Showing papers in "Botanica Marina in 2014"
TL;DR: A survey on macroalgal diversity along a transect off Hansneset, Kongsfjorden, western Svalbard, between 0- and >15-m depths in 2012/2013 identified 58 species of macroalgae, 12 Chlorophyta, 31 Phaeophyceae, and 15 Rhodophyta.
Abstract: We did a survey on macroalgal diversity along a transect off Hansneset (78°39′N, 11°57′E), Kongsfjorden,
western Svalbard, between 0- and > 15-m depths in 2012/2013. One major intention was to compare our data
to a similar study performed in 1996/1998 at the same site and to document possible changes. We identified 58 species of macroalgae, 12 Chlorophyta, 31 Phaeophyceae, and 15 Rhodophyta. One species (Sphacelorbus nanus) is a new record for Svalbard. Fourteen species are new records for the Kongsfjorden area. Fertile tetrasporophytes of Turnerella pennyi (Cruoria phase) and the microscopic Chlorochytrium stage of Spongomorpha aeruginosa are also recorded for the first time from Svalbard. An increase from 20 to 45 species in the littoral in 2012/2013 compared with 1996/1998 was recorded. This study increases the total macroalgal species diversity of Kongsfjorden to 76. While 62 species were found in 1996/1998 and 58 in 2012/2013, only 42 were common to both investigations. We have made some taxonomic annotations to 20 species/ genera. Strikingly, we did not find again some red algae, such as Hildenbrandia rubra, Palmaria palmata, Polysiphonia
spp., or Scagelia pylaisaei, that had been recorded in 1996/1998. Possible reasons for the changes based on
recent knowledge from Kongsfjorden are discussed.
32 citations
TL;DR: Thirty-seven fungi were recorded from 457 samples of driftwood and intertidal decayed wood of Avicennia marina collected from three sites along the Red Sea coast of Saudi Arabia, extending the knowledge of the diversity of marine fungi from Saudi Arabia.
Abstract: Abstract This study extends our knowledge of the diversity of marine fungi from Saudi Arabia, which is virtually unknown. Thirty-seven fungi (28 ascomycetes, eight asexual fungi, and one basidiomycete) were recorded from 457 samples of driftwood and intertidal decayed wood of Avicennia marina collected from three sites along the Red Sea coast of Saudi Arabia. The three sites include two mangrove sites, namely: Yanbu and Farasan Island, while the third site is a sandy shore nearby Yanbu city. Thirty-one fungi were new records for Saudi Arabia. Swampomyces triseptatus is the only species common to the three sites. The recorded marine fungi were latitudinally distributed with fungi recorded from Yanbu (subtropical site) largely different from those at Farasan Island mangrove (tropical site) with only six common fungi recorded. Amarenographium solium was the most common fungus at Yanbu mangrove, while Lineolata rhizophorae dominated the fungal community at Farasan Island mangrove. Swampomyces armeniacus was commonly recorded at the two mangrove sites. Torpedospora radiata was the most common species recorded from driftwood samples collected at Yanbu beach. A new collection of Diatrypasimilis australiensis enabled us to make a detailed morphological study of the fungus. Mycelia with chlamydospores were isolated from the samples and subsequently sequenced, and they grouped in the Corollospora clade with various degrees of confidence, but did not sporulate on natural material or in culture.
29 citations
TL;DR: It is indicated that extremely low and high salinity stress negatively influenced the chlorophyll fluorescence parameters and growth of these two diatoms.
Abstract: In this study, we investigated changes of fluorescence parameters, specific growth rate, and relative chlorophyll content (the ratio of the chlorophyll content after salinity exposure to that of the same samples at inoculation) in the two diatoms Phaeodactylum tricornutum Bohlin and Chaetoceros gracilis Schuett, during exposure of the cultures to different salinities (1–90 psu for P. tricornutum and 1–70 psu for C. gracilis) for different times (12, 24, and 48 h). The results indicated that the maximal photochemical efficiency of PSII (Fᵥ/Fₘ), maximal relative electron transport rate (rETRₘₐₓ), and photochemical quenching (qP) decreased significantly with the degree of salinity stress and increased with increasing exposure times in the two diatoms. For P. tricornutum, the values of Fᵥ/Fₘ at salinities of 20–40 psu were always higher than those in other salinity treatments, rETRₘₐₓ reached maximal values at salinities of 20–30 psu, and qP peaked at salinities of 10–20 psu. For C. gracilis, the values of Fᵥ/Fₘ at salinities of 5–40 psu were always higher than those at 1 psu or at 50–70 psu. The highest values of rETRₘₐₓ were also observed at salinities of 5–40 psu, whereas qP decreased slowly with increasing salinity from 10 to 60 psu. The changes in non-photochemical quenching (NPQ) were different in the two diatoms. For P. tricornutum, there were no significant differences below 60 psu for all three exposure times. Above 60 psu, however, NPQ in P. tricornutum increased with salinity up to 80 psu and decreased at 90 psu. For C. gracilis, NPQ decreased with increasing salinity from 1 to 20 psu, but increased at salinities of 20–70 psu during the 12- and 24-h periods, and was always low after 48 h. The specific growth rate of the two diatoms was inhibited at both low and high salinities, and decreased with increasing exposure times. The relative chlorophyll content of the two diatoms showed a similar trend to each other, with lower chlorophyll content occurring at extremely low and high salinities. These results indicated that extremely low and high salinity stress negatively influenced the chlorophyll fluorescence parameters and growth of these two diatoms.
28 citations
TL;DR: In this paper, the authors provide an updated checklist of the true mangrove species of the Andaman and Nicobar islands. But despite extensive studies on mangroves ecosys -tems of Andaman & Nicobar Islands since the 1870s, knowledge of exact species composition is far from com- plete, and there is a lack of comprehensive locality data.
Abstract: Despite extensive studies on mangrove ecosys - tems of Andaman and Nicobar Islands since the 1870s, knowledge of exact species composition is far from com- plete, and there is a lack of comprehensive locality data The present study was designed to review the existing literature and to provide an updated checklist of the true mangrove species of the Islands Preliminary surveys were carried out in seven regions (four from the Andaman group and three from the Nicobar group), and the specific survey sites for detailed study (n = 51) were selected based on representativeness, importance, and accessibility Dur- ing 2009-2013, all the selected sites were visited, and mangrove species occurrence was recorded At present, 25 true mangrove species distributed among 10 families and 14 genera were identified vis-a-vis 17 to 36 species reported in earlier studies The discernible changes in species num- bers from earlier studies could mainly be attributed to our exclusion of associated littoral vegetation and of species unlikely to be present among the true mangroves of the Islands Given their limited geographical area, the low similarity index values between the Andaman and Nico- bar Island groups ( ≤ 04) indicate a need for periodical surveys, as mangrove biodiversity is usually homogenous in regions where there are no impassable dispersal barri- ers Further, regular updating of information on the extent and status of mangroves in the Islands is imperative not only to improve our understanding of phytogeography but also for better management and conservation
27 citations
TL;DR: This paper provides the first comprehensive checklist of the seaweeds of Cyprus, based on both literature records and new collections, and reports 30 taxa reported for the first time from Cyprus.
Abstract: This paper provides the first comprehensive checklist of the seaweeds of Cyprus, based on both lit- erature records and new collections. The total number of species and infraspecific taxa currently accepted is 313, including 53 green algae (Ulvophyceae), 90 brown algae (Phaeophyceae), and 170 red algae (Rhodophyta). Among them, 30 taxa are reported for the first time from Cyprus: 7 green algae, 9 brown algae, and 14 red algae, while 9 taxa are regarded as aliens. In addition, 10 taxa pending confir- mation of their presence, 3 excludenda, and 3 inquirenda are briefly discussed.
23 citations
TL;DR: The preparation of photoprotective extracts obtained from Solieria chordalis showed maximum absorption wavelengths ranging from 280 to 340 nm and 270 to 350 nm, respectively, and several compounds were detected in the seaweed extract by high-performance liquid chromatography.
Abstract: The photoadaptive responses of macroalgal communities to abiotic stresses have been studied, and a number of UV-absorbing molecules have been identified. Among these compounds, photoprotective compounds such as mycosporine-like amino acids and carotenoids have been isolated from various red macroalgal species. However, several substances still need to be character- ized. We describe the preparation of photoprotective extracts obtained from Solieria chordalis . Two solvents, 2-octyl dodecanol and octyldodecyl ester of l -pyrro- lidone carboxylic acid, were selected based on their cos- metic functions for performing an ultrasound-assisted extraction. The efficiency of extraction was monitored by spectrophotometry and in vitro photoprotective activ- ity measurements. 2-Octyl dodecanol and octyldodecyl ester of l -pyrrolidone carboxylic acid extracts showed maximum absorption wavelengths ranging from 280 to 340 nm and 270 to 350 nm, respectively. The anti UV-B capacity for protecting a synthetic chlorophyll solution was assessed by measuring its pseudo first-order degra- dation kinetics at room temperature. Under irradiation at 312 nm, chlorophyll introduced in the 2-octyl dodecanol S. chordalis extract showed the slowest degradation kinet- ics with a half-life t of 121.0 min. Several compounds were detected in the seaweed extract by high-performance liquid chromatography. Among them, the mycosporine- like amino acid, palythenic acid, was detected in the algal extract.
22 citations
TL;DR: The results indicate that the images captured by ALOS AVNIR-2 are informative and useful for mapping the Sargassum beds in Southeast Asia.
Abstract: Sargassum species grow on rocks and dead coral, forming dense seaweed beds in their growth sea- sons. Sargassum beds play a range of ecological roles in coastal waters, but their sustainability is threatened by pollution and reclamation within ASEAN countries with rapid economic growth. Before conservation initiatives can be implemented, it is necessary to establish their pre- sent distribution. These beds can be mapped using the noncommercial satellite, ALOS, which can provide multi- band images using high spatial resolution optical sensors (sensitive to 10 m -2 plots), AVNIR-2. These images are of suf- ficient quality for examining coastal ecosystems and, in this study, for mapping the Sargassum beds in the waters off the coast of Sattahip, Chon Buri Province, Thailand. This coastal zone is a natural marine park reserve and protected from human activities such as fishery and recla- mation. Biomass data were obtained in January, February, March, and December 2009 from quadrat sampling. The biomass of Sargassum aquifolium (Turner) C.Agardh at a bottom depth of 1 m and 1.5-2 m was determined to be 7.73 and 92.75 g dw m -2 , while that of Sargassum oligocystum Montagne was found to be 44.05 and 87.97 g dw m -2 , respectively. Ground truth data were obtained in February and October 2012 from serial images taken by manta tow. Supervised classification is a procedure for identifying spectrally similar areas on an image by identifying "train- ing" sites of known targets and then extrapolating those spectral signatures to other areas of unknown targets. By applying this methodology, the Sargassum beds off Sat- tahip can be detected with an accuracy of about 70%. It is estimated that the error is caused by mixel effects of the bottom substrates in individual pixels, each of which covers an area of 10 × 10 m. Our results indicate that the images captured by ALOS AVNIR-2 are informative and useful for mapping the Sargassum beds in Southeast Asia.
21 citations
TL;DR: The results suggest that MAA content in P. columbina varied in the short-term and the changes were related to the solar irradiance received and NO3- availability.
Abstract: Abstract Short-term variations of mycosporine-like amino acids (MAAs) in Pyropia columbina (Montage) W.A. Nelson exposed to nitrate (NO3-) enrichment under different outdoor light treatments during the spring ozone depletion of 2008 in Punta Arenas (Chile) were investigated. Segments of P. columbina thalli were cultivated under three treatments of solar radiation without or with NO3- supply (0.38 mmol l-1): PAR (P), PAR+UVA (PA), and PAR+UVA+UVB (PAB). Samples were taken at 8:00 h (initial value), 9:30, 12:30, 15:30, and 18:00 h on November 8 and at 9:00 h on November 9 (recovery period). A complex dynamic of MAAs affected by light quality and NO3- supply was observed. During the light period, the highest content of MAAs was reached under PAB and NO3- enrichment, whereas MAAs increased during the recovery period in P and PAB with no NO3- supply. Five MAAs were identified: porphyra-334, shinorine, asterina-330, palythine, and mycosporine-glycine. The hourly accumulation of each MAA varied mainly according to the time of exposure and NO3- supply. In general, the percentage of porphrya-334 increased, whereas the other MAAs decreased during the exposure period. These results suggest that MAA content in P. columbina varied in the short-term (hours) and the changes were related to the solar irradiance received and NO3- availability.
21 citations
TL;DR: A new genus Galene is proposed to include three species from New Zealand, two of which are described as new here and transfer Cryptonemia rotunda to this new genus.
Abstract: Abstract New Zealand foliose red algae belonging to the family Halymeniaceae were examined with a focus on species that have been placed in the genera Halymenia and Cryptonemia. Phylogenetic analyses of plastid-encoded rbcL and morphological observations were undertaken. Samples from northern New Zealand, referred to as Halymenia latifolia, were compared genetically with H. latifolia from its type locality in France. The New Zealand material was clearly separate from the genus Halymenia and from H. latifolia, and was found to be closely related to Halymenia abyssicola from Mexico. The new genus Amalthea is described to accommodate the New Zealand taxon. Samples referred to Cryptonemia sp. from New Zealand formed a well-supported clade with Cryptonemia rotunda from Korea and Japan. This clade was distinct from the clade containing the generitype Cryptonemia lomation from France and other species of Cryptonemia. We propose a new genus Galene to include three species from New Zealand, two of which are described as new here and transfer Cryptonemia rotunda to this new genus.
19 citations
TL;DR: P. rhizophorae differs from other members of the Diatrypaceae in that this species has apically truncate asci without an apical apparatus, which deliquesce at maturity, whereas diatrypaceous species have persistent long-stalked asci with a more or less truncate apex.
Abstract: Abstract Pedumispora rhizophorae, a marine ascomycete reported only from mangrove habitats, was referred to the Diaporthales on the basis of morphological characteristics. To clarify the phylogenetic classification of P. rhizophorae, we re-examined the morphological features of a recent collection of this fungus and evaluated its taxonomic position at the molecular level. Phylogenetic analyses revealed that P. rhizophorae is distantly placed from the Diaporthales, and groups in the Diatrypaceae, Xylariales with strong support. Pedumispora rhizophorae shares many features with members of the Diatrypaceae, including its saprobic habit on decaying plant material, ascomata embedded in a pseudostroma, the presence of paraphyses and pigmented ascospores. However, P. rhizophorae differs from other members of the Diatrypaceae in that this species has apically truncate asci without an apical apparatus, which deliquesce at maturity, whereas diatrypaceous species have persistent long-stalked asci with a more or less truncate apex. Within the Diatrypaceae, the ascospores of most species are allantoid in shape and unicellular, whereas P. rhizophorae possesses septate, filiform ascospores with apical cells lacking cytoplasm. Filiform ascospores and deliquescing asci are common in many unitunicate marine ascomycetes and are regarded as an adaptation to aquatic environment.
19 citations
TL;DR: The occurrence of small macroalgal thalli that have short life cycles induced high species replacement and subsequently high β diversity, with spatial heterogeneity and environmental gradient as drivers of β diversity.
Abstract: β Diversity is an ecological concept used to describe the turnover of species across a wide range of spatial and temporal scales, but such knowledge is lacking for macroalgal assemblages of the Red Sea. β Diversity pat- terns for Red Sea macroalgae were evaluated from different sites (Hurghada, Safaga, and Al-Quseir) and seasons across different environmental disturbances. β Diversity was studied by partitioning the total number of species (γ diversity) into additive components. Geographical hetero- geneity was more important than seasonal heterogeneity in structuring macroalgae both at species and functional group levels. Species replacement as a component of β diversity produced dissimilarity in species composition and taxonomic structure. Replacement of species between sites was responsible for the presence of new functional groups of macroalgae. High β diversity and taxonomic similarity values were characteristic of the macroalgae of the Red Sea. The occurrence of small macroalgal thalli that have short life cycles induced high species replacement and subsequently high β diversity, with spatial heteroge- neity and environmental gradient as drivers of β diversity. Anthropogenic disturbance at the Safaga site was sug- gested to induce variation of macroalgal assemblages and functional groups. Excluding rare species from the data set did not change the high values of β diversity.
TL;DR: The data suggest that secondary metabolites from algae and their associated microbiota are an important source of QS inhibitors, which potentially can be used in future biotechnological applications.
Abstract: Abstract The ability of polar (1:1 water/methanol) and non-polar (dichloromethane) extracts of macroalgae from Arraial do Cabo, RJ, Brazil, to inhibit quorum sensing (QS) was investigated. Before extraction, half of the algae were treated with 30% ethanol to kill and remove surface-associated bacteria. Twenty of 22 polar extracts inhibited the QS of the acyl homoserine lactone (AHL) producer and reporter Chromobacterium violaceum CV017 with minimal inhibitory concentrations (MIC) ranging from 0.28 μg ml-1 (Ulva fasciata) to 189 μg ml-1 (Codium sp.). The MIC of non-polar extracts varied from 69 μg ml-1 (Sargassum furcatum) to 2730 μg ml-1 (Peyssonnelia capensis). Usually, extracts from algae with associated bacteria had a higher bioactivity than ones without them. Among 11 algal species tested, 50% of extracts with associated bacteria were toxic to C. violaceum CV026. None of the extracts contained AHLs, which was shown using reporters C. violaceum CV026 and Agrobacterium tumefaciens NTL4 (pZLR4). Polar (11%) and non-polar extracts (2%) inhibited QS-dependent attachment of Pseudomonas aeruginosa PA01 at tissue-level concentrations. Our data suggest that secondary metabolites from algae and their associated microbiota are an important source of QS inhibitors, which potentially can be used in future biotechnological applications.
TL;DR: Cyst morphology, germination characteristics, and toxicity were investigated using samples from Isla San José in the Gulf of California, and Morphological features and size of cysts generally agree with previous descriptions, particularly morphotypes found in the subtropical North Atlantic.
Abstract: Pyrodinium bahamense is a meroplanktonic dinoflagellate that produces paralytic shellfish toxins that cause human poisoning along tropical and subtropical coasts. Cyst morphology, germination characteristics, and toxicity were investigated using samples from Isla San Jose in the Gulf of California. Morphology was observed through light and scanning electron microscopy. Germination was tested at different temperature (15°C-35°C) and salinity (15-35) conditions in different culture media (natural sea- water, GSe, and f/2). To elucidate toxicity of vegetative cells grown from cyst germination, nine strains were subject to toxin analyses through fluorescence high-performance liq- uid chromatography. Morphological features and size of cysts generally agree with previous descriptions, particu- larly morphotypes found in the subtropical North Atlan- tic, where P. bahamense var. bahamense occurs. Cysts exhibit thermophilic and euryhaline characteristics. High- est germination occurred from 20°C to 35°C with the peak between 25°C and 30°C. Excystment occurred at salinities from 20 to 35. Germination occurred in the three culture media, but was highest in the optimal temperature range in the culture medium that included terrestrial soil extract and selenium. Only one strain exhibited toxicity with high saxitoxin concentration (95 pg STX eq cell -1 ).
TL;DR: The ascomatal morphology of this fungus is similar to other marine Dactylospora species, whereas the unique feature of the new fungus is a distinct perispore forming an ascospore appendage, which comprises a thick and hyaline sheath connected at the septum that opens at both ends.
Abstract: Abstract An apparently undescribed lignicolous Dactylospora species was collected on a rocky shore in northern Taiwan. The ascomatal morphology of this fungus is similar to other marine Dactylospora species, whereas the unique feature of the new fungus is a distinct perispore forming an ascospore appendage, which comprises a thick and hyaline sheath connected at the septum that opens at both ends. Dactylospora vrijmoediae is described and illustrated as new to science. On the basis of a phylogenetic analysis of the partial 18S and 28S rRNA and RPB2 genes, D. vrijmoediae occurs with other marine species, D. haliotrepha, D. mangrovei, and the terrestrial Sclerococcum sphaerale in an unnamed clade within the Eurotiomycetes, Ascomycota. The marine Dactylospora species are distantly placed and are separated from the terrestrial Dactylospora species included in the analysis (D. lobariella, D. imperfecta).
TL;DR: The photoprotection mechanisms in the marine microalga Isochrysis galbana were examined by comparing the photosynthetic characteristics in two I. galbANA strains IOAC724S and IOAC683S under high light and it was suggested that NPQ was not strong enough to dissipate the excess excitation energy, and CEF-I might protect the photosynthesis apparatus against photodamage.
Abstract: The photoprotection mechanisms in the marine microalga Isochrysis galbana were examined by comparing the photosynthetic characteristics in two I. galbana strains IOAC724S and IOAC683S under high light. The rDNA ITS regions of IOAC724S and IOAC683S were closely clustered in the Neighbor-Joining tree, suggesting that the two strains are very similar to each other genetically. Regulated energy dissipation in photosystem (PS) II (NPQ) and cyclic electron flow with PSI (CEF-I) can protect the photosynthetic apparatus against photodamage. There were no significant differences in NPQ and CEF-I between IOAC724S and IOAC683S under high light. In both strains, NPQ was very low, and CEF-I was maintained at a high level. This suggested that NPQ was not strong enough to dissipate the excess excitation energy, and CEF-I might protect the photosynthetic apparatus against photodamage in I. galbana. Photosynthetic linear electron flow was lower, but the alternative electron flow within PSII (AEF-II) was significantly higher in IOAC724S than in IOAC683S. The higher AEF-II in IOAC724S efficiently removed excess excitation energy, thereby, protecting the photosynthetic apparatus, as indicated by the lower value of quantum yield of the nonregulated energy dissipation of PSII and the lower content of hydrogen peroxide in IOAC724S.
TL;DR: The data indicate that bloom-forming overwintering Ulva simultaneously use multiple reproductive strategies, which indicates that blooming macroalgae in temperate coastal estuaries worldwide are influenced by seasonal macroalgal blooms during warm months, whereas bloom-forms are rarely encountered during winter.
Abstract: Temperate coastal estuaries worldwide such as Narragansett Bay, Rhode Island are impacted by seasonal macroalgal blooms (e.g. Ulva) during warm months, while bloomforming macroalgae are rarely encountered during winter. We assessed the ability of distromatic Ulva to overwinter via fragments, recruits, and/or microscopic propagules. We documented: a) small tissue fragments in sediment cores and the water column, b) recruits and microscopic propagules on field-based settlement tiles, and c) production of reproductive propagules, throughout the winter months. Laboratory culturing experiments indicated that both fragments and propagules are viable. Our data indicate that bloomforming overwintering Ulva simultaneously utilize multiple reproductive strategies.
TL;DR: The morphology of two new species of Mastogloia identified during a survey of the marine benthic diatom flora of Guam are described, one of which is distinctive in the combination of its valve shape and stria pattern reminiscent of Parlibellus.
Abstract: Abstract This paper describes the morphology of two new species of Mastogloia identified during a survey of the marine benthic diatom flora of Guam. Mastogloia parlibellioides sp. nov., classified in the section Decussatae, is distinctive in the combination of its valve shape and stria pattern reminiscent of Parlibellus, as well as the presence of rudimentary division walls extending from the free margin to the middle of each partectum. Mastogloia lyra sp. nov., classified in the section Sulcatae, subgroup 2, has internal lyre-shaped lateral sterna and partecta that are displaced toward the midline of the valve by a siliceous flange, which shows oblique partectal ducts. The descriptions of these two new species increase the knowledge base of biodiversity in a Pacific Ocean Mastogloia hotspot.
TL;DR: The first occurrence of the red seaweed Laurencia chondrioides in the eastern Mediterranean Sea is reported, representing a serious threat to the local marine flora.
Abstract: Abstract The Mediterranean coast of Israel is well known as a hotspot of invasive marine species, mostly from the Indian and Pacific oceans. Here, we report the first occurrence of the red seaweed Laurencia chondrioides in the eastern Mediterranean Sea. Large quantities of this species were observed in the algal drift on the sandy shores as well as on rocky surfaces of the upper and middle infralittoral zone. This highly abundant invasive species, present along the northern shore of Israel, represents a serious threat to the local marine flora. Some aspects of its ecology and invasive behavior in this region are also discussed.
TL;DR: It is concluded that the installation of kelp seeded substratum units may be an option for recovery of exploited M. pyrifera forests.
Abstract: Abstract In Chile, the brown alga Macrocystis pyrifera has been subject to strong harvesting pressure, resulting in severe reduction of natural beds, and a threat to the sustainability of the resource. Repopulation is a possible means for the recovery of overexploited natural populations of M. pyrifera. In this study, we determined density (ind. cm-2), length (mm) and biomass (g) of M. pyrifera sporophytes sown on three types of substrata (ceramic plates, pot scrubbers, clam shells). In laboratory experiments, sporophytes on ceramic plates were significantly longer than those on pot scrubbers or shells after 60 days, and their density was also higher. Juvenile sporophytes seeded on the three substrata were transferred to the sea and placed either inside or outside a M. pyrifera forest. At the end of the experiment in the sea under the kelp forest, highest biomass and length were obtained on the clam shell substrates, but the density did not show significant differences between the substrates. However, outside the kelp forest, no significant differences in kelp density or length were observed between the three substrates tested; but the biomass was significantly higher on the clam shells than on the other two substrata. We conclude that the installation of kelp seeded substratum units may be an option for recovery of exploited M. pyrifera forests.
TL;DR: The river-sea transition was marked by a decrease in the relative abundance of green algae and cyanobacteria, but an increase in chrysophyte algae, which contribute to the understanding of biological processes in the estuaries of large rivers flowing into the shelf zone of the Arctic Ocean.
Abstract: Abstract Changes in phytoplankton community composition related to salinity, allochthonous matter, and nutrients were found in the mixing zone that extended from the outflow of the lower Yenisei River into the Yenisei Gulf and Kara Sea in Russia. The highest cell abundance (140–662×103 cells m-3), biomass (138–950 mg m-3) and species diversity were found in the freshwater area (i.e., the lower reaches of the Yenisei River). The river-sea transition was marked by a decrease in the relative abundance of green algae and cyanobacteria, but an increase in chrysophyte algae. The ratio of freshwater and marine phytoplankton species was quantified in each habitat. The results contribute to our understanding of biological processes in the estuaries of large rivers flowing into the shelf zone of the Arctic Ocean.
TL;DR: The alternating arrangement of unilateral branch pairs and the placement of the scar cell between two pericentral cells are recognized as main characters to identify P. dokdoensis, a new species collected from Dokdo, Korea.
Abstract: Abstract The genus Polysiphonia Greville is characterized by having four ecorticated pericentral cells, rhizoids in open connection with the pericentral cells, four-celled carpogonial branches, spermatangial branches replacing the whole trichoblast, and tetrasporangia in straight series. Polysiphonia dokdoensis sp. nov. collected from Dokdo, Korea is here described as a new species on the basis of morphological and molecular data. Polysiphonia dokdoensis is characterized by having four ecorticated pericentral cells, unicellular rhizoids in open connection with pericentral cells, scar cells placed between two pericentral cells, an alternating arrangement of unilateral branch pairs, and tetrasporangia in straight series. The alternating arrangement of unilateral branch pairs and the placement of the scar cell between two pericentral cells are recognized as main characters to identify P. dokdoensis. Polysiphonia dokdoensis is morphologically identical to “P. atlantica” sensu Kim and Lee, which is now recognized as P. dokdoensis sp. nov. and distinguished from the authentic European P. atlantica by the distinguishing morphological character states. Phylogenetic analyses of rbcL confirm the placement of the new taxon as a distinct species in Polysiphonia sensu stricto.
TL;DR: In this article, the recruitment, distribution, and persistence of three Ulva species were investigated in relation to surface roughness using artificial substrates on intertidal rocky shores of the southern coast of Korea.
Abstract: Abstract Patterns in the recruitment, distribution, and persistence of three Ulva species, which can form green tides, were investigated in relation to surface roughness using artificial substrates on intertidal rocky shores of the southern coast of Korea. The vertical distributions of Ulva pertusa, Ulva linza, and Ulva compressa were well separated: U. compressa usually dominated in the upper zone and U. pertusa and U. linza in the lower zone. Ulva pertusa recruitment was observed during autumn, when inorganic nitrogen concentrations in the surface water column were highest. However, the recruitments of U. linza usually occurred during early winter and spring and that of U. compressa during summer–autumn. Ulva pertusa showed highest settlement on rough surfaces in both zones, whereas this pattern only appeared in the upper zone for U. linza and U. compressa. These results indicate that settlement patterns may be affected by desiccation in the upper zone and waves in the lower zone. Once blooms occurred, U. pertusa persisted for about twice as long as the other two Ulva species, suggesting that U. pertusa played an important role in community change. This is the first documentation of persistence periods related to recruitment in bloom-forming green macroalgae.
TL;DR: The increasing number of shipping and aquaculture activities worldwide and the ability of this species to be a successful invader suggest that P. morrowii is likely to beA cosmopolitan invasive species and that further management planning is required for its early detection and control.
Abstract: Seaweed invasions are recognized as one of the major threats to biological diversity and coastal resources. Nevertheless, the number of introduced macroalgae has been underestimated due to the increasing number of cryptic invasions. Polysiphonia morrowii is native to the North Pacific and several cryptic introductions of this species have been reported over the past decade. In this study, we recorded the presence of the invasive P. morrowii in the Southwestern Atlantic (Patagonia Argentina) using a morphological and molecular approach for the identification at species level. Polysiphonia morrowii specimens from Argentina showed no morphological differences from members of invasive populations in France. We found two different haplotypes, suggesting that P. morrowii was probably introduced into this area by multiple introduction events. The increasing number of shipping and aquaculture activities worldwide and the ability of this species to be a successful invader suggest that P. morrowii is likely to be a cosmopolitan invasive species and that further management planning is required for its early detection and control.
TL;DR: This research provides a characterization of different seagrass strategies, which involve differential changes in leaf pigmentation and morphological adjustments to survive under stresses during emersion in the intertidal zone.
Abstract: Abstract Intertidal seagrasses often cope with a complex combination of stresses during low tide, especially light, temperature, and desiccation, which influence seagrass survival mechanisms, consequently forming zonation patterns along the shore. To investigate whether seagrass pigment and leaf morphological characteristics change in response to emersion, we sampled three intertidal seagrass species (Halophila ovalis, Cymodocea rotundata, and Thalassia hemprichii) in Laem Yong Lam, Haad Chao Mai National Park, Trang, Thailand. Using transplantation methods across the upper and lower intertidal zones, where emersion times differ, we found that these three seagrass species have different adaptive strategies to grow under stresses in the intertidal zone. All three seagrass species responded to decreasing emersion times by decreasing leaf length and width. The leaf sheath of C. rotundata increased in length with decreasing emersion times. Our research provides a characterization of different seagrass strategies, which involve differential changes in leaf pigmentation and morphological adjustments to survive under stresses during emersion in the intertidal zone.
TL;DR: Interestingly, the expression of three CA subtypes, including one α-, one β-, and one γ-CA, analyzed by real-time quantitative PCR, showed induction by high salinity, which will help understand CCM in the genus Chlorella.
Abstract: Abstract In this study, the transcriptome of the marine microalga, Chlorella pyrenoidosa 820, was sequenced by high-throughput RNA-seq using Illumina HiSeq 2000. Because the genome sequence of this species is unknown, the resulting transcriptome was assembled de novo and annotated. This resulted in 4.71G clean nucleotides with a 56.91% GC content and yielded a total of 36,826 unigenes with a mean length of 1089 nt. Among these, 23,015 unigenes were annotated in the NCBI-NR, NCBI-NT, Swiss-Prot, KEGG, COG, and GO databases with a cutoff E-value of 10-5. In the annotated sequences, 21 unigenes were identified as carbonic anhydrase (CA), which is an important enzyme in the CO2-concentrating mechanism (CCM), and were homologous to nine α-, eight β-, and four γ-CAs. Interestingly, the expression of three CA subtypes, including one α-, one β-, and one γ-CA, analyzed by real-time quantitative PCR, showed induction by high salinity. These results will enrich the CA gene information in the database and will help understand CCM in the genus Chlorella.
TL;DR: Data suggest seasonal differences may be modulated by the environmental variability in the temperate kelp populations and support local coupling of these two organisms at their southern range limit, in spite of the particularly unique physical conditions which occur in these populations at times.
Abstract: Although several studies have described kelp- urchin interactions, little is known about these inter- actions toward the distributional range limits of these species in areas that may experience different physical conditions than at the center of the distributional range. We explored seasonal and latitudinal changes in the population structure of the giant kelp and the purple sea urchin at their southern limits in the northern hemisphere. Densities of both organisms were positively correlated, showing a significant effect of season and latitude, and were highest in the temperate kelp populations and in the spring. The near subtropical kelp populations, however, contained significantly larger urchins. Along the bound- ary between the kelp beds and the urchin barrens studied, no significant spatial difference was found in sea urchin size or density. However, a general pattern of increasing probability of urchin presence with distance outside of the bed was found in spring at all sites. Spring bottom tem- peratures were generally colder and more variable in the temperate kelp populations, potentially explaining the larger seasonal variability found there. Data suggest sea- sonal differences may be modulated by the environmental variability in the temperate kelp populations and support local coupling of these two organisms at their southern range limit, in spite of the particularly unique physical conditions which occur in these populations at times.
TL;DR: An updated checklist of the benthic marine algae (seaweeds) of Barbados, Lesser Antilles, is presented, with a total of 308 taxa, consisting of 168 taxa of red algae (Rhodophyta), 49Taxa of brown algae (Ochrophyta), and 91 taxaof green algae (Chlorophyta).
Abstract: An updated checklist of the benthic marine algae (seaweeds) of Barbados, Lesser Antilles, is presented, with a total of 308 taxa, consisting of 168 taxa of red algae (Rhodophyta), 49 taxa of brown algae (Ochrophyta), and 91 taxa of green algae (Chlorophyta). Current nomenclature is provided. Obsolete names and taxonomic synonyms are indicated in brackets. The classification is based on contemporary systems increasingly derived from the results of molecular phylogenies. The following eight taxa are newly reported for Barbados: Polysiphonia foetidissima, Hypnea valentiae, Gracilaria cylindrica, Gracilaria intermedia, Sargassum buxifolium, Cladophora laetevirens, Avrainvillea mazei, and Avrainvilleanigricans f. spongiosa.
TL;DR: The Kok method was used to estimate whether mitochondrial respiration suppression occurs in the seagrasses Zostera marina and Ruppia maritima as well as in the macroalga Ulva intestinalis, and the respiration rate was clearly downregulated in light.
Abstract: To properly calculate the carbon budgets of coastal marine habitats, potential fluctuations in oxygen consumption due to mitochondrial respiration must be taken into account. As mitochondrial respi ...
TL;DR: Morphological and molecular data confirmed that the presence of unangia with (2–) 3–6 stalk cells and mostly unilateral symmetry with partial bilateral development is characteristic of this species and distinguishes it from the morphologically similar Neoralfsia expansa sensu Børgesen.
Abstract: To resolve the taxonomic status of Ralfsia han- cockii and its relationship to related species, we have car- ried out a morphological and molecular study (rbcL) on the topotype material of the species. Our analyses, using maximum parsimony and Bayesian posterior probability, located this species in a clade that is distinct and distant from other species of the genus Ralfsia and other genera of the family Ralfsiaceae, but is shared with the family Neoralfsiaceae. Morphological data confirmed that the presence of unangia with (2-) 3-6 stalk cells and mostly unilateral symmetry with partial bilateral development is characteristic of this species and distinguishes it from the morphologically similar Neoralfsia expansa sensu Borgesen. Similarities to N. expansa sensu Tanaka and Chihara, from which the latter species is distinguished by having paraphyses with thinner and larger basal cells, are discussed. We propose Neoralfsia hancockii comb. nov.
TL;DR: Insight is provided into metal accumulation by, and their effects on, submerged angiosperms colonizing coastal waters, and an earlier onset of cell death at the highest exposure concentration was associated with the highest uptake rate, and dead cell percentage on the ninth day tended to increase with uptake rate.
Abstract: Abstract Cadmium accumulation and leaf cell death in the brackish water-submerged angiosperm Ruppia maritima L. were investigated under laboratory conditions exposed to increasing metal concentrations (2.22–355.88 μm). The Michaelis-Menten equation satisfactorily described accumulation kinetics in plant compartments (leaves, rhizome-stems, roots). Equilibrium concentration and uptake rate generally tended to increase, whereas bioconcentration factor at equilibrium decreased, as exposure concentration increased. The relationship between tissue concentration and the set of exposure concentrations and times was adequately described by multiple regression equations. Leaf cell death was observed after 3 or 5 days depending on dosage, but dead cell percentage was small after 9 days, suggesting a rather slow progress of cell death. The lowest leaf cadmium concentration associated with the onset of cell death was within the range of cadmium concentrations reported for seagrasses from various locations, implying that cadmium poses a risk to submerged angiosperms in coastal waters. However, toxicity appeared to be related to the rate of metal uptake rather than to total tissue concentration; an earlier onset of cell death at the highest exposure concentration was associated with the highest uptake rate, and dead cell percentage on the ninth day tended to increase with uptake rate. The data presented provide insights into metal accumulation by, and their effects on, submerged angiosperms colonizing coastal waters.