scholarly journals The Bouraké semi-enclosed lagoon (New Caledonia). A natural laboratory to study the life-long adaptation of a coral reef ecosystem to climate change-like conditions

2021 ◽  
Author(s):  
Federica Maggioni ◽  
Mireille Pujo-Pay ◽  
Jérome Aucan ◽  
Carlo Cerrano ◽  
Barbara Calcinai ◽  
...  

Abstract. According to current experimental evidence, coral reefs could disappear within the century if CO2 emissions remain unabated. However, recent discoveries of diverse and high cover reefs that already thrive under extreme conditions seem to contradict these projections. Volcanic CO2 vents, semi-enclosed lagoons and mangrove estuaries are unique study sites where one or more ecologically relevant parameters for life in the oceans are close or even worse than currently projected for the year 2100. These natural analogues of future conditions hold new hope for the future of coral reefs and provide unique natural laboratories to explore how reef species could keep pace with climate change. To achieve this, it is essential to characterize their environment as a whole, and accurately consider all possible environmental factors that may differ from what is expected in the future and that may possibly alter the ecosystem response. In this study, we focus on the semi-enclosed lagoon of Bouraké (New Caledonia, SW Pacific Ocean) where a healthy reef ecosystem thrives in warm, acidified and deoxygenated water. We used a multi-scale approach to characterize the main physical-chemical parameters and mapped the benthic community composition (i.e., corals, sponges, and macroalgae). The data revealed that most physical and chemical parameters are regulated by the tide, strongly fluctuate 3 to 4 times a day, and are entirely predictable. The seawater pH and dissolved oxygen decrease during falling tide and reach extreme low values at low tide (7.2 pHT and 1.9 mg O2 L−1 at Bouraké, vs 7.9 pHT and 5.5 mg O2 L−1 at reference reefs). Dissolved oxygen, temperature, and pH fluctuates according to the tide of up to 4.91 mg O2 L−1, 6.50 °C, and 0.69 pHT units on a single day. Furthermore, the concentration of most of the chemical parameters was one- to 5-times higher at the Bouraké lagoon, particularly for organic and inorganic carbon and nitrogen, but also for some nutrients, notably silicates. Surprisingly, despite extreme environmental conditions and altered seawater chemical composition, our results reveal a diverse and high cover community of macroalgae, sponges and corals accounting for 28, 11 and 66 species, respectively. Both environmental variability and nutrient imbalance might contribute to their survival under such extreme environmental conditions. We describe the natural dynamics of the Bouraké ecosystem and its relevance as a natural laboratory to investigate the benthic organism’s adaptive responses to multiple stressors like future climate change conditions.

2021 ◽  
Vol 18 (18) ◽  
pp. 5117-5140
Author(s):  
Federica Maggioni ◽  
Mireille Pujo-Pay ◽  
Jérome Aucan ◽  
Carlo Cerrano ◽  
Barbara Calcinai ◽  
...  

Abstract. According to current experimental evidence, coral reefs could disappear within the century if CO2 emissions remain unabated. However, recent discoveries of diverse and high cover reefs that already live under extreme conditions suggest that some corals might thrive well under hot, high-pCO2, and deoxygenated seawater. Volcanic CO2 vents, semi-enclosed lagoons, and mangrove estuaries are unique study sites where one or more ecologically relevant parameters for life in the oceans are close to or even worse than currently projected for the year 2100. Although they do not perfectly mimic future conditions, these natural laboratories offer unique opportunities to explore the mechanisms that reef species could use to keep pace with climate change. To achieve this, it is essential to characterize their environment as a whole and accurately consider all possible environmental factors that may differ from what is expected in the future, possibly altering the ecosystem response. This study focuses on the semi-enclosed lagoon of Bouraké (New Caledonia, southwest Pacific Ocean) where a healthy reef ecosystem thrives in warm, acidified, and deoxygenated water. We used a multi-scale approach to characterize the main physical-chemical parameters and mapped the benthic community composition (i.e., corals, sponges, and macroalgae). The data revealed that most physical and chemical parameters are regulated by the tide, strongly fluctuate three to four times a day, and are entirely predictable. The seawater pH and dissolved oxygen decrease during falling tide and reach extreme low values at low tide (7.2 pHT and 1.9 mg O2 L−1 at Bouraké vs. 7.9 pHT and 5.5 mg O2 L−1 at reference reefs). Dissolved oxygen, temperature, and pH fluctuate according to the tide by up to 4.91 mg O2 L−1, 6.50 ∘C, and 0.69 pHT units on a single day. Furthermore, the concentration of most of the chemical parameters was 1 to 5 times higher at the Bouraké lagoon, particularly for organic and inorganic carbon and nitrogen but also for some nutrients, notably silicates. Surprisingly, despite extreme environmental conditions and altered seawater chemical composition measured at Bouraké, our results reveal a diverse and high cover community of macroalgae, sponges, and corals accounting for 28, 11, and 66 species, respectively. Both environmental variability and nutrient imbalance might contribute to their survival under such extreme environmental conditions. We describe the natural dynamics of the Bouraké ecosystem and its relevance as a natural laboratory to investigate the benthic organism's adaptive responses to multiple extreme environmental conditions.


Author(s):  
Sophie L Gilbert ◽  
Trevor Haynes ◽  
Mark S Lindberg ◽  
David Albert ◽  
Michelle Kissling ◽  
...  

Background. The Alexander Archipelago wolf, inhabiting the coastal temperate rainforest of North America, was recently evaluated for protection under the U.S. Endangered Species Act, but ultimately was not listed. Stressors thought to be impacting the population include about habitat alteration from industrial timber harvest and subsequent declines in prey (deer), increased human-caused mortality, and climate change. Methods. To evaluate how these factors likely will affect future abundance of wolves and deer, we constructed a model linking wolf and deer population dynamics to environmental conditions and management regulations. We restricted our model to Prince of Wales and outlying islands, because this area is partially isolated, is the focus of timber harvest in the region, and has the most empirical data available for model parameterization. We examined 6 combinations of future timber harvest, winter severity, wolf harvest regulations, and roads on population dynamics of deer and wolves, developed by a panel of experts. Results. Outcomes across scenarios after 30 years varied, with changes in wolf abundance ranging from a 156% increase to a 41% decline, whereas deer abundance declined from 10−37% after 30 years. Mean percentage of the 31 pack areas that were vacant after 30 years ranged from 0 to 67%, indicating that environmental conditions strongly affected pack success. Variation in wolf abundance was driven primarily by changes in wolf harvest regulations, with smaller contributions from road density, forest succession, and severe-winter frequency. Given current low estimated wolf numbers and continued legal and illegal harvest, this raises conservation concerns for the future of wolves in our study area. In addition, we found that wolf declines could be greater if wolves rely more heavily on deer in the future, for instance if salmon availability declines under future climate change, but also that reduction of deer hunting could increase wolf abundance. Discussion. The potential importance of illegal harvest in wolf population dynamics needs further acknowledgement and treatment. However, changes to harvest regulations, which would not reduce unreported harvest, could still be a powerful tool for management of this small, declining, and insular population. Nevertheless, maximum abundance of wolves appears to be curtailed by the steady decline in carrying capacity forecast across all timber management plans currently under consideration. Although we evaluated factors affecting wolf abundance individually, we encourage a holistic approach to management of this predator-prey system in an altered ecosystem.


2021 ◽  
Vol 9 ◽  
Author(s):  
Tamar L. Goulet ◽  
Denis Goulet

Symbiotic relationships enable partners to thrive and survive in habitats where they would either not be as successful, or potentially not exist, without the symbiosis. The coral reef ecosystem, and its immense biodiversity, relies on the symbioses between cnidarians (e.g., scleractinian corals, octocorals, sea anemones, jellyfish) and multiple organisms including dinoflagellate algae (family Symbiodiniaceae), bivalves, crabs, shrimps, and fishes. In this review, we discuss the ramifications of whether coral reef cnidarian symbioses are obligatory, whereby at least one of the partners must be in the symbiosis in order to survive or are facultative. Furthermore, we cover the consequences of cnidarian symbioses exhibiting partner flexibility or fidelity. Fidelity, where a symbiotic partner can only engage in symbiosis with a subset of partners, may be absolute or context dependent. Current literature demonstrates that many cnidarian symbioses are highly obligative and appear to exhibit absolute fidelity. Consequently, for many coral reef cnidarian symbioses, surviving changing environmental conditions will depend on the robustness and potential plasticity of the existing host-symbiont(s) combination. If environmental conditions detrimentally affect even one component of this symbiotic consortium, it may lead to a cascade effect and the collapse of the entire symbiosis. Symbiosis is at the heart of the coral reef ecosystem, its existence, and its high biodiversity. Climate change may cause the demise of some of the cnidarian symbioses, leading to subsequent reduction in biodiversity on coral reefs.


Author(s):  
Sophie L Gilbert ◽  
Trevor Haynes ◽  
Mark S Lindberg ◽  
David Albert ◽  
Michelle Kissling ◽  
...  

Background. The Alexander Archipelago wolf, inhabiting the coastal temperate rainforest of North America, was recently evaluated for protection under the U.S. Endangered Species Act, but ultimately was not listed. Stressors thought to be impacting the population include about habitat alteration from industrial timber harvest and subsequent declines in prey (deer), increased human-caused mortality, and climate change. Methods. To evaluate how these factors likely will affect future abundance of wolves and deer, we constructed a model linking wolf and deer population dynamics to environmental conditions and management regulations. We restricted our model to Prince of Wales and outlying islands, because this area is partially isolated, is the focus of timber harvest in the region, and has the most empirical data available for model parameterization. We examined 6 combinations of future timber harvest, winter severity, wolf harvest regulations, and roads on population dynamics of deer and wolves, developed by a panel of experts. Results. Outcomes across scenarios after 30 years varied, with changes in wolf abundance ranging from a 156% increase to a 41% decline, whereas deer abundance declined from 10−37% after 30 years. Mean percentage of the 31 pack areas that were vacant after 30 years ranged from 0 to 67%, indicating that environmental conditions strongly affected pack success. Variation in wolf abundance was driven primarily by changes in wolf harvest regulations, with smaller contributions from road density, forest succession, and severe-winter frequency. Given current low estimated wolf numbers and continued legal and illegal harvest, this raises conservation concerns for the future of wolves in our study area. In addition, we found that wolf declines could be greater if wolves rely more heavily on deer in the future, for instance if salmon availability declines under future climate change, but also that reduction of deer hunting could increase wolf abundance. Discussion. The potential importance of illegal harvest in wolf population dynamics needs further acknowledgement and treatment. However, changes to harvest regulations, which would not reduce unreported harvest, could still be a powerful tool for management of this small, declining, and insular population. Nevertheless, maximum abundance of wolves appears to be curtailed by the steady decline in carrying capacity forecast across all timber management plans currently under consideration. Although we evaluated factors affecting wolf abundance individually, we encourage a holistic approach to management of this predator-prey system in an altered ecosystem.


Author(s):  
Daniel P. Aldrich ◽  
Courtney M. Page-Tan ◽  
Christopher J. Paul

Anthropogenic climate change increasingly disrupts livelihoods, floods coastal urban cities and island nations, and exacerbates extreme weather events. There is near-universal consensus among scientists that in order to reverse or at least mitigate climate disruptions, limits must be imposed on anthropogenic sources of climate-forcing emissions and adaptation to changing global conditions will be necessary. Yet adaptation to current and future climate change at the individual, community, and national levels vary widely from merely coping, to engaging in adaptive change, to transformative shifts. Some of those affected simply cope with lower crop yields, flooded streets, and higher cooling bills. Others incrementally adapt to new environmental conditions, for example, by raising seawalls or shifting from one crop to another better suited for a hotter environment. The highest—and perhaps least likely—type of change involves transformation, radically altering practices with an eye toward the future. Transformative adaptation may involve a livelihood change or permanent migration; it might require shuttering whole industries and rethinking industrial policy at the national level. Entire island nations such as Fiji, for example, are considering relocating from vulnerable locations to areas better suited to rising sea levels. A great deal of research has shown how social capital (the bonding, bridging, and linking connections to others) provides information on trustworthiness, facilitates collective action, and connects us to external resources during disasters and crises. We know far less about the relationship between social capital and adaptation behaviors in terms of the choices that people make to accommodate changing environmental conditions. A number of unanswered but critical questions remain: How precisely does social capital function in climate change adaptation? To what degree does strong bonding social capital substitute for successful adaptation behaviors for individuals or groups? Which combinations of social factors make coping, adapting, and transforming most likely? How can social capital help migrating populations maintain cultural identity under stress? How can local networks be integrated into higher-level policy interventions to improve adaptation? Which political and social networks contribute to transformative responses to climate change at local, regional, and international levels? This article serves as a comprehensive literature review, overview of empirical findings to date, and a research agenda for the future.


2020 ◽  
Author(s):  
Rubén D. Manzanedo ◽  
Peter Manning

The ongoing COVID-19 outbreak pandemic is now a global crisis. It has caused 1.6+ million confirmed cases and 100 000+ deaths at the time of writing and triggered unprecedented preventative measures that have put a substantial portion of the global population under confinement, imposed isolation, and established ‘social distancing’ as a new global behavioral norm. The COVID-19 crisis has affected all aspects of everyday life and work, while also threatening the health of the global economy. This crisis offers also an unprecedented view of what the global climate crisis may look like. In fact, some of the parallels between the COVID-19 crisis and what we expect from the looming global climate emergency are remarkable. Reflecting upon the most challenging aspects of today’s crisis and how they compare with those expected from the climate change emergency may help us better prepare for the future.


2021 ◽  

Abstract This book is a collection of 77 expert opinions arranged in three sections. Section 1 on "Climate" sets the scene, including predictions of future climate change, how climate change affects ecosystems, and how to model projections of the spatial distribution of ticks and tick-borne infections under different climate change scenarios. Section 2 on "Ticks" focuses on ticks (although tick-borne pathogens creep in) and whether or not changes in climate affect the tick biosphere, from physiology to ecology. Section 3 on "Disease" focuses on the tick-host-pathogen biosphere, ranging from the triangle of tick-host-pathogen molecular interactions to disease ecology in various regions and ecosystems of the world. Each of these three sections ends with a synopsis that aims to give a brief overview of all the expert opinions within the section. The book concludes with Section 4 (Final Synopsis and Future Predictions). This synopsis attempts to summarize evidence provided by the experts of tangible impacts of climate change on ticks and tick-borne infections. In constructing their expert opinions, contributors give their views on what the future might hold. The final synopsis provides a snapshot of their expert thoughts on the future.


Author(s):  
Jaewon Jung ◽  
Sungeun Jung ◽  
Junhyeong Lee ◽  
Myungjin Lee ◽  
Hung Soo Kim

The interest in renewable energy to replace fossil fuel is increasing as the problem caused by climate change become more severe. Small hydropower (SHP) is evaluated as a resource with high development value because of its high energy density compared to other renewable energy sources. SHP may be an attractive and sustainable power generation environmental perspective because of its potential to be found in small rivers and streams. The power generation potential could be estimated based on the discharge in the river basin. Since the river discharge depends on the climate conditions, the hydropower generation potential changes sensitively according to climate variability. Therefore, it is necessary to analyze the SHP potential in consideration of future climate change. In this study, the future prospect of SHP potential is simulated for the period of 2021 to 2100 considering the climate change in three hydropower plants of Deoksong, Hanseok, and Socheon stations, Korea. As the results, SHP potential for the near future (2021 to 2040) shows a tendency to be increased and the highest increase is 23.4% at the Deoksong SPH plant. Through the result of future prospect, we have shown that hydroelectric power generation capacity or SHP potential will be increased in the future. Therefore, we believe that it is necessary to revitalize the development of SHP in order to expand the use of renewable energy. Also, a methodology presented in this study could be used for the future prospect of the small hydropower potential.


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