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Chan KYK, Ko WH. Modeling Fertilization Outcome in a Changing World. Integr Comp Biol 2024; 64:905-920. [PMID: 38871950 DOI: 10.1093/icb/icae071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 06/05/2024] [Accepted: 06/05/2024] [Indexed: 06/15/2024] Open
Abstract
Marine organisms have complex life histories. For broadcast spawners, successful continuation of the population requires their small gametes to make contact in the water column for sufficiently long periods for fertilization to occur. Anthropogenic climate change has been shown to impact fertilization success in various marine invertebrates, including sea urchins, which are key grazers in their habitats. Gamete performance of both sexes declined when exposed to elevated temperatures and/or pCO2 levels. Examples of reduced performance included slower sperm swimming speed and thinning egg jelly coat. However, such responses to climate change stress were not uniform between individuals. Such variations could serve as the basis for selection. Fertilization kinetics have long been modeled as a particle collision process. Here, we present a modified fertilization kinetics model that incorporates individual variations in performance in a more environmentally relevant regime, and which the performance of groups with different traits can be separately tracked in a mixture. Numerical simulations highlight that fertilization outcomes are influenced by changes in gamete traits as they age in sea water and the presence of competition groups (multiple dams or sires). These results highlight the importance of considering multiple individuals and at multiple time points during in vivo assays. We also applied our model to show that interspecific variation in climate stress vulnerabilities elevates the risk of hybridization. By making a numerical model open-source, we aim to help us better understand the fate of organisms in the face of climate change by enabling the community to consider the mean and variance of the response to capture adaptive potential.
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Affiliation(s)
| | - Wing Ho Ko
- Physics and Astronomy Department, Swarthmore College, Swarthmore, PA 19081, USA
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2
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Hudson ME, Sewell MA. Ocean acidification impacts sperm swimming performance and pHi in the New Zealand sea urchin Evechinus chloroticus. J Exp Biol 2022; 225:276137. [PMID: 35899479 DOI: 10.1242/jeb.243670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 07/20/2022] [Indexed: 11/20/2022]
Abstract
In sea urchins, spermatozoa are stored in the gonads in hypercapnic conditions (pH<7.0). During spawning, sperm are diluted in seawater of pH>8.0, and there is an alkalinization of the sperm's internal pH (pHi) through the release of CO2 and H+. Previous research has shown that when pHi is above 7.2-7.3, the dynein ATPase flagellar motors are activated, and the sperm become motile. It has been hypothesised that ocean acidification (OA), which decreases the pH of seawater, may have a narcotic effect on sea urchin sperm by impairing the ability to regulate pHi, resulting in decreased motility and swimming speed. Here we use data collected from the same individuals to test the relationship between pHi and sperm motility/performance in the New Zealand sea urchin Evechinus chloroticus (Valenciennes) under near- (2100) and far-future (2150) atmospheric pCO2 conditions (RCP 8.5: pH 7.77, 7.51). Decreasing seawater pH significantly negatively impacted the proportion of motile sperm), and four of the six computer-assisted sperm analysis (CASA) sperm performance measures. In control conditions, sperm had an activated pHi of 7.52. E. chloroticus sperm could not defend pHi. in future OA conditions; there was a stepped decrease in the pHi at pH 7.77, with no significant difference in mean pHi between pH 7.77 and 7.51. Paired measurements in the same males showed a positive relationship between pHi and sperm motility, but with a significant difference in the response between males. Differences in motility and sperm performance in OA conditions may impact fertilization success in a future ocean.
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Affiliation(s)
- Michael E Hudson
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.,Institute of Marine Science, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Mary A Sewell
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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3
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Kustra M, Carrier TJ. On the spread of microbes that manipulate reproduction in marine invertebrates. Am Nat 2022; 200:217-235. [DOI: 10.1086/720282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Lymbery RA, Brouwer J, Evans JP. Ocean acidification alters sperm responses to egg-derived chemicals in a broadcast spawning mussel. Biol Lett 2022; 18:20220042. [PMID: 35382588 PMCID: PMC8984365 DOI: 10.1098/rsbl.2022.0042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 03/16/2022] [Indexed: 11/25/2022] Open
Abstract
The continued emissions of anthropogenic carbon dioxide are causing progressive ocean acidification (OA). While deleterious effects of OA on biological systems are well documented in the growth of calcifying organisms, lesser studied impacts of OA include potential effects on gamete interactions that determine fertilization, which are likely to influence the many marine species that spawn gametes externally. Here, we explore the effects of OA on the signalling mechanisms that enable sperm to track egg-derived chemicals (sperm chemotaxis). We focus on the mussel Mytilus galloprovincialis, where sperm chemotaxis enables eggs to bias fertilization in favour of genetically compatible males. Using an experimental design based on the North Carolina II factorial breeding design, we test whether the experimental manipulation of seawater pH (comparing ambient conditions to predicted end-of-century scenarios) alters patterns of differential sperm chemotaxis. While we find no evidence that male-female gametic compatibility is impacted by OA, we do find that individual males exhibit consistent variation in how their sperm perform in lowered pH levels. This finding of individual variability in the capacity of ejaculates to respond to chemoattractants under acidified conditions suggests that climate change will exert considerable pressure on male genotypes that can withstand an increasingly hostile fertilization environment.
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Affiliation(s)
- Rowan A. Lymbery
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia
| | - Jill Brouwer
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia
| | - Jonathan P. Evans
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia
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Gallo A, Esposito MC, Cuccaro A, Buia MC, Tarallo A, Monfrecola V, Tosti E, Boni R. Adult exposure to acidified seawater influences sperm physiology in Mytilus galloprovincialis: Laboratory and in situ transplant experiments. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 265:115063. [PMID: 32806401 DOI: 10.1016/j.envpol.2020.115063] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/13/2020] [Accepted: 06/17/2020] [Indexed: 06/11/2023]
Abstract
The ongoing increase of CO2 in the atmosphere is inducing a progressive lowering of marine water pH that is predicted to decrease to 7.8 by the end of this century. In marine environment, physical perturbation may affect reproduction, which is crucial for species' survival and strictly depends on gamete quality. The effects of seawater acidification (SWAc) on gamete quality of broadcast spawning marine invertebrates result largely from experiments of gamete exposure while the SWAc impact in response to adult exposure is poorly investigated. Performing microcosm and in field experiments at a naturally acidified site, we investigated the effects of adult SWAc exposure on sperm quality parameters underlying fertilization in Mytilus galloprovincialis. These animals were exposed to pH 7.8 over 21 days and collected at different times to analyze sperm parameters as concentration, motility, viability, morphology, oxidative status, intra- and extra-cellular pH and mitochondrial membrane potential. Results obtained in the two experimental approaches were slightly different. Under field conditions, we found an increase in total sperm motility and mitochondrial membrane potential on days 7 and 14 from the start of SWAc exposure whereas, in microcosm, SWAc group showed an increase of total motility on day 14. In addition, sperm morphology and intracellular pH were affected in both experimental approaches; whereas oxidative stress was detected only in spermatozoa collected from mussels under natural SWAc. The overall analysis suggests that, in mussels, SWAc toxic mechanism in spermatozoa does not involve oxidative stress. This study represents the first report on mussel sperm quality impairment after adult SWAc exposure, which may affect fertilization success with negative ecological and economic consequences; it also indicates that, although naturally acidified areas represent ideal natural laboratories for investigating the impact of ocean acidification, microcosm experiments are necessary for examining action mechanisms.
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Affiliation(s)
- Alessandra Gallo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Maria Consiglia Esposito
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Alessia Cuccaro
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Maria Cristina Buia
- Center of Villa Dohrn Ischia - Benthic Ecology, Department of Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, P.ta S. Pietro, Ischia, Naples, Italy
| | - Andrea Tarallo
- Department of Research Infrastructures for Marine Biological Resources, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Vincenzo Monfrecola
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Elisabetta Tosti
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Raffaele Boni
- Department of Sciences, University of Basilicata, 85100, Potenza, Italy.
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Gallo A, Boni R, Tosti E. Gamete quality in a multistressor environment. ENVIRONMENT INTERNATIONAL 2020; 138:105627. [PMID: 32151884 DOI: 10.1016/j.envint.2020.105627] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/28/2020] [Accepted: 02/29/2020] [Indexed: 05/25/2023]
Abstract
Over the past few decades, accumulated evidence confirms that the global environment conditions are changing rapidly. Urban industrialization, agriculture and globalization have generated water, air and soil pollution, giving rise to an environment with a growing number of stress factors, which has a serious impact on the fitness, reproduction and survival of living organisms. The issue raises considerable concern on biodiversity conservation, which is now at risk: it is estimated that a number of species will be extinct in the near future. Sexual reproduction is the process that allows the formation of a new individual and is underpinned by gamete quality defined as the ability of spermatozoa and oocytes to interact during fertilization leading to the creation and development of a normal embryo. This review aimed to provide the current state of knowledge regarding the impact of a broad spectrum of environmental stressors on diverse parameters used to estimate and evaluate gamete quality in humans and in canonical animal models used for experimental research. Effects of metals, biocides, herbicides, nanoparticles, plastics, temperature rise, ocean acidification, air pollution and lifestyle on the physiological parameters that underlie gamete fertilization competence are described supporting the concept that environmental stressors represent a serious hazard to gamete quality with reproductive disorders and living organism failure. Although clear evidence is still limited, gamete capacity to maintain and/or recover physiological conditions is recently demonstrated providing further clues about the plasticity of organisms and their tolerance to the pressures of pollution that may facilitate the reproduction and the persistence of species within the scenario of global change. Changes in the global environment must be urgently placed at the forefront of public attention, with a massive effort invested in further studies aimed towards implementing current knowledge and identifying new methodologies and markers to predict impairment of gamete quality.
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Affiliation(s)
- Alessandra Gallo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale 1, 80121 Napoli, Italy
| | - Raffaele Boni
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy
| | - Elisabetta Tosti
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale 1, 80121 Napoli, Italy.
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Chirgwin E, Marshall DJ, Monro K. Physical and physiological impacts of ocean warming alter phenotypic selection on sperm morphology. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13483] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Evatt Chirgwin
- Centre for Geometric Biology/School of Biological Sciences Monash University Melbourne Vic Australia
| | - Dustin J. Marshall
- Centre for Geometric Biology/School of Biological Sciences Monash University Melbourne Vic Australia
| | - Keyne Monro
- Centre for Geometric Biology/School of Biological Sciences Monash University Melbourne Vic Australia
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Lymbery RA, Kennington WJ, Cornwall CE, Evans JP. Ocean acidification during prefertilization chemical communication affects sperm success. Ecol Evol 2019; 9:12302-12310. [PMID: 31832161 PMCID: PMC6854328 DOI: 10.1002/ece3.5720] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 07/19/2019] [Accepted: 09/15/2019] [Indexed: 12/19/2022] Open
Abstract
Ocean acidification (OA) poses a major threat to marine organisms, particularly during reproduction when externally shed gametes are vulnerable to changes in seawater pH. Accordingly, several studies on OA have focused on how changes in seawater pH influence sperm behavior and/or rates of in vitro fertilization. By contrast, few studies have examined how pH influences prefertilization gamete interactions, which are crucial during natural spawning events in most externally fertilizing taxa. One mechanism of gamete interaction that forms an important component of fertilization in most taxa is communication between sperm and egg-derived chemicals. These chemical signals, along with the physiological responses in sperm they elicit, are likely to be highly sensitive to changes in seawater chemistry. In this study, we experimentally tested this possibility using the blue mussel, Mytilus galloprovincialis, a species in which females have been shown to use egg-derived chemicals to promote the success of sperm from genetically compatible males. We conducted trials in which sperm were allowed to swim in gradients of egg-derived chemicals under different seawater CO2 (and therefore pH) treatments. We found that sperm had elevated fertilization rates after swimming in the presence of egg-derived chemicals in low pH (pH 7.6) compared with ambient (pH 8.0) seawater. This observed effect could have important implications for the reproductive fitness of external fertilizers, where gamete compatibility plays a critical role in modulating reproduction in many species. For example, elevated sperm fertilization rates might disrupt the eggs' capacity to avoid fertilizations by genetically incompatible sperm. Our findings highlight the need to understand how OA affects the multiple stages of sperm-egg interactions and to develop approaches that disentangle the implications of OA for female, male, and population fitness.
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Affiliation(s)
- Rowan A. Lymbery
- Centre for Evolutionary BiologySchool of Biological SciencesUniversity of Western AustraliaCrawleyWAAustralia
| | - W. Jason Kennington
- Centre for Evolutionary BiologySchool of Biological SciencesUniversity of Western AustraliaCrawleyWAAustralia
| | | | - Jonathan P. Evans
- Centre for Evolutionary BiologySchool of Biological SciencesUniversity of Western AustraliaCrawleyWAAustralia
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Ding J, Zhang L, Sun J, Shi D, Chi X, Yang M, Chang Y, Zhao C. Transgenerational effects of UV-B radiation on egg size, fertilization, hatching and larval size of sea urchins Strongylocentrotus intermedius. PeerJ 2019; 7:e7598. [PMID: 31523520 PMCID: PMC6714959 DOI: 10.7717/peerj.7598] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 07/31/2019] [Indexed: 01/14/2023] Open
Abstract
Transgenerational effects are important for phenotypic plasticity and adaptation of marine invertebrates in the changing ocean. Ultraviolet-B (UV-B) radiation is an increasing threat to marine invertebrates. For the first time, we reported positive and negative transgenerational effects of UV-B radiation on egg size, fertilization, hatchability and larval size of a marine invertebrate. Strongylocentrotus intermedius exposed to UV-B radiation showed positive transgenerational effects and adaptation on egg size, hatching rate and post-oral arm length of larvae. Negative transgenerational effects were found in body length, stomach length and stomach width of larvae whose parents were exposed to UV-B radiation. Sires probably play important roles in transgenerational effects of UV-B. The present study provides valuable information into transgenerational effects of UV-B radiation on fitness related traits of sea urchins (at least Strongylocentrotus intermedius).
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Affiliation(s)
- Jingyun Ding
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian, China
| | - Lingling Zhang
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian, China
| | - Jiangnan Sun
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian, China
| | - Dongtao Shi
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian, China
| | - Xiaomei Chi
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian, China
| | - Mingfang Yang
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian, China
| | - Yaqing Chang
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian, China
| | - Chong Zhao
- Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture and Rural Affairs, Dalian Ocean University, Dalian, China
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Smith KE, Byrne M, Deaker D, Hird CM, Nielson C, Wilson-McNeal A, Lewis C. Sea urchin reproductive performance in a changing ocean: poor males improve while good males worsen in response to ocean acidification. Proc Biol Sci 2019; 286:20190785. [PMID: 31337311 PMCID: PMC6661356 DOI: 10.1098/rspb.2019.0785] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 06/28/2019] [Indexed: 12/12/2022] Open
Abstract
Ocean acidification (OA) is predicted to be a major driver of ocean biodiversity change. At projected rates of change, sensitive marine taxa may not have time to adapt. Their persistence may depend on pre-existing inter-individual variability. We investigated individual male reproductive performance under present-day and OA conditions using two representative broadcast spawners, the sea urchins Lytechinus pictus and Heliocidaris erythrogramma. Under the non-competitive individual ejaculate scenario, we examined sperm functional parameters (e.g. swimming speed, motility) and their relationship with fertilization success under current and near-future OA conditions. Significant inter-individual differences in almost every parameter measured were identified. Importantly, we observed strong inverse relationships between individual fertilization success rate under current conditions and change in fertilization success under OA. Individuals with a high fertilization success under current conditions had reduced fertilization under OA, while individuals with a low fertilization success under current conditions improved. Change in fertilization success ranged from -67% to +114% across individuals. Our results demonstrate that while average population fertilization rates remain similar under OA and present-day conditions, the contribution by different males to the population significantly shifts, with implications for how selection will operate in a future ocean.
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Affiliation(s)
- Kathryn E. Smith
- College of Live and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Maria Byrne
- Schools of Medical and Biological Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Dione Deaker
- Schools of Medical and Biological Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Cameron M. Hird
- College of Live and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Clara Nielson
- College of Live and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Alice Wilson-McNeal
- College of Live and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Ceri Lewis
- College of Live and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
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