Identification and microgeographic distribution of <i>Mazzaella splendens</i> and <i>Mazzaella linearis</i> (Gigartinaceae, Rhodophyta)

Shaughnessy, Frank J.

doi:10.1139/b96-124

Cited by 9 publications

(27 citation statements)

References 14 publications

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“…Mazzaella splendens from sheltered habitats (figure 1a) can be discerned from wave-exposed populations of M. linearis (figure 1b), but a continuum of morphological intermediates (e.g. figure 1c) traverse the intervening wave-exposure gradient (Shaughnessy 1996). Mazzaella f laccida is also difficult to distinguish (compare figure 1d to e, f ) from M. splendens (Hommersand et al 1994) such that the 'Keys to the Benthic Marine Algae.of British Columbia.'…”

Section: Resultsmentioning

confidence: 99%

“…Ross et al (2003) outlined possible scenarios to explain the apparent morphological continuum observed in the field for the M. linearis/splendens complex: (i) a single species exists with substantial morphological plasticity in response to wave exposure; (ii) two species exist, but one or both display phenotypic plasticity such that the intermediate plants are strictly of one species or the other, or a mixture of plants from both; (iii) the intermediate plants may be tetrasporophytes of M. splendens, which was reported to have a possible heteromorphic aspect to its alternation of generations ; (iv) the intermediates are hybrids between the two species; and (v) combinations of the previous could also explain these individuals. To evaluate the previous hypotheses, as well as the published ecological results (Shaughnessy 1996 figure 1c) had ITS sequence consistent with placement in M. splendens, a result which was consistent with a morphological reevaluation of the voucher (Ross et al 2003); and another that was identified as M. f laccida (figure 1d ), based on their interpretation of the identification keys in Gabrielson et al (2000), also proved to be M. splendens, leaving uncertainty as to whether or not M. f laccida extends into BC. The ITS was thus a powerful tool for resolving an outstanding species issue in the flora adjacent to the Bamfield Marine Station, but it had shortcomings.…”

Section: Resultsmentioning

confidence: 99%

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Applying DNA barcoding to red macroalgae: a preliminary appraisal holds promise for future applications

Saunders

2005

Phil. Trans. R. Soc. B

666

528

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Marine macroalgae, especially the Rhodophyta, can be notoriously difficult to identify owing to their relatively simple morphology and anatomy, convergence, rampant phenotypic plasticity, and alternation of heteromorphic generations. It is thus not surprising that algal systematists have come to rely heavily on genetic tools for molecular assisted alpha taxonomy. Unfortunately the number of suitable marker systems in the three available genomes is enormous and, although most workers have settled on one of three or four models, the lack of an accepted standard hinders the comparison of results between laboratories. The advantages of a standard system are obvious for practical purposes of species discovery and identification; as well, compliance with a universal marker, such as cox1 being developed under the label 'DNA barcode', would allow algal systematists to benefit from the rapidly emerging technologies. Novel primers were developed for red algae to PCR amplify and sequence the 5 0 cox1 'barcode' region and were used to assess three known species-complex questions: (i) Mazzaella species in the Northeast Pacific; (ii) species of the genera Dilsea and Neodilsea in the Northeast Pacific; and (iii) Asteromenia peltata from three oceans. These models were selected because they have all caused confusion with regards to species number, distribution, and identification in the field, and because they have all been studied with molecular tools. In all cases the DNA barcode resolved accurately and unequivocally species identities and, with the enhanced sampling here, turned up a variety of novel observations in need of further taxonomic investigation.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Applying DNA barcoding to red macroalgae: a preliminary appraisal holds promise for future applications

Saunders

2005

Phil. Trans. R. Soc. B

666

528

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“…M. splendens also does not have the developmental option of making its blade narrower like those of M. linearis in order to reach a length necessary for reproduction. Blades of M. splendens actually become wider when regrown at a high impact site with M. linearis (Shaughnessy 1994). Thus, the ability of M. linearis to produce longer, potentially reproductive blades within a high impact site is still greater than for M. splendens within this kind of site.…”

Section: Discussionmentioning

confidence: 98%

“…In contrast, M. linearis is only found in outer coast habitats subject to high wave impact and it has a longer, thicker stipe supporting the narrowest blade (Shaughnessy 1996). Differences in stipe and blade shape between M. linearis and the wide bladed form of M. splendens are not due to phenotypic plasticity, as they reproduce their original morphologies when regrown from holdfasts in reciprocal transplant sites (Shaughnessy 1994).…”

Section: Introductionmentioning

confidence: 98%

Size, survival and the potential for reproduction in transplants of Mazzaella splendens and M. linearis (Rhodophyta)

Shaughnessy¹,

DeWreede²

2001

Mar. Ecol. Prog. Ser.

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Biomechanical models of red algae have been developed that make predictions about blade survivorship based on tissue strengths, drag coefficients, and blade surface areas. The first 2 objectives of the present field study were therefore to examine actual survivorship of genets (i.e. holdfast + blades) from wide-and narrow-bladed species of Mazzaella G. DeToni f., as well as to compare blade survivorship to predictions of their survival from a previous biomechanics study of the 2 species. The third and fourth objectives were, respectively, to determine the most frequent break location in the genet, and finally to ascertain if surviving blades are likely to be reproductive. Low intertidal transplant sites were established at a wave-sheltered site where the wide-bladed form of Mazzaella splendens (Setchell et Gardner) Fredericq occurs, and in a high wave impact habitat of the narrow-bladed Mazzaella linearis (Setchell et Gardner) Fredericq. Short and long blades size classes (SC1, SC2, respectively) were included for each species because separate population sampling established that SC1 blades are almost never reproductive, whereas SC2 blades are potentially reproductive. Within the high wave impact transplant site, genet survival of experimental (i.e. transplanted to site of the other species) M. splendens was initially lower than for control (i.e. transplanted within native site) M. linearis presumably due to drag on the larger M. splendens blades. As predicted by the biomechanics model, long blades of control M. linearis survive better than those of experimental M. splendens, but not as well as short blades of experimental M. splendens. However, the narrow blade of M. linearis allows it to reach a reproductively mature length, whereas the short, broken survivors of experimental M. splendens are not long enough to be reproductive. In the sheltered transplant site, genet survival for control M. splendens and experimental M. linearis was similar, but replicate M. linearis populations located higher in the intertidal were stressed (i.e. bleached) and more likely to die. Survivorship for SC2 blades of experimental M. linearis was not greater than SC2 blades of control M. splendens as predicted by the biomechanics model; survivorship of these 2 treatments was similar. For both species, the junction between the stipe and holdfast was rarely the most frequent break location as predicted by previous studies of Mazzaella and other red algae. We conclude that M. linearis is more likely to survive and become reproductive at high wave impact sites because its narrow blade can persist in the face of large hydrodynamic forces. In contrast, in a sheltered site the widebladed form of M. splendens is still at a hydrodynamic disadvantage relative to M. linearis, but M. splendens is able to survive long enough to produce wide, potentially reproductive blades because it is apparently more tolerant of abiotic conditions (e.g. high irradiance, desiccation) within these sites.

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“…Relative to other species in the Gigartinaceae, M. splendens and M linearis are closely related because they have similar carposporangial anatomy (Kim 1976) as well as similar base sequences for the large subunit of the Rubisco gene (Hommersand et al 1994). The 2 species are distinguished by the depth of the tetrasporangial sorus in the blade (Kim 1976) and, in Barkley Sound, Canada, M. splendens has a short thin stipe with wide or intermediate-width blades whereas M. linearis has a long thick stipe and narrow blades (Shaughnessy 1996). A reciprocal common garden experiment where each species was regrown from holdfasts demonstrated that these vegetative differences were due to genetic differentiation rather than phenotypic plasticity (Shaughnessy 1994).…”

Section: Introductionmentioning

confidence: 99%

Consequences of morphology and tissue strength to blade survivorship of two closely related Rhodophyta species

Shaughnessy¹,

Wreede²,

Bell³

1996

Mar. Ecol. Prog. Ser.

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In Barkley Sound, British Columbia, Canada, the wide-bladed red alga Mazzaella splendens occurs intertidally at low to intermediate wave exposure sites but not at adjacent high wave exposure intertidal sites that are occupied by the narrow-bladed sister species Mazzaella linearis. This study used morphological and biomechanical characteristics of both species to determine whether or not drag and acceleration forces could prevent blades of M. splendens from surviving at high exposure sites and hence account, in part, for their distributions For each species, these hydrodynamic forces were calculated for gametophyte and sporophyte phases and, when possible, short and long thalli. The most frequent break location when thalli were pulled by a spring-scale was the junction between the stipe and holdfast. The following predictions were made by a model that compared hydrodynamic forces which a blade would experience to the measured force required to break the stipe/holdfast junction: (1) long blades of M. splendens should not occur at high wave exposure sites, (2) within the range of wave exposure occupied by M. splendens, sporophytes should be more abundant than gametophytes when and where wave exposure is greatest and (3) long blades of M linearis are predicted to occur at high wave exposure sites. All 3 of these predictions agree with other studies of natural populations. Two predictions do not agree with field observations: (1) long M. linearis gametophytes are predicted to have greater survivorship at higher water velocities than long sporophytes but, in natural populations, sporophytes are actually more abundant when wave action is greater and (2) short blades of M. splendens are predicted to survive very high water velocities but, in reality, are absent from high wave exposure sites in Barkley Sound. The latter contradlct~on suggests that recruitment of M. splendens at high wave exposure sltes is prevented at a life history stage prior to the development of short blades.

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Identification and microgeographic distribution of Mazzaella splendens and Mazzaella linearis (Gigartinaceae, Rhodophyta)

Cited by 9 publications

References 14 publications

Applying DNA barcoding to red macroalgae: a preliminary appraisal holds promise for future applications

Applying DNA barcoding to red macroalgae: a preliminary appraisal holds promise for future applications

Size, survival and the potential for reproduction in transplants of Mazzaella splendens and M. linearis (Rhodophyta)

Consequences of morphology and tissue strength to blade survivorship of two closely related Rhodophyta species

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