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Cunningham EM, Cuthbert RN, Coughlan NE, Kregting L, Cairnduff V, Dick JTA. Microplastics do not affect the feeding rates of a marine predator. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 779:146487. [PMID: 34030230 DOI: 10.1016/j.scitotenv.2021.146487] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/24/2021] [Accepted: 03/11/2021] [Indexed: 05/12/2023]
Abstract
Microplastics may affect the physiology, behaviour and populations of aquatic and terrestrial fauna through many mechanisms, such as direct consumption and sensory disruption. However, the majority of experimental studies have employed questionably high dosages of microplastics that have little environmental relevance. Predation, in particular, is a key trophic interaction that structures populations and communities and influences ecosystem functioning, but rarely features in microplastic research. Here, we quantify the effects of low (~65-114 MP/L) and high (~650-1140 MP/L) microplastic concentrations on the feeding behaviour of a ubiquitous and globally representative key marine predator, the shore crab, Carcinus maenas. We used a functional response approach (predator consumption across prey densities) to determine crab consumption rates towards a key marine community prey species, the blue mussel Mytilus edulis, under low and high microplastic concentrations with acute (8h) and chronic (120h) microplastic exposure times. For both the acute and chronic microplastic exposure experiments, proportional prey consumption by crabs did not differ with respect to microplastic concentration, but significantly decreased over increasing prey densities. The crabs thus displayed classical, hyperbolic Type II functional responses in all experimental groups, characterised by high consumption rates at low prey densities. Crab attack rates, handling times and maximum feeding rates (i.e. functional response curves) were not significantly altered under lower or higher microplastics concentrations, or by acute or chronic microplastic exposures. Here, we show that functional response analyses could be widely employed to ascertain microplastic impacts on consumer-resource interactions. Furthermore, we suggest that future studies should adopt both acute and chronic microplastic exposure regimes, using environmentally-relevant microplastic dosages and types as well as elevated future scenarios of microplastic concentrations.
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Affiliation(s)
- Eoghan M Cunningham
- Queen's University Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry BT22 1PF, UK.
| | - Ross N Cuthbert
- GEOMAR, Helmholtz-Zentrum für Ozeanforschung Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany; Queen's University Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry BT22 1PF, UK
| | - Neil E Coughlan
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork, Ireland; Queen's University Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry BT22 1PF, UK
| | - Louise Kregting
- School of Natural and Built Environment, Queen's University Belfast, Belfast BT9 5BN, UK; Queen's University Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry BT22 1PF, UK
| | - Victoria Cairnduff
- Queen's University Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry BT22 1PF, UK
| | - Jaimie T A Dick
- Queen's University Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry BT22 1PF, UK; Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, BT9 5DL, UK
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Harvey BP, Kon K, Agostini S, Wada S, Hall-Spencer JM. Ocean acidification locks algal communities in a species-poor early successional stage. GLOBAL CHANGE BIOLOGY 2021; 27:2174-2187. [PMID: 33423359 DOI: 10.1111/gcb.15455] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 11/13/2020] [Indexed: 06/12/2023]
Abstract
Long-term exposure to CO2 -enriched waters can considerably alter marine biological community development, often resulting in simplified systems dominated by turf algae that possess reduced biodiversity and low ecological complexity. Current understanding of the underlying processes by which ocean acidification alters biological community development and stability remains limited, making the management of such shifts problematic. Here, we deployed recruitment tiles in reference (pHT 8.137 ± 0.056 SD) and CO2 -enriched conditions (pHT 7.788 ± 0.105 SD) at a volcanic CO2 seep in Japan to assess the underlying processes and patterns of algal community development. We assessed (i) algal community succession in two different seasons (Cooler months: January-July, and warmer months: July-January), (ii) the effects of initial community composition on subsequent community succession (by reciprocally transplanting preestablished communities for a further 6 months), and (iii) the community production of resulting communities, to assess how their functioning was altered (following 12 months recruitment). Settlement tiles became dominated by turf algae under CO2 -enrichment and had lower biomass, diversity and complexity, a pattern consistent across seasons. This locked the community in a species-poor early successional stage. In terms of community functioning, the elevated pCO2 community had greater net community production, but this did not result in increased algal community cover, biomass, biodiversity or structural complexity. Taken together, this shows that both new and established communities become simplified by rising CO2 levels. Our transplant of preestablished communities from enriched CO2 to reference conditions demonstrated their high resilience, since they became indistinguishable from communities maintained entirely in reference conditions. This shows that meaningful reductions in pCO2 can enable the recovery of algal communities. By understanding the ecological processes responsible for driving shifts in community composition, we can better assess how communities are likely to be altered by ocean acidification.
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Affiliation(s)
- Ben P Harvey
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Koetsu Kon
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Sylvain Agostini
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Shigeki Wada
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Jason M Hall-Spencer
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
- Marine Biology and Ecology Research Centre, University of Plymouth, Plymouth, UK
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Brown NEM, Bernhardt JR, Harley CDG. Energetic context determines species and community responses to ocean acidification. Ecology 2020; 101:e03073. [DOI: 10.1002/ecy.3073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 03/02/2020] [Accepted: 03/16/2020] [Indexed: 11/10/2022]
Affiliation(s)
- Norah E. M. Brown
- Department of Zoology University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
| | - Joey R. Bernhardt
- Department of Zoology University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
| | - Christopher D. G. Harley
- Department of Zoology University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
- Institute for the Oceans and Fisheries University of British Columbia Vancouver V6T 1Z4 British Columbia Canada
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Lim EG, Harley CDG. Caprellid amphipods ( Caprella spp.) are vulnerable to both physiological and habitat-mediated effects of ocean acidification. PeerJ 2018; 6:e5327. [PMID: 30083460 PMCID: PMC6074802 DOI: 10.7717/peerj.5327] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/05/2018] [Indexed: 11/30/2022] Open
Abstract
Ocean acidification (OA) is one of the most significant threats to marine life, and is predicted to drive important changes in marine communities. Although OA impacts will be the sum of direct effects mediated by alterations of physiological rates and indirect effects mediated by shifts in species interactions and biogenic habitat provision, direct and indirect effects are rarely considered together for any given species. Here, we assess the potential direct and indirect effects of OA on a ubiquitous group of crustaceans: caprellid amphipods (Caprella laeviuscula and Caprella mutica). Direct physiological effects were assessed by measuring caprellid heart rate in response to acidification in the laboratory. Indirect effects were explored by quantifying caprellid habitat dependence on the hydroid Obelia dichotoma, which has been shown to be less abundant under experimental acidification. We found that OA resulted in elevated caprellid heart rates, suggestive of increased metabolic demand. We also found a strong, positive association between caprellid population size and the availability of OA-vulnerable O. dichotoma, suggesting that future losses of biogenic habitat may be an important indirect effect of OA on caprellids. For species such as caprellid amphipods, which have strong associations with biogenic habitat, a consideration of only direct or indirect effects could potentially misestimate the full impact of ocean acidification.
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Affiliation(s)
- Emily G Lim
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Christopher D G Harley
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.,Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada
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Bracken MES, Silbiger NJ, Bernatchez G, Sorte CJB. Primary producers may ameliorate impacts of daytime CO 2 addition in a coastal marine ecosystem. PeerJ 2018; 6:e4739. [PMID: 29761055 PMCID: PMC5949060 DOI: 10.7717/peerj.4739] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 04/19/2018] [Indexed: 11/20/2022] Open
Abstract
Predicting the impacts of ocean acidification in coastal habitats is complicated by bio-physical feedbacks between organisms and carbonate chemistry. Daily changes in pH and other carbonate parameters in coastal ecosystems, associated with processes such as photosynthesis and respiration, often greatly exceed global mean predicted changes over the next century. We assessed the strength of these feedbacks under projected elevated CO2 levels by conducting a field experiment in 10 macrophyte-dominated tide pools on the coast of California, USA. We evaluated changes in carbonate parameters over time and found that under ambient conditions, daytime changes in pH, pCO2, net ecosystem calcification (NEC), and O2 concentrations were strongly related to rates of net community production (NCP). CO2 was added to pools during daytime low tides, which should have reduced pH and enhanced pCO2. However, photosynthesis rapidly reduced pCO2 and increased pH, so effects of CO2 addition were not apparent unless we accounted for seaweed and surfgrass abundances. In the absence of macrophytes, CO2 addition caused pH to decline by ∼0.6 units and pCO2 to increase by ∼487 µatm over 6 hr during the daytime low tide. As macrophyte abundances increased, the impacts of CO2 addition declined because more CO2 was absorbed due to photosynthesis. Effects of CO2addition were, therefore, modified by feedbacks between NCP, pH, pCO2, and NEC. Our results underscore the potential importance of coastal macrophytes in ameliorating impacts of ocean acidification.
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Affiliation(s)
- Matthew E S Bracken
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA, United States of America
| | - Nyssa J Silbiger
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA, United States of America.,Department of Biology, California State University, Northridge, Northridge, CA, United States of America
| | - Genevieve Bernatchez
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA, United States of America
| | - Cascade J B Sorte
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA, United States of America
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Brown NEM, Milazzo M, Rastrick SPS, Hall-Spencer JM, Therriault TW, Harley CDG. Natural acidification changes the timing and rate of succession, alters community structure, and increases homogeneity in marine biofouling communities. GLOBAL CHANGE BIOLOGY 2018; 24:e112-e127. [PMID: 28762601 DOI: 10.1111/gcb.13856] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 07/14/2017] [Indexed: 06/07/2023]
Abstract
Ocean acidification may have far-reaching consequences for marine community and ecosystem dynamics, but its full impacts remain poorly understood due to the difficulty of manipulating pCO2 at the ecosystem level to mimic realistic fluctuations that occur on a number of different timescales. It is especially unclear how quickly communities at various stages of development respond to intermediate-scale pCO2 change and, if high pCO2 is relieved mid-succession, whether past acidification effects persist, are reversed by alleviation of pCO2 stress, or are worsened by departures from prior high pCO2 conditions to which organisms had acclimatized. Here, we used reciprocal transplant experiments along a shallow water volcanic pCO2 gradient to assess the importance of the timing and duration of high pCO2 exposure (i.e., discrete events at different stages of successional development vs. continuous exposure) on patterns of colonization and succession in a benthic fouling community. We show that succession at the acidified site was initially delayed (less community change by 8 weeks) but then caught up over the next 4 weeks. These changes in succession led to homogenization of communities maintained in or transplanted to acidified conditions, and altered community structure in ways that reflected both short- and longer-term acidification history. These community shifts are likely a result of interspecific variability in response to increased pCO2 and changes in species interactions. High pCO2 altered biofilm development, allowing serpulids to do best at the acidified site by the end of the experiment, although early (pretransplant) negative effects of pCO2 on recruitment of these worms were still detectable. The ascidians Diplosoma sp. and Botryllus sp. settled later and were more tolerant to acidification. Overall, transient and persistent acidification-driven changes in the biofouling community, via both past and more recent exposure, could have important implications for ecosystem function and food web dynamics.
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Affiliation(s)
- Norah E M Brown
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Marco Milazzo
- DiSTeM, CoNISMa, University of Palermo, Palermo, Italy
| | - Samuel P S Rastrick
- Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, UK
- Institute of Marine Research, Bergen, Norway
| | - Jason M Hall-Spencer
- Marine Biology and Ecology Research Centre, University of Plymouth, Plymouth, UK
- Shimoda Marine Research Centre, Tsukuba University, Tsukuba, Japan
| | | | - Christopher D G Harley
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
- Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, BC, Canada
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