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Alter K, Jacquemont J, Claudet J, Lattuca ME, Barrantes ME, Marras S, Manríquez PH, González CP, Fernández DA, Peck MA, Cattano C, Milazzo M, Mark FC, Domenici P. Hidden impacts of ocean warming and acidification on biological responses of marine animals revealed through meta-analysis. Nat Commun 2024; 15:2885. [PMID: 38570485 PMCID: PMC10991405 DOI: 10.1038/s41467-024-47064-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 03/19/2024] [Indexed: 04/05/2024] Open
Abstract
Conflicting results remain on the impacts of climate change on marine organisms, hindering our capacity to predict the future state of marine ecosystems. To account for species-specific responses and for the ambiguous relation of most metrics to fitness, we develop a meta-analytical approach based on the deviation of responses from reference values (absolute change) to complement meta-analyses of directional (relative) changes in responses. Using this approach, we evaluate responses of fish and invertebrates to warming and acidification. We find that climate drivers induce directional changes in calcification, survival, and metabolism, and significant deviations in twice as many biological responses, including physiology, reproduction, behavior, and development. Widespread deviations of responses are detected even under moderate intensity levels of warming and acidification, while directional changes are mostly limited to more severe intensity levels. Because such deviations may result in ecological shifts impacting ecosystem structures and processes, our results suggest that climate change will likely have stronger impacts than those previously predicted based on directional changes alone.
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Affiliation(s)
- Katharina Alter
- Royal Netherlands Institute for Sea Research, Department of Coastal Systems, P.O. Box 59, 1790, AB, Den Burg, The Netherlands.
| | - Juliette Jacquemont
- School of Aquatic and Fishery Sciences, University of Washington, 1122 NE Boat St, 98195, Seattle, WA, USA
- National Center for Scientific Research, PSL Université Paris, CRIOBE, CNRS-EPHE-UPVD, Maison de l'Océan, 195 rue Saint-Jacques, 75005, Paris, France
| | - Joachim Claudet
- National Center for Scientific Research, PSL Université Paris, CRIOBE, CNRS-EPHE-UPVD, Maison de l'Océan, 195 rue Saint-Jacques, 75005, Paris, France
| | - María E Lattuca
- Centro Austral de Investigaciones Científicas (CADIC-CONICET), Bernardo Houssay 200, V9410CAB, Ushuaia, Argentina
| | - María E Barrantes
- Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur; Instituto de Ciencias Polares, Ambiente y Recursos Naturales (UNTDF - ICPA), Fuegia Basket 251, V9410BXE, Ushuaia, Argentina
| | - Stefano Marras
- CNR-IAS, Consiglio Nazionale delle Ricerche, Instituto per lo studio degli Impatti Antropici e Sostenibilità in ambiente marino. Località Sa Mardini, 09170, Torregrande, Oristano, Italy
| | - Patricio H Manríquez
- Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Coquimbo, Chile
- Laboratorio de Ecología y Conducta de la Ontogenia Temprana (LECOT), Coquimbo, Chile
| | - Claudio P González
- Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Coquimbo, Chile
- Laboratorio de Ecología y Conducta de la Ontogenia Temprana (LECOT), Coquimbo, Chile
| | - Daniel A Fernández
- Centro Austral de Investigaciones Científicas (CADIC-CONICET), Bernardo Houssay 200, V9410CAB, Ushuaia, Argentina
- Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur; Instituto de Ciencias Polares, Ambiente y Recursos Naturales (UNTDF - ICPA), Fuegia Basket 251, V9410BXE, Ushuaia, Argentina
| | - Myron A Peck
- Royal Netherlands Institute for Sea Research, Department of Coastal Systems, P.O. Box 59, 1790, AB, Den Burg, The Netherlands
- Wageningen University, Department of Animal Sciences, Marine Animal Ecology Group, De Elst 1, 6708, WD, Wageningen, The Netherlands
| | - Carlo Cattano
- NBFC, National Biodiversity Future Center, Palermo, Italy
- Department of Integrative Marine Ecology, Stazione Zoologica Anton Dohrn (SZN), Lungomare Cristoforo Colombo, I-90149, Palermo, Italy
| | - Marco Milazzo
- NBFC, National Biodiversity Future Center, Palermo, Italy
- Dipartimento di Scienze della Terra e del Mare (DiSTeM), Università di Palermo, Via Archirafi 20, I-90123, Palermo, Italy
| | - Felix C Mark
- Section of Integrative Ecophysiology, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, Bremerhaven, 27570, Germany
| | - Paolo Domenici
- CNR-IAS, Consiglio Nazionale delle Ricerche, Instituto per lo studio degli Impatti Antropici e Sostenibilità in ambiente marino. Località Sa Mardini, 09170, Torregrande, Oristano, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
- CNR-IBF, Area di Ricerca San Cataldo, Via G. Moruzzi N°1, 56124, Pisa, Italy
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Finnegan S, Harnik PG, Lockwood R, Lotze HK, McClenachan L, Kahanamoku SS. Using the Fossil Record to Understand Extinction Risk and Inform Marine Conservation in a Changing World. ANNUAL REVIEW OF MARINE SCIENCE 2024; 16:307-333. [PMID: 37683272 DOI: 10.1146/annurev-marine-021723-095235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/10/2023]
Abstract
Understanding the long-term effects of ongoing global environmental change on marine ecosystems requires a cross-disciplinary approach. Deep-time and recent fossil records can contribute by identifying traits and environmental conditions associated with elevated extinction risk during analogous events in the geologic past and by providing baseline data that can be used to assess historical change and set management and restoration targets and benchmarks. Here, we review the ecological and environmental information available in the marine fossil record and discuss how these archives can be used to inform current extinction risk assessments as well as marine conservation strategies and decision-making at global to local scales. As we consider future research directions in deep-time and conservationpaleobiology, we emphasize the need for coproduced research that unites researchers, conservation practitioners, and policymakers with the communities for whom the impacts of climate and global change are most imminent.
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Affiliation(s)
- Seth Finnegan
- Department of Integrative Biology, University of California, Berkeley, California, USA; ,
| | - Paul G Harnik
- Department of Earth and Environmental Geosciences, Colgate University, Hamilton, New York, USA;
| | - Rowan Lockwood
- Department of Geology, William & Mary, Williamsburg, Virginia, USA;
| | - Heike K Lotze
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada;
| | - Loren McClenachan
- Department of History and School of Environmental Studies, University of Victoria, Victoria, British Columbia, Canada;
| | - Sara S Kahanamoku
- Department of Integrative Biology, University of California, Berkeley, California, USA; ,
- Hawai'i Sea Grant College Program, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA
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3
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Deutsch C, Penn JL, Lucey N. Climate, Oxygen, and the Future of Marine Biodiversity. ANNUAL REVIEW OF MARINE SCIENCE 2024; 16:217-245. [PMID: 37708422 DOI: 10.1146/annurev-marine-040323-095231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
The ocean enabled the diversification of life on Earth by adding O2 to the atmosphere, yet marine species remain most subject to O2 limitation. Human industrialization is intensifying the aerobic challenges to marine ecosystems by depleting the ocean's O2 inventory through the global addition of heat and local addition of nutrients. Historical observations reveal an ∼2% decline in upper-ocean O2 and accelerating reports of coastal mass mortality events. The dynamic balance of O2 supply and demand provides a unifying framework for understanding these phenomena across scales from the global ocean to individual organisms. Using this framework, we synthesize recent advances in forecasting O2 loss and its impacts on marine biogeography, biodiversity, and biogeochemistry. We also highlight three outstanding uncertainties: how long-term global climate change intensifies ocean weather events in which simultaneous heat and hypoxia create metabolic storms, how differential species O2 sensitivities alter the structure of ecological communities, and how global O2 loss intersects with coastal eutrophication. Projecting these interacting impacts on future marine ecosystems requires integration of climate dynamics, biogeochemistry, physiology, and ecology, evaluated with an eye on Earth history. Reducing global and local impacts of warming and O2 loss will be essential if humankind is to preserve the health and biodiversity of the future ocean.
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Affiliation(s)
- Curtis Deutsch
- Department of Geosciences, Princeton University, Princeton, New Jersey, USA;
- High Meadows Environmental Institute, Princeton University, Princeton, New Jersey, USA
| | - Justin L Penn
- Department of Geosciences, Princeton University, Princeton, New Jersey, USA;
| | - Noelle Lucey
- High Meadows Environmental Institute, Princeton University, Princeton, New Jersey, USA
- Smithsonian Tropical Research Institute, Balboa Ancón, Panama
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Kumala L, Thomsen M, Canfield DE. Respiration kinetics and allometric scaling in the demosponge Halichondria panicea. BMC Ecol Evol 2023; 23:53. [PMID: 37726687 PMCID: PMC10507823 DOI: 10.1186/s12862-023-02163-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 09/04/2023] [Indexed: 09/21/2023] Open
Abstract
BACKGROUND The aquiferous system in sponges represents one of the simplest circulatory systems used by animals for the internal uptake and distribution of oxygen and metabolic substrates. Its modular organization enables sponges to metabolically scale with size differently than animals with an internal circulatory system. In this case, metabolic rate is typically limited by surface to volume constraints to maintain an efficient supply of oxygen and food. Here, we consider the linkeage between oxygen concentration, the respiration rates of sponges and sponge size. RESULTS We explored respiration kinetics for individuals of the demosponge Halichondria panicea with varying numbers of aquiferous modules (nmodules = 1-102). From this work we establish relationships between the sponge size, module number, maximum respiration rate (Rmax) and the half-saturation constant, Km, which is the oxygen concentration producing half of the maximum respiration rate, Rmax. We found that the nmodules in H. panicea scales consistently with sponge volume (Vsp) and that Rmax increased with sponge size with a proportionality > 1. Conversly, we found a lack of correlation between Km and sponge body size suggesting that oxygen concentration does not control the size of sponges. CONCLUSIONS The present study reveals that the addition of aquiferous modules (with a mean volume of 1.59 ± 0.22 mL) enables H. panicea in particular, and likely demosponges in general, to grow far beyond constraints limiting the size of their component modules and independent of ambient oxygen levels.
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Affiliation(s)
- Lars Kumala
- Department of Biology, University of Southern Denmark, Odense M, 5230, Denmark.
- Marine Biological Research Centre, University of Southern Denmark, Kerteminde, 5300, Denmark.
- Nordcee, Department of Biology, University of Southern Denmark, Odense M, 5230, Denmark.
| | - Malte Thomsen
- Department of Biology, University of Southern Denmark, Odense M, 5230, Denmark
- Marine Biological Research Centre, University of Southern Denmark, Kerteminde, 5300, Denmark
- Nordcee, Department of Biology, University of Southern Denmark, Odense M, 5230, Denmark
| | - Donald E Canfield
- Department of Biology, University of Southern Denmark, Odense M, 5230, Denmark
- Nordcee, Department of Biology, University of Southern Denmark, Odense M, 5230, Denmark
- Danish Institute for Advanced Study (DIAS), University of Southern Denmark, Odense M, 5230, Denmark
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Sperling EA, Boag TH, Duncan MI, Endriga CR, Marquez JA, Mills DB, Monarrez PM, Sclafani JA, Stockey RG, Payne JL. Breathless through Time: Oxygen and Animals across Earth's History. THE BIOLOGICAL BULLETIN 2022; 243:184-206. [PMID: 36548971 DOI: 10.1086/721754] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
AbstractOxygen levels in the atmosphere and ocean have changed dramatically over Earth history, with major impacts on marine life. Because the early part of Earth's history lacked both atmospheric oxygen and animals, a persistent co-evolutionary narrative has developed linking oxygen change with changes in animal diversity. Although it was long believed that oxygen rose to essentially modern levels around the Cambrian period, a more muted increase is now believed likely. Thus, if oxygen increase facilitated the Cambrian explosion, it did so by crossing critical ecological thresholds at low O2. Atmospheric oxygen likely remained at low or moderate levels through the early Paleozoic era, and this likely contributed to high metazoan extinction rates until oxygen finally rose to modern levels in the later Paleozoic. After this point, ocean deoxygenation (and marine mass extinctions) is increasingly linked to large igneous province eruptions-massive volcanic carbon inputs to the Earth system that caused global warming, ocean acidification, and oxygen loss. Although the timescales of these ancient events limit their utility as exact analogs for modern anthropogenic global change, the clear message from the geologic record is that large and rapid CO2 injections into the Earth system consistently cause the same deadly trio of stressors that are observed today. The next frontier in understanding the impact of oxygen changes (or, more broadly, temperature-dependent hypoxia) in deep time requires approaches from ecophysiology that will help conservation biologists better calibrate the response of the biosphere at large taxonomic, spatial, and temporal scales.
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Woods HA, Moran AL, Atkinson D, Audzijonyte A, Berenbrink M, Borges FO, Burnett KG, Burnett LE, Coates CJ, Collin R, Costa-Paiva EM, Duncan MI, Ern R, Laetz EMJ, Levin LA, Lindmark M, Lucey NM, McCormick LR, Pierson JJ, Rosa R, Roman MR, Sampaio E, Schulte PM, Sperling EA, Walczyńska A, Verberk WCEP. Integrative Approaches to Understanding Organismal Responses to Aquatic Deoxygenation. THE BIOLOGICAL BULLETIN 2022; 243:85-103. [PMID: 36548975 DOI: 10.1086/722899] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
AbstractOxygen bioavailability is declining in aquatic systems worldwide as a result of climate change and other anthropogenic stressors. For aquatic organisms, the consequences are poorly known but are likely to reflect both direct effects of declining oxygen bioavailability and interactions between oxygen and other stressors, including two-warming and acidification-that have received substantial attention in recent decades and that typically accompany oxygen changes. Drawing on the collected papers in this symposium volume ("An Oxygen Perspective on Climate Change"), we outline the causes and consequences of declining oxygen bioavailability. First, we discuss the scope of natural and predicted anthropogenic changes in aquatic oxygen levels. Although modern organisms are the result of long evolutionary histories during which they were exposed to natural oxygen regimes, anthropogenic change is now exposing them to more extreme conditions and novel combinations of low oxygen with other stressors. Second, we identify behavioral and physiological mechanisms that underlie the interactive effects of oxygen with other stressors, and we assess the range of potential organismal responses to oxygen limitation that occur across levels of biological organization and over multiple timescales. We argue that metabolism and energetics provide a powerful and unifying framework for understanding organism-oxygen interactions. Third, we conclude by outlining a set of approaches for maximizing the effectiveness of future work, including focusing on long-term experiments using biologically realistic variation in experimental factors and taking truly cross-disciplinary and integrative approaches to understanding and predicting future effects.
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Global environmental changes more frequently offset than intensify detrimental effects of biological invasions. Proc Natl Acad Sci U S A 2022; 119:e2117389119. [PMID: 35622892 DOI: 10.1073/pnas.2117389119] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Significance International concern about the consequences of human-induced global environmental changes has prompted a renewed focus on reducing ecological effects of biological invasions, climate change, and nutrient pollution. Our results show that the combined effects of nonnative species invasions and abiotic global environmental changes are often negative but no worse than invasion impacts alone. Invasion impacts are also more strongly detrimental than warming temperatures or nitrogen deposition, two common stressors. Thus, reducing the spread of invasive species is critical for mitigating harms from anthropogenic changes to global ecosystems.
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Sobczyk R, Czortek P, Serigstad B, Pabis K. Modelling of polychaete functional diversity: Large marine ecosystem response to multiple natural factors and human impacts on the West African continental margin. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 792:148075. [PMID: 34465033 DOI: 10.1016/j.scitotenv.2021.148075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/16/2021] [Accepted: 05/22/2021] [Indexed: 06/13/2023]
Abstract
Polychaetes are one of the most diverse groups of marine organisms, characterized by high species richness, diversity of feeding guilds, life styles, and mobility types. Marine annelids are useful indicators of ecosystem responses to changes in environmental conditions. The aim of our study was to assess the influence of natural and anthropogenic factors on functional diversity of polychaete communities in the Gulf of Guinea, a large marine ecosystem (LME) located in West Africa. This area can be considered as a model marine ecosystem affected by various human influences, such as pollution associated with the oil industry. Material was collected in 2012 across the coast of Ghana. Samples were gathered along four transects, each with six sampling stations (25-1000 m depth range). Analyses of functional richness and evenness, based on generalized linear mixed-effect models and hierarchical partitioning, allowed for complex assessments of the interactions between polychaete communities and environmental factors (e.g., sediments, total organic matter, salinity, fluorescence, oxygen, concentration of toxic metals, total hydrocarbons). Overall species richness of polychaetes was outstandingly high, with 253 species recorded. Functional richness decreased along a depth gradient, while functional evenness increased with depth, and was positively correlated with Ba content, which reached the highest values in the upper bathyal. Gravel content was an important factor in shaping functional composition of shallow water communities. High values of functional richness observed in the shallows may be an expression of high stability of this ecosystem, at the same time indicating its high resilience. Elevated concentrations of lead also influenced community structure at a local scale. Our study demonstrated how a complex set of factors operating along a depth gradient can influence the functional composition of communities. These results are crucial for future management of industrial and environmental protection activities in this region.
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Affiliation(s)
- Robert Sobczyk
- Department of Invertebrate Zoology and Hydrobiology, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland.
| | - Patryk Czortek
- Institute of Botany - Bialowieza Geobotanical Station, University of Warsaw, Sportowa 19, 17-230 Bialowieza, Poland
| | | | - Krzysztof Pabis
- Department of Invertebrate Zoology and Hydrobiology, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland
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Decreasing Phanerozoic extinction intensity as a consequence of Earth surface oxygenation and metazoan ecophysiology. Proc Natl Acad Sci U S A 2021; 118:2101900118. [PMID: 34607946 DOI: 10.1073/pnas.2101900118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2021] [Indexed: 11/18/2022] Open
Abstract
The decline in background extinction rates of marine animals through geologic time is an established but unexplained feature of the Phanerozoic fossil record. There is also growing consensus that the ocean and atmosphere did not become oxygenated to near-modern levels until the mid-Paleozoic, coinciding with the onset of generally lower extinction rates. Physiological theory provides us with a possible causal link between these two observations-predicting that the synergistic impacts of oxygen and temperature on aerobic respiration would have made marine animals more vulnerable to ocean warming events during periods of limited surface oxygenation. Here, we evaluate the hypothesis that changes in surface oxygenation exerted a first-order control on extinction rates through the Phanerozoic using a combined Earth system and ecophysiological modeling approach. We find that although continental configuration, the efficiency of the biological carbon pump in the ocean, and initial climate state all impact the magnitude of modeled biodiversity loss across simulated warming events, atmospheric oxygen is the dominant predictor of extinction vulnerability, with metabolic habitat viability and global ecophysiotype extinction exhibiting inflection points around 40% of present atmospheric oxygen. Given this is the broad upper limit for estimates of early Paleozoic oxygen levels, our results are consistent with the relative frequency of high-magnitude extinction events (particularly those not included in the canonical big five mass extinctions) early in the Phanerozoic being a direct consequence of limited early Paleozoic oxygenation and temperature-dependent hypoxia responses.
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Impacts of hypoxic events surpass those of future ocean warming and acidification. Nat Ecol Evol 2021; 5:311-321. [PMID: 33432134 DOI: 10.1038/s41559-020-01370-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 12/01/2020] [Indexed: 01/28/2023]
Abstract
Over the past decades, three major challenges to marine life have emerged as a consequence of anthropogenic emissions: ocean warming, acidification and oxygen loss. While most experimental research has targeted the first two stressors, the last remains comparatively neglected. Here, we implemented sequential hierarchical mixed-model meta-analyses (721 control-treatment comparisons) to compare the impacts of oxygen conditions associated with the current and continuously intensifying hypoxic events (1-3.5 O2 mg l-1) with those experimentally yielded by ocean warming (+4 °C) and acidification (-0.4 units) conditions on the basis of IPCC projections (RCP 8.5) for 2100. In contrast to warming and acidification, hypoxic events elicited consistent negative effects relative to control biological performance-survival (-33%), abundance (-65%), development (-51%), metabolism (-33%), growth (-24%) and reproduction (-39%)-across the taxonomic groups (mollusks, crustaceans and fish), ontogenetic stages and climate regions studied. Our findings call for a refocus of global change experimental studies, integrating oxygen concentration drivers as a key factor of ocean change. Given potential combined effects, multistressor designs including gradual and extreme changes are further warranted to fully disclose the future impacts of ocean oxygen loss, warming and acidification.
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Effects of Seasonal Anoxia on the Microbial Community Structure in Demosponges in a Marine Lake in Lough Hyne, Ireland. mSphere 2021; 6:6/1/e00991-20. [PMID: 33536324 PMCID: PMC7860989 DOI: 10.1128/msphere.00991-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Climate change is expanding marine oxygen minimum zones (OMZs), while anthropogenic nutrient input depletes oxygen concentrations locally. The effects of deoxygenation on animals are generally detrimental; however, some sponges (Porifera) exhibit hypoxic and anoxic tolerance through currently unknown mechanisms. Sponges harbor highly specific microbiomes, which can include microbes with anaerobic capabilities. Sponge-microbe symbioses must also have persisted through multiple anoxic/hypoxic periods throughout Earth's history. Since sponges lack key components of the hypoxia-inducible factor (HIF) pathway responsible for hypoxic responses in other animals, it was hypothesized that sponge tolerance to deoxygenation may be facilitated by its microbiome. To test this hypothesis, we determined the microbial composition of sponge species tolerating seasonal anoxia and hypoxia in situ in a semienclosed marine lake, using 16S rRNA amplicon sequencing. We discovered a high degree of cryptic diversity among sponge species tolerating seasonal deoxygenation, including at least nine encrusting species of the orders Axinellida and Poecilosclerida. Despite significant changes in microbial community structure in the water, sponge microbiomes were species specific and remarkably stable under varied oxygen conditions, which was further explored for Eurypon spp. 2 and Hymeraphia stellifera However, some symbiont sharing occurred under anoxia. At least three symbiont combinations, all including large populations of Thaumarchaeota, corresponded with deoxygenation tolerance, and some combinations were shared between some distantly related hosts. We propose hypothetical host-symbiont interactions following deoxygenation that could confer deoxygenation tolerance.IMPORTANCE The oceans have an uncertain future due to anthropogenic stressors and an uncertain past that is becoming clearer with advances in biogeochemistry. Both past and future oceans were, or will be, deoxygenated in comparison to present conditions. Studying how sponges and their associated microbes tolerate deoxygenation provides insights into future marine ecosystems. Moreover, sponges form the earliest branch of the animal evolutionary tree, and they likely resemble some of the first animals. We determined the effects of variable environmental oxygen concentrations on the microbial communities of several demosponge species during seasonal anoxia in the field. Our results indicate that anoxic tolerance in some sponges may depend on their symbionts, but anoxic tolerance was not universal in sponges. Therefore, some sponge species could likely outcompete benthic organisms like corals in future, reduced-oxygen ecosystems. Our results support the molecular evidence that sponges and other animals have a Neoproterozoic origin and that animal evolution was not limited by low-oxygen conditions.
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12
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Levin LA, Wei C, Dunn DC, Amon DJ, Ashford OS, Cheung WWL, Colaço A, Dominguez‐Carrió C, Escobar EG, Harden‐Davies HR, Drazen JC, Ismail K, Jones DOB, Johnson DE, Le JT, Lejzerowicz F, Mitarai S, Morato T, Mulsow S, Snelgrove PVR, Sweetman AK, Yasuhara M. Climate change considerations are fundamental to management of deep-sea resource extraction. GLOBAL CHANGE BIOLOGY 2020; 26:4664-4678. [PMID: 32531093 PMCID: PMC7496832 DOI: 10.1111/gcb.15223] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 05/12/2020] [Indexed: 05/19/2023]
Abstract
Climate change manifestation in the ocean, through warming, oxygen loss, increasing acidification, and changing particulate organic carbon flux (one metric of altered food supply), is projected to affect most deep-ocean ecosystems concomitantly with increasing direct human disturbance. Climate drivers will alter deep-sea biodiversity and associated ecosystem services, and may interact with disturbance from resource extraction activities or even climate geoengineering. We suggest that to ensure the effective management of increasing use of the deep ocean (e.g., for bottom fishing, oil and gas extraction, and deep-seabed mining), environmental management and developing regulations must consider climate change. Strategic planning, impact assessment and monitoring, spatial management, application of the precautionary approach, and full-cost accounting of extraction activities should embrace climate consciousness. Coupled climate and biological modeling approaches applied in the water and on the seafloor can help accomplish this goal. For example, Earth-System Model projections of climate-change parameters at the seafloor reveal heterogeneity in projected climate hazard and time of emergence (beyond natural variability) in regions targeted for deep-seabed mining. Models that combine climate-induced changes in ocean circulation with particle tracking predict altered transport of early life stages (larvae) under climate change. Habitat suitability models can help assess the consequences of altered larval dispersal, predict climate refugia, and identify vulnerable regions for multiple species under climate change. Engaging the deep observing community can support the necessary data provisioning to mainstream climate into the development of environmental management plans. To illustrate this approach, we focus on deep-seabed mining and the International Seabed Authority, whose mandates include regulation of all mineral-related activities in international waters and protecting the marine environment from the harmful effects of mining. However, achieving deep-ocean sustainability under the UN Sustainable Development Goals will require integration of climate consideration across all policy sectors.
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Affiliation(s)
- Lisa A. Levin
- Integrative Oceanography Division and Center for Marine Biodiversity and ConservationScripps Institution of OceanographyUniversity of California, San DiegoLa JollaCAUSA
| | - Chih‐Lin Wei
- Institute of OceanographyNational Taiwan UniversityTaipeiTaiwan
| | - Daniel C. Dunn
- School of Earth and Environmental SciencesUniversity of QueenslandSt LuciaQldAustralia
| | - Diva J. Amon
- Life Sciences DepartmentNatural History MuseumLondonUK
| | - Oliver S. Ashford
- Integrative Oceanography Division and Center for Marine Biodiversity and ConservationScripps Institution of OceanographyUniversity of California, San DiegoLa JollaCAUSA
| | - William W. L. Cheung
- Institute for the Oceans and FisheriesThe University of British ColumbiaVancouverBCCanada
| | - Ana Colaço
- IMARInstituto do Mar, and Instituto de Investigação em Ciências do Mar – Okeanos da Universidade dos AçoresHortaPortugal
| | - Carlos Dominguez‐Carrió
- IMARInstituto do Mar, and Instituto de Investigação em Ciências do Mar – Okeanos da Universidade dos AçoresHortaPortugal
| | - Elva G. Escobar
- Instituto de Ciencias del Mar y LimnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
| | - Harriet R. Harden‐Davies
- Australian National Centre for Ocean Resources and SecurityUniversity of WollongongWollongongNSWAustralia
| | - Jeffrey C. Drazen
- Department of OceanographyUniversity of Hawaii at ManoaHonoluluHIUSA
| | - Khaira Ismail
- Faculty of Science and Marine EnvironmentUniversiti Malaysia TerengganuKuala TerengganuMalaysia
| | - Daniel O. B. Jones
- Ocean Biogeochemistry and Ecosystems GroupNational Oceanography CentreSouthamptonUK
| | - David E. Johnson
- Global Ocean Biodiversity InitiativeSeascape Consultants Ltd.RomseyUK
| | - Jennifer T. Le
- Integrative Oceanography Division and Center for Marine Biodiversity and ConservationScripps Institution of OceanographyUniversity of California, San DiegoLa JollaCAUSA
| | - Franck Lejzerowicz
- Jacobs School of EngineeringUniversity of California San DiegoLa JollaCAUSA
| | - Satoshi Mitarai
- Marine Biophysics UnitOkinawa Institute of Science and Technology Graduate UniversityOkinawaJapan
| | - Telmo Morato
- IMARInstituto do Mar, and Instituto de Investigação em Ciências do Mar – Okeanos da Universidade dos AçoresHortaPortugal
| | - Sandor Mulsow
- Instituto Ciencias Marinas y LimnológicasUniversidad Austral de ChileValdiviaChile
| | - Paul V. R. Snelgrove
- Department of Ocean Sciences and Biology DepartmentMemorial University of NewfoundlandSt. John'sNLCanada
| | - Andrew K. Sweetman
- The Lyell Centre for Earth and Marine Science and TechnologyHeriot Watt UniversityEdinburghUK
| | - Moriaki Yasuhara
- School of Biological Sciences and Swire Institute of Marine ScienceThe University of Hong KongHong Kong SARChina
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13
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Cole DB, Mills DB, Erwin DH, Sperling EA, Porter SM, Reinhard CT, Planavsky NJ. On the co-evolution of surface oxygen levels and animals. GEOBIOLOGY 2020; 18:260-281. [PMID: 32175670 DOI: 10.1111/gbi.12382] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 01/04/2020] [Accepted: 01/22/2020] [Indexed: 05/22/2023]
Abstract
Few topics in geobiology have been as extensively debated as the role of Earth's oxygenation in controlling when and why animals emerged and diversified. All currently described animals require oxygen for at least a portion of their life cycle. Therefore, the transition to an oxygenated planet was a prerequisite for the emergence of animals. Yet, our understanding of Earth's oxygenation and the environmental requirements of animal habitability and ecological success is currently limited; estimates for the timing of the appearance of environments sufficiently oxygenated to support ecologically stable populations of animals span a wide range, from billions of years to only a few million years before animals appear in the fossil record. In this light, the extent to which oxygen played an important role in controlling when animals appeared remains a topic of debate. When animals originated and when they diversified are separate questions, meaning either one or both of these phenomena could have been decoupled from oxygenation. Here, we present views from across this interpretive spectrum-in a point-counterpoint format-regarding crucial aspects of the potential links between animals and surface oxygen levels. We highlight areas where the standard discourse on this topic requires a change of course and note that several traditional arguments in this "life versus environment" debate are poorly founded. We also identify a clear need for basic research across a range of fields to disentangle the relationships between oxygen availability and emergence and diversification of animal life.
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Affiliation(s)
- Devon B Cole
- School of Earth and Atmospheric Science, Georgia Institute of Technology, Atlanta, Georgia
| | - Daniel B Mills
- Department of Geological Sciences, Stanford University, Stanford, California
| | - Douglas H Erwin
- Department of Paleobiology, National Museum of Natural History, Washington, District of Columbia
- Santa Fe Institute, Santa Fe, New Mexico
| | - Erik A Sperling
- Department of Geological Sciences, Stanford University, Stanford, California
| | - Susannah M Porter
- Department of Earth Science, University of California Santa Barbara, Santa Barbara, California
| | - Christopher T Reinhard
- School of Earth and Atmospheric Science, Georgia Institute of Technology, Atlanta, Georgia
| | - Noah J Planavsky
- Department of Geology and Geophysics, Yale University, New Haven, Connecticut
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14
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Sperling EA, Stockey RG. The Temporal and Environmental Context of Early Animal Evolution: Considering All the Ingredients of an "Explosion". Integr Comp Biol 2019; 58:605-622. [PMID: 30295813 DOI: 10.1093/icb/icy088] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Animals originated and evolved during a unique time in Earth history-the Neoproterozoic Era. This paper aims to discuss (1) when landmark events in early animal evolution occurred, and (2) the environmental context of these evolutionary milestones, and how such factors may have affected ecosystems and body plans. With respect to timing, molecular clock studies-utilizing a diversity of methodologies-agree that animal multicellularity had arisen by ∼800 million years ago (Ma) (Tonian period), the bilaterian body plan by ∼650 Ma (Cryogenian), and divergences between sister phyla occurred ∼560-540 Ma (late Ediacaran). Most purported Tonian and Cryogenian animal body fossils are unlikely to be correctly identified, but independent support for the presence of pre-Ediacaran animals is recorded by organic geochemical biomarkers produced by demosponges. This view of animal origins contrasts with data from the fossil record, and the taphonomic question of why animals were not preserved (if present) remains unresolved. Neoproterozoic environments demanding small, thin, body plans, and lower abundance/rarity in populations may have played a role. Considering environmental conditions, geochemical data suggest that animals evolved in a relatively low-oxygen ocean. Here, we present new analyses of sedimentary total organic carbon contents in shales suggesting that the Neoproterozoic ocean may also have had lower primary productivity-or at least lower quantities of organic carbon reaching the seafloor-compared with the Phanerozoic. Indeed, recent modeling efforts suggest that low primary productivity is an expected corollary of a low-O2 world. Combined with an inability to inhabit productive regions in a low-O2 ocean, earliest animal communities would likely have been more food limited than generally appreciated, impacting both ecosystem structure and organismal behavior. In light of this, we propose the "fire triangle" metaphor for environmental influences on early animal evolution. Moving toward consideration of all environmental aspects of the Cambrian radiation (fuel, heat, and oxidant) will ultimately lead to a more holistic view of the event.
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Affiliation(s)
- Erik A Sperling
- Department of Geological Sciences, Stanford University, 450 Serra Mall, Building 320, Stanford, CA 94305, USA
| | - Richard G Stockey
- Department of Geological Sciences, Stanford University, 450 Serra Mall, Building 320, Stanford, CA 94305, USA
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15
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Dunn DC, Van Dover CL, Etter RJ, Smith CR, Levin LA, Morato T, Colaço A, Dale AC, Gebruk AV, Gjerde KM, Halpin PN, Howell KL, Johnson D, Perez JAA, Ribeiro MC, Stuckas H, Weaver P. A strategy for the conservation of biodiversity on mid-ocean ridges from deep-sea mining. SCIENCE ADVANCES 2018; 4:eaar4313. [PMID: 29978040 PMCID: PMC6031377 DOI: 10.1126/sciadv.aar4313] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 05/23/2018] [Indexed: 05/24/2023]
Abstract
Mineral exploitation has spread from land to shallow coastal waters and is now planned for the offshore, deep seabed. Large seafloor areas are being approved for exploration for seafloor mineral deposits, creating an urgent need for regional environmental management plans. Networks of areas where mining and mining impacts are prohibited are key elements of these plans. We adapt marine reserve design principles to the distinctive biophysical environment of mid-ocean ridges, offer a framework for design and evaluation of these networks to support conservation of benthic ecosystems on mid-ocean ridges, and introduce projected climate-induced changes in the deep sea to the evaluation of reserve design. We enumerate a suite of metrics to measure network performance against conservation targets and network design criteria promulgated by the Convention on Biological Diversity. We apply these metrics to network scenarios on the northern and equatorial Mid-Atlantic Ridge, where contractors are exploring for seafloor massive sulfide (SMS) deposits. A latitudinally distributed network of areas performs well at (i) capturing ecologically important areas and 30 to 50% of the spreading ridge areas, (ii) replicating representative areas, (iii) maintaining along-ridge population connectivity, and (iv) protecting areas potentially less affected by climate-related changes. Critically, the network design is adaptive, allowing for refinement based on new knowledge and the location of mining sites, provided that design principles and conservation targets are maintained. This framework can be applied along the global mid-ocean ridge system as a precautionary measure to protect biodiversity and ecosystem function from impacts of SMS mining.
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Affiliation(s)
- Daniel C. Dunn
- Marine Geospatial Ecology Lab, Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University, Durham, NC 27708, USA
| | - Cindy L. Van Dover
- Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University, Beaufort, NC 28516, USA
| | - Ron J. Etter
- Biology Department, University of Massachusetts, Boston, MA 02125, USA
| | - Craig R. Smith
- Department of Oceanography, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Lisa A. Levin
- Center for Marine Biodiversity and Conservation and Integrative Oceanography Division, Scripps Institution of Oceanography, UC San Diego, La Jolla, CA 92093, USA
- Deep-Ocean Stewardship Initiative and Deep Ocean Observing Strategy, University of Southampton, University Road, Southampton, UK
| | - Telmo Morato
- IMAR Instituto do Mar, Departamento de Oceanografia e Pescas, and MARE Marine and Environmental Sciences Centre, University of the Azores, Horta, Portugal
| | - Ana Colaço
- IMAR Instituto do Mar, Departamento de Oceanografia e Pescas, and MARE Marine and Environmental Sciences Centre, University of the Azores, Horta, Portugal
| | - Andrew C. Dale
- Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll, UK
| | - Andrey V. Gebruk
- Shirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, Russia
| | - Kristina M. Gjerde
- IUCN Global Marine and Polar Programme and World Commission on Protected Areas, Cambridge, MA 02138, USA
- Middlebury Institute of International Studies, Monterey, CA 93940, USA
| | - Patrick N. Halpin
- Marine Geospatial Ecology Lab, Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University, Durham, NC 27708, USA
| | - Kerry L. Howell
- Deep-Sea Conservation Research Unit, School of Biological and Marine Sciences, Plymouth University, Drake Circus, Plymouth, UK
| | | | - José Angel A. Perez
- Centro de Ciências Tecnológicas da Terra e do Mar, Universidade do Vale do Itajaí, Itajaí, Santa Catarina, Brazil
| | - Marta Chantal Ribeiro
- Faculty of Law, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Portugal
| | - Heiko Stuckas
- Senckenberg Natural History Collections Dresden, Dresden, Germany
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16
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Chu JWF, Curkan C, Tunnicliffe V. Drivers of temporal beta diversity of a benthic community in a seasonally hypoxic fjord. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172284. [PMID: 29765677 PMCID: PMC5936942 DOI: 10.1098/rsos.172284] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 03/13/2018] [Indexed: 05/03/2023]
Abstract
Global expansion of oxygen-deficient (hypoxic) waters will have detrimental effects on marine life in the Northeast Pacific Ocean (NEP) where some of the largest proportional losses in aerobic habitat are predicted to occur. However, few in situ studies have accounted for the high environmental variability in this region while including natural community-assembly dynamics. Here, we present results from a 14-month deployment of a benthic camera platform tethered to the VENUS cabled observatory in the seasonally hypoxic Saanich Inlet. Our time series continuously recorded natural cycles of deoxygenation and reoxygenation that allowed us to test whether a community from the NEP showed hysteresis in its recovery compared to hypoxia-induced decline, and to address the processes driving temporal beta diversity under variable states of hypoxia. Using high-frequency ecological time series, we reveal (i) differences in the response and recovery of the epibenthic community are rate-limited by recovery of the sessile species assemblage; (ii) both environmental and biological processes influence community assembly patterns at multiple timescales; and (iii) interspecific processes can drive temporal beta diversity in seasonal hypoxia. Ultimately, our results illustrate how different timescale-dependent drivers can influence the response and recovery of a marine habitat under increasing stress from environmental change.
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Affiliation(s)
- Jackson W. F. Chu
- Department of Biology, University of Victoria, PO Box 3080, Victoria, BC V8 W 2Y2, Canada
- Fisheries and Oceans Canada, Institute of Ocean Sciences, Sidney, BC V8 L 4B2, Canada
- Author for correspondence: Jackson W. F. Chu e-mail:
| | - Curtis Curkan
- School of Earth & Ocean Sciences, University of Victoria, PO Box 3080, Victoria, BC V8 W 2Y2, Canada
| | - Verena Tunnicliffe
- Department of Biology, University of Victoria, PO Box 3080, Victoria, BC V8 W 2Y2, Canada
- School of Earth & Ocean Sciences, University of Victoria, PO Box 3080, Victoria, BC V8 W 2Y2, Canada
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17
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Abstract
Oxygen loss in the ocean, termed deoxygenation, is a major consequence of climate change and is exacerbated by other aspects of global change. An average global loss of 2% or more has been recorded in the open ocean over the past 50-100 years, but with greater oxygen declines in intermediate waters (100-600 m) of the North Pacific, the East Pacific, tropical waters, and the Southern Ocean. Although ocean warming contributions to oxygen declines through a reduction in oxygen solubility and stratification effects on ventilation are reasonably well understood, it has been a major challenge to identify drivers and modifying factors that explain different regional patterns, especially in the tropical oceans. Changes in respiration, circulation (including upwelling), nutrient inputs, and possibly methane release contribute to oxygen loss, often indirectly through stimulation of biological production and biological consumption. Microbes mediate many feedbacks in oxygen minimum zones that can either exacerbate or ameliorate deoxygenation via interacting nitrogen, sulfur, and carbon cycles. The paleo-record reflects drivers of and feedbacks to deoxygenation that have played out through the Phanerozoic on centennial, millennial, and hundred-million-year timescales. Natural oxygen variability has made it difficult to detect the emergence of a climate-forced signal of oxygen loss, but new modeling efforts now project emergence to occur in many areas in 15-25 years. Continued global deoxygenation is projected for the next 100 or more years under most emissions scenarios, but with regional heterogeneity. Notably, even small changes in oxygenation can have significant biological effects. New efforts to systematically observe oxygen changes throughout the open ocean are needed to help address gaps in understanding of ocean deoxygenation patterns and drivers.
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Affiliation(s)
- Lisa A Levin
- Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0218, USA;
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18
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Lee MR, Torres R, Manríquez PH. The combined effects of ocean warming and acidification on shallow-water meiofaunal assemblages. MARINE ENVIRONMENTAL RESEARCH 2017; 131:1-9. [PMID: 28919151 DOI: 10.1016/j.marenvres.2017.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 08/30/2017] [Accepted: 09/05/2017] [Indexed: 06/07/2023]
Abstract
Climate change due to increased anthropogenic CO2 in the atmosphere is causing an increase in seawater temperatures referred to as ocean warming and a decrease in seawater pH, referred to as ocean acidification. The meiofauna play an important role in the ecology of marine ecosystems and the functions they provide. Using microcosms, meiofaunal assemblages were exposed to two temperatures (15 and 19 °C) and two pHs (pCO2 of 400 and 1000 ppm), both individually and in combination, for a period of 90 days. The hypothesis that increased temperature will increase meiofaunal abundance was not supported. The hypothesis that a reduced pH will reduce meiofaunal abundance and species richness was supported. The combination of future conditions of temperature and pH (19 °C and pCO2 of 1000 ppm) did not affect overall abundance but the structure of the nematode assemblage changed becoming dominated by a few opportunistic species.
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Affiliation(s)
- Matthew R Lee
- Centro i∼mar, Universidad de Los Lagos, Camino a Chinquihue km.6, Puerto Montt, Chile.
| | - Rodrigo Torres
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Coyhaique, Chile; Centro de Investigación: Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Chile
| | - Patricio H Manríquez
- Laboratorio de Ecología y Conducta de la Ontogenia Temprana (LECOT), Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Coquimbo, Chile
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19
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Gallo ND, Levin LA. Fish Ecology and Evolution in the World's Oxygen Minimum Zones and Implications of Ocean Deoxygenation. ADVANCES IN MARINE BIOLOGY 2016; 74:117-198. [PMID: 27573051 DOI: 10.1016/bs.amb.2016.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Oxygen minimum zones (OMZs) and oxygen limited zones (OLZs) are important oceanographic features in the Pacific, Atlantic, and Indian Ocean, and are characterized by hypoxic conditions that are physiologically challenging for demersal fish. Thickness, depth of the upper boundary, minimum oxygen levels, local temperatures, and diurnal, seasonal, and interannual oxycline variability differ regionally, with the thickest and shallowest OMZs occurring in the subtropics and tropics. Although most fish are not hypoxia-tolerant, at least 77 demersal fish species from 16 orders have evolved physiological, behavioural, and morphological adaptations that allow them to live under the severely hypoxic, hypercapnic, and at times sulphidic conditions found in OMZs. Tolerance to OMZ conditions has evolved multiple times in multiple groups with no single fish family or genus exploiting all OMZs globally. Severely hypoxic conditions in OMZs lead to decreased demersal fish diversity, but fish density trends are variable and dependent on region-specific thresholds. Some OMZ-adapted fish species are more hypoxia-tolerant than most megafaunal invertebrates and are present even when most invertebrates are excluded. Expansions and contractions of OMZs in the past have affected fish evolution and diversity. Current patterns of ocean warming are leading to ocean deoxygenation, causing the expansion and shoaling of OMZs, which is expected to decrease demersal fish diversity and alter trophic pathways on affected margins. Habitat compression is expected for hypoxia-intolerant species, causing increased susceptibility to overfishing for fisheries species. Demersal fisheries are likely to be negatively impacted overall by the expansion of OMZs in a warming world.
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Affiliation(s)
- N D Gallo
- Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States.
| | - L A Levin
- Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States
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