Members of the family Parviluciferaceae (Alveolata, Perkinsozoa) are the well-known dinoflagellate parasitoids along with Amoebophrya ceratii species complex and parasitic chytrid Dinomyces arenysensis and contain six species across three genera (i.e., Parvilucifera infectans, P. sinerae, P. rostrata, and P. corolla, Dinovorax pyriformis, and Snorkelia prorocentri) so far. Among Parvilucifera species, the two species, P. infectans and P. sinerae, are very similar or almost identical each other morphologically and genetically, thereby make it difficult to distinguish between the two. The only main difference between the two species known so far is the number of sporangium wall (i.e., 2 layers in P. infectans vs. 3 layers in P. sinerae). During sampling in Masan bay, Korea during the spring season of 2015, the dinoflagellate Akashiwo sanguinea cells infected by the parasite Parvilucifera were observed and this host-parasite system was established in culture. Using this culture, its morphological and ultrastructural features with special emphasis on the variation in the number of sporangium wall over developmental times, were investigated. In addition, the sequences of rDNA regions and ${\beta}-tubulin$ genes were determined. The result clearly demonstrated that the trophocyte at 36 h was covered with 4 layers, and then outer layer of the sporocyte gradually degraded over time, resulting in wall structure consisting of two layers, with even processes being detached from 7-day-old sporangium with smooth surface, indicating that the difference in the number of layers seems not to be an appropriate ultrastructural character for distinguishing P. infectans and P. sinerae. While pairwise comparison of the large subunit rDNA sequences showed 100% identity among P. infectans / P. sinerae species complex, genetic differences were found in the small subunit (SSU) rDNA sequences but the differences were relatively small (11-13 nucleotides) compared with those (190-272 nucleotides) found among the rest of Parvilucifera species (P. rostrata and P. corolla). Those small differences in SSU rDNA sequences of P. infectans / P. sinerae species complex may reflect the variations within inter- strains of the same species from different geographical areas. Taken together, all morphological, ultrastructural, and molecular data from the present study suggest that they are the same species.

The phototrophic dinoflagellate genus Scrippsiella is known to have a worldwide distribution. Here, we report for the first time, the occurrence of Scrippsiella lachrymosa in Korean waters. Unlike the other stains of S. lachrymosa whose cultures had been established from cysts in the sediments, the clonal culture of the Korean strain of S. lachrymosa was established from motile cells. When the sulcal plates of S. lachrymosa, which have not been fully described to date, were carefully examined using scanning electron microscopy, the Korean strain of S. lachrymosa clearly exhibited the anterior sulcal plate (s.a.), right sulcal plate (s.d.), left sulcal plate (s.s.), median sulcal plate (s.m.), and posterior sulcal plate (s.p.). When properly aligned, the large subunit (LSU) rDNA sequence of the Korean strain of S. lachrymosa was ca. 1% different from those of two Norwegian strains of S. lachrymosa, the only strains for which LSU sequences have been reported. The internal transcribed spacer (ITS) rDNA sequence of the Korean strain of S. lachrymosa was also ca. 1% different from those of the Scottish and Chinese strains and 3% different from those of the Canadian, German, Greek, and Portuguese strains. Thus, the Korean S. lachrymosa strain has unique LSU and ITS sequences. The abundances of S. lachrymosa in the waters of 28 stations, located in the East, West, and South Sea of Korea, were quantified in four seasons from January 2016 to October 2017, using quantitative real-time polymerase chain reaction method and newly designed specific primer-probe sets. Its abundances were >$0.1cells\;mL^{-1}$ at eight stations in January and March 2016 and March 2017, and its highest abundance in Korean waters was $26cells\;mL^{-1}$. Thus, S. lachrymosa has a nationwide distribution in Korean waters as motile cells.

Alaria is the second largest genus of the Laminariales, which is distributed far into the northern Pacific and Atlantic oceans. Due to its high morphological plasticity, over 100 specific and sub-specific names have been used in Alaria, this has been tailored down to the present 17 species through morphological revision and molecular phylogenetic analysis. Endemic species of Alaria from Russian Far East have not been thoroughly revised since their original description, and few of them were confirmed using molecular data until recently. We carried out morphological and molecular studies on A. paradisea which is an endemic species distributed on the Kurile Islands, first described by Miyabe and Nagai in 1932 as Pleuropterum paradiseum. The range of morphological variability and its distribution was re-evaluated using the type specimen as well as other specimens. Analyses of partial mitochondrial cytochrome c oxidase subunit 1 and nuclear-encoded internal transcribed spacer sequences showed that A. paradisea nested within the genus Alaria, but differs morphologically from any other Alaria species in having additional sporophylls with a central midrib (${\beta}-sporophylls$). Our results showed that A. paradisea clearly belongs to the genus Alaria based on DNA data, although the key morphological character that was used to include this species to the genus Pleuropterum, ${\beta}-sporophylls$, is stable and distinguishes it from other Alaria species.

Red algal mitochondrial genomes (mtDNAs) can provide useful information on species identification. mtDNAs of Pyropia / Porphyra (Bangiales, Rhodophyta) have shown diverse variation in their size and gene structure. In particular, the introns and intronic open reading frames found in the ribosomal RNA large subunit gene (rnl) and cytochrome c oxidase subunit 1 gene (cox1) significantly vary the mitochondrial genome size in Pyropia / Porphyra species. In this study, we examined the exon / intron structure of rnl and cox1 genes of Pyropia yezoensis at the intraspecific level. The combined data of rnl and cox1 genes exhibited 12 genotypes for 40 P. yezoensis strains, based on the existence of introns. These genotypes were more effective to identify P. yezoensis strains in comparison to the traditional DNA barcode cox1 marker (5 haplotypes). Therefore, the variation in gene structure of rnl and cox1 can be a novel molecular marker to discriminate the strains of Pyropia species.

Foliose species of the Bangiaceae (Porphyra s. l.) are very important in Korean fisheries, and their taxonomy and ecophysiology have received much attention because of the potential for developing or improving aquaculture techniques. Although 20 species of foliose Bangiales have been listed from the Korean coast, some of them remain uncertain and need further comparative morphological studies with molecular comparison. In this study, we confirm the distribution of four Pyropia species from the east coast of Korea, Pyropia kinositae, P. moriensis, P. onoi, and P. retorta sp. nov., based on morphology and rbcL sequence data. Although P. onoi was listed in North Korea in old floral works, its occurrence on the east coast of South Korea is first revealed in this study based on molecular data. P. kinositae and P. moriensis, which were originally described from Hokkaido, Japan, are first reported on the east coast of Korea in this study. Pyropia retorta sp. nov. and P. yezonesis share a similar thallus color and narrow spermatangial patches in the upper portion of the frond, and they have a sympatric distribution. However, P. retorta can be distinguished by the curled or twisted thalli and by molecular data. The biogeographic pattern of the two native species, P. kinositae and P. retorta, suggests that the east coast of Korea may have been a place of refugia during the Last Glacial Maximum (LGM), and then recolonized to the northern part of Japan through the restored East Korean Warm Current after the LGM.

We examined the species diversity of Herposiphonia on Korean coasts, based on a combination of morphology and molecular analyses of the mitochondrial COI-5P DNA barcode marker and plastid rbcL gene. We report the presence of eight species including three novel species: H. donghaensis sp. nov., H. jejuinsula sp. nov., H. sparsa sp. nov., H. caespitosa, H. fissidentoides, H. insidiosa, H. parca, and H. subdisticha. Specimens were separated into eight clades in both the COI-5P and rbcL gene analyses, with 1.3-19.6 and 6.6-15% interspecific sequence divergence, respectively. These eight species are also distinguishable by several morphological characteristics such as: branching pattern (d/i pattern in H. donghaensis sp. nov. and H. sparsa sp. nov.; d/d/d/i pattern in others), shape of determinate branch (ligulate in H. fissidentoides; terete in others), number of vegetative trichoblasts (1-2 in H. insidiosa and H. sparsa sp. nov.; 3-4 in H. caespitosa; absent in others), and number of segments and pericentral cells in determinate branches. About three novel species revealed by our analyses, H. donghaensis sp. nov. is newly discovered, and H. jejuinsula sp. nov. and H. sparsa sp. nov. were previously reported in Korea as H. nuda and H. secunda, respectively. Our results show that DNA barcoding and rbcL analyses are useful for delimiting species boundaries and discovering cryptic species diversity in the genus Herposiphonia.

Crustose calcareous algae (CCA) constitute one of the main reef builders on the Abrolhos Bank, Brazil. Once CCA taxonomy is locally understood, differences in growth-forms may be useful for the delimitation of taxa using characteristics such as the presence or absence of surface protuberances. Here, growth-forms were used to identify and quantify the most common CCA taxa on the shallow reefs (3-10 m) of the Abrolhos Bank to determine possible changes in the CCA community over a period of 10 years, and the ecological significance of CCA to local reefs was interpreted. The CCA assemblages were surveyed from 2006-2015 by using fixed photoquadrats at four sites in the inner (10-20 km from the mainland) and mid-shelf reefs (40-75 km from the mainland). The five most common CCA taxa were Pneophyllum conicum, the Lithophyllum kaiserii / Lithophyllum sp. complex, Melyvonnea erubescens, the Hydrolithon boergesenii / Porolithon onkodes complex and Peyssonelia sp. The overall mean CCA cover on the reefs was 20%. A comparison with a previous monitoring study in the same region indicated that the CCA cover nearly doubled from 2003-2008 to 2006-2015. This study reveals that the coral-killing species P. conicum dominated CCA flora on the shallow Abrolhos reefs in the last decade, and the local specific abundance of CCA slightly fluctuated over time and was species- and site-specific. The information obtained in this study contributes to the understanding of the ecology of the key calcifying components of the Abrolhos reefs and provides a useful baseline for exploring the responses of CCA to future environmental changes.

Saccharina japonica was introduced to both Korea and China from Hokkaido, Japan, and it has become an economically important species in both nations. After a long period of cultivation, several varieties of S. japonica have been developed in Korea and China. In this study, we conducted aquacultural research on the persistence of thalli from two kelp cultivars, one from China (Huangguan No. 1) and one from Korea (Sugwawon No. 301), between December 2015 and November 2016 in Haenam, Korea. The maximum length was $247.8{\pm}13.0$ and $227.5{\pm}42.0cm$, respectively, which were significantly longer in Sugwawon No. 301 than in Huangguan No. 1. The maximum width was $29.9{\pm}5.4$ and $23.2{\pm}1.9cm$, respectively, which were significantly wider in Huangguan No. 1 than in Sugwawon No. 301. The mean biomass obtained from the culture ropes was for Sugwawon No. 301 was $3.5{\pm}0.3kg\;wet\;wt\;m^{-1}$ and for while Huangguan No. 1 was $3.1{\pm}1.0kg\;wet\;wt\;m^{-1}$ of culture rope. After August, the persistence of the thalli of Sugwawon No. 301 was two months longer than that of Huangguan No. 1. We found that the Sugwawon No. 301 performed as well as the Huangguan No. 1 in Korean waters possibly due to increased flexibility as a result of the different cell arrangements of the two cultivars. Overall, the use of the Sugwawon No. 301 cultivar rather than the Huangguan No. 1 cultivar of S. japonica appears the best alternative to help to ensure a stable year round algal feed supply for the Korean abalone industry.

Turkish towel (Chondracanthus exasperatus), Pacific dulse (Palmaria mollis, also known as Red ribbon seaweed), and sea lettuce (Ulva spp.) were cultivated in a land-based intensive culture system at the Manchester Research Station, USA from August 2013 to September 2014. Macroalgae were grown in tumble-aerated tanks, harvested bimonthly for seasonal growth calculations, and analyzed for protein, lipid, ash, and amino acid content. Growth rate of all three species exhibited a similar pattern, with the highest specific growth rates occurring during the summer months (Turkish towel: 7.8%, Pacific dulse: 8.2%, and sea lettuce: 6.2%). Growth of all three species was lowest around winter solstice; with negative growth only observed in sea lettuce. On a dry weight basis significant differences in protein content existed between the three species with highest values for sea lettuce ($29.5{\pm}1.4%$). Lipid content varied between species (0.95-2.78%) with significantly higher lipid observed in sea lettuce (0.58-4.82%). No significant differences were detected on a seasonal basis among each species. Essential amino acids accounted for $43{\pm}0.9$ to $47{\pm}1.2%$ of total amino acids with Turkish towel having the highest value. Turkish towel had a significantly higher taurine level ($0.82{\pm}0.27$) than the other macroalgae. The levels of persistent organic pollutants and heavy metals were low. The estimated annual product of the three species ranged from 50- to $70-mt\;dry\;weight\;ha^{-1}\;y^{-1}$, significantly higher than conventional crops. Land-based culture of these species can produce year-round harvest, consistent product quality, and low contaminant levels.

Low efficiency in microalgal biomass production was largely attributed to the low density of algal cell cultures. Though mutations that reduced the level of chlorophyll or pigment content increased efficiency of photon usage and thus the cell-culture density under high-illumination growth conditions (e.g., >$500{\mu}mol\;photon\;m^{-2}\;s^{-1}$), it was unclear whether algae could increase cell-culture density under low-illumination conditions (e.g., ${\sim}50{\mu}mol\;photon\;m^{-2}\;s^{-1}$). To address this question, we performed forward genetic screening in Chlamydomonas reinhardtii. A pool of >1,000 insertional mutants was constructed and subjected to continuous subcultures in shaking flasks under low-illumination conditions. Complexity of restriction fragment length polymorphism (RFLP) pattern in cultures indicated the degree of heterogeneity of mutant populations. We showed that the levels of RFLP complexity decreased when cycles of subculture increased, suggesting that cultures were gradually populated by high cell-culture density (HCD) strains. Analysis of the 3 isolated HCD mutants after 30 cycles of subcultures confirmed that their maximal biomass production was 50-100% higher than that of wild type under low-illumination. Furthermore, levels of chlorophyll content in HCD mutant strains were similar to that of wild type. Inverse polymerase chain reaction analysis identified the locus of insertion in two of three HCD strains. Molecular and transcriptomic analyses suggested that two HCD mutants were a result of the gain-of-function phenotype, both linking to the abnormality of mitochondrial functions. Taken together, our results demonstrate that HCD strains can be obtained through continuous subcultures under low illumination conditions.