Posts Tagged 'multiple factors'

Ocean warming has a greater effect than acidification on the early life history development and swimming performance of a large circumglobal pelagic fish

Ocean warming and acidification are serious threats to marine life; however, their individual and combined effects on large pelagic and predatory fishes are poorly understood. We determined the effects of projected future temperature and carbon dioxide (CO2) levels on survival, growth, morphological development and swimming performance on the early life stages of a large circumglobal pelagic fish, the yellowtail kingfish Seriola lalandi. Eggs, larvae and juveniles were reared in cross‐factored treatments of temperature (21 and 25°C) and pCO2 (500 and 985 μatm) from fertilisation to 25 days post hatching (dph). Temperature had the greatest effect on survival, growth and development. Survivorship was lower, but growth and morphological development were faster at 25°C, with surviving fish larger and more developed at 1, 11 and 21 dph. Elevated pCO2 affected size at 1 dph, but not at 11 or 21 dph, and did not affect survival or morphological development. Elevated temperature and pCO2 had opposing effects on swimming performance at 21 dph. Critical swimming speed (Ucrit) was increased by elevated temperature but reduced by elevated pCO2. Additionally, elevated temperature increased the proportion of individuals that responded to a startle stimulus, reduced latency to respond and increased maximum escape speed, potentially due to the more advanced developmental stage of juveniles at 25°C. By contrast, elevated pCO2 reduced the distance moved and average speed in response to a startle stimulus. Our results show that higher temperature is likely to be the primary driver of global change impacts on kingfish early life history; however, elevated pCO2 could affect critical aspects of swimming performance in this pelagic species. Our findings will help parameterise and structure fisheries population dynamics models and improve projections of impacts to large pelagic fishes under climate change scenarios to better inform adaptation and mitigation responses

Continue reading ‘Ocean warming has a greater effect than acidification on the early life history development and swimming performance of a large circumglobal pelagic fish’

The interactive effects of ocean acidification, food availability, and source location on the growth and physiology of the California mussel

Research shows ocean acidification (OA) can have largely negative impacts on marine organisms and ecosystems. Prior laboratory studies show that shelled marine invertebrates (e.g., molluscs) exhibit reduced growth rates and weaker shells when experiencing OA-related stress. However, populations of the critical intertidal mussel species, Mytilus californianus, which experience naturally acidic water due to upwelling in certain parts of Northern California have been observed to have relatively stronger and thicker shells and higher growth rates than those that experience less frequent exposure to upwelling. To address the discrepancies between negative effects of OA exposure in the laboratory and seemingly positive effects off OA exposure in the field we collected juvenile mussels from four separate locations on the northern California coast that vary in exposure to upwelling-driven OA and raised them under ambient, constantly acidified, or intermittently acidified seawater conditions. Half of the mussels in each of the experimental treatments were given access to either ambient or elevated food concentrations. Although higher food availability increased shell and overall mussel growth, variation in mussel life-history traits among locations appears to be driven primarily by inherent differences (i.e. genetics or epigenetics). In particular, overall growth, soft tissue mass, and shell dissolution in mussels were associated with source-specific upwelling strength while adductor muscle mass along with shell growth and strength of mussels were associated with source-specific levels of predation risk. Oxygen consumption of mussels did not significantly vary among food, pH or source location treatments, suggesting that differences in growth rates were not due to differences in differences in metabolic or energetic efficiencies between individuals. Although not statistically significant, mussels from areas of high crab predation risk tended to survive crab attacks in the lab better than mussels from other areas. My data suggests that the adaptive potential of M. californianus to respond to future OA conditions is dependent on local environmental factors such as upwelling strength, food availability, and predation risk. My study addresses a significant gap in our understanding of the mechanism behind conflicting observations of increased growth in the field associated with low pH and previous laboratory results, demonstrating the importance of environmental context in shaping the organismal response to current and future OA conditions.

Continue reading ‘The interactive effects of ocean acidification, food availability, and source location on the growth and physiology of the California mussel’

Boosted nutritional quality of food by CO2 enrichment fails to offset energy demand of herbivores under ocean warming, causing energy depletion and mortality

Highlights

• We tested if energy transfer via feeding is boosted under future seawater conditions.
• Energy budget of herbivores and nutritional quality of their food were determined.
• Energy budget raised by feeding on the more nutritious food under ocean acidification.
• When combined with warming, however, mass mortality occurred due to energy depletion.
• Enhanced food quality inadequately offsets the energy demand under ocean warming.

Abstract

The CO2-boosted trophic transfer from primary producers to herbivores has been increasingly discovered at natural CO2 vents and in laboratory experiments. Despite the emerging knowledge of this boosting effect, we do not know the extent to which it may be enhanced or dampened by ocean warming. We investigated whether ocean acidification and warming enhance the nutritional quality (C:N ratio) and energy content of turf algae, which is speculated to drive higher feeding rate, greater energy budget and eventually faster growth of herbivores. This proposal was tested by observing the physiological (feeding rate, respiration rate and energy budget) and demographic responses (growth and survival) of a common grazing gastropod (Phasianella australis) to ocean acidification and warming in a 6-month mesocosm experiment. Whilst we observed the boosting effect of ocean acidification and warming in isolation on the energy budget of herbivores by either increasing feeding rate on the more nutritious algae or increasing energy gain per feeding effort, their growth and survival were reduced by the sublethal thermal stress under ocean warming, especially when both climate change stressors were combined. This reduced growth and survival occurred as a consequence of depleted energy reserves, suggesting that the boosting effect via trophic transfer might not sufficiently compensate for the increased energy demand imposed by ocean warming. In circumstances where ocean acidification and warming create an energy demand on herbivores that outweighs the energy enhancement of their food (i.e. primary producers), the performance of herbivores to control their blooming resources likely deteriorates and thus runaway primary production ensues.

Continue reading ‘Boosted nutritional quality of food by CO2 enrichment fails to offset energy demand of herbivores under ocean warming, causing energy depletion and mortality’

Combined effects of ocean acidification and temperature on planula larvae of the moon jellyfish Aurelia coerulea

Highlights

• We addressed the impact of ocean acidification and seawater temperature increases on scyphozoan planulae.
A. coerulea planulae can cope well with decreased pH conditions through rapid settlement.
• Elevated seawater temperature appears to be a crucial stress factor for A. coerulea planulae.

Abstract

Rapidly rising levels of atmospheric CO2 have caused two environmental stressors, ocean acidification and seawater temperature increases, which represent major abiotic threats to marine organisms. Here, we investigated for the first time the combined effects of ocean acidification and seawater temperature increases on the behavior, survival, and settlement of the planula larvae of Aurelia coerulea, which is considered a nuisance species around the world. Three pH levels (8.1, 7.7 and 7.3) and two temperature levels (24 °C and 27 °C) were used in the present study. There were no interactive effects of temperature and pH on the behavior, survival, and settlement of planula larvae of A. coerulea. We found that the swimming speed and mortality of the planula larvae of A. coerulea were significantly affected by temperature, and low pH significantly affected settlement. Planula larvae of A. coerulea from the elevated temperature treatment moved faster and showed higher mortality than those at the control temperature. The settlement rate of A. coerulea planulae was significantly higher at the pH level of 7.3 than at other pH levels. These results suggest that seawater temperature increase, rather than reduced pH, was the main stress factor affecting the survival of A. coerulea planulae. Overall, the planula larvae of the common jellyfish A. coerulea appeared to be resistant to ocean acidification, but may be negatively affected by future seawater temperature increases.

Continue reading ‘Combined effects of ocean acidification and temperature on planula larvae of the moon jellyfish Aurelia coerulea’

Ocean warming has greater and more consistent negative effects than ocean acidification on the growth and health of subtropical macroalgae

Macroalgae are the major habitat-forming organisms in many coastal temperate and subtropical marine systems. Although climate change has been identified as a major threat to the persistence of macroalgal beds, the combined effects of ocean warming and ocean acidification on algal performance are poorly understood. Here we investigate the effects of increased temperature and acidification on the growth, calcification and nutritional content of 6 common subtropical macroalgae; Sargassum linearifolium, Ulva sp., Amphiroa anceps, Corallina officinalis, Delisea pulchra and Laurencia decussata. Algae were reared in a factorial cross of 3 temperatures (23°C [ambient], 26°C and 28°C) and 3 pH levels (8.1 [ambient], 7.8 and 7.6) for 2 wk. The highest (28°C) temperature decreased the growth of all 6 macroalgal species, irrespective of the pH levels. In contrast, the effect of decreased pH on growth was variable. The growth of Ulva sp. and C. officinalis increased, L. decussata decreased, while the remaining 3 species were unaffected. Interestingly, the differential responses of macroalgae to ocean acidification were unrelated to whether or not a species was a calcifying alga, or their carbon-uptake mechanism—2 processes that are predicted to be sensitive to decreased pH. The growth of the calcifying algae (C. officinalis and A. anceps) was not affected by reduced pH but calcification of these 2 algae was reduced when exposed to a combination of reduced pH and elevated temperature. The 3 species capable of uptake of bicarbonate, S. linearifolium, L. decussata and Ulva sp., displayed positive, negative and neutral changes in growth, respectively, in response to reduced pH. The C:N ratio for 5 of the 6 species was unaffected by either pH or temperature. The consistent and predictable negative effects of temperature on the growth and calcification of subtropical macroalgae suggests that this stressor poses a greater threat to the persistence of subtropical macroalgal populations than ocean acidification under ongoing and future climate change.

Continue reading ‘Ocean warming has greater and more consistent negative effects than ocean acidification on the growth and health of subtropical macroalgae’

Combined effects of ocean acidification and warming on physiological response of the diatom Thalassiosira pseudonana to light challenges

Highlights

• Photoinactivation was induced by multiple environmental changes.
• Higher pCO2 alleviates the negative effect of temperature rise on PSII.
• Ocean acidification stimulates much faster PsbA removal.
• NPQ and SOD induction showed different response to temperature.

Abstract

Diatoms are one of the most important groups of phytoplankton in terms of abundance and ecological functionality in the ocean. They usually dominate the phytoplankton communities in coastal waters and experience frequent and large fluctuations in light. In order to evaluate the combined effects of ocean warming and acidification on the diatom’s exploitation of variable light environments, we grew a globally abundant diatom Thalassiosira pseudonana under two levels of temperature (18, 24 °C) and pCO2 (400, 1000 μatm) to examine its physiological performance after light challenge. It showed that the higher temperature increased the photoinactivation rate in T. pseudonana at 400 μatm pCO2, while the higher pCO2 alleviated the negative effect of the higher temperature on PSII photoinactivation. Higher pCO2 stimulated much faster PsbA removal, but it still lagged behind the photoinactivation of PSII under high light. Although the sustained phase of nonphotochemical quenching (NPQs) and activity of superoxide dismutase (SOD) were provoked during the high light exposure in T. pseudonana under the combined pCO2 and temperature conditions, it could not offset the damage caused by these multiple environmental changes, leading to decreased maximum photochemical yield.

Continue reading ‘Combined effects of ocean acidification and warming on physiological response of the diatom Thalassiosira pseudonana to light challenges’

Effects of water warming and acidification on bioconcentration, metabolization and depuration of pharmaceuticals and endocrine disrupting compounds in marine mussels (Mytilus galloprovincialis)

Highlights

• Citalopram showed the highest bioconcentration in mussels, methylparaben the lowest.
• Response to warming and acidification differed depending on the compound.
• Acidification decreased mussels capacity to metabolize venlafaxine.
• Acidification was the dominant factor when both stressors were combined.

Abstract

Warming and acidification are expected impacts of climate change to the marine environment. Besides, organisms that live in coastal areas, such as bivalves, can also be exposed to anthropogenic pollutants like pharmaceuticals (PhACs) and endocrine disrupting compounds (EDCs). In this study, the effects of warming and acidification on the bioconcentration, metabolization and depuration of five PhACs (sotalol, sulfamethoxazole, venlafaxine, carbamazepine and citalopram) and two EDCs (methylparaben and triclosan) were investigated in the mussel species (Mytilus galloprovincialis), under controlled conditions. Mussels were exposed to warming and acidification, as well as to the mixture of contaminants up to 15.7 μg L−1 during 20 days; followed by 20 days of depuration. All contaminants bioconcentrated in mussels with levels ranging from 1.8 μg kg−1 dry weight (dw) for methylparaben to 12889.4 μg kg−1 dw for citalopram. Warming increased the bioconcentration factor (BCF) of sulfamethoxazole and sotalol, whereas acidification increased the BCF of sulfamethoxazole, sotalol and methylparaben. In contrast, acidification decreased triclosan levels, while both stressors decreased venlafaxine and citalopram BCFs. Warming and acidification facilitated the elimination of some of the tested compounds (i.e. sotalol from 50% in control to 60% and 68% of elimination in acidification and warming respectively). However, acidification decreased mussels’ capacity to metabolize contaminants (i.e. venlafaxine). This work provides a first insight in the understanding of aquatic organisms’ response to emerging contaminants pollution under warming and acidification scenarios.

Continue reading ‘Effects of water warming and acidification on bioconcentration, metabolization and depuration of pharmaceuticals and endocrine disrupting compounds in marine mussels (Mytilus galloprovincialis)’


Subscribe to the RSS feed

Powered by FeedBurner

Follow AnneMarin on Twitter

Blog Stats

  • 1,083,823 hits

OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

OUP book