work. Six new species are distinguished by both molecular and morphological traits, and they are provisionally named as Amphiroa sp. 1, Amphiroa sp. 2, Amphiroa sp. 3, Lithophyllum sp. 1, Lithophyllum sp. 2 and Lithophyllum sp. 3. Another 10 species are cryptic and cannot be distinguished based on traditionally used morphological traits. These include Amphiroa sp. 4, Lithophyllum sp. 4, three species that are morphologically named under Amphiroa beauvoisii , and six that share the morphology described for Amphiroa fragilissima . All four markers used were useful for species delimitation. However, a combination of practical aspects and levels of intra- and interspecific divergence values led us to propose the use of rbc L-3P as a standard DNA barcode marker for the Corallinales.

Continuous and intensive selective breeding reduces the genetic diversity of cultivated Pyropia stock, thereby increasing its susceptibility to diseases, and hindering the sustainable development of the Pyropia industry. To develop new Pyropia germplasms with desirable agronomic traits, a new Pyropia yezoensis strain, “Huangyou No. 1” was bred from a wild subtidal population. In this study, the genetic diversity of this strain was analyzed using AFLP. Totally, 249 loci were obtained, of which 248 were polymorphic with a polymorphism rate of 99.6%, using seven primer pairs. The intra-population polymorphism rates of the populations Wild 1 and Wild 2 were the highest (47.39% and 59.44%, respectively), while they were relatively low (20.88–24.5%) in the cultivated populations. The genetic distances between the breeding Pyropia populations cultivated in the same aquaculture farm were low. Specifically, the F 2 offspring of “Huangyou No. 1” and the control cultivar, cultivated using the “never-drying” protocol, were genetically distant from the other populations, including that from the same seedlings, yet cultivated using the “periodic-drying” protocol. The never-drying cultivation protocol had a high likelihood of influencing genetic diversity of Pyropia yezoensis .

The sessile bryozoan Membranipora membranacea frequently colonizes the phaeophyte Saccharina japonica. Identifying early colonization markers using proteomics could assist in the early detection of epiphytic contamination. Different sections of thallus tissue proximal to the bryozoan (i.e. the 1-cm zone beyond the boundary of the colony) and tissue from the colony-front (i.e. the narrow zone under the newly formed front of the colony after removing the bryozoans) were separated. From the proteomic profiles of S. japonica , we detected 151 protein spots (99 up-, 50 down-, and 2 similarly regulated) from proximal tissues and 151 spots (69 up-, 75 down-, and 7 same-regulated) from colony-front tissues. Hundred and ten spots were detected from distal healthy thallus tissue, used as a control. The protein SSP15 was specifically up-regulated in the proximal tissues by ca. 1395-fold, while it exhibited little expression at the colony-front and in distal healthy tissues. ATPases were markedly up-regulated in both the proximal and colony-front tissues by 3198- and 2475-fold, respectively. Rpl1P and SRSF proteins were specifically up-regulated only in colony-front tissues by 5724- and 273-fold, respectively. Therefore, these proteins may be used as specific biomarkers for the early detection of bryozoan colonization on each tissue type of the seaweed.

There exists a massive pool of biodiversity in marine ecosystems. This biodiversity is an excellent source for acquiring an inventory of enzymes that can be used for a variety of biotech applications. This diversity has, to date, not been fully exploited. One major reason being the difficulties that arise in culturing many microorganisms in the laboratory, as opposed to natural conditions. However, advents of newer omics techniques, such as metagenomics have greatly enhanced the opportunity for sustainable resource management. It is in this context that metagenomics is rapidly emerging as an alternative approach to conventional microbial screening. Metagenomics allows for exhaustive screening of microbial genomes in their natural environments. In this review, an overview of work that uses genomic strategies to examine the biotechnological potential of the marine reservoir was explored. These genomic strategies include homology-driven screening of enormous amounts of sequence data and activity-based functional screening of genomic and metagenomic libraries. Finally, the review concludes with an overview of some of the potential challenges and future prospects of metagenomics in bioprospecting novel biocatalysts and bioactive compounds from marine sources.