bluuebunny/crossref_metadata_2025 huggingface dataset:
100  Effects of chelated iron on gametogenesis in kelp gametophytes
Authors: Lewis R. J. , Chambers M. K. , Coburn M. E.
Published: January 2004

Gametogenesis in several species of kelp gametophytes was investigated in relation to the supply of chelated iron (Fe‐EDTA) in the culture medium. Spores of Laminaria setchellii, Egregia menziesii, Alaria marginata, Dictyoneurum californicum, and Macrocystis pyrifera were grown in Provasoli's Enriched Seawater with and without added Fe‐EDTA. All species showed a decrease in gametogenesis without added Fe‐EDTA. Gametophytes of E. menziesii showed predominant gametogenesis even without supplied iron, resulting in all cells being converted to gametes so that vegetative growth did not continue. Vegetative gametophytes were obtained in the other species. M. pyrifera did not show any gametogenesis without added Fe‐EDTA. L. setchellii, A. marginata and D. californicum were intermediate in their response. In addition, Fe‐EDTA supply was delayed by 1, 2 and 3 weeks with spores of M. pyrifera, resulting in an intermediate degree of gametogenesis which decreased as the delay grew longer. Fe‐EDTA supply was also investigated using isolated female gametophytes of two strains of M. pyrifera and one of Macrocystis integrifolia. None of the three strains produced gametes without the addition of Fe‐EDTA. Gametophytes of M. integrifolia required the least amount of added Fe‐EDTA to achieve gametogenesis while gametophytes of M. pyrifera required higher amounts, with the two strains showing different responses. Thus, by varying the supply of chelated iron, it is possible to control vegetative growth or gametogenesis in most of these kelp species. In addition, different species and individuals show varied responses to added chelated iron.
101  Effect of Karlodinium Micrum Toxin on Success of the Parasitic Dinoflagellate Amoebophyra SP.
Authors: Lewis S. B. , Cooney S. K. , Marshall L. E. , Coats D. W.
Published: January 2004

Parasitic dinoflagellates of the genus Amoebophrya infect and kill bloom‐forming dinoflagellates, including the toxic species Karlodinium micrum. Unlike non‐toxic hosts, K. micrum is partially resistant to infection, a trait that may be related to toxin production. Here we tested the hypothesis that parasitism of K. micrum is inversely related to toxin concentration in the culture medium. Time‐course studies were conducted to determine the influence of extracted toxin and toxin carrier (methanol) on host growth, parasite prevalence, and parasite load. Results indicate that methanol concentrations below 0.1% have no effect on these variables. When methanol concentration was maintained below 0.1%, extracted toxin equivalent to 100 to 10,000 K. micrum per ml had no effect on host abundance. We are currently analyzing sample to assess the fate of Amoebophrya dinospores when exposed to K. micrum toxin. We will also consider the effect of intracellular host toxin on parasite success, by examining the fate of Amoebophrya dinospores when inoculated to K. micrum cultures that express different levels of toxin production. Understanding the effect of toxins on parasite success will contribute to our knowledge of host‐parasite biology and provide insight into the role of dinoflagellate toxins as a defense against parasitism.
102  Characterization of an Arsenate Reductase Encoded by ORF slr0946 from the Cyanobacterium Synechocystis SP. PCC6803
Authors: Li R. , Kennelly P. J.
Published: January 2004

Arsenic is a human carcinogen that is frequently encountered in high concentrations in both aqueous environments and in human drinking water supplies. Many microorganisms have evolved arsenical detoxification systems in which arsenate (AsV) is enzymatically reduced to arsenite (AsIII). In this study we report the expression and characterization of the first arsenate reductase from a cyanobacterium, the product of slr0946 from the cyanobacterium Synechocystis sp. PCC6803. Slr0946 was expressed as an C‐terminally ‘His‐tagged’ fusion protein. The recombinant protein efficiently catalyzed the reduction of arsenate to arsenite using reducing equivalents supplied from NADPH via glutathione and glutaredoxin. Thioredoxin, the traditional reductant for previously characterized ArsC's, was ineffective. Slr0946 displayed both relatively high catalytic efficiency, Vmax 3.1 μmol/min/mg, as compared to other arsenate reductases. Its Km for arsenate was 1.25 mM. Slr0946 also exhibited vestigial phosphohydrolase activity toward p‐nitrophenyl phosphate. Both arsenate reductase activity and phosphohydrolase activity were dependent upon the presence of the conserved cysteine residue, Cys8. Mutation of either of two closely paired cysteines in Slr0946, Cys80 or Cys82, but not Cys13 to serine eliminated arsenate reductase activity. However, each of these altered forms did catalyze the hydrolysis of pNPP, indicating that these cysteines were not essential to this catalytic function. It has further been suggested that glutathione forms a mixed disulfide with one of these cysteines during catalysis. This suggestion was at least partially supported by the demonstration that Slr0946 forms an SDS‐resistant complex with [35S]glutathione in a manner that is dependent on the presence of both Cys8 and arsenate.
103  Assessing Microalgal Morphology from Century‐Old Herbarium Sheets Using SEM
Authors: Linton E. W. , Farmer M. A. , Triemer R. E.
Published: January 2004

Traditionally, type specimens have not been deposited for most unicellular algae. There are few known holotypes and those that are available are often of limited use. Samples from taxa described before 1900 commonly consist of materials dried down on herbarium sheets or mica. Dried algal samples can be rehydrated, but preservation is very poor and little structure can be determined from them. Whether wet or dry, the amount of information that can be derived from such samples using conventional light microscopy is limited. However, identification of microscopic algae from herbarium samples may be necessary when the original descriptions and/or illustration(s) are inadequate, questionable or when a taxon is under revision. We were able to derive high‐resolution images from dried algal samples using a JEOL 6300 field emission SEM. For example, we have imaged samples of Euglena spirogyra that were dried on mica chips in October of 1899 and stored in the Michigan State University herbarium. The overall shape of the cell body and the arrangement and ornamentation of the pellicle strips were clearly visible. Because of this success we decided to examine a variety of algal samples that had been preserved on mica. Algae such as Staurastrum, Scenedesmus, or Mallomonas (particularly the scales), retained the most structure while others such as Pediastrum and Pandorina, retained sufficient structure to allow their identification. We suggest that FESEM should be more broadly used for assessing structure in dried herbarium samples.
104  Identification of Pfiesteria Piscicida (Dinophyceae) and Pfiesteria‐Like Organisms Using its‐Specific PCR Assays
Authors: Litaker R. W. , Vandersea M. W. , Kibler S. R. , Tester P. A. , Reece K. S. , Stokes N. A. , Steidinger K. A. , Millie D. F. , Bendis B. J. , Pigg R. J.
Published: January 2004

The putative harmful algal bloom dinoflagellate, Pfiesteria piscicida, frequently co‐occurs with other morphologically similar species collectively known as Pfiesteria‐like organisms (PLOs). This study specifically evaluated whether unique sequences in the ribosomal internal transcribed spacer regions (ITS1 and ITS2) could be used to develop PCR assays capable of detecting PLOs in natural assemblages. ITS regions were selected because they are more variable than the flanking small subunit (SSU) or large subunit (LSU) ribosomal RNA genes and more likely to contain species‐specific sequences. Sequencing of the ITS regions revealed unique oligonucleotide primer binding sites for Pfiesteria piscicida, Pfiesteria shumwayae, Florida “Lucy” species, two cryptoperidiniopsoid species, “H/V14” and “PLO21,” and the estuarine mixotroph, Karlodinium micrum. These PCR assays had a minimum sensitivity of 100 cells in a 100 mL sample (1 cell mL‐1) and were successfully used to detect PLOs in the St. Johns River system in Florida, USA.
105  Astacene is a Major Secondary Carotenoid In The Green ALGA Palmellococcus Miniatus
Authors: Liu G. X. , Hu Q. , Sommerfeld M. , Hu Z. Y.
Published: January 2004

Astacene (3,3′‐dihydroxy‐2,3,2′,3′‐tetradehydro‐b,b′‐carotene‐b,b‐dione) is a red carotenoid reported in small quantities in some green algae, higher plants, and animals. However, it has been generally believed that astacene is an oxidative artifact of astaxanthin (3,3′‐dihydroxy‐b,b‐carotene‐4,4′‐dione). Astaxanthin is a naturally occurring pigment and a structural analogue of astacene. A recently isolated unicellular green alga, Palmellococcus miniatus, has been found to synthesize and accumulate large quantities of red secondary carotenoids under certain environmental stress conditions. In this study, chromatographic, spectrophotometric and mass spectrometric evidence has been used to confirm that astacene is a natural occurring pigment, which can comprise over 70% of the secondary carotenoids in stressed cells. Electron microscopy revealed that the accumulation of astacene was accompanied by the formation of numerous lipid bodies outside of the chloroplasts. Lipid bodies were isolated from the cells by French pressure cell disruption, followed by sucrose gradient density centrifugation. HPLC analysis indicated that lipid bodies were the sites of astacene accumulation. The possible physiological roles and distribution of this pigment among several groups of green algae will be discussed.
11  Nitrogen loading by invertebrates increases growth and diversity of intertidal macroalgae
Authors: Bracken M. E. , Nielsen K. J.
Published: January 2004

High‐zone intertidal pools along the Oregon coast are a nutrient‐poor habitat within a nutrient‐replete upwelling ecosystem. However, many seaweed species occur in tide pools, especially when sessile invertebrates are present. By converting particulate nitrogen into ammonium, filter‐feeding invertebrates can mediate the supply of nitrogen to seaweeds in tidepools. Invertebrates excrete substantial quantities of ammonium into tidepools, which seaweeds take up and assimilate as a nitrogen source. We investigated the ecological consequences of this local‐scale nitrogen source by evaluating the influence of invertebrate‐excreted ammonium on the growth and diversity of seaweeds in high‐intertidal pools. We measured the growth of a macroalga commonly found in high‐intertidal pools, the red alga Odonthalia floccosa (Esp.) Falkenb., when mussels were present and absent. Over a 24‐day tidal cycle, accumulation rates of inorganic nitrogen were 3 times higher, and rates of nitrogen uptake were 4.5 times higher, when mussels were present, resulting in 50% more seaweed growth. The number of macroalgal species increased with the rate of ammonium loading into tidepools as slow‐growing species tolerant of low nitrogen availability were supplemented by fast‐growing species with higher nitrogen requirements. Thus, especially in high‐intertidal pools, which are isolated from oceanic nitrate inputs for nearly 80% of the time, invertebrates are important contributors to the nitrogen budgets of seaweeds. This study highlights the role of local‐scale nutrient regeneration as a potential determinant of tidepool community structure and suggests that nutrient excretion by filter‐feeding invertebrates may influence the structure and dynamics of rocky intertidal communities.
118  A Nutritional Analysis of the Turf Algal Diet and Fecal Pellets of The Green Turtle, Chelonia Mydas L
Authors: McCutcheon S. M. , McDermid K. J. , Balazs G. H.
Published: January 2004

In 1978, the green turtle, Chelonia mydas, was listed as threatened in the United States under the Endangered Species Act. Any knowledge gained from an understanding of the diet and how it affects this species' ability to survive is crucial. Turf algae, the primary component of the diet of Chelonia mydas, and turtle fecal pellets were collected from Kaloko‐Honokohau National Historical Park on the island of Hawaii at monthly intervals. The turf algae and fecal pellets were subjected to nutritional analyses for protein, carbohydrate, lipid, ash, and caloric content. The fecal pellets were higher in protein content than the turf algae, which may be related to fermentation carried out by bacteria in the turtle hindgut that increases the amount of protein available for absorption. From the nutritional data, assimilation efficiencies were calculated for the green turtle.
119  Marine Algae of Pohnpei and Ant Atoll with Comparisons to Other Pacific Atolls and Island Groups
Authors: McDermid K. J. , Hodgson L. M. , Abbott I. A.
Published: January 2004

A study of benthic marine algae collected from Pohnpei Island and Ant Atoll, Federated States of Micronesia, documented the occurrence of 113 species of red algae (Rhodophyta), 60 species of green algae (Chlorophyta) and 17 species of brown algae (Phaeophyta), many of which are new records for Pohnpei, Ant Atoll and Micronesia. Added to reports from the literature, a total known marine benthic flora of Ant and Pohnpei (exclusive of Cyanobacteria and crustose coralline algae) now stands at 241. The high island, volcanic nature, and larger size of Pohnpei which is very different from the low, calcareous geomorphology of smaller Ant Atoll, led us to expect higher species numbers from Pohnpei relative to Ant, and greater differences in their algal floras than we found. Comparisons of the Ant‐Pohnpei algal flora were also made using Jaccard and Sorensen's indices to Ifaluk Atoll (Caroline Islands), Enewetak Atoll (Marshall Islands), the Northern Mariana Islands, and the distant south Pacific island groups of Fiji and French Polynesia. Biogeographical investigation of the marine algae flora revealed that Ant Atoll and Pohnpei have a large number of widespread and Indo‐Pacific species, but very few probable regional endemics.
12  Phylogeny of the euglenoid loricate genera trachelomonas and strombomonas based on morphological and molecular data
Authors: Brosnan S. , Triemer R. E.
Published: January 2004

Since the separation of the Trachelomonas subgroup “Saccatae” into a new genus, Strombomonas Deflandre (1930), there has been some question as to its validity. Deflandre's separation was based on morphological characteristics such as the shape of the lorica, lack of a distinctive collar, possession of a tailpiece, lack of ornamentation, and ability to aggregate particles on the lorica. Recent molecular analyses indicated that the loricate taxa were monophyletic, but few species have been sampled. The LSU rDNA from eleven Strombomonas and thirty‐eight Trachelomonas species was sequenced to evaluate the monophyly of the two genera. Bayesian and maximum‐likelihood analyses found one monophyletic clade for each genus. The Trachelomonas clade was weakly supported, but had five strongly supported subclades. Morphological characters, such as lorica development and pellicle strip reduction, also supported separation of the genera. Lorica development in Strombomonas occurred from the anterior of the cell to the posterior, forming a shroud over the protoplast whereas in Trachelomonas, a layer of mucilage was excreted over the entire protoplast, followed by creation of the collar at the anterior end. Taxa from both genera underwent exponential strip reduction at the anterior and posterior poles. In Strombomonas, only one reduction was visible in the anterior pole, while in most Trachelomonas species, two reductions were visible. Likewise, Strombomonas species possessed two whorls of strip reduction in their posterior end compared to a single whorl of strip reduction in Trachelomonas species. The combined morphological and molecular data support the retention of Trachelomonas and Strombomonas as separate genera.
120  Exploration of Morphological Variation Within the Genus Pediastrum Meyen 1829 (Chlorophyceae, Chlorophyta)
Authors: McManus H. A. , Lewis L. A.
Published: January 2004

Monographic works on the green algal genus, Pediastrum Meyen 1829 (Chlorophyceae, Chlorophyta), have described species, varieties and forms based on such characteristics as the size and shape of the marginal cells, pattern of cell wall sculpturing and extent of cell wall sculpturing. Depending on the author, the number of taxa assigned to the genus Pediastrum varies. Due to the lack of quantitative value to these characteristics, it has been difficult for other researchers to assign appropriate taxonomy to wild isolates. A molecular phylogeny including multiple strains from both culture collections and wild samples confirms relationships found by previous molecular studies on fewer taxa, in which the family Hydrodictyaceae forms a monophyletic group within the Sphaeropleales, and that the genera Hydrodictyon and Sorastrum are derived from Pediastrum. Hydrodicyton forms a monophyletic clade and consists of three species, H. reticulatum, H. africanum, and H. patenaeforme. Multiple isolates of H. reticulatum reveal little genetic variation between different geographic localities. Inclusion of wild isolates permits a more thorough exploration of morphological variation within the genus Pediastrum, and what characters may be taxonomically informative, particularly in the species P. boryanum and P. duplex. Wild isolates sampled from different areas also offers information regarding geographic variation and potential morphological convergence.
121  Influence of Benthic vs. Pelagic Seeding on Coastal Diatom Bloom Development
Authors: McQuoid M. R. , Godhe A.
Published: January 2004

Diatom blooms may be initiated by cells that have survived in the plankton or germinated resting stages from the sediments. However, it is not well understood how these different inocula contribute to bloom development. We followed diatom community development in twenty‐liter microcosms given different inocula. Surface sediment and phytoplankton were collected in Gullmar Fjord, Sweden. Replicate microcosms were then dosed with local sediment and/or plankton and incubated in situ in Gullmar Fjord. We also followed the concurrent development of the phytoplankton community in the fjord. Experiments run in both spring and fall 2002 showed that bloom development in the microcosms was significantly faster when seeded by planktonic cells. However, addition of sediment may have stimulated planktonic growth and also provided additional propagules. The type of inoculum used strongly influenced the diatom composition in the microcosms. Sediment additions, through germination of resting stages, resulted in communities dominated by Detonula confervacea and Thalassiosira minima in spring, and Skeletonema costatum in fall. Planktonic inocula resulted in blooms of T. nordenskioeldii and Chaetoceros debilis in spring, and S. costatum and several Chaetoceros spp. in fall. Microcosms dosed with both plankton and sediment showed a mixed species assemblage. Comparisons between the microcosms and fjord phytoplankton suggest an important role for benthic seeding of diatom blooms.
122  Local to Coastal‐Scale Macrophyte Community Structure: Surprizing Patterns and Possible Mechanisms
Authors: Menge B. A. , Allison G. , Freidenburg T. , Kavanaugh M. , Lubchenco J. , Nielsen K. , Schock C. , Wood S.
Published: January 2004

Understanding large‐scale patterns in ecological communities is a central goal of ecology, and yet, rigorous quantitative geographic data on distribution, abundance and diversity are almost totally lacking. Even in rocky intertidal habitats, our data on community structure are spatially and temporally limited, with most surveys limited to a few sites over short time periods. When linked to studies of community dynamics on similar scales, such studies should provide insights into the determinants of pattern at more relevant scales. In 1999 PISCO, the Partnership for Interdisciplinary Studies of Coastal Oceans, initiated survey programs aimed at determining patterns of community structure along the US west coast from Washington to Baja California. Sites are regularly spaced along the coast in a nested design, and were physically similar. Surveys used randomly placed quadrats in transects run parallel to shore in high, mid and low zones. Results show that, contrary to expectation, macroalgal diversity along the northern coast was higher, not lower than that along the southern coast. Possible factors associated with this unexpected pattern include along‐coast variation in tidal amplitude, time of tide, thermal stress, upwelling intensity and resulting nutrient gradients, disturbance from storms or sand burial, and grazing. We review evidence relevant to these factors, and focus on the possible role of grazing, using field experiments done under differing oceanographic conditions along the Oregon coast as a model. Although short‐term grazing rates can vary with oceanographic condition, we hypothesize that despite these results and those of many similar studies showing strong grazing effects on local spatial and short time scales, that bottom‐up factors are stronger determinants of macroalgal community structure on larger spatial scales and longer time scales.
123  Permanent Fluorescent Nuclear Staining of Binucleate Dinoflagellates
Authors: Morris R. L. , Silva M. , Rizzo P. J.
Published: January 2004

Typically, fluorescent microscopy of dinoflagellate nuclei is of poor resolution, due mainly to visual obstruction of the nuclei by plastids, pigment granules, and thecal plates. Moreover, the usual slide mounts using buffered glycerol are temporary, and fade after a week or so. We have developed a procedure to clear pigments from dinoflagellates, followed by fluorescent staining of the nuclei. The cells are then prepared as permanent mounts using an ultraviolet light‐catalyzed resin to produce stained samples which may be kept for at least three years with little loss of fluorescence. This procedure can also be used to prepare plastic embedded dinoflagellate cells which can then be sectioned at 1–2 nm, fluorescent stained, and permanently mounted. Suitable nuclear stains are DAPI, Hoechst 33258, ethidium bromide and acridine orange. The dinoflagellate (dinokaryotic), and endosymbiont (eukaryotic) nuclei are clearly visualized, revealing individual chromosomes in the dinoflagellate nucleus, and a highly lobed morphology of the endosymbiont nucleus.
124  Evidence for Lateral Transfer of a IE Intron between Fungal and Red Algal Small Subunit Ribosomal RNA Genes
Authors: Müller K. M. , Ellenor D. W. , Sherwood A. R. , Sheath R. G. , Cannone J. J. , Gutell R. R.
Published: January 2004

In a recent study of the North American biogeography of the red algae genus Hildenbrandia, the presence of group I introns were noted in the nuclear SSU rRNA gene of the marine species H. rubra (Hildenbrandiales). Group I introns in the nuclear encoded rRNAs have been previously reported in the Hildenbrandiales as well as the Bangiales. All reported introns within the red algae have been identified as belonging to the IC1 subclass and occur at two insertion sites in the nuclear small subunit rRNA (516 and 1506). However, an unclassified intron was discovered at position 989 in the nuclear SSU rRNA gene of a collection of H. rubra from British Columbia, Canada. We have determined that the intron is a member of the IE subclass and this is the first report of an IE intron and an intron in position 989 in the red algae. Phylogenetic analyses of the intron sequences reveal a close relationship between this group IE intron and similar ascomycete and basidiomycete fungal IE introns in the nuclear SSU rRNA genes at positions 989 and 1199. In addition, a common unique helix (structural signature) in the P13 domain of the Hildenbrandia intron and those of the fungi at the 989 and 1199 IE positions in the nuclear SSU rRNA gene also indicates a close relationship. Hence, this study provides evidence for a possible lateral transfer of the IE intron in position 989 between fungal and red algal nuclear SSU rRNA genes.
125  Changing Environmental Conditions and Changes in the Abundances of Rocky Intertidal Seaweeds on Southern California Shores
Authors: Murray S. N.
Published: January 2004

Environmental conditions have changed along the southern California coast during the past five decades. The human population has greatly expanded, and coastal habitats have become increasingly influenced by human activities. In addition, coastal waters have been subjected to shifts in ocean climate, including the regime shift of the 1970s that affected coastal plankton, fish, and sea bird populations. Changes in the abundances of intertidal seaweeds during this nearly fifty‐year period are less well known. The earliest available data for tracking seaweed abundances were obtained by E. Y. Dawson in the late 1950s. During the mid‐1970s, Mark Littler and colleagues performed a series of more intensive ecological studies at additional southern California sites. We re‐sampled fourteen of these rocky intertidal sites between 1998 and 2002 to determine changes in seaweed abundances since the mid‐1970s. All sites were sampled using line transect or plot‐based methods similar to those used by earlier investigators. Our abundance data were then compared with values reported from the late 1950s through the mid‐1970s for the same study sites. We found that macrophyte communities at many of our sites have become increasingly dominated by low‐producing, crustose and articulated coralline algae and turf‐forming seaweeds. During this same period, cover of several larger, and more productive, frondose algae declined. These shifts in seaweed abundances appear to have changed the structure and functioning of southern California intertidal communities through changes in the principal contributors to community primary productivity and reductions in the availability of habitat provided by algal canopies.
126  Porphyra Birdiae Neefus et Mathieson (Bangiales, Rhodophyta): A New Species from the Northwest Atlantic
Authors: Neefus C. D. , Mathieson A. C. , Klein A. S. , Teasdale B. , Bray T. , Yarish C.
Published: January 2004

Recent studies combining biochemical, molecular, and traditional morphological and ecological traits have shown that some currently recognized species of the red algal genus Porphyra are actually “form species” or “complexes” comprising several morphologically similar but genetically distinct taxa. Conflicting reports of chromosome numbers and differences in DNA sequences reported for Porphyra purpurea (Roth) C. Agardh have raised suspicion that more than one taxon has been confused under this name in the Northwest Atlantic. We have identified one of these cryptic taxa and have recently described it as a new species, Porphyra birdiae. Like P. purpurea (Roth) C. Agardh, it has an ovate to broadly elongate, foliose blade with reproductive areas segregated by a distinct line into male and female sectors. While reproductive specimens have historically been confused with P. purpurea, non‐reproductive specimens of P. birdiae have been incorrectly identified as P. umbilicalis Kützing. Although P. birdiae is morphologically similar to both of these species, sequences of SSU (nuclear small subunit rRNA gene) and rbcL (plastid ribulose‐1,5‐bisphosphate carboxylase/oxygenase large subunit gene) indicate that it is not closely related to either one. Based on rbcL sequences, P. birdiae is closely related to P. aestivalis Lindstrom et Fredericq, a proposed new species from Alaska.
127  Climate Variability and Phytoplankton Production in PNW Coast Estuaries
Authors: Newton J.
Published: January 2004

The west coast of North America receives strong forcing from climate modes such as El Niño‐Southern Oscillation and the Pacific Decadal Oscillation. Estuaries are poised at a sensitive interface because estuarine biota and habitat will be affected by variability in properties and processes associated with the ocean, the watershed, and the local weather. Observations from the Washington coast and Willapa Bay illustrate these three arenas of influence. Variation in ocean upwelling and ocean thermocline depth associated with the 1997–98 El Niño versus the 1999 La Niña affected temperature and nutrient availability in Willapa Bay. Variation in river flow associated with the 2000–01 drought affected estuarine circulation and residence time. And, variation in prevailing wind direction and/or cloudiness was highly correlated with phytoplankton biomass. This situation is responsible for the complexity of understanding climate impacts on estuarine systems. In order to help evaluate which mechanisms, remote oceanic processes or local watershed/estuarine characteristics, most affected Willapa Bay's phytoplankton production, several phytoplankton species were used as indicators of water mass origin and compared with primary productivity data to assess whether phytoplankton blooms were dominated by endemic or imported species. Our analysis resolved that the highest primary production (and the appearance of Pseudo‐nitzschia spp.) was associated with oceanic intrusions of phytoplankton biomass into Willapa Bay. This result underscores the dominant role that variation in ocean and climate play in controlling Pacific Northwest estuarine production. However, while the largest blooms were oceanic in origin, numerous medium‐sized production events were from either oceanic or estuarine sources, indicating a complex picture.
128  Capturing the Light Fantastic: Oceanographic and Tidal Influences on Intertidal Algae
Authors: Nielsen K. J. , Blanchette C. A. , Menge B. A. , Grantham B. , Lubchenco J.
Published: January 2004

Seaweeds experience many challenges to their persistence in intertidal zone habitats. Their growth rates must exceed losses associated with a range of ecological and physiological factors including desiccation, herbivory and wave forces. Growth rates depend on an alga's ability to capture and process light to build carbon‐based molecules. We examined local (tidal height) and large (oceanographic) scale influences on algal photosynthetic efficiency and light climate, respectively. At the local scale, we combined periodic measurements of physiological state using PAM fluorometry with traditional demographic monitoring of a Postelsia palmaeformis, population over a tidal height gradient. Parameter estimates derived from rapid fluorescence‐irradiance curves were correlated with longer‐term ecological performance measures including growth rate, morphology, survivorship and reproductive output. At larger scales, we made continuous in situ measurements of chlorophyll fluorescence and light attenuation in the intertidal zone at six sites during 2001 and 2002. Light attenuation to the benthos was sharply reduced at sites when chl‐a fluorescence was high. Long‐term, large‐scale monitoring of intertidal zone chl‐a and macroalgal abundances documents that striking differences among sites are persistent and associated with oceanographic factors. The light saturation parameter and maximum photosynthetic rate calculated for several common intertidal macrophytes, along with published values of the irradiance needed to saturate their growth rates, suggest that underwater light levels may limit intertidal algal growth where phytoplankton blooms are common and persistent. We conclude that physiological stress associated with tidal and oceanographic factors contribute to macroalgal distributions.
129  Cryptoendolithic Photosynthetic Communities Within Recent and Ancient Travertine in Yellowstone National Park
Authors: Norris T. B. , Castenholz R. W.
Published: January 2004

Travertine terraces have been deposited by calcareous hot springs in Yellowstone from as early as 365,000 years to the present. Most of these porous and non‐porous CaCO3 rocks (old or new) contain a 1–2 mm thick greenish band about 1–3 mm below the upper surface. These bands are composed of cyanobacteria and, sometimes, unicellular green algae. Although some moisture may be retained for much of the year, all undergo freezing in winter and desiccation in summer. DGGE (denaturing gradient gel electrophoresis), with subsequent 16S rDNA sequence analyses of bands, has shown that relatively few phylotypes of cyanobacteria are present, but some occur in travertine of very different ages, indicating secondary establishment of the communities. Clonal cultures of predominant types have also been established and sequenced. All those tested are able to survive extreme desiccation. Preliminary sequence analyses of cultures show that some strains are nearly identical to known cyanobacterial strains while others show little similarity. One sequence is 100% identical to the cyanobacterium Cyanobium gracile. This cyanobacterium is known to be distributed worldwide in lakes and brackish seas, but not in a cryptoendolithic environment. Another sequence shows 99% identity to two cyanobacteria isolated from Antarctic freshwater ponds. Both Antarctic ponds and Yellowstone travertine are environments in which adaptations for desiccation and/or freezing tolerance could be crucial. The lack of ecological similarity among some of these strains indicates that genes other than 16S rDNA must be used for differentiation. These results will be discussed along with the ecology of travertine habitats.
13  Viral control of phytoplankton
Authors: Brussaard C.
Published: January 2004

Viral control of phytoplankton Virus ecology is a young rapidly developing field that is changing our understanding of the functioning of marine ecosystems. Viruses are known to be ubiquitous, numerically dominant members of the aquatic microbial communities, infecting a wide spectrum of hosts, including planktonic microalgae. They are typically host‐specific agents of mortality and thus likely influence the dynamics and succession of phytoplankton. As well, viral infection can have major biogeochemical implications through cell lysis and the resulting transformation of released POM into DOM. Bloom forming algal species with their high cell abundance may allow a rapid propagation of lytic viruses, resulting in a direct and significant controlling impact of viruses on bloom dynamics. Besides the concentration of host and virus, other potential factors influencing the quantitative importance of viral control of phytoplankton are resistance of host strains to virus infection (host range), variations in morphotypes of the phytoplankton species, the type of limiting nutrient, and variables affecting the fate of viruses (UV, grazing, adsorption to aggregates). The current presentation will provide examples of viral infected phytoplankton and will address some of the processes involved in viral mediated mortality of microalgae.
130  “Plantae” Emended Based on the Common History of the Primary Plastid Endosymbiosis
Authors: Nozaki H. , Matsuzaki M. , Misumi O. , Kuroiwa T.
Published: January 2004

Phylogenetic relationships between three lineages of the primary photosynthetic eukaryotes (red algae, green plants and glaucophytes) seem to remain unresolved because previous nuclear multigene phylogenies used the highly reduced red algal endosymbiont (nucleomorph) and/or incomplete red algal gene sequences. Here we carried out nuclear multigene phylogeny of various lineages of only mitochondria‐containing eukaryotes, using complete sequences from the red alga Cyanidioschyzon merolae. Cellular slime molds were designated as the outgroup based on concatenated two paralogous tubulin gene sequences. Our phylogenetic analyses based on a 1525‐amino‐acid sequence of four concatenated nuclear genes (actin, elongation factor‐1a, a‐tubulin and b‐tubulin) resolved the presence of two large robust monophyletic groups (Groups A and B) and the basal eukaryotic lineages (Amoebozoa). Group A corresponded to the Opisthokonta (Metazoa and Fungi), whereas Group B included various primary and secondary plastid‐containing lineages (red algae, green plants, glaucophytes, euglenoids, heterokonts, and apicomplexans), Ciliophora, Kinetoplastida, and Heterolobosea. The red algae represented the most basal lineage within Group B. Therefore, the primary plastid endosymbiosis likely occurred once in the common ancestor of Group B, and the primary plastids were subsequently lost in the ancestor(s) of organisms which now lack primary plastids within group B. A new concept of ÒPlantaeÓ is proposed for phototrophic and nonphototrophic organisms belonging to Group B, on the basis of the common history of the primary plastid endosymbiosis. This new scenario of the plastid evolution is discussed in comparison with genome information recently accumulated and plastid genome comparison.
131  New Records of Cyanobacteria from Epilithic Habitats in the Great Smoky Mountains National Park
Authors: Olsen C. E. , Johansen J. R. , Gomez S. R. , Lowe R. L. , Casamatta D. A.
Published: January 2004

Great Smoky Mountains National Park is home to a diverse collection of plants and animals. The protection that the park provides, along with variations in climate, elevation, and geology supports this high biodiversity. In an effort to record the biodiversity within the park an All Taxa Biodiversity Inventory project was established in 1997. This inventory will serve as a baseline for the biodiversity in the park, and will be used to monitor future environmental impacts. Epilithic algae were collected from sites from Hen Wallow Falls and along Cataloochie Road in the Great Smoky Mountains National Park 5–6 May, 2002. Of the 54 cyanobacteria species identified from Hen Wallow Falls and Cataloochie Road sites, 41 were new species records to the park: 10 Chroococcales, 11 Oscillatoriales, and 20 Nostocales. Some of these did not fit published descriptions based on morphology and may be new to science. Of special interest are several taxa in the Nostocaceae: Anabaena, Trichormus, Nodularia, and Nostoc. A Capsosira species was highly unusual and undoubtedly represents a species new to science. Morphological characterization is complete, and efforts are now being made to characterize 16S rRNA and 16S‐23S ITS regions of selected strains.
132  Parasites and Phytoplankton, with a Special Emphasis on Dinoflagellate Infections
Authors: Park M. G.
Published: January 2004

Eukaryotic parasites are believed to play important roles in phytoplankton ecology and particularly in bloom dynamics of red‐tide dinoflagellates. Apart from the prokaryotic parasites such as viruses and bacteria, certain flagellates and fungi have received some degree of attention as eukaryotic parasites of phytoplankton. Our understanding of fungal parasites is largely based on studies for freshwater diatoms and dinoflagellates, although fungal infections are known for some marine phytoplankton, including diatoms. By comparison, the dinoflagellate genus Amoebophrya and the newly described Perkinsozoa Pavilucifera infectans are widely distributed in coastal waters of the world and are well known as eukaryotic parasites of dinoflagellates. Recent work indicates that these parasites have significant impacts on the ecophysiology and behavior of dinoflagellate hosts. Thus, the ecological roles of Amoebophrya spp. and Pavilucifera infectans should be carefully considered in developing concepts about plankton dynamics and material flows in marine food webs.
133  Studies on the Life History of the Portuguese Red Alga Porphyra Dioica (Brodie and Irvine) Under Varying Environmental Conditions
Authors: Pereira R. , Sousa‐Pinto I. , Yarish C.
Published: January 2004

The life history of Porphyra dioica collected in Porto, Portugal, was investigated under laboratory conditions. This is one of the most common Porphyra species on the North Coast of Portugal and can be found throughout the year. Field studies showed higher percentage cover, from 23 to 66%, during February through May. Varying temperature, light intensities and photoperiods were tested. The zygotospores germinated faster at 15°C, and at 25 μmol m−2·s−1. Growth rate of the conchocelis was affected by temperature rather than by photoperiod. In the three photoperiods tested, growth rate was always higher at 15°C, under 25 to 75 μmol m−2·s−1, although not significantly different from that at 20° C. Difference between these two temperatures and 5 and 10°C was significant. Conchosporangia formation was higher in 15°C and at short‐day, 8:16, Light:Dark and 25 to 75 μmol m−2·s−1 and was almost non‐existent in free floating conditions. Optimal conditions for conchosporangia maturation, 15° C, 8:16, Light:Dark and 5 to 25 μmol m−2·s−1 also promoted spore release after 18 weeks. Aeration appeared to be crucial for normal blade development. No archeospores were observed. The first findings of the optimal conditions for growth of the gametophyte stage will also be discussed.
134  Cryopreservation of Chlamydomonas Reinhardtii (Chlorophyceae): A Cause of Low Viability at High Cell Density
Authors: Piasecki B. P. , Brand J. J.
Published: January 2004

Cryopreservation provides a convenient method for long term storage of living organisms. Current protocols allow the successful cryopreservation of a wide range of algae, although many strains remain recalcitrant to cryopreservation. Chlamydomonas reinhardtii, a species utilized in many molecular and biochemical studies, survives cryopreservation best at low cell density. We show that reduced viability at higher cell densities is caused by the accumulation of a substance released from C. reinhardtii into the culture medium during cryopreservation. A mutant strain of C. reinhardtii (cw10) with a greatly reduced cell wall did not release a substance inhibitory to wild type or cw10 C. reinhardtii during cryopreservation, and could be cryopreserved with the same viability regardless of cell density. The inhibitory substance is small (mw<1300), polar, heat‐stable and organic. Chlamydomonas moewusii Gerloff and Chlamydomonas zebra Korschikov ex Pascher both produce substances that reduce the viability of cryopreserved C. reinhardtii. However, neither is affected by the inhibitory substance produced by themselves or C. rienhardtii. Pandorina morum (Müller) Bory and Volvox carteri f. nagariensis Iyengar are colonial Volvocalean algae related to C. reinhardtii that cannot be successfully cryopreserved. They both generate substances that inhibit C. reinhardtii during cryopreservation. The identification of the substance inhibitory to C. reinhardtii during cryopreservation should explain why this alga cryopreserves best at a low cell density, and may lead to protocols that facilitate the more successful cryopreservation of C. reinhardtii and related algae.
135  Life History and Ecology of Trentepohliaceae (Chlorophyta) in the West of Ireland
Authors: Rindi F. , Guiry M. D.
Published: January 2004

Species of subaerial green algae of the family Trentepohliaceae are common in tropical and temperate regions. Despite nearly two centuries of investigations, several important aspects of their biology (such as life history and taxonomic relationships of some species) are still poorly understood. In western Ireland, the abundance of Trentepohliaceae is a peculiar feature of the subaerial algal vegetation. Six species are present (Phycopeltis arundinacea, Printzina lagenifera, Trentepohlia abietina, T. aurea, T. iolithus and T. umbrina). Life history and phenology of these were examined by extensive field and culture studies. In contrast to most other subaerial algae, the Trentepohliaceae show a generally strict substratum‐specificity in western Ireland. T. iolithus, in particular, is remarkable for its occurrence on concrete walls, where it may produce extensive dark‐red growths. Our observations suggest that general statements about the life history of Trentepohlia should be reconsidered critically. There is no evidence that in Irish populations a regular alternation of isomorphic gametophytes and sporophytes takes place; biflagellate swarmers (usually considered gametes) behave as asexual spores and reproduce the same morphological phase. No fusion of gametes was observed and a detailed examination of the literature concerning the genus shows that this phenomenon is extremely rare. A combination of studies based on different types of data (molecular data, examination of very large numbers of field samples, chromosome numbers, culture studies) is considered fundamental to any definitive clarification of the taxonomy and life history of Trentepohlia.
136  Metabolic Flux Analysis of Halogenated Monoterpene Biosynthesis in Microplantlet Suspension Cultures of the Marine Red Macroalgae Ochtodes Secundiramea and Portieria Hornemannii
Authors: Polzin J. J. , Rorrer G. L.
Published: January 2004

The bioprocess engineering of marine macroalgae or “seaweeds” for the production of bioactive secondary metabolites is an emerging area of marine biotechnology. One novel metabolic theme is the biosynthesis of halogenated monoterpenes by red macroalgae. Specifically, two species of tropical marine red macroalgae, Ochtodes secundiramea and Portieria hornemannii, contain halogenated monoterpenes that serve as a chemical defense to herbivory. Some of these halogenated monoterpenes also possess potent activity against several human tumor cell lines. Field collections of O. secundiramea and P. hornemannii exhibit site‐to‐site variations in halogenated monoterpene (HMT) content. In contrast, microplantlets of O. secundiramea and P. hornemannii established through cell and tissue culture techniques have remarkably similar HMT profiles when cultivated in a photobioreactor under identical, controlled conditions. Both cultures share Apakaochtodene B as the only cyclic HMT, 10E‐bromomyrcene and 10E‐bromo‐3‐chloro‐a‐myrcene as the dominant acyclic HMTs, and myrcene as their common precursor. Furthermore, halogenated monoterpene biosynthesis in red macroalgae has three common manifolds: elaboration of myrcene from geranyl diphosphate by a novel marine monoterpene synthase, regio‐ and stereoselective bromination of mycrene by a novel marine halogenase, and bromonium‐ion assisted cyclization and halogenation of myrcene. Two quantitative tools of metabolic engineering – metabolic flux analysis and metabolic pathway analysis – were used to elucidate the factors that control halogenated monoterpene biosynthesis. By coordinated perfusion of nutrients, bromide, and key enzyme co‐factors to the photobioreactor culture, both the yield and distribution of halogenated products can be externally directed to target compounds. These efforts represent the first application of metabolic engineering principles to the manipulation of secondary metabolism in macrophytic marine organisms.
137  Gamete Recognition and Sexual Isolation in a Red Alga, Aglaothamnion Byssoides (Rhdophyta)
Authors: Ryu J. J. , Kim S. H. , West1 J. A. , Kim G. H.
Published: January 2004

The binding of fluorescein isothiocyanate (FITC) conjugated lectins to gametes of Aglaothamnion byssoides Itono during the fertilization was studied by the use of confocal microscope. The physiological effects of lectins and carbohydrates on gamete binding were also examined. Three lectins, concanavalin A (ConA), Soybean agglutinin (SBA) and wheat germ agglutinin (WGA) bound to the surface of spermatia, but each lectin labeled different region of the spermatium. SBA bound only to the spermatial appendages but ConA bound to the whole spermatial surface except spermatial appendages. WGA labeled narrow region which connects spermatial body and appendages. During fertilization, ConA and WGA specific substances on the spermatial surface moved towards the area contacting with trichogyne and accumulated on the surface of fertilization canal. Spermatial binding to trichogynes was inhibited by pre‐incubation of spermatia with SBA, while trichogyne receptors were blocked by the complementary carbohydrate, N‐acetyl‐D‐galactosamine. WGA and its complementary carbohydrate had little effect on gamete binding. For searching the step of sexual isolation, crossing experiment was performed between Aglaothamnion byssoides and twelve other red algal species. Results showed that the gamete recognition was genus‐specific: the gametes bound freely with their partners of the same genus. When two species from same genus were crossed, sexual isolation occurs gradually during the fertilization process. Therefore, sexual isolation in red algae appears to be determined by multi‐step process and gamete binding is the initial step.