Volume 62, Issue 2

A non-indigenous alga, Grateloupia turuturu (Halymeniales, Rhodophyta), was discovered in the Damariscotta Estuary (Maine, USA) in 2017, over 200 km north of its last reported location. Because of the presence of coastal facilities (aquaculture, marine laboratories) among potential vectors, we evaluated a mandated biosecurity protocol, namely, seawater treated with bleach at 50 ppm (50 mg l −1 ) free chlorine for ≥2 h and measured using test strips, for lethality against G. turuturu and several native algae. We report unexpected resilience to bleach-treatment ( Mastocarpus  >  Grateloupia  >  Palmaria ). Holdfasts of G. turuturu and Mastocarpus stellatus survived 50 and 1000 ppm free chlorine, respectively. Cystocarps on cultured blades of G. turuturu were particularly resistant to bleach-treatment; they produced outgrowths on fragmenting blades that became fertile tetrasporophytes in culture, suggesting reproductive adaptations of cystocarps to stressful conditions that may have broader evolutionary significance. Juvenile, microscopic crusts of G. turuturu were also bleach-resistant if covered by diatoms, and developed upright axes. Free chlorine test strips were inaccurate in seawater, and their use could increase the risk of failed biosecurity as a vector for invasion. Because chlorination at economic and environmentally safe levels is insufficient, we recommend a combination of treatments for comprehensive biosecurity.

The effects of salinity and temperature on the photosynthetic and growth performance of the seagrasses Cymodocea nodosa and Ruppia cirrhosa were studied to understand their local seasonality and distribution. Cymodocea nodosa shoots were collected from Cape Vrasidas, and R. cirrhosa shoots from the coastal lagoon Fanari, all from the Eastern Macedonian and Thrace Region, Greece. Effective quantum yield (ΔF/Fm′), leaf chlorophyll- a content (mg g −1 wet mass) and growth (% of maximum) were tested at different temperatures (10–40°C) and salinities (5–60). The results showed that: (a) R. cirrhosa was more euryhaline (5–55/60) than C. nodosa (10–50), (b) the upper thermal tolerance of C. nodosa (34–35°C) was higher than that of R. cirrhosa (32–34°C), (c) C. nodosa could not tolerate 10°C, whereas R. cirrhosa could, and (d) the growth optimum of C. nodosa was 30°C and that of R. cirrhosa 20–30°C. The thermal optima and tolerances of growth and photosynthesis confirm the seasonal patterns of R. cirrhosa but not of C. nodosa . However, the sensitivity of C. nodosa to low salinities and temperatures may explain its absence from shallow coastal lagoons. Ruppia cirrhosa could be vulnerable to future climate change.

While the seagrass Halophila stipulacea reproduces both sexually and asexually in its native range, reproduction is largely asexual in its invasive range in the Mediterranean and the Caribbean Seas. Here we make the first report of fruit-bearing H. stipulacea in the Caribbean. Although the lack of reports of H. stipulacea fruit could be the consequence of past survey effort, multiple recent reports of both flowers and fruit across the invasive range strongly suggest that introductions of H. stipulacea in the tropical western Atlantic and Caribbean included both sexes of this dioecious seagrass. This finding may have important implications for the future dispersal, survival, and maintenance of the non-native population.

Examining morphological and anatomical characters, eight bloom-forming Ulva species were identified from La Paz Bay, Gulf of California, Mexico. However, DNA sequencing, using a multi-gene approach ( rbc L, ITS2 and tuf A) revealed that, of the eight species, four species were genetically distinct, none of which belonged to the species they would have been ascribed based on morpho-anatomical observations. The Ulva lactuca and Ulva rigida morphotypes (blades two cells thick, unbranched, attached by a small discoid holdfast) corresponded to Ulva ohnoi ; the Ulva intestinalis morphotype (tubular and smooth thallus, one cell thick) corresponded to Ulva tepida ; the Ulva clathrata and Ulva flexuosa morphotypes (tubular to slightly compressed thallus) corresponded to Ulva torta. The Ulva acanthophora morphotype (more or less tubular, profusely branched) did not correspond molecularly to any currently described species. Attempts to sequence the remaining two species, morpho-anatomically identified as Ulva lobata and Ulva nematoidea , were unsuccessful. This study similarly highlights the high degree of cryptic diversity in the genus Ulva , provides a nomenclature adjustment for several species of the genus Ulva from northwestern Mexico and is the first to report U. ohnoi , U. tepida and U. torta for the region.

The morphology, molecular phylogeny and toxinology of two Coolia and one Prorocentrum dinoflagellate strains from Brazil were characterized. They matched with Coolia malayensis and Coolia tropicalis morphotypes, while the Prorocentrum strain fitted well with the morphology of Prorocentrum emarginatum . Complementary identification by molecular analyses was carried out based on LSU and ITS-5.8S rDNA. Phylogenetic analyses of Coolia strains (D1/D2 region, LSU rDNA), showed that C . malayensis (strain UFBA044) segregated together with sequences of this species from other parts of the world, but diverged earlier in a separate branch to sequences from São Paulo (Brazil) or Caribbean areas. Coolia tropicalis (strain UFBA055) grouped with other sequences of this species, in a subclade with an isolate from Belize, closer to a subgroup including isolates from Thailand, Australia and Hong Kong. Phylogenetic analyses (ITS-5.8S rDNA) of P. emarginatum (strain UFBA033) grouped together with another sequence of this species from China Sea. Diarrhetic shellfish poisoning toxins (OA, DTXs and PTX2) were not detected in P. emarginatum by mass spectrometry analyses. However, hemolytic assays in P. emarginatum and both Coolia strains in this study showed positive results.

Two species of Gelidium , Gelidium usmanghanii and Gelidium pusillum var. pakistanicum are reported only from Pakistan, but their taxonomic status, phylogenetic relationships, and distributions have not been assessed with molecular data. Analysis of rbc L sequences revealed that G. usmanghanii was a distinct species with a distribution extending at least to the coast of Oman. This analysis also resolved G. pusillum var. pakistanicum within a Gelidium millariana species complex that was distantly related to G. pusillum . Further analyses of rbc L and COI-5P sequences showed that G. pusillum var. pakistanicum was a distinct species in this complex, and based on these molecular, and previous morphological results, this variety is elevated to the rank of species as Gelidium pakistanicum stat. nov.

The brown algal family Scytosiphonaceae has recently received considerable attention resulting in the description of several new genera and species. However, members of the genus Scytosiphon and Petalonia remain polyphyletic. By integrating multi-gene phylogenetic data (mitochondrial cox 3 and plastid psa A and rbc L genes) with their known morpho-anatomies and life histories, we herein resurrect Hapterophycus canaliculatus , currently considered a member of genus Scytosiphon , and transfer Scytosiphon tenellus to the genus Petalonia .

This paper reports a recently discovered population of Caulerpa prolifera in the Azores (NE Atlantic), which becomes the westernmost record of this species in European waters. Morphological, anatomical and molecular characters were investigated for species recognition. The occurrence of the species in the Azores represents a northern expansion of its distributional range, covering now the whole Macaronesia region. It may have been brought by rafting from the western Atlantic through the Gulf Stream, but human-assisted transport may also have been involved in its arrival or dispersion.

The red alga Tiffaniella gorgonea (Wrangeliaceae, Rhodophyta) is found and described for the first time from the Mediterranean Sea. This species was collected growing as epiphyte on three species of Codium in the lower intertidal zone from Dalya, Cabo Negro and Al-Hoceima on the Mediterranean coast of Morocco. Moroccan specimens were studied in detail and compared with two other closely related species reported previously from Morocco and the Mediterranean Sea. A key to the Mediterranean and Moroccan species of Tiffaniella is provided. Habitat, geographical distribution, and the possible vector of introduction of the new alien are presented and discussed in this work. Taxonomic remarks, a description and images of the macroscopic and microscopic characters are provided for this taxon.

The value of macroalgae to the pharmaceutical and food industries has increased, due to their richness in compounds with relevant biological activities and health effects. However, there are still many species that are worth exploring, like the edible Fucus spiralis L., widespread throughout the European and African Atlantic coasts. In order to demonstrate the phycochemical, pharmacological and nutritional potential of F. spiralis , this work presents a comprehensive review of studies regarding the bioactivities of F. spiralis extracts and their phycochemicals. A critical analysis of studies is presented, identifying the challenges and opportunities, and unveiling the knowledge gaps in order to guide future research with this alga. Although the studies performed so far have shown the potential of F. spiralis , this review shows that there is still a big gap in the knowledge about its metabolites. In this context, it is suggested that future investigations should focus more on the isolation and unequivocal structural characterization of the metabolites, such as phlorotannins. In addition, some weaknesses in the reviewed literature are mentioned here, which should be avoided in future work, in order to allow a better evaluation of the validity of results and their comparison.

Land-based cultivation of marine macroalgae may open up the possibility to produce high quality algal biomass as required in various application areas all year round. In this context, the potential of a recently developed ring-shaped cultivation system with algae moving in a circular way, simulating the movement pattern in a standard tank cultivation vessel was evaluated using the green alga Ulva lactuca . Plants were cultivated under outdoor conditions at ambient (37 μmol CO 2 kg −1 seawater) and increased CO 2 concentration (152 μmol CO 2 kg −1 seawater). Biomass growth and photosynthetic performance of algae were analyzed over a test period of 7 d. Elevated CO 2 concentration significantly stimulated algal growth and also helped to compensate the effects of environmental stress conditions. This was indicated by the predominant stability of photosynthetic competence and represented by maximum photosynthetic electron transport rates, efficiency of light-harvesting and photon fluence rates (PFR) saturating photosynthetic electron transport at low PFR. At high PFR, no difference in photosynthetic competence was detected between algae cultivated at the high CO 2 -concentration and those grown at ambient CO 2 . Under elevated CO 2 concentrations, photochemical energy dissipation decreased more distinctly at low PFR. This may reflect a declining energy demand necessary to maintain photosynthetic capacity. Under elevated CO 2 , the apparent changes in the quantum yields of regulated and unregulated non-photochemical energy dissipation of PS II at high PFR possibly reflected the enhanced capacity of photoprotection under the prevailing environmental conditions.