Recruits of the temperate coral Oculina arbuscula mimic adults in their resilience to ocean acidification

2020 ◽  
Vol 636 ◽  
pp. 63-75 ◽  
Author(s):  
BV Varnerin ◽  
BM Hopkinson ◽  
DF Gleason
Keyword(s):  
Ocean Acidification ◽  
Soluble Protein ◽  
Linear Response ◽  
Energetic Cost ◽  
Life Stages ◽  
Respiration Rates ◽  
Algal Symbiont ◽  
Temperate Coral ◽  
Oculina Arbuscula ◽  
Current Century

Ocean acidification has been investigated extensively in scleractinian corals, but studies on different life stages of the same species are lacking. We investigated the response of recruits of the temperate coral Oculina arbuscula to increased CO2 concentrations, a species whose adults show significant tolerance to elevated concentrations of CO2. Specifically, we exposed small colonies (5-12 mm diameter) to 475, 710, and 1261 ppm CO2 for 75 d in the laboratory to address the hypothesis that, like adults, the health of O. arbuscula recruits is not affected by increased CO2 concentrations. Calcification rates were monitored regularly during the experiment, while mortality, respiration rates, photosynthetic rates, algal symbiont densities, and soluble protein were quantified at the end. As predicted, CO2 concentration did not impact survival, algal densities, or soluble protein concentrations in O. arbuscula recruits. In contrast, both calcification rates and photosynthesis:respiration ratios tended to be lower at higher CO2. Comparing the results of this study on recruits with published studies on adults suggested that both life stages exhibit a similar non-linear response to CO2 concentration, whereby recruits may be unable to counter the increased energetic cost of calcification that occurs at the highest CO2. Based on these results and environmental monitoring showing that mean pCO2 is increasing by ~2.4% yr-1 in the waters off Georgia, USA, we conclude that O. arbuscula recruits may begin to exhibit depressed calcification rates within the current century if CO2 emissions are not reduced.

scholarly journals Effect of ocean acidification on early life stages of Atlantic herring (<i>Clupea harengus</i> L.)

2011 ◽  
Vol 8 (12) ◽  
pp. 3697-3707 ◽  
Author(s):  
A. Franke ◽  
C. Clemmesen
Keyword(s):  
Ocean Acidification ◽  
Linear Relationship ◽  
Early Life ◽  
Clupea Harengus ◽  
Control Treatment ◽  
Future Research ◽  
Atlantic Herring ◽  
Life Stages ◽  
Early Life Stages ◽  
Newly Hatched Larvae

Abstract. Due to atmospheric accumulation of anthropogenic CO2 the partial pressure of carbon dioxide (pCO2) in surface seawater increases and the pH decreases. This process known as ocean acidification might have severe effects on marine organisms and ecosystems. The present study addresses the effect of ocean acidification on early developmental stages, the most sensitive stages in life history, of the Atlantic herring (Clupea harengus L.). Eggs of the Atlantic herring were fertilized and incubated in artificially acidified seawater (pCO2 1260, 1859, 2626, 2903, 4635 μatm) and a control treatment (pCO2 480 μatm) until the main hatch of herring larvae occurred. The development of the embryos was monitored daily and newly hatched larvae were sampled to analyze their morphometrics, and their condition by measuring the RNA/DNA ratios. Elevated pCO2 neither affected the embryogenesis nor the hatch rate. Furthermore the results showed no linear relationship between pCO2 and total length, dry weight, yolk sac area and otolith area of the newly hatched larvae. For pCO2 and RNA/DNA ratio, however, a significant negative linear relationship was found. The RNA concentration at hatching was reduced at higher pCO2 levels, which could lead to a decreased protein biosynthesis. The results indicate that an increased pCO2 can affect the metabolism of herring embryos negatively. Accordingly, further somatic growth of the larvae could be reduced. This can have consequences for the larval fish, since smaller and slow growing individuals have a lower survival potential due to lower feeding success and increased predation mortality. The regulatory mechanisms necessary to compensate for effects of hypercapnia could therefore lead to lower larval survival. Since the recruitment of fish seems to be determined during the early life stages, future research on the factors influencing these stages are of great importance in fisheries science.

scholarly journals Ocean acidification limits temperature-induced poleward expansion of coral habitats around Japan

2012 ◽  
Vol 9 (6) ◽  
pp. 7165-7196 ◽  
Author(s):  
Y. Yara ◽  
M. Vogt ◽  
M. Fujii ◽  
H. Yamano ◽  
C. Hauri ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Climate Models ◽  
Tropical Regions ◽  
Temperate Coral ◽  
Future Global Warming ◽  
Coral Communities ◽  
Potential Habitats ◽  
Suitable Habitats ◽  
Business As Usual

Abstract. Using results from four coupled global carbon cycle-climate models combined with in situ observations, we estimate the combined effects of future global warming and ocean acidification on potential habitats for tropical/subtropical and temperate coral communities in the seas around Japan. The suitability of the coral habitats are identified primarily on the basis of the currently observed ranges for temperature and saturation states Ω with regard to aragonite (Ωarag). We find that under the "business as usual" SRES A2 scenario, coral habitats will expand northward by several hundred kilometers by the end of this century. At the same time, coral habitats are projected to become sandwiched between the tropical regions, where the frequency of coral bleaching will increase, and the temperate-to-subpolar latitudes, where Ωarag will become too low to support sufficiently high calcification rates. As a result, the area of coral habitats around Japan that is suitable to tropical-subtropical communities will be reduced by half by the 2020s to 2030s, and is projected to disappear by the 2030s to 2040s. The suitable habitats for the temperate coral communities are also becoming smaller, although at a less pronounced rate due to their higher tolerance for low Ωarag.

scholarly journals Corals and Carbon: The physiological response of a protected deep-sea coral (Solenosmilia variabilis) to ocean acidification

2021 ◽  
Author(s):  
◽  
Malindi Gammon
Keyword(s):  
Treatment Group ◽  
Ocean Acidification ◽  
Deep Sea ◽  
Exposure Period ◽  
Interactive Effects ◽  
Tissue Loss ◽  
Control Group ◽  
Respiration Rates ◽  
Deep Sea Corals

<p>Calcifying corals provide important habitat complexity in the deep-sea and are consistently associated with a biodiversity of fish and other invertebrates. Little is understood about how deep-sea corals may respond to predicted scenarios of ocean acidification (OA), but any predicted changes will have wider impacts on the ecosystem.   Colonies of Solenosmilia variabilis, a species of deep-sea coral found in the waters surrounding New Zealand, were collected during a cruise in March 2014 from the Louisville Seamount chain. Over 12-months, coral samples were maintained in temperature controlled (~3.5°C) continuous flow-through tanks. A control group of coral colonies was held in seawater with pH 7.88 and a treatment group in pH 7.65. These two pH levels were designed to reflect current pH conditions and end-of-century conditions, respectively. In addition to investigating changes in growth and morphology, measurements of respiration and intracellular pH (pHi) were taken after a mid-term (6 months for respiration; 9 months for pHi) and long-term (12 months for both respiration and pHi) exposure period. An established method used in measuring the pHi of shallow water corals was adapted for use with deep-sea corals for the first time. pHi was independent from the seawater treatment and ranged from 7.67 – 8.30. Respiration rate was not influenced by the reduced seawater pH tested here. Respiration rates were highly variable, ranging from 0.065 to 1.756 μg O2 g-1 protein h-1 and pHi ranged from 7.67 – 8.30. Yearly growth rates were also variable, ranging from 0.53 to 3.068 mm year-1, and again showed no detectable difference between the treatment and control colonies. However, a loss in the colouration of coral skeletons was observed in the treatment group and was attributed to a loss of tissue. This could indicate a reallocation of energy, allowing for the maintenance of those other physiological parameters measured here (e.g. growth and respiration rates). If this is indeed occurring, it would be consistent with the idea of phenotypic plasticity, where corals can alternate between soft-bodied and fossilizing forms, allowing them to survive past periods of environmental stress.   This research is an important first step towards understanding the sensitivity of deep-sea corals to OA and the potential for acclimation, and suggests that in many respects, S. variabilis might not be susceptible to end-of-century projections of OA. Nevertheless, the observed tissue loss is interesting and warrants further investigation to assess its long-term implications. Furthermore, the impacts of greater levels of OA, and the interactive effects of other ecological parameters such as food availability, need to be tested.</p>

scholarly journals A method for studying the metabolic activity of individual tardigrades by measuring oxygen uptake using micro-respirometry

2020 ◽  
pp. jeb.233072
Author(s):  
Bjarke H. Pedersen ◽  
Hans Malte ◽  
Hans Ramløv ◽  
Kai Finster
Keyword(s):  
Steady State ◽  
Reproductive Success ◽  
Environmental Factors ◽  
Oxygen Uptake ◽  
Respiration Rate ◽  
Metabolic Activity ◽  
Life Stages ◽  
Respiration Rates ◽  
Single Organism ◽  
Insight Into

Studies of tardigrade biology have been severely limited by the sparsity of appropriate quantitative techniques, informative on a single-organism level. Therefore, many studies rely on motility-based survival scoring and quantifying reproductive success. Measurements of O2 respiration rates, as an integrating expression of the metabolic activity of single tardigrades, would provide a more comprehensive insight into how an individual tardigrade is responding to specific environmental factors or changes in life stages. Here we present and validate a new method for determining the O2 respiration rate (nmol O2 mg−1 hour−1) of single tardigrades under steady state, using O2-microsensors. As an example, we show that the O2 respiration rate determined in MilliQ water for individuals of Richtersius coronifer and of Macrobiotus macrocalix at 22 °C was 10.8±1.8 nmol O2 mg−1 hour−1 and 13.1±2.3 nmol O2 mg−1 hour−1, respectively.

scholarly journals Low recruitment due to altered settlement substrata as primary constraint for coral communities under ocean acidification

2017 ◽  
Vol 284 (1862) ◽  
pp. 20171536 ◽  
Author(s):  
Katharina E. Fabricius ◽  
Sam H. C. Noonan ◽  
David Abrego ◽  
Lindsay Harrington ◽  
Glenn De'ath
Keyword(s):  
Coral Reefs ◽  
Ocean Acidification ◽  
Field Experiments ◽  
Later Life ◽  
Coralline Algae ◽  
Life Stages ◽  
Crustose Coralline Algae ◽  
Coral Recruitment ◽  
Recovery Potential ◽  
Coral Communities

The future of coral reefs under increasing CO 2 depends on their capacity to recover from disturbances. To predict the recovery potential of coral communities that are fully acclimatized to elevated CO 2 , we compared the relative success of coral recruitment and later life stages at two volcanic CO 2 seeps and adjacent control sites in Papua New Guinea. Our field experiments showed that the effects of ocean acidification (OA) on coral recruitment rates were up to an order of magnitude greater than the effects on the survival and growth of established corals. Settlement rates, recruit and juvenile densities were best predicted by the presence of crustose coralline algae, as opposed to the direct effects of seawater CO 2 . Offspring from high CO 2 acclimatized parents had similarly impaired settlement rates as offspring from control parents. For most coral taxa, field data showed no evidence of cumulative and compounding detrimental effects of high CO 2 on successive life stages, and three taxa showed improved adult performance at high CO 2 that compensated for their low recruitment rates. Our data suggest that severely declining capacity for reefs to recover, due to altered settlement substrata and reduced coral recruitment, is likely to become a dominant mechanism of how OA will alter coral reefs.

scholarly journals Physiological response of a golden tide alga (<i>Sargassum muticum</i>) to the interaction of ocean acidification and phosphorus enrichment

2017 ◽  
Vol 14 (3) ◽  
pp. 671-681 ◽  
Author(s):  
Zhiguang Xu ◽  
Guang Gao ◽  
Juntian Xu ◽  
Hongyan Wu
Keyword(s):  
Nitrate Reductase ◽  
Ocean Acidification ◽  
Soluble Protein ◽  
Nitrate Reductase Activity ◽  
Nitrate Uptake ◽  
Dark Respiration ◽  
Reductase Activity ◽  
Soluble Carbohydrates ◽  
Promoting Effect ◽  
Nitrate Uptake Rate

Abstract. The development of golden tides is potentially influenced by global change factors, such as ocean acidification and eutrophication, but related studies are very scarce. In this study, we cultured a golden tide alga, Sargasssum muticum, at two levels of pCO2 (400 and 1000 µatm) and phosphate (0.5 and 40 µM) to investigate the interactive effects of elevated pCO2 and phosphate on the physiological properties of the thalli. Higher pCO2 and phosphate (P) levels alone increased the relative growth rate by 41 and 48 %, the net photosynthetic rate by 46 and 55 %, and the soluble carbohydrates by 33 and 62 %, respectively, while the combination of these two levels did not promote growth or soluble carbohydrates further. The higher levels of pCO2 and P alone also enhanced the nitrate uptake rate by 68 and 36 %, the nitrate reductase activity (NRA) by 89 and 39 %, and the soluble protein by 19 and 15 %, respectively. The nitrate uptake rate and soluble protein was further enhanced, although the nitrate reductase activity was reduced when the higher levels of pCO2 and P worked together. The higher pCO2 and higher P levels alone did not affect the dark respiration rate of the thalli, but together they increased it by 32 % compared to the condition of lower pCO2 and lower P. The neutral effect of the higher levels of pCO2 and higher P on growth and soluble carbohydrates, combined with the promoting effect on soluble protein and dark respiration, suggests that more energy was drawn from carbon assimilation to nitrogen assimilation under conditions of higher pCO2 and higher P; this is most likely to act against the higher pCO2 that caused acid–base perturbation via synthesizing H+ transport-related protein. Our results indicate that ocean acidification and eutrophication may not boost golden tide events synergistically, although each one has a promoting effect.

Interactive Effects of Ocean Acidification, Elevated Temperature, and Reduced Salinity on Early-Life Stages of the Pacific Oyster

2014 ◽  
Vol 48 (17) ◽  
pp. 10079-10088 ◽  
Author(s):  
Ginger W. K. Ko ◽  
R. Dineshram ◽  
Camilla Campanati ◽  
Vera B. S. Chan ◽  
Jon Havenhand ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Ocean Acidification ◽  
Early Life ◽  
Pacific Oyster ◽  
Interactive Effects ◽  
Life Stages ◽  
Early Life Stages ◽  
The Pacific
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