scholarly journals Variation in marine benthic community composition allows discrimination of multiple stressors

2003 ◽  
Vol 261 ◽  
pp. 63-73 ◽  
Author(s):  
HS Lenihan ◽  
CH Peterson ◽  
SL Kim ◽  
KE Conlan ◽  
R Fairey ◽  
...  
2020 ◽  
Vol 287 (1928) ◽  
pp. 20200709
Author(s):  
Ana Giraldo-Ospina ◽  
Gary A. Kendrick ◽  
Renae K. Hovey

Marine heatwaves (MHWs) have been documented around the world, causing widespread mortality of numerous benthic species on shallow reefs (less than 15 m depth). Deeper habitats are hypothesized to be a potential refuge from environmental extremes, though we have little understanding of the response of deeper benthic communities to MHWs. Here, we show how increasing depth moderates the response of seaweed- and coral-dominated benthic communities to an extreme MHW across a subtropical–temperate biogeographical transition zone. Benthic community composition and key habitat-building species were characterized across three depths (15, 25 and 40 m) before and several times after the 2011 Western Australian MHW to assess resistance during and recovery after the heatwave. We found high natural variability in benthic community composition along the biogeographic transition zone and across depths with a clear shift in the composition after the MHW in shallow (15 m) sites but a lot less in deeper communities (40 m). Most importantly, key habitat-building seaweeds such as Ecklonia radiata and Syctothalia dorycarpa which had catastrophic losses on shallow reefs, remained and were less affected in deeper communities. Evidently, deep reefs have the potential to act as a refuge during MHWs for the foundation species of shallow reefs in this region.


2020 ◽  
Vol 86 (12) ◽  
Author(s):  
Ferran Romero ◽  
Vicenç Acuña ◽  
Sergi Sabater

ABSTRACT Freshwater ecosystems are exposed to multiple stressors, but their individual and combined effects remain largely unexplored. Here, we investigated the response of stream biofilm bacterial communities to warming, hydrological stress, and pesticide exposure. We used 24 artificial streams on which epilithic (growing on coarse sediments) and epipsammic (growing on fine sediments) stream biofilms were maintained. Bacterial community composition and estimated function of biofilms exposed during 30 days to individual and combined stressors were assessed using 16S rRNA gene metabarcoding. Among the individual effects by stressors, hydrological stress (i.e., a simulated low-flow situation) was the most relevant, since it significantly altered 57% of the most abundant bacterial taxa (n = 28), followed by warming (21%) and pesticide exposure (11%). Regarding the combined effects, 16% of all stressor combinations resulted in significant interactions on bacterial community composition and estimated function. Antagonistic responses prevailed (57 to 89% of all significant interactions), followed by synergisms (11 to 43%), on specific bacterial taxa, indicating that multiple-stressor scenarios could lead to unexpected shifts in the community composition and associated functions of riverine bacterial communities. IMPORTANCE Freshwater ecosystems such as rivers are of crucial importance for human well-being. However, human activities result in many stressors (e.g., toxic chemicals, increased water temperatures, and hydrological alterations) cooccurring in rivers and streams worldwide. Among the many organisms inhabiting rivers and streams, bacteria are ecologically crucial; they are placed at the base of virtually all food webs and they recycle the organic matter needed for bigger organisms. Most of these bacteria are in close contact with river substratum, where they form the biofilms. There is an urgent need to evaluate the effects of these stressors on river biofilms, so we can anticipate future environmental problems. In this study, we experimentally exposed river biofilms to a pesticide mixture, an increase in water temperature and a simulated low-flow condition, in order to evaluate the individual and joint effects of these stressors on the bacterial community composition and estimated function.


2014 ◽  
Vol 36 (2) ◽  
pp. 129-140 ◽  
Author(s):  
Alexander T. Lowe ◽  
Ross Whippo ◽  
Aaron W. E. Galloway ◽  
Kevin H. Britton-Simmons ◽  
Megan N. Dethier

Coral Reefs ◽  
2018 ◽  
Vol 37 (4) ◽  
pp. 1157-1168 ◽  
Author(s):  
James P. W. Robinson ◽  
Ivor D. Williams ◽  
Lauren A. Yeager ◽  
Jana M. McPherson ◽  
Jeanette Clark ◽  
...  

2013 ◽  
Vol 161 (2) ◽  
pp. 329-337
Author(s):  
Zannè Zeeman ◽  
George M. Branch ◽  
Deena Pillay ◽  
Astrid Jarre

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Chris Roelfsema ◽  
Eva M. Kovacs ◽  
Kathryn Markey ◽  
Julie Vercelloni ◽  
Alberto Rodriguez-Ramirez ◽  
...  

AbstractThis paper describes benthic coral reef community composition point-based field data sets derived from georeferenced photoquadrats using machine learning. Annually over a 17 year period (2002–2018), data were collected using downward-looking photoquadrats that capture an approximately 1 m2 footprint along 100 m–1500 m transect surveys distributed along the reef slope and across the reef flat of Heron Reef (28 km2), Southern Great Barrier Reef, Australia. Benthic community composition for the photoquadrats was automatically interpreted through deep learning, following initial manual calibration of the algorithm. The resulting data sets support understanding of coral reef biology, ecology, mapping and dynamics. Similar methods to derive the benthic data have been published for seagrass habitats, however here we have adapted the methods for application to coral reef habitats, with the integration of automatic photoquadrat analysis. The approach presented is globally applicable for various submerged and benthic community ecological applications, and provides the basis for further studies at this site, regional to global comparative studies, and for the design of similar monitoring programs elsewhere.


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