scholarly journals Global change differentially modulates coral physiology and suggests future shifts in Caribbean reef assemblages

2021 ◽  
Author(s):  
Colleen B Bove ◽  
Sarah W. Davies ◽  
Justin B Ries ◽  
James Umbanhowar ◽  
Bailey C Thomasson ◽  
...  
Keyword(s):  
Global Change ◽  
Coral Reefs ◽  
Ocean Acidification ◽  
Stress Responses ◽  
Physiological Responses ◽  
Ocean Warming ◽  
Caribbean Reef ◽  
Algal Symbiont ◽  
Coral Holobiont ◽  
Reef Environments

Global change driven by anthropogenic carbon emissions is altering ecosystems at unprecedented rates, especially coral reefs, whose symbiosis with algal endosymbionts ise particularly vulnerable to increasing ocean temperatures and altered carbonate chemistry. Here, we assess the physiological responses of the coral holobiont (animal host + algal symbiont) of three Caribbean coral species from two reef environments after exposure to simulated ocean warming (28, 31 °C), acidification (300 - 3290 μatm), and the combination of stressors for 93 days. We used multidimensional analyses to assess how multiple coral holobiont physiological parameters respond to ocean acidification and warming. Our results demonstrate significantly diminishing holobiont physiology in S. siderea and P. astreoides in response to projected ocean acidification, while future warming elicited severe declines in P. strigosa. Offshore S. siderea fragments exhibited higher physiological plasticity than inshore counterparts, suggesting that this offshore population has the capacity to modulate their physiology in response to changing conditions, but at a cost to the holobiont. Plasticity of P. strigosa and P. astreoides was not clearly different between natal reef environments, however, temperature evoked a greater plastic response in both species. Interestingly, while these species exhibit unique physiological responses to ocean acidification and warming, when data from all three species are modeled together, convergent stress responses to these conditions are observed, highlighting the overall sensitivities of tropical corals to these stressors. Our results demonstrate that while ocean warming is a severe acute stressor that will have dire consequences for coral reefs globally, chronic exposure to acidification may also impact coral physiology to a greater extent than previously assumed. The variety of responses to global change we observe across species will likely manifest in altered Caribbean reef assemblages in the future.

Symbiodinium thermophilum symbionts in Porites harrisoni and Cyphastrea microphthalma in the northern Persian Gulf, Iran

2017 ◽  
Vol 98 (8) ◽  
pp. 2067-2073 ◽  
Author(s):  
Tooba Varasteh ◽  
Mohammad Reza Shokri ◽  
Hassan Rajabi-Maham ◽  
Safoura Behzadi ◽  
Benjamin C. C. Hume
Keyword(s):  
Coral Reefs ◽  
Stress Tolerance ◽  
Persian Gulf ◽  
Algal Symbionts ◽  
Algal Symbiont ◽  
Coral Holobiont ◽  
Iranian Coast ◽  
Coral Communities ◽  
The Persian Gulf ◽  
Rare Group

Coral communities of the Persian Gulf (PG) withstand maximum and annual ranges of water temperatures that surpass those found on the majority of reefs elsewhere. As such, these communities may inform on how coral reefs might adapt to the warmer waters of the future. Depending on the algal symbiont (genus Symbiodinium) harboured, advantages in stress tolerance may be conferred to the coral holobiont. Characterizing the algal component is therefore critical in determining the coral holobiont's tolerance phenotype. Coral associations off the Arabian coastline of the PG have been characterized as biogeographically unique, containing a rare group of taxonomically ancestral and thermotolerant algal symbionts, the Symbiodinium thermophilum group. In contrast, waters off the Iranian coast remain poorly characterized with a notable lack of S. thermophilum group symbionts identified in coral associations to date. Here, we characterize the algal component of two reef building corals (Porites harrisoni and Cyphastrea microphthalma) predominant at three sites spanning almost the entire length of the PG's Iranian coast. Genotyping using the chloroplastic 23S and nuclear ITS2 genes, we demonstrate the presence of S. thermophilum group symbionts. We discuss the probable physical drivers of these associations and highlight the need for further research in these relatively understudied waters.

scholarly journals Whole transcriptome analysis reveals changes in expression of immune-related genes during and after bleaching in a reef-building coral

2015 ◽  
Vol 2 (4) ◽  
pp. 140214 ◽  
Author(s):  
Jorge H. Pinzón ◽  
Bishoy Kamel ◽  
Colleen A. Burge ◽  
C. Drew Harvell ◽  
Mónica Medina ◽  
...  
Keyword(s):  
Immune System ◽  
Coral Reefs ◽  
Coral Bleaching ◽  
Transcriptome Analysis ◽  
Coral Host ◽  
Bleaching Event ◽  
Algal Symbiont ◽  
Coral Holobiont ◽  
Whole Transcriptome Analysis ◽  
Whole Transcriptome

Climate change is negatively affecting the stability of natural ecosystems, especially coral reefs. The dissociation of the symbiosis between reef-building corals and their algal symbiont, or coral bleaching, has been linked to increased sea surface temperatures. Coral bleaching has significant impacts on corals, including an increase in disease outbreaks that can permanently change the entire reef ecosystem. Yet, little is known about the impacts of coral bleaching on the coral immune system. In this study, whole transcriptome analysis of the coral holobiont and each of the associate components (i.e. coral host, algal symbiont and other associated microorganisms) was used to determine changes in gene expression in corals affected by a natural bleaching event as well as during the recovery phase. The main findings include evidence that the coral holobiont and the coral host have different responses to bleaching, and the host immune system appears suppressed even a year after a bleaching event. These results support the hypothesis that coral bleaching changes the expression of innate immune genes of corals, and these effects can last even after recovery of symbiont populations. Research on the role of immunity on coral's resistance to stressors can help make informed predictions on the future of corals and coral reefs.

scholarly journals Combining mesocosms with models to unravel the effects of global warming and ocean acidification on temperate marine ecosystems

2020 ◽  
Author(s):  
Hadayet Ullah ◽  
Ivan Nagelkerken ◽  
Silvan U. Goldenberg ◽  
Damien Fordham
Keyword(s):  
Climate Change ◽  
Global Change ◽  
Ocean Acidification ◽  
Food Web ◽  
Marine Ecosystems ◽  
Ocean Warming ◽  
Trophic Levels ◽  
Individual Species ◽  
Combined Effects ◽  
Biodiversity Change

Ocean warming and species exploitation have already caused large-scale reorganization of biological communities across the world. Accurate projections of future biodiversity change require a comprehensive understanding of how entire communities respond to global change. We combined a time-dynamic integrated food web modelling approach (Ecosim) with a community-level mesocosm experiment to determine the independent and combined effects of ocean warming and acidification, and fisheries exploitation, on a temperate coastal ecosystem. The mesocosm enabled important physiological and behavioural responses to climate stressors to be projected for trophic levels ranging from primary producers to top predators, including sharks. We show that under current-day rates of exploitation, warming and ocean acidification will benefit most species in higher trophic levels (e.g. mammals, birds, demersal finfish) in their current climate ranges, with the exception of small pelagic fish, but these benefits will be reduced or lost when these physical stressors co-occur. We show that increases in exploitation will, in most instances, suppress any positive effects of human-driven climate change, causing individual species biomass to decrease at high-trophic levels. Species diversity at the trailing edges of species distributions is likely to decline in the face of ocean warming, acidification and exploitation.We showcase how multi-level mesocosm food web experiments can be used to directly inform dynamic food web models, enabling the ecological processes that drive the responses of marine ecosystems to scenarios of global change to be captured in model projections and their individual and combined effects to be teased apart. Our approach for blending theoretical and empirical results from mesocosm experiments with computational models will provide resource managers and conservation biologists with improved tools for forecasting biodiversity change and altered ecosystem processes due to climate change.

scholarly journals Effects of ocean acidification on calcification of symbiont-bearing reef foraminifers

2011 ◽  
Vol 8 (8) ◽  
pp. 2089-2098 ◽  
Author(s):  
K. Fujita ◽  
M. Hikami ◽  
A. Suzuki ◽  
A. Kuroyanagi ◽  
K. Sakai ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Ocean Acidification ◽  
Elevated Pco2 ◽  
Ion Concentration ◽  
Saturation State ◽  
Carbonate Concentration ◽  
Algal Symbionts ◽  
Algal Symbiont ◽  
Coral Reef Ecosystems ◽  
Fertilization Effects

Abstract. Ocean acidification (decreases in carbonate ion concentration and pH) in response to rising atmospheric pCO2 is generally expected to reduce rates of calcification by reef calcifying organisms, with potentially severe implications for coral reef ecosystems. Large, algal symbiont-bearing benthic foraminifers, which are important primary and carbonate producers in coral reefs, produce high-Mg calcite shells, whose solubility can exceed that of aragonite produced by corals, making them the "first responder" in coral reefs to the decreasing carbonate saturation state of seawater. Here we report results of culture experiments performed to assess the effects of ongoing ocean acidification on the calcification of symbiont-bearing reef foraminifers using a high-precision pCO2 control system. Living clone individuals of three foraminiferal species (Baculogypsina sphaerulata, Calcarina gaudichaudii, and Amphisorus hemprichii) were subjected to seawater at five pCO2 levels from 260 to 970 μatm. Cultured individuals were maintained for about 12 weeks in an indoor flow-through system under constant water temperature, light intensity, and photoperiod. After the experiments, the shell diameter and weight of each cultured specimen were measured. Net calcification of B. sphaerulata and C. gaudichaudii, which secrete a hyaline shell and host diatom symbionts, increased under intermediate levels of pCO2 (580 and/or 770 μatm) and decreased at a higher pCO2 level (970 μatm). Net calcification of A. hemprichii, which secretes a porcelaneous shell and hosts dinoflagellate symbionts, tended to decrease at elevated pCO2. Observed different responses between hyaline and porcelaneous species are possibly caused by the relative importance of elevated pCO2, which induces CO2 fertilization effects by algal symbionts, versus associated changes in seawater carbonate chemistry, which decreases a carbonate concentration. Our findings suggest that ongoing ocean acidification might favor symbiont-bearing reef foraminifers with hyaline shells at intermediate pCO2 levels (580 to 770 μatm) but be unfavorable to those with either hyaline or porcelaneous shells at higher pCO2 levels (near 1000 μatm).

scholarly journals Effects of ocean acidification on calcification of symbiont-bearing reef foraminifers

2011 ◽  
Vol 8 (1) ◽  
pp. 1809-1829 ◽  
Author(s):  
K. Fujita ◽  
M. Hikami ◽  
A. Suzuki ◽  
A. Kuroyanagi ◽  
H. Kawahata
Keyword(s):  
Coral Reefs ◽  
Ocean Acidification ◽  
Ion Concentration ◽  
Saturation State ◽  
Benthic Foraminifers ◽  
Carbonate Ion ◽  
Algal Symbiont ◽  
Coral Reef Ecosystems ◽  
Flow Through ◽  
Carbonate Species

Abstract. Ocean acidification (decreases in carbonate ion concentration and pH) in response to rising atmospheric pCO2 is generally expected to reduce rates of calcification by reef calcifying organisms, with potentially severe implications for coral reef ecosystems. Large, algal symbiont-bearing benthic foraminifers, which are important primary and carbonate producers in coral reefs, produce high-Mg calcite shells, whose solubility can exceed that of aragonite produced by corals, making them the "first responder" in coral reefs to the decreasing carbonate saturation state of seawater. Here we report results of culture experiments performed to assess the effects of ongoing ocean acidification on the calcification of symbiont-bearing reef foraminifers using a high-precision pCO2 control system. Living clone individuals of three foraminiferal species (Baculogypsina sphaerulata, Calcarina gaudichaudii, and Amphisorus hemprichii) were subjected to seawater at five pCO2 levels from 260 to 970 μatm. Cultured individuals were maintained for about 12 weeks in an indoor flow-through system under constant water temperature, light intensity, and photoperiod. After the experiments, the shell diameter and weight of each cultured specimen were measured. Net calcification of Baculogypsina and Calcarina, which secrete a hyaline shell and host diatom symbionts, increased under intermediate levels of pCO2 (580 and/or 770 μatm) and decreased at a higher pCO2 level (970 μatm). Net calcification of Amphisorus, which secretes a porcelaneous shell and hosts dinoflagellate symbionts, tended to decrease at elevated pCO2. These different responses among the three species are possibly due to differences in calcification mechanisms (in particular, the specific carbonate species used for calcification) between hyaline and porcelaneous taxa, and to links between calcification by the foraminiferal hosts and photosynthesis by the algal endosymbionts. Our findings suggest that ongoing ocean acidification might favor symbiont-bearing reef foraminifers with hyaline shells at intermediate pCO2 levels (580 to 770 μatm) but be unfavorable to those with either hyaline or porcelaneous shells at higher pCO2 levels (near 1000 μatm).

Social isolation of goats: significance of visual contact with conspecifics on behavioral and physiological responses

2021 ◽  
Author(s):  
Govind Kannan ◽  
Zaira M Estrada-Reyes ◽  
Phaneendra Batchu ◽  
Brou Kouakou ◽  
Thomas H Terrill ◽  
...  
Keyword(s):  
Social Isolation ◽  
Stress Responses ◽  
Repeated Measures ◽  
Physiological Stress ◽  
Physiological Responses ◽  
Average Weight ◽  
Median Frequency ◽  
Visual Contact ◽  
Time Interaction ◽  
Rank Score

Abstract Social isolation can increase distress in goats, particularly when they cannot maintain visual contact with conspecifics. This experiment was conducted to determine the behavioral and physiological responses in goats during isolation with or without visual contact with conspecifics. Male Spanish goats (uncastrated, 8-mo old, average weight 29.4 ± 0.59 kg) were randomly assigned to a control (CO) group with no isolation or to one of four isolation treatment (TRT) pens (1.5 × 1.5 m) with: (1) open grill panels but with no visual contact with conspecifics (IO), (2) covered grill to prevent visual contact (IC), (3) open grill with visual contact (IV), or (3) covered grill with a 30 × 30 cm window to allow visual contact (IW) for 90 min of social isolation (n = 12 goats/TRT). Blood samples were collected at 0, 30, 60, and 90 min (Time) from isolated and control goats. The experiment was repeated one week later using the same animals, with each goat being subjected to the same isolation treatment the second time to study the effect of prior exposure to isolation. Friedman’s Two-Way ANOVA by Ranks Test in SAS showed that the median frequency of vocalization (rank score) in goats was high in IO group, low in IV and IW groups, and intermediate in IC group (P < 0.01). Vocalization rank score was also higher (P < 0.01) during the first 30 min of isolation in goats. Median frequency of visual contact was higher in the IW group than in the IV group (P < 0.01). Frequency of climbing behavior was high in IC and IO groups, low in IV group, and intermediate in IW group (P < 0.01). Repeated Measures Analysis using GLM procedures in SAS revealed that plasma cortisol and glucose concentrations tended (P < 0.1) to be the highest in IO group than in CO, IC, IV, and IW groups. Cortisol levels were also higher (Time; P < 0.05) at 0 and 90 min compared to 30 and 60 min. Norepinephrine concentrations decreased (P < 0.05) with Time, and plasma non-esterified fatty acid (NEFA) levels were affected by TRT × Time interaction (P < 0.01). Overall, epinephrine, norepinephrine, glucose, and NEFA concentrations were lower (P < 0.01) and cortisol concentrations and lymphocyte counts higher (P < 0.01) when goats were exposed to isolation the second time. The results showed that goats with no visual contact with conspecifics during social isolation had greater physiological stress responses and spent more time vocalizing or trying to escape the pen, which may indicate distress.

Fishing catch shares in the face of global change: a framework for integrating cumulative impacts and single species management

2010 ◽  
Vol 67 (12) ◽  
pp. 1968-1982 ◽  
Author(s):  
Isaac C. Kaplan ◽  
Phillip S. Levin ◽  
Merrick Burden ◽  
Elizabeth A. Fulton
Keyword(s):  
Global Change ◽  
Ocean Acidification ◽  
Fishery Management ◽  
Single Species ◽  
Ecosystem Model ◽  
Careful Consideration ◽  
Reference Points ◽  
Cumulative Impacts ◽  
English Sole ◽  
Modeling Tools

Any fishery management scheme, such as individual fishing quotas (IFQs) or marine protected areas, should be designed to be robust to potential shifts in the biophysical system. Here we couple possible catch scenarios under an IFQ scheme with ocean acidification impacts on shelled benthos and plankton, using an Atlantis ecosystem model for the US West Coast. IFQ harvest scenarios alone, in most cases, did not have strong impacts on the food web, beyond the direct effects on harvested species. However, when we added the impacts of ocean acidification, the abundance of commercially important groundfish such as English sole ( Pleuronectes vetulus ), arrowtooth flounder ( Atheresthes stomias ), and yellowtail rockfish ( Sebastes flavidus ) declined up to 20%–80%, owing to the loss of shelled prey items from their diet. English sole exhibited a 10-fold decline in potential catch and economic yield when confronted with strong acidification impacts on shelled benthos. Therefore, it seems prudent to complement IFQs with careful consideration of potential global change effects such as acidification. Our analysis provides an example of how new ecosystem modeling tools that evaluate cumulative impacts can be integrated with established management reference points and decision mechanisms.

scholarly journals Rhodoliths in Brazil: Current knowledge and potential impacts of climate change

2016 ◽  
Vol 64 (spe2) ◽  
pp. 117-136 ◽  
Author(s):  
Paulo Antunes Horta ◽  
Pablo Riul ◽  
Gilberto M. Amado Filho ◽  
Carlos Frederico D. Gurgel ◽  
Flávio Berchez ◽  
...  
Keyword(s):  
Climate Change ◽  
Global Change ◽  
Ocean Acidification ◽  
Heat Waves ◽  
Current Knowledge ◽  
Coastal Pollution ◽  
Brazil Current ◽  
Run Off ◽  
Benthic Ecosystems ◽  
Impacts Of Climate Change

Abstract Rhodolith beds are important marine benthic ecosystems, representing oases of high biodiversity among sedimentary seabed environments. They are found frequently and abundantly, acting as major carbonate 'factories' and playing a key role in the biogeochemical cycling of carbonates in the South Atlantic. Rhodoliths are under threat due to global change (mainly related to ocean acidification and global warming) and local stressors, such as fishing and coastal run-off. Here, we review different aspects of the biology of these organisms, highlighting the predicted effects of global change, considering the additional impact of local stressors. Ocean acidification (OA) represents a particular threat that can reduce calcification or even promote the decalcification of these bioengineers, thus increasing the eco-physiological imbalance between calcareous and fleshy algae. OA should be considered, but this together with extreme events such as heat waves and storms, as main stressors of these ecosystems at the present time, will worsen in the future, especially if possible interactions with local stressors like coastal pollution are taken into consideration. Thus, in Brazil there is a serious need for starting monitoring programs and promote innovative experimental infrastructure in order to improve our knowledge of these rich environments, optimize management efforts and enhance the needed conservation initiatives.

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