Volume 58, Issue 4

In this study, we investigated the rate and pattern of expansion of a non-native eelgrass, Zostera japonica , in relation to the distribution of the native eelgrass Zostera marina in a coastal estuary of the northeastern Pacific Ocean. The distributions of the Zostera congeners were monitored between 1997 and 2014 in Yaquina Estuary on the central Oregon coast, USA, using digital classification of color infrared aerial photographs and ground surveys. Correction factors for seasonal variations in cover were obtained to normalise the annual photo survey results to a common date (mid-August). Major expansions in the distributions of Z. japonica meadows over most of the 17-year study period were observed. However, there was no indication that the large (∼1500%) increase in areal extent of Z. japonica in the lower estuary between 1997 and 2007 was accompanied by a change in areal extent of the native Z. marina in this system.

The biraphid genus Olifantiella (Bacillariophyta), which was recently discovered from the Mascarene Islands (Indian Ocean), is also present in coral reef environments of the islands of Tahiti and Moorea (South Pacific) as an epiphyte on the mangrove Rhizophora stylosa . The genus Olifantiella may be considered elusive because all of its currently known species are very small and difficult to identify under a light microscope. Several Olifantiella taxa first described from Rodrigues Island are also present in the South Pacific, along with three new taxa: O. societatis sp. nov., O. sp., and O. pilosella var. rhizophorae var. nov. Olifantiella societatis resembles O. paucistriata but the buciniportula opening of the former is oblong and faces one stria only. Olifantiella societatis and O. sp. show distinctive features of the genus Olifantiella but are very rare. A description of the buciniportula in O. pilosella is given. Although it is still unclear, the role of the buciniportula may be related to the excretion of mucilaginous material. The diversity of Olifantiella taxa between the Mascarene and Society archipelagos is similar with 6–7 species, five of which are common to both. Olifantiella mascarenica and O. pilosella are the most common members of the genus in the Mascarene Islands and the South Pacific, respectively. Olifantiella has only been previously described from the Indo-Pacific Basin, but it may be a widespread tropical genus. This genus has probably been overlooked in the past or misidentified as Navicula because of its overall naviculoid shape and small size. Electron microscopy remains essential in determining the identity of very small diatoms such as Olifantiella .

The encrusting bryozoan Membranipora membranacea frequently colonizes late-harvested blades of the cultured Saccharina japonica . We measured the proximate compositions, amino acid and fatty acid profiles and metal contents of bryozoans, colonized blades and healthy blades. Bryozoans contained high levels of crude ash (657 g kg -1 dry weight) and arsenic (As; 49 mg kg -1 dry weight) contents, exceeding the recommended range for human food, and had relatively low levels of essential amino acids. The content of inorganic As in bryozoans was 31% of the provisional tolerable weekly intake for inorganic As established by the World Health Organization. Hence, bryozoans decrease the food and fodder quality of the seaweed product. After removing the bryozoans, we found that the seaweed blade tissues beneath the colonies had elevated levels of potassium, iodine and docosahexaenoic acid and reduced levels of copper, chromium and cadmium compared to healthy tissues. Thus, lacy crust bryozoans must be removed from the surface of seaweed prior to its use as food or fodder.

The growth, reproduction, and senescence patterns of the epiphytic marine alga Phaeosaccion collinsii were tracked over two consecutive seasons at its type locality of Little Nahant, Nahant, MA (USA). We investigated the potential and/or combined effects of temperature and ambient nutrient supply (NO 3 - and PO 4 3- ) on the phenology of this ephemeral species in its natural environment by collecting microscopic and macroscopic P. collinsii specimens from blades of eelgrass ( Zostera marina) in a shallow coastal subtidal zone. Our results suggest that temperature is a strong driver of the alga’s in situ cycle and that the optimal temperature for P. collinsii growth and reproduction may be between 5 and 8°C, a narrower temperature threshold than previous laboratory studies on this subject have suggested. Several large winter storms also allowed us to observe the effect of physical disturbance on the integrity of the eelgrass beds and the population of microscopic and macroscopic P. collinsii. This study contributes the first in situ information on the abiotic conditions necessary for the successful growth and development of P. collinsii and a greater understanding of the life cycle of this unique golden brown alga.

Malate dehydrogenase (MDH) is an enzyme that catalyzes the interconversion of malate and oxaloacetate substrates and is widely distributed from prokaryotes to eukaryotes. It plays crucial roles in many important metabolic pathways and includes different isoforms based on coenzyme specificity and cellular localization. To study MDH in rhodophytes, we obtained a full-length cDNA clone (here designated PhMDH ) encoding an NAD-malate dehydrogenase in the marine red alga Pyropia haitanensis . The nucleotide sequence of PhMDH was 1521 bp, including an open reading frame (ORF) of 984 bp. The amino acid sequence showed 73% identity with other MDHs in proteobacteria. Two MDH-like domains were detected in the 5–145 and 156–320 regions. Real-time fluorescent quantitative PCR (qPCR) was used to examine mRNA expression levels during the gametophyte and sporophyte phases. The transcription of PhMDH in the gametophyte was barely detectable, whereas PhMDH in the sporophyte showed a much higher expression level. The activity of PhMDH in the filamentous sporophyte was approximately double that of the leafy gametophyte. Considering these results, we suggest that PhMDH may be localized in the cytosol and play a role in carbon fixation in the sporophyte stage.

Morphological identification of species in the order Gelidiales can be difficult and controversial because of phenotypic plasticity, the low numbers of reproductive specimens and poorly defined taxonomic boundaries. A DNA barcoding survey of Brazilian specimens of Gelidiales, employing neighbor-joining and Automatic Barcode Gap Discovery analyses, indicated the presence of 23 statistically robust primary species hypotheses (PSH). In addition to the cytochrome oxidase I gene (COI-5P), the chloroplast universal plastid amplicon (UPA) marker was also sequenced and submitted to the same analyses. Representatives of each COI-5P/UPA PSH were selected for rbc L sequence analysis to further corroborate the occurrence of 23 species and to infer their phylogenetic relationships. These analyses confirmed the identity of six species previously cited for Brazil: Gelidiella acerosa , G . ligulata , Gelidium crinale , G . floridanum , Pterocladiella bartlettii and P . capillacea . Three new reports for Brazil were also detected: Gelidium microdonticum , Pterocladiella beachiae and P . australafricanensis . Fourteen species remain unidentified and require detailed morphological evaluation.

In this study, a revised checklist of macroalgae of Iran with an updated nomenclature and taxonomy has been compiled based on published records. Using currently accepted names, 309 species and infraspecific taxa of macroalgae have been identified to date, including 78 Chlorophyta (within 15 families), 70 Ochrophyta (Phaeophyceae; within 7 families) and 161 Rhodophyta (within 30 families). The brown alga Sargassum with 25 taxa was the most diverse genus, and the Rhodomelaceae (Rhodophyta) with 36 taxa was the most species-rich family. The Cheney ratio of 3.4 and the species composition of brown seaweeds suggest that the Iranian marine algal flora is warm-temperate. Sørensen similarity indices were used to compare the marine algal flora of Iran with that of Saudi Arabia within the Persian Gulf and the Sultanate of Oman within the Gulf of Oman. The algal diversity of the Iranian coast within the Gulf of Oman is less than that within the Persian Gulf, and this difference is attributed to undercollecting. Given that this is the first inclusive checklist of macroalgae of Iran, covering the coast lying within the Persian Gulf and the Gulf of Oman, it could serve as a foundation for future phycological and biogeographical studies of the taxa in the country and the region.

The occurrence of the red algal species Hypoglossum caloglossoides (Delesseriaceae, Ceramiales) is reported for the first time from shallow sub-littoral sites in both the Mediterranean Sea and the Red Sea. This small but morphologically distinctive species, originally described from Lord Howe Island in the southwestern South Pacific Ocean, has been recorded from scattered tropical and subtropical locations around the globe. Some aspects of its ecology in the north Israeli Mediterranean are also discussed.

The red alga Gayliella fimbriata (Ceramiaceae, Rhodophyta) is reported for the first time from the Mediterranean Sea. This species was collected growing as an epiphyte on Laurencia obtusa in the sublittoral zone at Antalya (Mediterranean coast of Turkey). Gayliella fimbriata is characterized by its protruding clavate gland cells. Features to distinguish the four Turkish species of Gayliella from one another are provided.