Volume 56, Issue 2

A second addendum to Schneider and Wynne’s (Schneider, C.W. and M.J. Wynne. 2007. A synoptic review of the classification of red algal genera a half a century after Kylin’s “Die Gattungen der Rhodophyceen”. Bot. Mar. 50: 197–249.) “Synoptic review” of red algal genera and their classification is presented, with an updating of names of new taxa at the generic level and higher. In the past few years, the hierarchy of some genera has changed due to new subfamilies, which are cited and referenced below. There have also been the descriptions of some higher taxa in the past few years.

The monotypic kallymeniacean genus Ionia established as Iona cornu-cervi is endemic to the Sea of Okhotsk. We observed the type material of the species deposited in the Komarov Botanical Institute of the Russian Academy of Sciences (LE, St. Petersburg, Russia) and compared it with fresh collections near the type locality. Analysis of the rbc L dataset revealed that I. cornu-cervi was not distinct from other genera of the Kallymeniaceae but consistently nested within the genus Callophyllis and formed a sister relationship with Callophyllis variegata . Here, we propose the new combination Callophyllis cornu-cervi based on I. cornu-cervi and treat the genus Ionia as a synonym of Callophyllis . Callophyllis cornu-cervi is distinguished by a thallus with many slightly convoluted segments positioned at an angle to each other, forming an erect and more or less rigid plant, and a medulla composed of intermingled large and small cells.

We describe for the first time the morphology of Gelidium crinale from its natural habitat in Atlantic Patagonia with special consideration of diagnostic characters. Observations and morphometric measurements were done on fresh specimens using scanning electron and inverted light microscopy. This report is a new record for Atlantic Patagonian coasts. The thalli comprise prostrate and erect axes; they are subterete at the base and compressed to flattened at the apices. The basal parts are scarcely and irregularly branched, while the apical parts are highly ramified and subdichotomously branched. The lengths of thalli and the ramification patterns differ from previous descriptions, and were variable between seasons and life history phases. “Brush-like” haptera confirmed the identity of the algae as members of the Gelidiaceae. Internal rhizoidal filaments are abundant and distributed in groups throughout the medulla. The life history was of the “ Polysiphonia -type”; occurrences of carposporophytes and tetrasporophytes were variable.

Gracilaria parvispora is reported for the first time as an invasive species in northwestern Mexico based on morphological, anatomical and molecular data. The species is widely distributed in the region, where it colonizes sandy and rocky habitats from intertidal areas down to a depth of 1.5 m. The morphological and anatomical data from the Mexican specimens matched the circumscription of the species in Hawaiian waters. Two molecular markers ( rbc L and cox 1) showed that the Mexican populations were closer to the Hawaiian populations than the Korean populations, which may relate to a similarity in seawater temperatures between Hawaii and Baja California. Gracilaria parvispora formed extensive mats together with Gracilaria vermiculophylla. It was found in stomach samples from a green turtle ( Chelonia mydas ) in the coastal lagoons of Baja California Sur. The ecological impacts of the two alien Gracialria species on other native species and communities have yet to be determined. This is the first demonstration of a second invasive Gracilaria species, following the introduction of G. vermiculophylla into the northwestern Mexico region.

Polysiphonia tripinnata , a member of the Rhodomelaceae originally described from the Mediterranean Sea, is newly recorded off the European Atlantic coast. It was collected mostly from sand-covered rocks between the low intertidal zone and the upper subtidal zone of 18 sites from the Iberian Peninsula. Most locations were from the southern Iberian Peninsula; nevertheless, it was also found at three sites on the northern coast (Galicia and Basque Country). In this work, the vegetative and reproductive morphologies of P. tripinnata are described and for the first time a detailed description of female structures is provided. Polysiphonia tripinnata is distinguished from its congeners by its decumbent robust thalli attached to the substratum by abundant rhizoids cut off from the pericentral cells; axes are ecorticate with (14–) 17–19 (–20) pericentral cells; branches of indeterminate and/or determinate growth are alternately arranged and form in the axils of trichoblasts, which are borne on every segment; carpogonial branches are four-celled, cystocarps are globose; tetrasporangia are formed in spiral series. The type material of P. tripinnata has been examined and a lectotype is designated for the species. Differences between P. tripinnata and similar species are discussed. Moreover, COI-5P sequences of P. tripinnata as well as Polysiphonia nigra and Boergeseniella spp. are provided to allow subsequent assignment to these entities using the DNA barcode tool.

Ocean acidification reduces the concentration of carbonate ions and increases those of bicarbonate ions in seawater compared with the present oceanic conditions. This altered composition of inorganic carbon species may, by interacting with ultraviolet radiation (UVR), affect the physiology of macroalgal species. However, very little is known about how calcareous algae respond to UVR and ocean acidification. Therefore, we conducted an experiment to determine the effects of UVR and ocean acidification on the calcified rhodophyte Corallina officinalis using CO 2 -enriched cultures with and without UVR exposure. Low pH increased the relative electron transport rates (rETR) but decreased the CaCO 3 content and had a miniscule effect on growth. However, UVA (4.25 W m -2 ) and a moderate level of UVB (0.5 W m -2 ) increased the rETR and growth rates in C. officinalis , and there was a significant interactive effect of pH and UVR on UVR-absorbing compound concentrations. Thus, at low irradiance, pH and UVR interact in a way that affects the multiple physiological responses of C. officinalis differently. In particular, changes in the skeletal content induced by low pH may affect how C. officinalis absorbs and uses light. Therefore, the light quality used in ocean acidification experiments will affect the predictions of how calcified macroalgae will respond to elevated CO 2 .

The concentrations of six trace metals (Mn, Zn, Cu, Pb, Co and Cd) in five compartments (blades, sheaths, vertical rhizomes, main axis plus additional branches and roots) of the seagrass Cymodocea nodosa from the Gulf of Thessaloniki, Greece were determined monthly, together with potential associated variables (climate variables, sediment metal concentrations, plant compartment biomass, size and age). Uni- and multivariate data analyses were applied. Univariate analyses showed that leaf blades displayed the highest annual mean concentration of most metals (Mn, Zn, Pb, Co, Cd) analyzed, whereas sheaths had the highest Cu concentration; metal concentrations in blades generally showed a wider monthly variability than those in the other plant compartments, and especially roots. The multivariate pattern of metals in leaf blades showed a seasonal periodicity that appeared to be governed by the cumulative effect of plant growth dynamics and sediment metal content. In particular, most metal concentrations increased from April onwards, with enhancement of blade biomass, size and age, and remained high throughout the blade growing season, whereas Cu concentration showed the opposite pattern; an additional increase in blade Zn concentration during early winter coincided with a marked increase in sediment Zn content. The multivariate patterns of metals in the other plant compartments showed no distinct seasonality and were not markedly related to the examined variables. These findings are not consistent with the assumption that metals in seagrass tissues display an overall seasonal trend of markedly higher levels during the cold period. The present study stresses the need for more knowledge on metal seasonality in seagrass compartments and on the associated variables.

Posidonia oceanica seedlings produced from beach-cast fruits were planted in an area where this Mediterranean seagrass was lost as a consequence of fish-farming. The effects of substratum type (dead matte vs. meadow) and planting level (above vs. below bottom surface) on seedling survivorship and leaf development were evaluated after 3 years. Seedling capacity to resist uprooting was also tested by comparing survivorship and leaf development after 2 years in seedlings firmly anchored in dead matte by artificial means (mesh-pot) with those planted without any anchoring other than their roots. Survivorship in dead matte was 44% after 3 years and was not affected by planting level. Seedling planting inside the meadow led to complete mortality after 3 years. Seedlings planted below the bottom surface branched during the second year and 50% had produced from one to five additional shoots after 3 years. After 2 years, survivorship and leaf development of seedlings planted with mesh-pot anchoring was similar to that of seedlings planted without anchoring. Current environmental conditions in the impacted area allow P. oceanica seedlings to survive, but natural recovery might be limited by propagule availability. Planting of seedlings in dead matte without anchoring does not affect survivorship and leaf development and might be a feasible technique for restoration of P. oceanica meadows.

A new species, Gayralia brasiliensis (Ulotrichales, Chlorophyta), is described from Brazil on the basis of ontogenetic, morphological, and molecular phylogenetic data. Liberation of zooids from the monostromatically bladed thalli occurred by disintegration of the zooidangium wall, releasing four biflagellate cells with prominent eyespots. Fusion of zooids was not observed. After zooid attachment, cell divisions gave rise to uniseriate filaments that developed into fan-shaped blades. Only asexual reproduction was observed; this took place through recycling of blades by germination of zooids. Phylogenetic analysis based on rDNA internal transcribed spacer (ITS) sequences showed that G. brasiliensis specimens formed a monophyletic group closely related to Monostroma nitidum and two unidentified monostromatic species from Japan and Tanzania. The genus Monostroma was polyphyletic in our analysis. ITS sequences also confirmed the presence of a second monostromatic species of Ulotrichales in the Brazilian coast, Gayralia oxysperma . There were overlapping morphological and life history traits between G. brasiliensis and G. oxysperma . However, these two species were clearly divergent based on ITS sequences and ontogeny.