Grazer Interactions with Invasive Agarophyton vermiculophyllum (Rhodophyta): Comparisons to Related versus Unrelated Native Algae

2020 ◽  
Vol 238 (3) ◽  
pp. 145-153
Author(s):  
S. K. Berke ◽  
E. L. Keller ◽  
C. N. Needham ◽  
C. R. Salerno
Keyword(s):  
2018 ◽  
Vol 62 (3) ◽  
pp. 292-298
Author(s):  
András J. Kovács ◽  
Zsolt Méhes ◽  
Imre Tolner ◽  
László Tolner

Native algae strains have been domesticated and stimulated in activated sludge wastewater treatment operations. The term of domestication indicates that we did not add any selected algae to the wastewater, but made use of species existing in the system. The term of proliferation indicates a stimulation of the biological oxidation process by provision of CO2 with the air stream and illumination of the reactor. The idea of domestication of algae present in communal wastewater systems was demonstrated. Stimulation of the system with domesticated algae community did improve efficiency of the treatment process. Removal of organic components in terms of reduction of chemical and biological oxidation demands (dissolved COD, BOD) as well as nitrogen and phosphorous contents was superior to extent of removal in conventional activated sludge system. We did conclude that conventional systems lack available light and carbon resources for these microorganisms. Upon providing these, symbiotic operation can contribute to reducing greenhouse gas emissions and increase of the rate of pollutants removal kinetics. Symbiotic operation increased the production of biomass expressed in terms of total suspended solids. Biodiesel potential of the filterable biomass was in the range of 8-18%. Because of technical difficulties in manipulation of the excess sludge other than biodiesel synthesis processing scheme has been recommended for economically viable processing.


2004 ◽  
Vol 55 (3) ◽  
pp. 223 ◽  
Author(s):  
Joseph P. Valentine ◽  
Craig R. Johnson

The Asian kelp Undaria pinnatifida has recently invaded the coastlines of several countries across both hemispheres. Although the occurrence and subsequent spread of the alga has been well documented, the processes underpinning establishment and spread remain poorly understood. Recent work involving canopy manipulations has demonstrated that disturbance to the native algal canopy facilitates establishment of U. pinnatifida sporophytes at high densities, however, the kelp’s response to a natural disruption of the native algal canopy has not been assessed. In summer/autumn 2001, we examined the response of U. pinnatifida to the significant dieback of a common native canopy forming macroalga (Phyllospora comosa) on the east coast of Tasmania. The response of U. pinnatifida and native algae to the dieback was observed during the season for growth of U. pinnatifida sporophytes (spring 2001) and compared with adjacent areas where dieback did not occur. Undaria pinnatifida sporophytes established at high densities (6.75 ± 1.99 stipes m–2) in dieback areas, but remained rare or entirely absent in control areas where the native canopy was intact. The dieback also resulted in bleaching of encrusting algae and increased cover of understorey algae and sediment. The results support the findings of our recent artificial disturbance experiments, confirming the importance of disturbance events for the successful establishment of U. pinnatifida at high densities.


Diversity ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 54 ◽  
Author(s):  
Lindsay M. Marks ◽  
Daniel C. Reed ◽  
Sally J. Holbrook

Invasive species are a growing threat to conservation in marine ecosystems, yet we lack a predictive understanding of ecological factors that influence the invasiveness of exotic marine species. We used surveys and manipulative experiments to investigate how an exotic seaweed, Sargassum horneri, interacts with native macroalgae and herbivores off the coast of California. We asked whether the invasion (i.e., the process by which an exotic species exhibits rapid population growth and spread in the novel environment) of S. horneri is influenced by three mechanisms known to affect the invasion of exotic plants on land: competition, niche complementarity and herbivory. We found that the removal of S. horneri over 3.5 years from experimental plots had little effect on the biomass or taxonomic richness of the native algal community. Differences between removal treatments were apparent only in spring at the end of the experiment when S. horneri biomass was substantially higher than in previous sampling periods. Surveys across a depth range of 0–30 m revealed inverse patterns in the biomass of S. horneri and native subcanopy-forming macroalgae, with S. horneri peaking at intermediate depths (5–20 m) while the aggregated biomass of native species was greatest at shallow (<5 m) and deeper (>20 m) depths. The biomass of S. horneri and native algae also displayed different seasonal trends, and removal of S. horneri from experimental plots indicated the seasonality of native algae was largely unaffected by fluctuations in S. horneri. Results from grazing assays and surveys showed that native herbivores favor native kelp over Sargassum as a food source, suggesting that reduced palatability may help promote the invasion of S. horneri. The complementary life histories of S. horneri and native algae suggest that competition between them is generally weak, and that niche complementarity and resistance to grazing are more important in promoting the invasion success of S. horneri.


ENERGYO ◽  
2018 ◽  
Author(s):  
N. K. Soni ◽  
A. K. Varma ◽  
P. Mondal ◽  
M. N. Srivastava
Keyword(s):  
Bio Oil ◽  

2019 ◽  
Vol 62 (2) ◽  
pp. 83-96 ◽  
Author(s):  
Kyle Capistrant-Fossa ◽  
Susan H. Brawley

Abstract A non-indigenous alga, Grateloupia turuturu (Halymeniales, Rhodophyta), was discovered in the Damariscotta Estuary (Maine, USA) in 2017, over 200 km north of its last reported location. Because of the presence of coastal facilities (aquaculture, marine laboratories) among potential vectors, we evaluated a mandated biosecurity protocol, namely, seawater treated with bleach at 50 ppm (50 mg l−1) free chlorine for ≥2 h and measured using test strips, for lethality against G. turuturu and several native algae. We report unexpected resilience to bleach-treatment (Mastocarpus > Grateloupia > Palmaria). Holdfasts of G. turuturu and Mastocarpus stellatus survived 50 and 1000 ppm free chlorine, respectively. Cystocarps on cultured blades of G. turuturu were particularly resistant to bleach-treatment; they produced outgrowths on fragmenting blades that became fertile tetrasporophytes in culture, suggesting reproductive adaptations of cystocarps to stressful conditions that may have broader evolutionary significance. Juvenile, microscopic crusts of G. turuturu were also bleach-resistant if covered by diatoms, and developed upright axes. Free chlorine test strips were inaccurate in seawater, and their use could increase the risk of failed biosecurity as a vector for invasion. Because chlorination at economic and environmentally safe levels is insufficient, we recommend a combination of treatments for comprehensive biosecurity.


2010 ◽  
Vol 61 (6) ◽  
pp. 724 ◽  
Author(s):  
Ignacio Gestoso ◽  
Celia Olabarria ◽  
Jesús S. Troncoso

Marine macroalgae harbour abundant and diverse assemblages of epifauna. Patterns of distribution and abundance of epifauna, which are often variable in space and time, differ markedly among macroalgae species. Non-indigenous seaweeds may alter composition and structure of epifaunal assemblages and therefore harbour different assemblages from those associated with native macroalgae. In this study, we analysed the epifaunal assemblages associated with the native algae Bifurcaria bifurcata and the invasive alga Sargassum muticum on the southern part of the Galician coast (north-west Spain). In particular, we tested the hypothesis that there were differences in the epifaunal assemblages associated with the native and invasive algae. We used a hierarchical spatial sampling design to identify if these differences were consistent over space and time. Results indicated that there were significant differences between epifaunal assemblages associated with both algae. The fact that such differences were, in general, consistent at different spatial scales suggests that biological factors related to the specific habitat might play a more important role than physical factors as determinants of epifaunal distribution. This study also showed that S. muticum seems to supply a new and additional habitat for the native epifauna, contributing to increases in the spatial and temporal variability of epifaunal assemblages.


Green ◽  
2013 ◽  
Vol 3 (5-6) ◽  
Author(s):  
N. K. Soni ◽  
A. K. Varma ◽  
P. Mondal ◽  
M. N. Srivastava
Keyword(s):  
Bio Oil ◽  

AbstractThe present paper deals with the production of bio-oil from algal biomass collected from Solani aqua-duct, Roorkee. The taxonomy of algal sample shows the dominance of


Hydrology ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 65 ◽  
Author(s):  
Daniel Amato ◽  
Celia Smith ◽  
Thomas Duarte

Gracilaria coronopifolia and an invasive congener, Gracilaria salicornia, were examined across an SGD gradient in the field and laboratory. Tissue samples of both species were cultured for 16 days along an onshore-offshore SGD gradient at Wailupe, Oahu. G. salicornia tolerated the extremely variable salinity, temperature, and nutrient levels associated with SGD. In marked contrast, half of G. coronopifolia plants suffered tissue loss and even death at SGD-rich locations in the field and in laboratory treatments simulating high SGD flux. Measurements of growth, photosynthesis, and branch development via two novel metrics indicated that the 27‰ simulated-SGD treatment provided optimal conditions for the apparently less tolerant G. coronopifolia in the laboratory. Benthic community analyses revealed that G. salicornia dominated the nearshore reef exposed to SGD compared with the offshore reef, which had a greater diversity of native algae. Ultimately, SGD inputs to coastal environments likely influence benthic community structure and zonation on otherwise oligotrophic reefs.


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