Ocean acidification alters fish–jellyfish symbiosis

Symbiotic relationships are common in nature, and are important for individual fitness and sustaining species populations. Global change is rapidly altering environmental conditions, but, with the exception of coral–microalgae interactions, we know little of how this will affect symbiotic relationships. We here test how the effects of ocean acidification, from rising anthropogenic CO 2 emissions, may alter symbiotic interactions between juvenile fish and their jellyfish hosts. Fishes treated with elevated seawater CO 2 concentrations, as forecast for the end of the century on a business-as-usual greenhouse gas emission scenario, were negatively affected in their behaviour. The total time that fish (yellowtail scad) spent close to their jellyfish host in a choice arena where they could see and smell their host was approximately three times shorter under future compared with ambient CO 2 conditions. Likewise, the mean number of attempts to associate with jellyfish was almost three times lower in CO 2 -treated compared with control fish, while only 63% (high CO 2 ) versus 86% (control) of all individuals tested initiated an association at all. By contrast, none of three fish species tested were attracted solely to jellyfish olfactory cues under present-day CO 2 conditions, suggesting that the altered fish–jellyfish association is not driven by negative effects of ocean acidification on olfaction. Because shelter is not widely available in the open water column and larvae of many (and often commercially important) pelagic species associate with jellyfish for protection against predators, modification of the fish–jellyfish symbiosis might lead to higher mortality and alter species population dynamics, and potentially have flow-on effects for their fisheries.

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Ocean acidification boosts reproduction in fish via indirect effects

PLoS Biology ◽

10.1371/journal.pbio.3001033 ◽

2021 ◽

Vol 19 (1) ◽

pp. e3001033

Author(s):

Ivan Nagelkerken ◽

Tiphaine Alemany ◽

Julie M. Anquetin ◽

Camilo M. Ferreira ◽

Kim E. Ludwig ◽

...

Keyword(s):

Ocean Acidification ◽

Indirect Effects ◽

Energy Levels ◽

Reproductive Investment ◽

Energy Budgets ◽

Rocky Reef ◽

Negative Effects ◽

Species Population ◽

In The Wild ◽

Physiological Homeostasis

Ocean acidification affects species populations and biodiversity through direct negative effects on physiology and behaviour. The indirect effects of elevated CO2 are less well known and can sometimes be counterintuitive. Reproduction lies at the crux of species population replenishment, but we do not know how ocean acidification affects reproduction in the wild. Here, we use natural CO2 vents at a temperate rocky reef and show that even though ocean acidification acts as a direct stressor, it can indirectly increase energy budgets of fish to stimulate reproduction at no cost to physiological homeostasis. Female fish maintained energy levels by compensation: They reduced activity (foraging and aggression) to increase reproduction. In male fish, increased reproductive investment was linked to increased energy intake as mediated by intensified foraging on more abundant prey. Greater biomass of prey at the vents was linked to greater biomass of algae, as mediated by a fertilisation effect of elevated CO2 on primary production. Additionally, the abundance and aggression of paternal carers were elevated at the CO2 vents, which may further boost reproductive success. These positive indirect effects of elevated CO2 were only observed for the species of fish that was generalistic and competitively dominant, but not for 3 species of subordinate and more specialised fishes. Hence, species that capitalise on future resource enrichment can accelerate their reproduction and increase their populations, thereby altering species communities in a future ocean.

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Negative effects of ocean acidification on two crustose coralline species using genetically homogeneous samples

Marine Environmental Research ◽

10.1016/j.marenvres.2013.10.010 ◽

2014 ◽

Vol 94 ◽

pp. 1-6 ◽

Cited By ~ 13

Author(s):

Aki Kato ◽

Mana Hikami ◽

Naoki H. Kumagai ◽

Atsushi Suzuki ◽

Yukihiro Nojiri ◽

...

Keyword(s):

Ocean Acidification ◽

Negative Effects

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Prediction of greenhouse gas emission from municipal solid waste for South Korea

Environmental Engineering Research ◽

10.4491/eer.2019.019 ◽

2019 ◽

Vol 25 (4) ◽

pp. 462-469

Author(s):

Kanchan Popli ◽

Jeejae Lim ◽

Hyeon Kyeong Kim ◽

Young Min Kim ◽

Nguyen Thanh Tuu ◽

...

Keyword(s):

South Korea ◽

Municipal Solid Waste ◽

Greenhouse Gas ◽

Solid Waste ◽

Total Population ◽

Greenhouse Gas Emission ◽

Ghg Emission ◽

Dynamics Model ◽

The Government ◽

Business As Usual

This study is proposing a System Dynamics Model for estimating Greenhouse Gas (GHG) emission from treating Municipal Solid Waste (MSW) in South Korea for years 2000 to 2030. The government of country decided to decrease the total GHG emission from waste sector in 2030 as per Business-as-usual level. In context, four scenarios are generated to predict GHG emission from treating the MSW with three processes i.e., landfill, incineration and recycling. For prior step, MSW generation rate is projected for present and future case using population and waste generation per capita data. It is found that population and total MSW are directly correlated. The total population will increase to 56.27 million and total MSW will be 21.59 million tons in 2030. The methods for estimating GHG emission from landfill, incineration and recycling are adopted from IPCC, 2006 guidelines. The study indicates that Scenario 2 is best to adopt for decreasing the total GHG emission in future where recycling waste is increased to 75% and landfill waste is decreased to 7.6%. Lastly, it is concluded that choosing proper method for treating the MSW in country can result into savings of GHG emission.

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Shell mineralogy of a foundational marine species, Mytilus californianus, over half a century in a changing ocean

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2004769118 ◽

2021 ◽

Vol 118 (3) ◽

pp. e2004769118

Author(s):

Elizabeth M. Bullard ◽

Ivan Torres ◽

Tianqi Ren ◽

Olivia A. Graeve ◽

Kaustuv Roy

Keyword(s):

Ocean Acidification ◽

Historical Data ◽

Mineralogical Composition ◽

Marine Species ◽

Mytilus Californianus ◽

Negative Effects ◽

Saturation State ◽

Long Term Changes ◽

Time Periods

Anthropogenic warming and ocean acidification are predicted to negatively affect marine calcifiers. While negative effects of these stressors on physiology and shell calcification have been documented in many species, their effects on shell mineralogical composition remains poorly known, especially over longer time periods. Here, we quantify changes in the shell mineralogy of a foundation species, Mytilus californianus, under 60 y of ocean warming and acidification. Using historical data as a baseline and a resampling of present-day populations, we document a substantial increase in shell calcite and decrease in aragonite. These results indicate that ocean pH and saturation state, not temperature or salinity, play a strong role in mediating the shell mineralogy of this species and reveal long-term changes in this trait under ocean acidification.

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Nitrogen enrichment offsets direct negative effects of ocean acidification on a reef-building crustose coralline alga

Biology Letters ◽

10.1098/rsbl.2018.0371 ◽

2018 ◽

Vol 14 (7) ◽

pp. 20180371 ◽

Cited By ~ 6

Author(s):

Maggie D. Johnson ◽

Robert C. Carpenter

Keyword(s):

Ocean Acidification ◽

Nutrient Enrichment ◽

Multiple Stressors ◽

Crustose Coralline Alga ◽

Nitrogen Enrichment ◽

Coralline Alga ◽

Ambient Conditions ◽

Negative Effects ◽

Near Shore ◽

Near Future

Ocean acidification (OA) and nutrient enrichment threaten the persistence of near shore ecosystems, yet little is known about their combined effects on marine organisms. Here, we show that a threefold increase in nitrogen concentrations, simulating enrichment due to coastal eutrophication or consumer excretions, offset the direct negative effects of near-future OA on calcification and photophysiology of the reef-building crustose coralline alga, Porolithon onkodes . Projected near-future pCO 2 levels (approx. 850 µatm) decreased calcification by 30% relative to ambient conditions. Conversely, nitrogen enrichment (nitrate + nitrite and ammonium) increased calcification by 90–130% in ambient and high pCO 2 treatments, respectively. pCO 2 and nitrogen enrichment interactively affected instantaneous photophysiology, with highest relative electron transport rates under high pCO 2 and high nitrogen. Nitrogen enrichment alone increased concentrations of the photosynthetic pigments chlorophyll a , phycocyanin and phycoerythrin by approximately 80–450%, regardless of pCO 2 . These results demonstrate that nutrient enrichment can mediate direct organismal responses to OA. In natural systems, however, such direct benefits may be counteracted by simultaneous increases in negative indirect effects, such as heightened competition. Experiments exploring the effects of multiple stressors are increasingly becoming important for improving our ability to understand the ramifications of local and global change stressors in near shore ecosystems.

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Microplastic exposure interacts with habitat degradation to affect behaviour and survival of juvenile fish in the field

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2020.1947 ◽

2020 ◽

Vol 287 (1937) ◽

pp. 20201947 ◽

Cited By ~ 1

Author(s):

Mark I. McCormick ◽

Douglas P. Chivers ◽

Maud C. O. Ferrari ◽

Makeely I. Blandford ◽

Gerrit B. Nanninga ◽

...

Keyword(s):

Coral Reef ◽

Management Strategy ◽

Habitat Degradation ◽

Synergistic Effects ◽

Juvenile Fish ◽

Control Fish ◽

Dead Coral ◽

Reef Restoration ◽

Low Concentrations ◽

Restoration Strategies

Coral reefs are degrading globally due to increased environmental stressors including warming and elevated levels of pollutants. These stressors affect not only habitat-forming organisms, such as corals, but they may also directly affect the organisms that inhabit these ecosystems. Here, we explore how the dual threat of habitat degradation and microplastic exposure may affect the behaviour and survival of coral reef fish in the field. Fish were caught prior to settlement and pulse-fed polystyrene microplastics six times over 4 days, then placed in the field on live or dead-degraded coral patches. Exposure to microplastics or dead coral led fish to be bolder, more active and stray further from shelter compared to control fish. Effect sizes indicated that plastic exposure had a greater effect on behaviour than degraded habitat, and we found no evidence of synergistic effects. This pattern was also displayed in their survival in the field. Our results highlight that attaining low concentrations of microplastic in the environment will be a useful management strategy, since minimizing microplastic intake by fishes may work concurrently with reef restoration strategies to enhance the resilience of coral reef populations.

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Reviews and Syntheses: Responses of coccolithophores to ocean acidification: a meta-analysis

Biogeosciences ◽

10.5194/bg-12-1671-2015 ◽

2015 ◽

Vol 12 (6) ◽

pp. 1671-1682 ◽

Cited By ~ 80

Author(s):

J. Meyer ◽

U. Riebesell

Keyword(s):

Ocean Acidification ◽

Dissolved Inorganic Carbon ◽

Meta Analysis ◽

Physiological Responses ◽

Total Alkalinity ◽

Adaptive Responses ◽

Negative Effects ◽

Ecological Fitness ◽

Negative Effect ◽

Gephyrocapsa Oceanica

Abstract. Concerning their sensitivity to ocean acidification, coccolithophores, a group of calcifying single-celled phytoplankton, are one of the best-studied groups of marine organisms. However, in spite of the large number of studies investigating coccolithophore physiological responses to ocean acidification, uncertainties still remain due to variable and partly contradictory results. In the present study we have used all existing data in a meta-analysis to estimate the effect size of future pCO2 changes on the rates of calcification and photosynthesis and the ratio of particulate inorganic to organic carbon (PIC / POC) in different coccolithophore species. Our results indicate that ocean acidification has a negative effect on calcification and the cellular PIC / POC ratio in the two most abundant coccolithophore species: Emiliania huxleyi and Gephyrocapsa oceanica. In contrast, the more heavily calcified species Coccolithus braarudii did not show a distinct response when exposed to elevated pCO2/reduced pH. Photosynthesis in Gephyrocapsa oceanica was positively affected by high CO2, while no effect was observed for the other coccolithophore species. There was no indication that the method of carbonate chemistry manipulation was responsible for the inconsistent results regarding observed responses in calcification and the PIC / POC ratio. The perturbation method, however, appears to affect photosynthesis, as responses varied significantly between total alkalinity (TA) and dissolved inorganic carbon (DIC) manipulations. These results emphasize that coccolithophore species respond differently to ocean acidification, both in terms of calcification and photosynthesis. Where negative effects occur, they become evident at CO2 levels in the range projected for this century in the case of unabated CO2 emissions. As the data sets used in this meta-analysis do not account for adaptive responses, ecological fitness and ecosystem interactions, the question remains as to how these physiological responses play out in the natural environment.

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Ocean acidification causes structural deformities in juvenile coral skeletons

Science Advances ◽

10.1126/sciadv.1501130 ◽

2016 ◽

Vol 2 (2) ◽

pp. e1501130 ◽

Cited By ~ 28

Author(s):

Taryn Foster ◽

James L. Falter ◽

Malcolm T. McCulloch ◽

Peta L. Clode

Keyword(s):

Ocean Acidification ◽

Structural Changes ◽

Three Dimensional ◽

Significant Risk ◽

Skeletal Structure ◽

Juvenile Coral ◽

Mineral Deposition ◽

Coral Reef Ecosystems ◽

New Recruits ◽

Business As Usual

Rising atmospheric CO2is causing the oceans to both warm and acidify, which could reduce the calcification rates of corals globally. Successful coral recruitment and high rates of juvenile calcification are critical to the replenishment and ultimate viability of coral reef ecosystems. Although elevatedPco2(partial pressure of CO2) has been shown to reduce the skeletal weight of coral recruits, the structural changes caused by acidification during initial skeletal deposition are unknown. We show, using high-resolution three-dimensional x-ray microscopy, that ocean acidification (Pco2~900 μatm, pH ~7.7) not only causes reduced overall mineral deposition but also a deformed and porous skeletal structure in newly settled coral recruits. In contrast, elevated temperature (+3°C) had little effect on skeletal formation except to partially mitigate the effects of elevatedPco2. The striking structural deformities we observed show that new recruits are at significant risk, being unable to effectively build their skeletons in thePco2conditions predicted to occur for open ocean surface waters under a “business-as-usual” emissions scenario [RCP (representative concentration pathway) 8.5] by the year 2100.

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