The Experts below are selected from a list of 5076 Experts worldwide ranked by ideXlab platform
Kuninao Tada - One of the best experts on this subject based on the ideXlab platform.
-
nutrient and phytoplankton dynamics in harima nada eastern seto inland sea japan during a 35 year period from 1973 to 2007
Estuaries and Coasts, 2010Co-Authors: Tetsuya Nishikawa, Yutaka Hori, Satoshi Nagai, Kazutaka Miyahara, Yukinobu Nakamura, Kazuhiro Harada, Minoru Tanda, Takehiko Manabe, Kuninao TadaAbstract:Long-term monitoring of water quality and phytoplankton was conducted at 19 sampling stations in Harima-Nada, eastern Seto Inland Sea, Japan for 35 years from 1973 to 2007. There were two significant long-term changes, an increase in winter water temperatures of 0.042°C year−1, and a decrease in dissolved inorganic nitrogen (DIN) from about 10 μM in the 1970s to ~5 μM in the late 1990s due to the reduction in nutrient inputs. DIN concentrations and total phytoplankton cell density were both higher during the 1970s to the early 1980s and then exhibited a significant decrease in the mid 1980s and remained relatively constant thereafter. Diatoms were the dominant phytoplankton group (>90%) over the 35-year period, and there was a dramatic shift from Skeletonema dominance (~70%) to Chaetoceros in the mid 1980s. This shift in diatom species may be attributed to differences in the life cycle of Skeletonema and Chaetoceros and the response to the decrease in DIN concentration.
Angelo Fontana - One of the best experts on this subject based on the ideXlab platform.
-
production of octadienal in the marine diatom Skeletonema costatum
Organic Letters, 2003Co-Authors: Giuliana Dippolito, Guido Cimino, Giovanna Romano, Tonino Caruso, Aldo Spinella, Angelo FontanaAbstract:Marine diatoms produce α,β,γ,δ-unsaturated aldehydes that have detrimental effects on the reproduction of their natural predators. The production of these defensive metabolites is suggested to involve enzymatic oxidation of polyunsaturated fatty acids. In this paper, feeding experiments with labeled precursor provide clear evidence in support of the origin of octadienals 1 and 2 from 6,9,12-hexadecatrienoic acid (5), thus proving the involvement of novel lipoxygenase/lyase activity for the oxidation of C16 fatty acids.
-
new birth control aldehydes from the marine diatom Skeletonema costatum characterization and biogenesis
Tetrahedron Letters, 2002Co-Authors: Giuliana Dippolito, Olimpia Iadicicco, Adrianna Ianora, Antonio Miralto, Guido Cimino, Giovanna Romano, Angelo FontanaAbstract:Abstract The paper describes the identification of short-chain aldehydes ( 4 – 7 ) from the marine diatom Skeletonema costatum , and their effects on copepod egg viability and sea urchin cell division. Compounds 4 – 7 were isolated as carboethoxyethylidene (CET) derivatives and their characterization was performed by NMR and GCMS analyses. Evidence is presented to support the defensive role and biosynthetic origin of these compounds in S. costatum .
Adriana Zingone - One of the best experts on this subject based on the ideXlab platform.
-
global diversity and biogeography of Skeletonema species bacillariophyta
Protist, 2008Co-Authors: Wiebe H C F Kooistra, Diana Sarno, Sergio Balzano, Haifeng Gu, Robert A Andersen, Adriana ZingoneAbstract:Abstract Recent studies have shown that the cosmopolitan diatom Skeletonema costatum sensu lato is composed of several morphologically and genetically distinct species. To assess whether the separate species have a cosmopolitan distribution, we analysed 184 strains from marine and estuarine sites worldwide. We identified the strains using light and electron microscopy, and we sequenced the hyper-variable region of nuclear LSU rDNA. All recently described species were genetically distinct, and all but two were morphologically distinct. Variability was found for the only ultrastructural character used to distinguish Skeletonema dohrnii and S. marinoi, which cannot be identified based on morphology alone. Furthermore, multiple genetically distinct taxa, which may represent cryptic species, were found within the S. menzelii and S. tropicum clades. We found that all currently recognized species of Skeletonema are widespread, however, gaps seem to occur in their geographical ranges. For example, some species are found in both the northern and southern temperate latitudes whereas other species appear to have only subtropical to tropical ranges. Skeletonema pseudocostatum and S. grethae seem to have more restricted geographical ranges because the former was not found along American coasts and the latter was encountered only in US waters. A taxonomic update is provided for Skeletonema strains currently available in several culture collections, which could aid reinterpretation of results obtained in comparative studies using these strains.
-
diversity in the genus Skeletonema bacillariophyceae iii phylogenetic position and morphological variability of Skeletonema costatum and Skeletonema grevillei with the description of Skeletonema ardens sp nov
Journal of Phycology, 2007Co-Authors: Diana Sarno, Paul E. Hargraves, Sergio Balzano, Wiebe H C F Kooistra, Adriana ZingoneAbstract:Skeletonema costatum (Grev.) Cleve emend. Zingone et Sarno and S. grevillei Sarno et Zingone were known only from the type material collected from Hong Kong waters more than a century ago. Both species have now been collected as live material, and their morphology and phylogenetic position are investigated in this study. Eight Skeletonema strains isolated from Florida, USA; Uruguay; and Brazil are attributed to S. costatum, while one strain from Oman is ascribed to S. grevillei based on morphological similarity to the type material of these species. In addition, a new Skeletonema species, S. ardens Sarno et Zingone, is described for a strain from Singapore and two from northern Australian waters. Skeletonema ardens has terminal fultoportula processes ending in a tapered, undulate protrusion and long intercalary fultoportulae with 1:1 junctions. The rimoportula of terminal valves is located at the margin of the valve face. No major morphological variations were observed within S. grevillei and S. ardens along a salinity gradient, whereas in S. costatum, the processes shortened and the valves came into close contact at low salinities, as already described for S. subsalsum (Cleve) Bethge. Consistent with their morphology, Skeletonema costatum and Skeletonema subsalsum also had similar rDNA sequences. Skeletonema grevillei and S. ardens were distinct in the large subunit (LSU) phylogeny. Skeletonema ardens exhibited consistent intraspecific genetic differences in both the LSU and small subunit (SSU) rDNA.
-
diversity in the genus Skeletonema bacillariophyceae i a reexamination of the type material of s costatum with the description of s grevillei sp nov
Journal of Phycology, 2005Co-Authors: Adriana Zingone, Isabella Percopo, Pat A Sims, Diana SarnoAbstract:The type material of Skeletonema costatum (Greville) Cleve was reexamined with the aims of providing an EM description of the species and clarifying which of the recently recognized Skeletonema Greville species, if any, deserves the epithet costatum. Two permanent mounts and two loose samples from the same collections from Hong Kong Bay were examined. Two distinct Skeletonema species were found in all materials. Based on the original description and on the observation of the lectotype, it was concluded that the most abundant morph in the type material is S. costatum. Cells were heavily silicified and 5-16 μm in diameter. The external processes of the fultoportulae in the terminal valves were open tubules with claw-shaped tips. The intercalary fultoportulae processes were closed flattened tubules with a pore at their base, each attached to two processes of the sibling valve (1:2 junction). The rimoportula had a long process and was located marginally in all valves. The second morph in the type material was described as Skeletonema grevillei Sarno et Zingone sp. nov. Cells were delicate, 4-7.5 μm in diameter, and formed short colonies. The fultoportulae processes in the terminal valves were open tubes having narrow tips with truncated or spiny margins. In the intercalary valves, they formed knuckle-like generally 1:1 junctions. A scallop-work of silica bridges joined the bases of the processes. The rimoportula was marginal in all valves. Neither S. costatum nor S. grevillei match any Skeletonema species that have been recently analyzed by combined morphological and molecular approaches.
Tetsuya Nishikawa - One of the best experts on this subject based on the ideXlab platform.
-
nutrient and phytoplankton dynamics in harima nada eastern seto inland sea japan during a 35 year period from 1973 to 2007
Estuaries and Coasts, 2010Co-Authors: Tetsuya Nishikawa, Yutaka Hori, Satoshi Nagai, Kazutaka Miyahara, Yukinobu Nakamura, Kazuhiro Harada, Minoru Tanda, Takehiko Manabe, Kuninao TadaAbstract:Long-term monitoring of water quality and phytoplankton was conducted at 19 sampling stations in Harima-Nada, eastern Seto Inland Sea, Japan for 35 years from 1973 to 2007. There were two significant long-term changes, an increase in winter water temperatures of 0.042°C year−1, and a decrease in dissolved inorganic nitrogen (DIN) from about 10 μM in the 1970s to ~5 μM in the late 1990s due to the reduction in nutrient inputs. DIN concentrations and total phytoplankton cell density were both higher during the 1970s to the early 1980s and then exhibited a significant decrease in the mid 1980s and remained relatively constant thereafter. Diatoms were the dominant phytoplankton group (>90%) over the 35-year period, and there was a dramatic shift from Skeletonema dominance (~70%) to Chaetoceros in the mid 1980s. This shift in diatom species may be attributed to differences in the life cycle of Skeletonema and Chaetoceros and the response to the decrease in DIN concentration.
Diana Sarno - One of the best experts on this subject based on the ideXlab platform.
-
global diversity and biogeography of Skeletonema species bacillariophyta
Protist, 2008Co-Authors: Wiebe H C F Kooistra, Diana Sarno, Sergio Balzano, Haifeng Gu, Robert A Andersen, Adriana ZingoneAbstract:Abstract Recent studies have shown that the cosmopolitan diatom Skeletonema costatum sensu lato is composed of several morphologically and genetically distinct species. To assess whether the separate species have a cosmopolitan distribution, we analysed 184 strains from marine and estuarine sites worldwide. We identified the strains using light and electron microscopy, and we sequenced the hyper-variable region of nuclear LSU rDNA. All recently described species were genetically distinct, and all but two were morphologically distinct. Variability was found for the only ultrastructural character used to distinguish Skeletonema dohrnii and S. marinoi, which cannot be identified based on morphology alone. Furthermore, multiple genetically distinct taxa, which may represent cryptic species, were found within the S. menzelii and S. tropicum clades. We found that all currently recognized species of Skeletonema are widespread, however, gaps seem to occur in their geographical ranges. For example, some species are found in both the northern and southern temperate latitudes whereas other species appear to have only subtropical to tropical ranges. Skeletonema pseudocostatum and S. grethae seem to have more restricted geographical ranges because the former was not found along American coasts and the latter was encountered only in US waters. A taxonomic update is provided for Skeletonema strains currently available in several culture collections, which could aid reinterpretation of results obtained in comparative studies using these strains.
-
diversity in the genus Skeletonema bacillariophyceae iii phylogenetic position and morphological variability of Skeletonema costatum and Skeletonema grevillei with the description of Skeletonema ardens sp nov
Journal of Phycology, 2007Co-Authors: Diana Sarno, Paul E. Hargraves, Sergio Balzano, Wiebe H C F Kooistra, Adriana ZingoneAbstract:Skeletonema costatum (Grev.) Cleve emend. Zingone et Sarno and S. grevillei Sarno et Zingone were known only from the type material collected from Hong Kong waters more than a century ago. Both species have now been collected as live material, and their morphology and phylogenetic position are investigated in this study. Eight Skeletonema strains isolated from Florida, USA; Uruguay; and Brazil are attributed to S. costatum, while one strain from Oman is ascribed to S. grevillei based on morphological similarity to the type material of these species. In addition, a new Skeletonema species, S. ardens Sarno et Zingone, is described for a strain from Singapore and two from northern Australian waters. Skeletonema ardens has terminal fultoportula processes ending in a tapered, undulate protrusion and long intercalary fultoportulae with 1:1 junctions. The rimoportula of terminal valves is located at the margin of the valve face. No major morphological variations were observed within S. grevillei and S. ardens along a salinity gradient, whereas in S. costatum, the processes shortened and the valves came into close contact at low salinities, as already described for S. subsalsum (Cleve) Bethge. Consistent with their morphology, Skeletonema costatum and Skeletonema subsalsum also had similar rDNA sequences. Skeletonema grevillei and S. ardens were distinct in the large subunit (LSU) phylogeny. Skeletonema ardens exhibited consistent intraspecific genetic differences in both the LSU and small subunit (SSU) rDNA.
-
diversity in the genus Skeletonema bacillariophyceae i a reexamination of the type material of s costatum with the description of s grevillei sp nov
Journal of Phycology, 2005Co-Authors: Adriana Zingone, Isabella Percopo, Pat A Sims, Diana SarnoAbstract:The type material of Skeletonema costatum (Greville) Cleve was reexamined with the aims of providing an EM description of the species and clarifying which of the recently recognized Skeletonema Greville species, if any, deserves the epithet costatum. Two permanent mounts and two loose samples from the same collections from Hong Kong Bay were examined. Two distinct Skeletonema species were found in all materials. Based on the original description and on the observation of the lectotype, it was concluded that the most abundant morph in the type material is S. costatum. Cells were heavily silicified and 5-16 μm in diameter. The external processes of the fultoportulae in the terminal valves were open tubules with claw-shaped tips. The intercalary fultoportulae processes were closed flattened tubules with a pore at their base, each attached to two processes of the sibling valve (1:2 junction). The rimoportula had a long process and was located marginally in all valves. The second morph in the type material was described as Skeletonema grevillei Sarno et Zingone sp. nov. Cells were delicate, 4-7.5 μm in diameter, and formed short colonies. The fultoportulae processes in the terminal valves were open tubes having narrow tips with truncated or spiny margins. In the intercalary valves, they formed knuckle-like generally 1:1 junctions. A scallop-work of silica bridges joined the bases of the processes. The rimoportula was marginal in all valves. Neither S. costatum nor S. grevillei match any Skeletonema species that have been recently analyzed by combined morphological and molecular approaches.
