More Like this

1. A Morphological and Molecular Analysis of a Bloom of the Filamentous Green Alga Pithophora

   https://doi.org/10.3390/w13060760  

   Lor, Blia; Zohn, Merry; Meade, Marcus J.; Cahoon, A. Bruce; Manoylov, Kalina M. (March 2021, Water)

   null (Ed.)

   Filamentous representatives of Cladophorales (Chlorophyta) are major contributors to algal biomass of littoral communities. In the present study, community analysis of a reported bloom in the Ogeechee River in Georgia provided an opportunity to combine morphological and genetic analyses with ecological information related to an understudied nuisance alga. A polyphasic approach of incorporating genotypic and phenotypic methods led to the identification of the algal community as Pithophora roettleri (Roth) Wittrock. Morphological analysis showed a monospecific community based on the average length and diameter of the heterosporous intercalary and terminal akinetes, along with the diameter of the principal filaments. Single-gene and concatenated-gene phylogenetic analyses of the LSU (28S rRNA) and SSU (18S rRNA) markers further confirmed this species identification. In this study, we conducted a morphological treatment of P. roettleri, produced 17 novel gene sequences, and produced a new, schematic diagram illustrating the four steps of the asexual reproduction of an intercalary akinete. Morphological characteristics, like the position and shape of akinetes documented here, and the availability of genetic sequences can improve identification and further ecological understanding of filamentous green algae. Flowing mats of P. roettleri, like those observed in this study, can lower light availability for other biota and structurally alter the habitat. 

   more » « less
2. Ontogenetic Variation in Blade Toughness May Contribute to the Spread of Turbinaria ornata Across the South Pacific

   https://doi.org/10.1111/jpy.13292  

   Betancourt, Austin M.; Fenwick, Ileana F.; Howard, Hunter B.; Long, Alexys E.; Fong, Peggy; Barber, Paul H.; Fong, Caitlin R. (October 2022, Journal of Phycology)

   Coral reefs are shifting from coral to algal-dominated ecosystems worldwide. Recently, Turbinaria ornata, a marine alga native to coral reefs of the South Pacific, has spread in both range and habitat usage. Given dense stands of T. ornata can function as an alternative stable state on coral reefs, it is imperative to understand the factors that underlie its success. We tested the hypothesis that T. ornata demonstrates ontogenetic variation in allocation to anti-herbivore defense, specifically that blade toughness varied nonlinearly with thallus size. We quantified the relationship between T. ornata blade toughness and thallus size for individual thalli within algal stands (N=345) on 7 fringing reefs along the north shore of Moorea, French Polynesia. We found that blade toughness was greatest at intermediate sizes that typically form canopies, with overall reduced toughness in both smaller individuals that refuge within the understory and older reproductive individuals that ultimately detach and form floating rafts. We posit this variation in blade toughness reduces herbivory on the thalli that are most exposed to herbivores and may facilitate reproduction in dispersing stages, both of which may aid the proliferation of T. ornata. 

   more » « less
3. Rediscovery of Tetraedriella subglobosa Pascher, a member of the Eustigmatophyceae

   https://doi.org/10.5507/fot.2016.018  

   Fawley, Marvin W.; Fawley, Karen P. (April 2017, Fottea)

   An algal strain from an acidic pool near the shore of Lake Mácha, Czech Republic, was identified as Tetraëdriella subglobosa Pascher by light microscopy. Phylogenetic analysis of nuclear 18S rDNA and plastid rbcL sequence data indicated that this alga is a member of the Eustigmatophyceae, rather than the Xanthophyceae as presently classified. This is the first report of T. subglobosa since Pascher’s description of the species in 1930. 

   more » « less
4. Marine Benthic Algae from Ni‘ihau and Adjacent Lehua Islet, Main Hawaiian Islands

   Tsuda, R.T.; Abbott, I.A.; Spalding, H.L.; Giuseffi, L.M.; Okano, R.; Kennedy, B.H.; Sherwood, A.R. (July 2021, Bishop Museum occasional papers)

   null (Ed.)

   The published records of marine benthic algal species from the privately-owned island of Ni‘ihau (Hawaiian Islands) are represented by four species cited in abbott (1999) and abbott & Huisman (2004). The species consist of the red alga Chondrophycus dotyi (y. Saito) k.w. Nam [= Laurencia dotyi y. Saito], two brown algae Dictyopteris plagio - gramma (Montagne) Vickers and Distromium flabellatum womersley, and the green alga Pseudochlorodesmis parva w. J. gilbert [= Siphonogramen parvum (w.J. gilbert) I.a. abbott & Huisman]. Distromium flabellatum and Pseudochlorodesmis parva were collected in waters between Ni‘ihau and Lehua Islet. The paucity of algal records from Ni‘ihau is not surprising, very few collections have been made along its coastline because of its remoteness and general lack of access. 

   more » « less
5. Long-term ecological monitoring of reefs on Hawai’i Island (2003-2020): Characterization of a common cryptic crust, Ramicrusta hawaiiensis (Peyssonneliales, Rhodophyta)

   https://doi.org/10.3389/fmars.2022.1009471  

   Grady, Bryant W.; Kittle, Ronald P.; Pugh, Ashley; Lamson, Megan R.; Richards, Joseph L.; Fredericq, Suzanne; McDermid, Karla J.; Allen, Quintin; Asner, Gregory P. (October 2022, Frontiers in Marine Science)

   The recently described crustose calcifying red algal species Ramicrusta hawaiiensis, known only from mesophotic depths off Lehua Island, west of Kaua’i Island, was found in shallow benthic reef habitats (3-18 m deep) along the western coast of Hawai’i Island. Molecular and microscopy techniques were used for genetic confirmation and for detailed morphological and anatomical examination. Two independent benthic cover survey datasets collected from west Hawai’i Island were used to investigate temporal and geographic distribution of Ramicrusta . In both datasets, we report Ramicrusta at approximately 60% of the sites surveyed. Benthic cover for this alga varies among sites and among years and its presence in west Hawai’i is evident since at least 2003. These findings help to document Hawaiian coral reef ecosystem change and benthic community composition reshuffling. This study also emphasizes the critical importance of taxonomy and proper identification of macroalgal species to understand the potential for phase-shifts of dominant taxa in coral reef ecosystems after environmental disturbances and fluctuations in abiotic factors. In the last decade, members of the red algal order Peyssonneliales have increased in abundance and overgrown other benthic species in reef ecosystems in the Caribbean and tropical Pacific. The novel aspect of finding abundant Ramicrusta in much shallower water than originally described, the decadal presence of Ramicrusta , and its potential for competition with other benthic organisms make this research valuable to coral reef ecology and justify further investigation of Ramicrusta ecology and biology in the Hawaiian Islands and globally. 

   more » « less