scholarly journals Submarine Groundwater Discharge Differentially Modifies Photosynthesis, Growth, and Morphology for Two Contrasting Species of Gracilaria (Rhodophyta)

Hydrology ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 65 ◽  
Author(s):  
Daniel Amato ◽  
Celia Smith ◽  
Thomas Duarte
Keyword(s):  
Benthic Community ◽  
Submarine Groundwater Discharge ◽  
Tissue Loss ◽  
Coastal Environments ◽  
Benthic Community Structure ◽  
Marked Contrast ◽  
Tissue Samples ◽  
Flux Measurements ◽  
Branch Development ◽  
Native Algae

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.

scholarly journals Shift in polar benthic community structure in a fast retreating glacial area of Marian Cove, West Antarctica

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hanna Bae ◽  
In-Young Ahn ◽  
Jinsoon Park ◽  
Sung Joon Song ◽  
Junsung Noh ◽  
...  
Keyword(s):  
Community Structure ◽  
Benthic Community ◽  
Adaptive Strategy ◽  
Ecological Impacts ◽  
Glacier Retreat ◽  
Benthic Diatoms ◽  
Subtidal Zone ◽  
Benthic Community Structure ◽  
Community Shift ◽  
Global Issue

AbstractGlacier retreat is a major long-standing global issue; however, the ecological impacts of such retreats on marine organisms remain unanswered. Here, we examined changes to the polar benthic community structure of “diatoms” under current global warming in a recently retreated glacial area of Marian Cove, Antarctica. The environments and spatiotemporal assemblages of benthic diatoms surveyed in 2018–2019 significantly varied between the intertidal (tidal height of 2.5 m) and subtidal zone (10 and 30 m). A distinct floral distribution along the cove (~ 4.5 km) was characterized by the adaptive strategy of species present, with chain-forming species predominating near the glacier. The predominant chain-forming diatoms, such as Fragilaria striatula and Paralia sp., are widely distributed in the innermost cove over years, indicating sensitive responses of benthic species to the fast-evolving polar environment. The site-specific and substrate-dependent distributions of certain indicator species (e.g., F. striatula, Navicula glaciei, Cocconeis cf. pinnata) generally reflected such shifts in the benthic community. Our review revealed that the inner glacier region reflected trophic association, featured with higher diversity, abundance, and biomass of benthic diatoms and macrofauna. Overall, the polar benthic community shift observed along the cove generally represented changing environmental conditions, (in)directly linked to ice-melting due to the recent glacier retreat.

scholarly journals Do installed stream logjams change benthic community structure?

Limnologica ◽  
2014 ◽  
Vol 49 ◽  
pp. 68-72 ◽  
Author(s):  
Todd Wellnitz ◽  
Se Yeon Kim ◽  
Eric Merten
Keyword(s):  
Community Structure ◽  
Benthic Community ◽  
Benthic Community Structure

scholarly journals An evaluation of benthic community structure in and around the Sackville Spur closed area (Northwest Atlantic) in relation to the protection of vulnerable marine ecosystems

2012 ◽  
Vol 69 (2) ◽  
pp. 213-222 ◽  
Author(s):  
Christopher R. S. Barrio Froján ◽  
Kevin G. MacIsaac ◽  
Andrew K. McMillan ◽  
María del Mar Sacau Cuadrado ◽  
Philip A. Large ◽  
...  
Keyword(s):  
Community Structure ◽  
Benthic Community ◽  
Evaluation Process ◽  
Marine Ecosystems ◽  
Benthic Community Structure ◽  
Sponge Spicule ◽  
Northwest Atlantic ◽  
Depth Limit ◽  
Closed Area ◽  
Macrofaunal Community

Abstract Barrio Froján, C. R. S., MacIsaac, K. G., McMillan, A. K., del Mar Sacau Cuadrado, M., Large, P. A., Kenny, A. J., Kenchington, E., and de Cárdenas González,  E. 2012. An evaluation of benthic community structure in and around the Sackville Spur closed area (Northwest Atlantic) in relation to the protection of vulnerable marine ecosystems. – ICES Journal of Marine Science, 69: 213–222. The benthic macrofaunal community structure is investigated within and around a closed area at Sackville Spur in the Northwest Atlantic to ascertain whether continued exclusion of bottom fishing can be justified. This and other similar closed areas have been introduced by the Northwest Atlantic Fisheries Organisation (NAFO) to protect areas of likely occurrence of taxa that are indicative of vulnerable marine ecosystems (VMEs) from the damaging effects of bottom-contact fishing gear. Results reveal subtle yet significant differences in macrofaunal assemblage composition and community structure between inside and outside the closed area, between above and below the 1200-m depth contour (i.e. the historical depth limit of fishing), and between areas where dense sponge spicule mats are either present or absent. Differences were observed in many assemblage metrics; however, the most revealing was the greater abundance, biomass, diversity, and number of VME indicative taxa inside the closed area than outside. Overall community composition is also significantly different between treatments. Depth, sediment temperature, and the proportion of clay within sediments are important in shaping the faunal assemblage. The importance of the effects of fishing is discussed, although it is not possible to ascertain if fishing is the direct cause behind observed differences in the macrofaunal assemblage. A continued closure of the area is recommended, as well as options for streamlining the evaluation process of other closed areas.

Changes in benthic community structure following construction of a harbour impoundment scheme

1995 ◽  
Vol 29 (3-4) ◽  
pp. 449-457 ◽  
Author(s):  
J. A. Smith ◽  
G. E. Millward ◽  
N. H. Babbedge ◽  
M. J. Attrill ◽  
M. B. Jones
Keyword(s):  
Community Structure ◽  
Benthic Community ◽  
Benthic Community Structure

scholarly journals White Syndrome-Affected Corals Have a Distinct Microbiome at Disease Lesion Fronts

2016 ◽  
Vol 83 (2) ◽  
Author(s):  
F. Joseph Pollock ◽  
Naohisa Wada ◽  
Gergely Torda ◽  
Bette L. Willis ◽  
David G. Bourne
Keyword(s):  
Disease Ecology ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Health States ◽  
Host Coral ◽  
Tissue Samples ◽  
Content Type ◽  
White Syndrome ◽  
Community Profiling

ABSTRACT Coral tissue loss diseases, collectively known as white syndromes (WSs), induce significant mortality on reefs throughout the Indo-Pacific, yet definitive confirmation of WS etiologies remains elusive. In this study, we integrated ecological disease monitoring, bacterial community profiling, in situ visualization of microbe-host interactions, and cellular responses of the host coral through an 18-month repeated-sampling regime. We assert that the observed pathogenesis of WS lesions on acroporid corals at Lizard Island (Great Barrier Reef) is not the result of apoptosis or infection by Vibrio bacteria, ciliates, fungi, cyanobacteria, or helminths. Histological analyses detected helminths, ciliates, fungi, and cyanobacteria in fewer than 25% of WS samples, and helminths and fungi were also observed in 12% of visually healthy samples. The abundances of Vibrio-affiliated sequences (assessed using 16S rRNA amplicon sequencing) did not differ significantly between health states and never exceeded 3.3% of reads in any individual sample. In situ visualization detected Vibrio bacteria only in summer WS lesion samples and revealed no signs of these bacteria in winter disease samples (or any healthy tissue samples), despite continued disease progression year round. However, a 4-fold increase in Rhodobacteraceae-affiliated bacterial sequences at WS lesion fronts suggests that this group of bacteria could play a role in WS pathogenesis and/or serve as a diagnostic criterion for disease differentiation. While the causative agent(s) underlying WSs remains elusive, the microbial and cellular processes identified in this study will help to identify and differentiate visually similar but potentially distinct WS etiologies. IMPORTANCE Over the past decade, a virulent group of coral diseases known as white syndromes have impacted coral reefs throughout the Indian and Pacific Oceans. This article provides a detailed case study of white syndromes to combine disease ecology, high-throughput microbial community profiling, and cellular-scale host-microbe visualization over seasonal time scales. We provide novel insights into the etiology of this devastating disease and reveal new diagnostic criteria that could be used to differentiate visually similar but etiologically distinct forms of white syndrome.

scholarly journals Characteristics of Benthos communities in Laoting area of Hebei Province

2020 ◽  
Vol 206 ◽  
pp. 02024
Author(s):  
Li Guanglou ◽  
Cao Hongmei ◽  
Ye wei
Keyword(s):  
Community Structure ◽  
Benthic Community ◽  
Dominant Species ◽  
Diversity Index ◽  
Hebei Province ◽  
Benthic Community Structure ◽  
Number Of Species ◽  
Evenness Index ◽  
Sea Area ◽  
Richness Index

According to a survey of benthos in the Laoting sea area of Hebei Province on May 24th 2019, a total of 40 benthos species were obtained, of which mollusks have the largest number, followed by annelids and arthropods. The dominant species are Sternaspis sculata and Ringicula doliaris. The number of species obtained in this survey is much lower than the historical average. The diversity index is significantly lower than that in the April 2008 survey, and the evenness index and richness index have declined slightly, indicating that the benthic community structure in this sea area tends to be simplistic, stability tends to deteriorate.

scholarly journals Slow Community Development Enhances Abiotic Limitation of Benthic Community Structure in a High Arctic Kelp Bed

2021 ◽  
Vol 8 ◽  
Author(s):  
Christina Bonsell ◽  
Kenneth H. Dunton
Keyword(s):  
Community Structure ◽  
Community Development ◽  
Benthic Community ◽  
Beaufort Sea ◽  
High Arctic ◽  
Coralline Algae ◽  
Physical Factors ◽  
Crustose Coralline Algae ◽  
Benthic Community Structure ◽  
Kelp Bed

We examined the patterns of propagule recruitment to assess the timescale and trajectory of succession and the possible roles of physical factors in controlling benthic community structure in a shallow High Arctic kelp bed in the Beaufort Sea, Alaska. Spatial differences in established epilithic assemblages were evaluated against static habitat attributes (depth, distance from river inputs) and environmental factors (temperature, salinity, current speed, underwater light) collected continuously over 2–6 years. Our measurements revealed that bottom waters remained below freezing (mean winter temperatures ∼−1.8°C) and saline (33–36) with negligible light levels for 8–9 months. In contrast, the summer open water period was characterized by variable salinities (22–36), higher temperatures (up to 8–9°C) and measurable irradiance (1–8 mol photons m–2 day–1). An inshore, near-river site experienced strong, acute, springtime drops in salinity to nearly 0 in some years. The epilithic community was dominated by foliose red algae (47–79%), prostrate kelps (2–19%), and crustose coralline algae (0–19%). Strong spatial distinctions among sites included a positive correlation between cover by crustose coralline algae and distance to river inputs, but we found no significant relationships between multi-year means of physical factors and functional groups. Low rates of colonization and the very slow growth rates of recruits are the main factors that contribute to prolonged community development, which augments the influence of low-frequency physical events over local community structure. Mortality during early succession largely determines crustose coralline algal and invertebrate prevalence in the established community, while kelp seem to be recruitment-limited. On scales > 1 m, community structure varies with bathymetry and exposure to freshwater intrusion, which regulate frequency of primary and physiological disturbance. Colonization rates (means of 3.3–69.9 ind. 100 cm–1 year–1 site–1) were much lower than studies in other Arctic kelp habitats, and likely reflect the nature of a truly High Arctic environment. Our results suggest that community development in the nearshore Beaufort Sea occurs over decades, and is affected by combinations of recruitment limitation, primary disturbance, and abiotic stressors. While seasonality exerts strong influence on Arctic systems, static habitat characteristics largely determine benthic ecosystem structure by integrating seasonal and interannual variability over timescales longer than most ecological studies.

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