In 2015 the United Nations General Assembly decided to develop an international legally binding instrument (ILBI) under the United Nations Convention on the Law of the Sea (UNCLOS) on the conservation and sustainable use of marine biological diversity of areas beyond national jurisdiction. To that end, it established a Preparatory Committee (PrepCom), to make substantive recommendations to the General Assembly on the elements of a draft text of an ILBI. The PrepCom has identified the tension between the principle of the common heritage of mankind and high seas freedoms embodied in UNCLOS as one of the issues which must be addressed in such an international agreement. Some participants in the process have proposed a sui generis regime as a way of resolving any apparent clash of these international legal principles, particularly as it relates to marine genetic resources and their access and benefit sharing. This article argues that environmental stewardship may provide the framework for such a sui generis regime. For it to do so, however, it must be grounded in international legal principles and act as a balance between competing values, perspectives and interests in the conservation and sustainable use of marine biodiversity beyond national jurisdiction. If appropriately redefined in this way, environmental stewardship can deliver a governance framework which addresses some of the central issues with which the PrepCom will have to deal. These include the practical problems of access and benefit sharing of the marine genetic resources of areas beyond national jurisdiction, and reconciling the conflicting pressure for international decision-making for the conservation and sustainable use of marine biological diversity on the one hand, and the maintenance of existing regional and sectoral frameworks on the other. Environmental stewardship, redefined, can provide an intellectual framework for an ILBI under UNCLOS on marine biodiversity beyond national jurisdiction.
If one uses Facebook, Facetime, Skype, Netflix, or any application of the internet internationally, a submarine cable is involved. Fibre optic cables bind the world together from governments, banks, shipping, airlines and other major logistic industries to homes and personal electronic devices. Server farms maintained by major telecom and content companies allow vast amounts of data to be stored and retrieved from the cloud. Not often appreciated is the fact that these server locations worldwide are connected by submarine fibre optic cables. In this sense, the cloud is beneath the sea. While submarine communication cables have been in steady use since 1850, their preeminent place in the modern world has never been as dominant and personal as now. Since 1884, this critical international infrastructure has rested upon international treaties, now reflected in universally accepted provisions of the 1982 United Nations Convention on the Law of the Sea (UNCLOS) that provides for freedoms to lay and maintain international submarine cables. Recently, calls have mounted in the context of marine biodiversity beyond national jurisdiction (BBNJ) for centralized control of submarine cables and for express or de facto diminishment of the freedoms related to them that have served the world’s peoples for so long. This monograph examines the time proven importance of the existing international treaties, the largely peer review science on the environmental interaction of submarine cables with high seas environments, and the current submarine cable issues in the context of the BBNJ debates.
Given the socio-economic consequences associated with declaring areas of ocean protected in order to achieve conservation objectives, this paper contributes to the growing global need to assess Marine Protected Areas (MPAs) as an effective management tool. It adds to the current body of knowledge on MPA effectiveness by conducting an evaluation of the Tobago Cays Marine Park (TCMP), located in St. Vincent and the Grenadines (SVG) in the eastern Caribbean, using a modified MPA effectiveness framework. Due to the limited information existing about the current performance of this MPA, this assessment also provides needed insight on the effect that the TCMP is having on the marine ecosystem, as well as its overall management performance. By comparing the performance of the MPA over a 10-year span (2007 and 2016), the results indicate that overall, the TCMP could be described as having limited success when key management categories of context, planning, input, process, output and outcomes are evaluated. In particular, efforts dedicated to planning, process and outcomes are assessed as deficient. Furthermore, the analysis revealed that efforts to realize the stated goals relating to conservation, public awareness and public education were being neglected. However, considerable effort was being expended by TCMP staff on achieving the remaining goal focusing on deriving economic benefits from touristic activities in the Park. Preliminary field research examining the effects of the TCMP on the abundance and density of an economically important species, Lobatus gigas, (commonly referred to as the queen conch) showed the TCMP as having no effect towards conch protection. The results and recommendations of this study, combined with continued monitoring of a recommended targeted suite of indicators, could contribute to better-informed adaptive MPA management, leading to progress towards the achievement of the stated goals for the TCMP.
Ecosystem-based fisheries-management (EBFM) is increasingly used in the United States (U.S.), including in the Gulf of Mexico (GOM). Producing distribution maps for marine organisms is a critical step in the implementation of EBFM. In particular, distribution maps are important inputs for many spatially-explicit ecosystem models, such as OSMOSE models, as well as for biophysical models used to predict annual recruitment anomalies due to oceanographic factors. In this study, we applied a recently proposed statistical modelling framework to produce distribution maps for: (i) younger juveniles (ages 0–1) of red snapper (Lutjanus campechanus), red grouper (Epinephelus morio), and gag (Mycteroperca microlepis), so as to be able to define the potential larval settlement areas of the three species in a biophysical model; and (ii) the functional groups and life stages represented in the OSMOSE model of the West Florida Shelf (“OSMOSE-WFS”). This statistical modelling framework consists of: (i) compiling a large database blending all of the encounter/non-encounter data of the GOM collected by the fisheries-independent and fisheries-dependent surveys using random sampling schemes, referred to as the “comprehensive survey database;” (ii) employing the comprehensive survey database to fit spatio-temporal binomial generalized linear mixed models (GLMMs) that integrate the confounding effects of survey and year; and (iii) using the predictions of the fitted spatio-temporal binomial GLMMs to generate distribution maps. This large endeavour allowed us to produce distribution maps for younger juveniles of red snapper, red grouper and gag and nearly all of the other functional groups and life stages represented in OSMOSE-WFS, at different seasons. Using Pearson residuals, the probabilities of encounter predicted by all spatio-temporal binomial GLMMs were demonstrated to be reasonable. Moreover, the results obtained for younger juvenile fish concur with the literature, provide additional insights into the spatial distribution patterns of these life stages, and highlight important future research avenues.
The Zoological Department of Oxford University has reviewed and synthesised major marine science findings which have been published since Rio+20 in 2012.
The purpose of this synthesis is to determine how our understanding of the ocean at an Earth System level, with a particular focus on the role of the high seas, has changed in the last five years.
The synthesis has highlighted conclusions from 271 published papers and reports relevant to the functions of the ocean.
Ecosystem-based management (EBM) is now widely accepted as the best means of managing the complex interactions in marine systems. However, progress towards implementing and operationalizing it has been slow. We take a pragmatic approach to EBM. Our simple definition is balancing human activities and environmental stewardship in a multiple-use context. In this paper, we present case studies on the development and implementation of EBM in Australia. The case studies (Australia’s Ocean Policy, the Great Barrier Reef, New South Wales (NSW) marine estate, Gladstone Harbour, and South Australia and Spencer Gulf) span different spatial scales, from national to regional to local. They also cover different levels of governance or legislated mandate. We identify the key learnings, necessary components and future needs to support better implementation. These include requirements for clearly identified needs and objectives, stakeholder ownership, well defined governance frameworks, and scientific tools to deal with conflicts and trade-offs. Without all these components, multi-sector management will be difficult and there will be a tendency to maintain a focus on single sectors. While the need to manage individual sectors remains important and is often challenging, this alone will not necessarily ensure sustainable management of marine systems confronted by increasing cumulative impacts.
Tidal sand ridges are large-scale bedforms that occur in the offshore area of shelf seas. They evolve on a time scale of centuries due to tide-topography interactions while being further shaped by wind waves. During their evolution, ridges are also affected by changes in sea level, strength and direction of the tidal current. According to their present-day behavior, ridges are classified as ‘active’ (sand transport everywhere), ‘quasi-active’ (sand transport only on parts of the ridges) and ‘inactive’ (no sand transport anywhere). Using a nonlinear morphodynamic model, the present study extends earlier work by investigating the effect of sea level rise and changes in the amplitude and principal direction of the tidal current on the growth time and height of active tidal sand ridges. Besides, the role of sea level rise and tidal current variation in the presence of quasi-active/inactive ridges is explored. Two specific settings are considered, which are characteristic for the Dutch Banks in the North Sea and for sand ridges in the Celtic Sea. The time range considered here is less than 20,000 years, roughly the period from the Last Glacial Maximum to the present.
Generally active tidal sand ridges occur if the tidal current amplitude is larger than 0.5 m/s. For these ridges, with increasing rates of sea level rise, their growth time becomes longer, and the root mean square height keeps on increasing. A smaller initial tidal current amplitude gives rise to a larger growth time, while changes in the principal current direction have a minor effect on the characteristics of the ridges. On the considered time scale, assuming a constant wave climate, quasi-active tidal sand ridges occur mainly as a result of a decreasing tidal current amplitude such that the effective velocity (in the sense of stirring sand) becomes smaller than the critical velocity for sand erosion. The ridges further become inactive on a time scale that depends inversely on the rate of sea level rise. Modeled ridges are compared with observed ridges. Similarities are found and quantitative differences are explained.
Estuarine artificialization eliminates estuarine ecosystems’ original natural attributes on which estuarine health and function are dependent, and induces various ecological and social problems. Preventing estuaries from being overly artificialized and implementing ecological restoration for damaged estuaries is an urgent management concern. This study intended to quantitatively identify the artificialized degree of estuarine areas of interest at different stages to depict their state evolution trajectory by acquiring and analyzing the spatiotemporal maps of estuarine ecosystem naturalness. The Xiaoqinghe estuary, located in the southern coast of Laizhou Bay, was selected as a case study area. The ecosystem naturalness and regional naturalness in this estuary were evaluated through the developed naturalness index, which integrates the dynamic information of land cover and human interference intensity into an assessment framework of ecosystem naturalness spectrum created here. Results showed that the Xiaoqinghe estuary was a relatively natural estuary with higher naturalness in the early 1980s, but was highly artificialized in 2010–2015, with its average naturalness reducing by 43% over the past three decades. Those areas occupied by salt marshes and shrub-grass lowlands in 1984 have greatly deviated from their original natural state due to the highest loss of regional naturalness. The current state characteristics suggest that the Xiaoqinghe estuary has considerably lost its ability to conserve biodiversity and provide ecosystem services, and the intensity and manner of human activities should be adjusted and limited spatially. The findings and methodology illustrated in this paper can also contribute to the sustainable management of artificialized estuaries elsewhere.
Business names, as recorded by state tax departments, offer a possible indicator of cultural ecosystem services provided by nearby natural resources. Using oysters in the Chesapeake Bay as an example, we process spatial and quantitative analyses that can potentially identify cultural value for integration into monitoring efforts that aim to incorporate a variety of ecosystem services. Businesses named directly after oysters provide a useful lens to capture the many reasons people value oysters culturally, but also provide an easy aggregate indicator that could potentially be added to regular regional monitoring programs in order to factor in cultural value to adaptive management policies.
A coupled ecosystem modeling approach was used to evaluate how select combinations of large-scale river diversions in the lower Mississippi River Deltaic Plain may affect the distribution, biomass, and landings of fish and shellfish over decades relative to a future without action. These river diversions are controlled openings in the riverbank of the Mississippi River designed to reintroduce sediment, water, and nutrients into hydrologically isolated coastal wetlands in order to mitigate wetland loss. We developed a spatial ecosystem model using Ecopath with Ecosim (EwE) software, and prepared it to receive output from a Delft3D hydrodynamic model coupled to primary production models. The Delft3D model provided environmental drivers including salinity, temperature, Chl a, total suspended solids, and change in wetland cover as a result of simulated river diversions over decadal model runs. Driver output was averaged either daily, monthly, or annually depending on the parameter. A novel oyster-specific subroutine is introduced in this paper to incorporate information at daily intervals in Ecospace, while Ecospace runs on a monthly time step. The ecosystem model simulates biomass and distribution of fish and shellfish species, and landings of targeted fisheries species, as a result of environmental changes projected for a preliminary set of management scenarios designed to evaluate and screen select combinations of river diversions. Abundant local field samples and landings data allowed for model calibration and validation. The results of simulations indicate that inflow of Mississippi River water in estuaries may cause local shifts in species assemblages. These changes were in some cases direct effects of decreased salinity, such as locally reduced Spotted Seatrout biomass. Changes in some other species in the affected areas resulted from indirect effects; for example, reduced Chl a (as a result of increased TSS) resulted in near-field reductions of Gulf Menhaden. The simulations also showed that local biomass reductions were mostly the result of redistribution, since the scenario with the proposed diversions open had minimal impact on the total biomass or landings of species simulated in the Mississippi River Delta as compared to a future without action. The model and its output were used as a decision support tool to help evaluate and compare alternative management actions. The results of this study played a role in the decision by the Coastal Protection and Restoration Authority to prioritize moving forward to conduct more detailed analyses through engineering and design of the two middle diversions but not the two lower diversions that were tested in this study.
Fish production from sea-cages is a globally significant and expanding industry, but farm production can be constrained due to localised but extreme seabed enrichment, which requires the farm to be rested for extended periods. This study compares the effectiveness of three potential techniques for accelerating seabed recovery in highly enriched sediments. Benthic changes induced by in-situ ‘harrowing’ (heavy raking of the seabed), ‘irrigation’ with oxygenated surface-water, and simulated sediment ‘removal’ are described in relation to passive recovery. Treatment effectiveness was assessed after four months based on physico-chemical and biological analyses of sediments, changes in benthic respiration in mesocosm experiments, and an assessment of the instantaneous water column effects induced during treatment. Results indicated significant sediment plumes associated with reduced dissolved oxygen levels, particularly during ‘removal’, but the magnitude and duration of the changes were negligible in an ecological effects context. Two treatments, ‘harrowing’ (HA) and ‘irrigation’ (IR), had little impact on seabed condition, particularly when compared with the natural recovery that occurred over the study period. Whereas, the ‘removal’ (RE) treatment (exposing the underlying sediment) significantly improved the physico-chemical and biological properties, and appeared to facilitate benthic recolonization. These findings suggest that, removal of degraded surface sediments has the potential to accelerate seabed recovery and can be a useful management strategy where trace metal concentrations (e.g. copper and zinc) have become unacceptably elevated. However, commercial-scale implementation would be contingent upon: i) further evaluation of water column effects associated with larger-scale treatments, and ii) the ability to safely dispose of the sediments.
Economic losses from floods along the Gulf of Mexico have triggered much debate on different strategies to reduce risk and future adverse impacts from storm events. While much of the discussion has focused on structural engineering approaches to flood mitigation, increasing emphasis is being placed on avoidance strategies, such as the protection of undeveloped open spaces. This study leverage previous work to examine undeveloped lands across approximately 2600 watersheds along the Gulf of Mexico.
Different types and spatial configurations of naturally-occurring open spaces are statistically evaluated across landscapes for their effects on reducing observed flood losses (economic damage to building and/or contents) under the National Flood Insurance Program (NFIP) occurring from 2008 through 2014. Statistical models isolate the influence of natural open spaces, while controlling for multiple socioeconomic, environmental, and development-based local conditions. Results estimate the dollar-savings in flood losses by maintaining open spaces over time. This study provides quantitative guidance on which types and spatial characteristics of open spaces are most effective in reducing the adverse impacts from floods. Findings indicate that large, expansive, and continuous patches of naturally-occurring open spaces most effectively reduce losses from flood events.
Coastal lagoons with small catchment basins are highly sensitive to natural processes and anthropogenic activities. To figure out the environmental changes of a coastal lagoon and its contribution to carbon burial, two sediment cores were collected in Xincun Lagoon, southeastern Hainan Island and 210Pb activities, grain size parameters, total organic carbon (TOC), total nitrogen (TN), total inorganic carbon (TIC) and stable carbon isotopes (δ13C) were measured. The results show that in 1770–1815, the decreasing water exchange capacity with outer open water, probably caused by the shifting and narrowing of the tidal inlet, not only diminished the currents and fined the sediments in the lagoon, but also reduced the organic matter of marine sources. From 1815 to 1950, the sedimentary environment of Xincun Lagoon was frequently influenced by storm events. These extreme events resulted in the high fluctuation of sediment grain size and sorting, as well as the great variation in contributions of terrestrial (higher plants, soils) and marine sources (phytoplankton, algae, seagrass). The extremely high content of TIC, compared to TOC before 1950 could be attributed to the large-scale coverage of coral reefs. However, with the boost of seawater aquaculture activities after 1970, the health growth of coral species was severely threatened, and corresponding production and inorganic carbon burial flux reduced. The apparent enhanced inorganic carbon burial rate after 1990 might result from the concomitant carbonate debris produced by seawater aquaculture. This result is important for local government long-term coastal management and environmental planning.
Microplastic fibers make up a large proportion of microplastics found in the environment, especially in urban areas. There is good reason to consider synthetic textiles a major source of microplastic fibers, and it will not diminish since the use of synthetic fabrics, especially polyester, continues to increase. In this study we provide quantitative data regarding the size and mass of microplastic fibers released from synthetic (polyester) textiles during simulated home washing under controlled laboratory conditions. Consideration of fabric structure and washing conditions (use of detergents, temperature, wash duration, and sequential washings) allowed us to study the propensity of fiber shedding in a mechanistic way. Thousands of individual fibers were measured (number, length) from each wash solution to provide a robust data set on which to draw conclusions. Among all the variables tested, the use of detergent appeared to affect the total mass of fibers released the most, yet the detergent composition (liquid or powder) or overdosing of detergent did not significantly influence microplastic release. Despite different release quantities due to the addition of a surfactant (approximately 0.025 and 0.1 mg fibers/g textile washed, without and with detergent, respectively), the overall microplastic fiber length profile remained similar regardless of wash condition or fabric structure, with the vast majority of fibers ranging between 100 and 800 μm in length irrespective of wash cycle number. This indicates that the fiber staple length and/or debris encapsulated inside the fabric from the yarn spinning could be directly responsible for releasing stray fibers. This study serves as a first look toward understanding the physical properties of the textile itself to better understand the mechanisms of fiber shedding in the context of microplastic fiber release into laundry wash water.
Samples of microplastic (n = 924) from two beaches in south west England have been analysed by field-portable-x-ray fluorescence (FP-XRF) spectrometry, configured in a low-density mode and with a small-spot facility, for the heavy metals, Cd and Pb, and the halogen, Br. Primary plastics in the form of pre-production pellets were the principal type of microplastic (>70%) on both beaches, with secondary, irregularly-shaped fragments representing the remainder of samples. Cadmium and Pb were detected in 6.9% and 7.5% of all microplastics, respectively, with concentrations of either metal that exceeded 103 μg g−1 usually encountered in red and yellow pellets or fragments. Respective correlations of Cd and Pb with Se and Cr were attributed to the presence of the coloured, inorganic pigments, cadmium sulphoselenide and lead chromate. Bromine, detected in 10.4% of microplastics and up to concentrations of about 13,000 μg g−1, was mainly encountered in neutrally-coloured pellets. Its strong correlation with Sb, whose oxides are effective fire suppressant synergists, suggests the presence of a variety of brominated flame retardants arising from the recycling of plastics originally used in casings for heat-generating electrical equipment. The maximum bioaccessible concentrations of Cd and Pb, evaluated using a physiological extraction based on the chemical characteristics of the proventriculus-gizzard of the northern fulmar, were about 50 μg g−1 and 8 μg g−1, respectively. These concentrations exceed those estimated for the diet of local seabirds by factors of about 50 and 4, respectively.
Plastics debris, especially microplastics, have been found worldwide in all marine compartments. Much research has been carried out on adsorbed pollutants on plastic pieces and hydrophobic organic compounds (HOC) associated with microplastics. However, only a few studies have focused on plastic additives. These chemicals are incorporated into plastics from which they can leach out as most of them are not chemically bound. As a consequence of plastic accumulation and fragmentation in oceans, plastic additives could represent an increasing ecotoxicological risk for marine organisms. The present work reviewed the main class of plastic additives identified in the literature, their occurrence in the marine environment, as well as their effects on and transfers to marine organisms. This work identified polybrominated diphenyl ethers (PBDE), phthalates, nonylphenols (NP), bisphenol A (BPA) and antioxidants as the most common plastic additives found in marine environments. Moreover, transfer of these plastic additives to marine organisms has been demonstrated both in laboratory and field studies. Upcoming research focusing on the toxicity of microplastics should include these plastic additives as potential hazards for marine organisms, and a greater focus on the transport and fate of plastic additives is now required considering that these chemicals may easily leach out from plastics.
Self-organized spatial patterns occur in many terrestrial, aquatic, and marine ecosystems. Theoretical models and observational studies suggest self-organization, the formation of patterns due to ecological interactions, is critical for enhanced ecosystem resilience. However, experimental tests of this cross-ecosystem theory are lacking. In this study, we experimentally test the hypothesis that self-organized pattern formation improves the persistence of mussel beds (Mytilus edulis) on intertidal flats. In natural beds, mussels generate self-organized patterns at two different spatial scales: regularly spaced clusters of mussels at centimeter scale driven by behavioral aggregation and large-scale, regularly spaced bands at meter scale driven by ecological feedback mechanisms. To test for the relative importance of these two spatial scales of self-organization on mussel bed persistence, we conducted field manipulations in which we factorially constructed small-scale and/or large-scale patterns. Our results revealed that both forms of self-organization enhanced the persistence of the constructed mussel beds in comparison to nonorganized beds. Small-scale, behaviorally driven cluster patterns were found to be crucial for persistence, and thus resistance to wave disturbance, whereas large-scale, self-organized patterns facilitated reformation of small-scale patterns if mussels were dislodged. This study provides experimental evidence that self-organization can be paramount to enhancing ecosystem persistence. We conclude that ecosystems with self-organized spatial patterns are likely to benefit greatly from conservation and restoration actions that use the emergent effects of self-organization to increase ecosystem resistance to disturbance.
Body Mass Index (BMI) is not only the prevailing tool used for defining and diagnosing obesity, but it is also a tool that intervenes into fisheries governance, and into fishers’ lives and bodies. All fishers on board vessels over 100 gross tons (GT) must hold a seaman’s licence; too high a BMI may lead to a “loss-of-licence” and the inability to undertake their occupation. From a governmentality perspective, this paper discusses the use of the seaman’s licence and explores how BMI may be an instrument in fisheries governance. We examine how safety policies link to storylines around health and obesity to produce healthy and safe fishers, and how this in turn links to the overall objective of governmentality: to produce productive labourers (fishers). We explore the multiple materialities of the BMI by looking at Norwegian fisheries’ safety policies from a Foucauldian perspective and question the wider implications of a safety policy focused on BMI and obesity.
The impact of crude oil pollution on early life stages (ELS) of fish, including larvae and embryos, has received considerable attention in recent years. Of the organic components present in crude oil, polycyclic aromatic hydrocarbons (PAHs) are considered the main class of compounds responsible for toxic effects in marine organisms. Although evidence suggests that they are more toxic, alkylated PAHs remain much less studied than their unsubstituted congeners. Recently, it was established that embryos of Atlantic haddock (Melanogrammus aeglefinus) are particularly sensitive to dispersed crude oil, and it was hypothesized that this was caused by direct interaction with crude oil droplets, which adhered to the chorion of exposed embryos. Such a phenomenon would increase the potential for uptake of less water-soluble compounds, including alkylated PAHs. In the current study, we compared the uptake of parent and alkylated PAHs in Atlantic cod (Gadus morhua) and haddock embryos exposed to dispersed crude oil at a range of environmentally relevant concentrations (10–600 μg oil/liter seawater). Although the species are biologically very similar, the cod chorion does not become fouled with oil droplets, even when the two species are exposed to dispersions of crude oil droplets under similar conditions. A close correlation between the degree of fouling and toxicological response (heart defects, craniofacial malformation) was observed. Oil droplet fouling in haddock led to both quantitative and qualitative differences in PAH uptake. Finally, kinetic data on a large suite of PAHs showed differential elimination, suggesting differential metabolism of unsubstituted versus alkylated compounds.
Shallow marine ecosystems naturally experience fluctuating physicochemical conditions across spatial and temporal scales. Widespread coral-bleaching events, induced by prolonged heat stress, highlight the importance of how the duration and frequency of thermal stress influence the adaptive physiology of photosymbiotic calcifiers. Large benthic foraminifera harboring algal endosymbionts are major tropical carbonate producers and bioindicators of ecosystem health. Like corals, they are sensitive to thermal stress and bleach at temperatures temporarily occurring in their natural habitat and projected to happen more frequently. However, their thermal tolerance has been studied so far only by chronic exposure, so how they respond under more realistic episodic heat-event scenarios remains unknown. Here, we determined the physiological responses of Amphistegina gibbosa, an abundant western Atlantic foraminifera, to four different treatments––control, single, episodic, and chronic exposure to the same thermal stress (32°C)––in controlled laboratory cultures. Exposure to chronic thermal stress reduced motility and growth, while antioxidant capacity was elevated, and photosymbiont variables (coloration, oxygen-production rates, chlorophyll a concentration) indicated extensive bleaching. In contrast, single- and episodic-stress treatments were associated with higher motility and growth, while photosymbiont variables remained stable. The effects of single and episodic heat events were similar, except for the presumable occurrence of reproduction, which seemed to be suppressed by both episodic and chronic stress. The otherwise different responses between treatments with thermal fluctuations and chronic stress indicate adaptation to thermal peaks, but not to chronic exposure expected to ensue when baseline temperatures are elevated by climate change. This firstly implies that marine habitats with a history of fluctuating thermal stress potentially support resilient physiological mechanisms among photosymbiotic organisms. Secondly, there seem to be temporal constraints related to heat events among coral reef environments and reinforces the importance of temporal fluctuations in stress exposure in global-change studies and projections.