scholarly journals Rapid multi-generational acclimation of coralline algal reproductive structures to ocean acidification

2021 ◽  
Vol 288 (1950) ◽  
Author(s):  
B. Moore ◽  
S. Comeau ◽  
M. Bekaert ◽  
A. Cossais ◽  
A. Purdy ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Growth Rates ◽  
Natural Habitat ◽  
Algal Growth ◽  
Coralline Algae ◽  
Reproductive Structures ◽  
Highly Sensitive ◽  
Negative Effect ◽  
Coral Reef Ecosystems

The future of coral reef ecosystems is under threat because vital reef-accreting species such as coralline algae are highly susceptible to ocean acidification. Although ocean acidification is known to reduce coralline algal growth rates, its direct effects on the development of coralline algal reproductive structures (conceptacles) is largely unknown. Furthermore, the long-term, multi-generational response of coralline algae to ocean acidification is extremely understudied. Here, we investigate how mean pH, pH variability and the pH regime experienced in their natural habitat affect coralline algal conceptacle abundance and size across six generations of exposure. We show that second-generation coralline algae exposed to ocean acidification treatments had conceptacle abundances 60% lower than those kept in present-day conditions, suggesting that conceptacle development is initially highly sensitive to ocean acidification. However, this negative effect of ocean acidification on conceptacle abundance disappears after three generations of exposure. Moreover, we show that this transgenerational acclimation of conceptacle development is not facilitated by a trade-off with reduced investment in growth, as higher conceptacle abundances are associated with crusts with faster growth rates. These results indicate that the potential reproductive output of coralline algae may be sustained under future ocean acidification.

scholarly journals Effects of light and temperature on Mg uptake, growth, and calcification in the proxy climate archive <i>Clathromorphum</i> <i>compactum</i>

2018 ◽  
Vol 15 (19) ◽  
pp. 5745-5759 ◽  
Author(s):  
Siobhan Williams ◽  
Walter Adey ◽  
Jochen Halfar ◽  
Andreas Kronz ◽  
Patrick Gagnon ◽  
...  
Keyword(s):  
Sea Ice ◽  
Cell Walls ◽  
Natural Habitat ◽  
Algal Growth ◽  
High Light ◽  
Coralline Algae ◽  
Growth Increments ◽  
Environmental Controls ◽  
Wall Calcification ◽  
Ice Conditions

Abstract. The shallow-marine benthic coralline alga Clathromorphum compactum is an important annual- to sub-annual-resolution archive of Arctic and subarctic environmental conditions, allowing reconstructions going back > 600 years. Both Mg content, in the high-Mg calcitic cell walls, and annual algal growth increments have been used as a proxy for past temperatures and sea ice conditions. The process of calcification in coralline algae has been debated widely, with no definitive conclusion about the role of light and photosynthesis in growth and calcification. Light received by algal specimens can vary with latitude, water depth, sea ice conditions, water turbidity, and shading. Furthermore, field calibration studies of Clathromorphum sp. have yielded geographically disparate correlations between MgCO3 and sea surface temperature. The influence of other environmental controls, such as light, on Mg uptake and calcification has received little attention. We present results from an 11-month mesocosm experiment in which 123 wild-collected C. compactum specimens were grown in conditions simulating their natural habitat. Specimens grown for periods of 1 and 2 months in complete darkness show that the typical complex of anatomy and cell wall calcification develops in new tissue without the presence of light, demonstrating that calcification is metabolically driven and not a side effect of photosynthesis. Also, we show that both light and temperature significantly affect MgCO3 in C. compactum cell walls. For specimens grown at low temperature (2 ∘C), the effects of light are smaller, with a 1.4 mol % MgCO3 increase from low-light (mean = 17 lx) to high-light conditions (mean = 450 lx). At higher (10 ∘C) temperature there was a 1.8 mol % MgCO3 increase from low to high light. It is therefore concluded that site- and possibly specimen-specific temperature calibrations must be applied, to account for effects of light when generating Clathromorphum-derived temperature calibrations.

scholarly journals Sensitivity towards elevated <i>p</i>CO<sub>2</sub> in great scallop (<i>Pecten maximus</i> Lamarck) embryos and fed larvae

2016 ◽  
Author(s):  
Sissel Andersen ◽  
Ellen S. Grefsrud ◽  
Torstein Harboe
Keyword(s):  
Ocean Acidification ◽  
Shell Growth ◽  
Elevated Pco2 ◽  
Pecten Maximus ◽  
Negative Effects ◽  
Great Scallop ◽  
Scallop Larvae ◽  
Negative Effect ◽  
Seawater Carbonate Chemistry

Abstract. The increasing amount of dissolved anthropogenic CO2 has caused a drop in pH-values in the open ocean known as ocean acidification. This change in seawater carbonate chemistry has been shown to have a negative effect on a number of marine organisms. Early life stages are the most vulnerable, and especially the organisms that produce calcified structures in the phylum Mollusca. Few studies have looked at effects on scallops, and this is the first study presented including fed larvae of the great scallop (Pecten maximus) followed until day 14 post-fertilization. Fertilized eggs from unexposed parents were exposed to three levels of pCO2 using four replicate units: 465 (ambient), 768 and 1294 μatm, corresponding to pHNBS of 7.94, 7.74 and 7.54, respectively. All of the observed parameters were negatively affected by elevated pCO2: survival, larval development, shell growth and normal shell development. The latter was observed to be affected only two days after fertilization. Negative effects on the fed larvae at day 7 were similar to what was shown earlier for unfed P. maximus larvae. Growth rate in the group at 768 μatm seemed to decline after day 7, indicating that the ability to overcome the environmental change at moderately elevated pCO2 was lost over time. Food availability may not decrease the sensitivity to elevated pCO2 in scallop larvae. Unless genetic adaptation and acclimatization counteract the negative effects of long term elevated pCO2, populations of scallops may be negatively affected by ocean acidification in the future.

scholarly journals Changes in coral reef communities across a natural gradient in seawater pH

2015 ◽  
Vol 1 (5) ◽  
pp. e1500328 ◽  
Author(s):  
Hannah C. Barkley ◽  
Anne L. Cohen ◽  
Yimnang Golbuu ◽  
Victoria R. Starczak ◽  
Thomas M. DeCarlo ◽  
...  
Keyword(s):  
Coral Reef ◽  
Ocean Acidification ◽  
Benthic Communities ◽  
Coral Community ◽  
Low Ph ◽  
Coralline Algae ◽  
Negative Effects ◽  
Skeletal Density ◽  
Coral Communities ◽  
Coral Reef Ecosystems

Ocean acidification threatens the survival of coral reef ecosystems worldwide. The negative effects of ocean acidification observed in many laboratory experiments have been seen in studies of naturally low-pH reefs, with little evidence to date for adaptation. Recently, we reported initial data suggesting that low-pH coral communities of the Palau Rock Islands appear healthy despite the extreme conditions in which they live. Here, we build on that observation with a comprehensive statistical analysis of benthic communities across Palau’s natural acidification gradient. Our analysis revealed a shift in coral community composition but no impact of acidification on coral richness, coralline algae abundance, macroalgae cover, coral calcification, or skeletal density. However, coral bioerosion increased 11-fold as pH decreased from the barrier reefs to the Rock Island bays. Indeed, a comparison of the naturally low-pH coral reef systems studied so far revealed increased bioerosion to be the only consistent feature among them, as responses varied across other indices of ecosystem health. Our results imply that whereas community responses may vary, escalation of coral reef bioerosion and acceleration of a shift from net accreting to net eroding reef structures will likely be a global signature of ocean acidification.

Periphyton response to long-term nutrient enrichment in a shaded headwater stream

2005 ◽  
Vol 62 (9) ◽  
pp. 2033-2045 ◽  
Author(s):  
Jennifer L Greenwood ◽  
Amy D Rosemond
Keyword(s):  
Growth Rates ◽  
Nutrient Enrichment ◽  
Algal Species ◽  
Light Availability ◽  
Algal Growth ◽  
Detectable Effect ◽  
Long Term Effects ◽  
Tree Canopies ◽  
Periphyton Biomass

We maintained elevated but moderate concentrations of nitrogen and phosphorus continuously for 2 years in a heavily shaded headwater stream and compared effects on stream periphyton with a reference stream. Both streams were sampled for 1 year before treatment. Some measures of periphyton biomass (ash-free dry mass and chlorophyll a) responded positively to enrichment. Increased chlorophyll a was likely a result of higher chlorophyll per cell, as total algal biovolume did not change with enrichment. These differences were greatest during high-light months (November-May), when cellular growth rates (a proxy for production) were also highest with enrichment. Algal assemblages were dominated by diatoms and remained similar between the treatment and reference streams throughout the enrichment period. Although nutrients stimulated algal growth rates, the long-term effects of nutrient addition on periphyton biomass were small in magnitude compared with other published values and were potentially suppressed by light availability and invertebrate consumption. These and other factors may have also been important in limiting the algal species pool and thus a taxonomic response to enrichment. Our results indicate that in headwater streams with intact tree canopies, chronic nutrient enrichment at moderate concentrations may have little detectable effect on benthic algal composition or periphyton biomass. Although nutrients stimulated algal growth rates, the long-term effects of nutrient addition on periphyton biomass were small in magnitude compared with other published values and were potentially suppressed by light availability and invertebrate consumption. These and other factors may have also been important in limiting the algal species pool and thus a taxonomic response to enrichment. Our results indicate that in headwater streams with intact tree canopies, chronic nutrient enrichment at moderate concentrations may have little detectable effect on benthic algal composition or periphyton biomass.

scholarly journals Effects of light and temperature on Mg uptake, growth, and calcification in the proxy climate archive <i>Clathromorphum compactum</i>

2018 ◽  
Author(s):  
Siobhan Williams ◽  
Walter Adey ◽  
Jochen Halfar ◽  
Andreas Kronz ◽  
Patrick Gagnon ◽  
...  
Keyword(s):  
Sea Ice ◽  
Cell Walls ◽  
Natural Habitat ◽  
Algal Growth ◽  
High Light ◽  
Coralline Algae ◽  
Growth Increments ◽  
Environmental Controls ◽  
Wall Calcification ◽  
Ice Conditions

Abstract. The shallow–marine benthic coralline alga Clathromorphum compactum is an important annual to sub-annual resolution archive of Arctic and Subarctic environmental conditions, allowing reconstructions going back > 600 years. Both Mg content, in the high Mg-calcitic cell walls, and annual algal growth increments have been used as a proxy for past temperatures and sea ice conditions. The process of calcification in coralline algae has been debated widely, with no definitive conclusion about the role of light and photosynthesis in growth and calcification. Light received by algal specimens can vary with latitude, water depth, sea ice conditions, water turbidity, and shading. Furthermore, field calibration studies of Clathromorphum sp. have yielded geographically disparate correlations between MgCO3 and sea surface temperature. The influence of other environmental controls, such as light, on Mg uptake and calcification has received little attention. We present results from an 11-month microcosm experiment in which numerous, wild-collected C. compactum specimens were grown in conditions simulating their natural habitat. Specimens grown for periods of one and two months in complete darkness show that the typical complex of anatomy and cell wall calcification develops in new tissue without the presence of light, demonstrating that calcification is metabolically-driven and not a side effect of photosynthesis. Also, we show that both light and temperature significantly affect MgCO3 in C. compactum cell walls. For specimens grown at low temperature (2 °C), the effects of light are smaller (1.4 mol % MgCO3 increase from low [mean = 17 lux] to high light conditions [mean = 450 lux]) than at higher (10 °C) temperature (1.8 mol % MgCO3 increase from low to high light). It is therefore concluded that site, and possibly specimen-specific, temperature calibrations must be applied, to account for effects of light when generating Clathromorphum-derived temperature calibrations.

scholarly journals Coral reef calcifiers buffer their response to ocean acidification using both bicarbonate and carbonate

2013 ◽  
Vol 280 (1753) ◽  
pp. 20122374 ◽  
Author(s):  
S. Comeau ◽  
R. C. Carpenter ◽  
P. J. Edmunds
Keyword(s):  
Coral Reef ◽  
Ocean Acidification ◽  
Conceptual Models ◽  
Sea Water ◽  
Empirical Support ◽  
Ion Concentration ◽  
Coralline Algae ◽  
Crustose Coralline Algae ◽  
Carbonate Ion ◽  
Negative Effect

Central to evaluating the effects of ocean acidification (OA) on coral reefs is understanding how calcification is affected by the dissolution of CO 2 in sea water, which causes declines in carbonate ion concentration [CO 3 2− ] and increases in bicarbonate ion concentration [HCO 3 − ]. To address this topic, we manipulated [CO 3 2− ] and [HCO 3 − ] to test the effects on calcification of the coral Porites rus and the alga Hydrolithon onkodes , measured from the start to the end of a 15-day incubation, as well as in the day and night. [CO 3 2− ] played a significant role in light and dark calcification of P. rus , whereas [HCO 3 − ] mainly affected calcification in the light. Both [CO 3 2− ] and [HCO 3 − ] had a significant effect on the calcification of H. onkodes , but the strongest relationship was found with [CO 3 2− ]. Our results show that the negative effect of declining [CO 3 2− ] on the calcification of corals and algae can be partly mitigated by the use of HCO 3 − for calcification and perhaps photosynthesis. These results add empirical support to two conceptual models that can form a template for further research to account for the calcification response of corals and crustose coralline algae to OA.

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

The Reproduction Vector of the Russian Economy: 1999-2007

2008 ◽  
pp. 94-109 ◽  
Author(s):  
D. Sorokin
Keyword(s):  
Economic Policy ◽  
Human Capital ◽  
Growth Rates ◽  
Developed Countries ◽  
Gdp Per Capita ◽  
Real Sector ◽  
Russian Economy ◽  
Per Capita ◽  
The Developed Countries

The problem of the Russian economy’s growth rates is considered in the article in the context of Russia’s backwardness regarding GDP per capita in comparison with the developed countries. The author stresses the urgency of modernization of the real sector of the economy and the recovery of the country’s human capital. For reaching these goals short- or mid-term programs are not sufficient. Economic policy needs a long-term (15-20 years) strategy, otherwise Russia will be condemned to economic inertia and multiplying structural disproportions.

Infrastructure mortgage in Russia: Opportunities and prospects

2019 ◽  
pp. 114-133
Author(s):  
G. I. Idrisov ◽  
Y. Yu. Ponomarev
Keyword(s):  
Federal Government ◽  
Public Debt ◽  
Budget Deficit ◽  
Expert Assessment ◽  
Inflation Expectations ◽  
Direct Impact ◽  
Long Run ◽  
Gdp Growth Rate ◽  
Negative Effect

The article shows that depending on the goals pursued by the federal government and the available interbudgetary tools a different design of infrastructure mortgage is preferable. Three variants of such mortgage in Russia are proposed, each of which is better suited for certain types of projects and uses different forms of subsidies. According to our expert assessment the active use of infrastructure mortgage in Russia can increase the average annual GDP growth rate by 0.5 p. p. on the horizon of 5—7 years. In the long run the growth of infrastructure financing through the use of infrastructure mortgage could increase long-term economic growth by 0.9 p. p., which in 20—30 years can add 20—30% of GDP to the economy. However, the change in the structure of budget expenditures in the absence of an increase in the budget deficit and public debt will cause no direct impact on monetary policy. The increase in the deficit and the build-up of public debt will have a negative effect on inflation expectations, which will require monetary tightening for a longer time to stabilize them.

The depressing (negative) effect of oestradiol benzoate on the in vitro secretion of LH and FSH by the pituitary gland of the LRH-pretreated long-term ovariectomized rat changes into the augmentative (positive) effect after discontinuation of the LRH-pretreatment

1985 ◽  
Vol 110 (3) ◽  
pp. 329-337 ◽  
Author(s):  
G. A. Schuiling ◽  
H. Moes ◽  
T. R. Koiter
Keyword(s):  
Depressing Effect ◽  
Ovx Rats ◽  
Gonadotrophin Secretion ◽  
Oestradiol Benzoate ◽  
Negative Effect ◽  
Positive Effect ◽  
Perifusion System

Abstract. The effect of pretreatment in vivo with oestradiol benzoate on in vitro secretion of LH and FSH was studied in long-term ovariectomized (OVX) rats both at the end of a 5-day continuous in vivo pretreatment with LRH and 4-days after cessation of such LRH pretreatment. Rats were on day 0 sc implanted with osmotic minipumps which released LRH at the rate of 250 ng/h. Control rats were implanted with a piece of silicone elastomer with the dimensions of a minipump. On days 2 and 4 the rats were injected with either 3 μg EB or with oil. On day 5 part of the rats were decapitated and the in vitro autonomous (i.e. non-LRH-stimulated) and 'supra-maximally' LRHstimulated release of LH and FSH was studied using a perifusion system. From other rats the minipumps were removed on day 5 and perifusion was performed on day 9. On the 5th day of the in vivo LRH pretreatment the pituitary LH/FSH stores were partially depleted; the pituitaries of the EB-treated rats more so than those of the oil-injected rats. EB alone had no significant effect on the content of the pituitary LH- and FSH stores. On day 9, i.e. 4 days after removal of the minipumps, the pituitary LH and FSH contents had increased in both the oil- and the EB injected rats, but had not yet recovered to control values. In rats not subjected to the 5-days pretreatment with LRH EB had a positive effect on the supra-maximally LRH-stimulated secretion of LH and FSH as well as on the non-stimulated secretion of LH. EB had no effect on the non-stimulated secretion of FSH. After 5 days of in vivo pretreatment with LRH only, the in vitro non-stimulated and supra-maximally LRH-stimulated secretion of both LH and FSH were strongly impaired, the effect correlating well with the LRH-induced depletion of the pituitary LH/FSH stores. In such LRH-pretreated rats EB had on day 5 a negative effect on the (already depressed) LRH-stimulated secretion of LH (not on that of FSH). EB had no effect on the non-stimulated LH/FSH secretion. It could be demonstrated that the negative effect of the combined LRH/EB pretreatment was mainly due to the depressing effect of this treatment on the pituitary LH and FSH stores: the effect of oestradiol on the pituitary LRH-responsiveness (release as related to pituitary gonadotrophin content) remained positive. In LRH-pretreated rats, however, this positive effect of EB was smaller than in rats not pretreated with LRH. Four days after removal of the minipumps there was again a positive effect of EB on the LRH-stimulated secretion of LH and FSH as well as on the non-stimulated secretion of LH. The positive effect of EB on the pituitary LRH-responsiveness was as strong as in rats which had not been exposed to exogenous LRH. The non-stimulated secretion of FSH was again not affected by EB. The results demonstrate that the effect of EB on the oestrogen-sensitive components of gonadotrophin secretion consists of two components: an effect on the pituitary LRH-responsiveness proper, and an effect on the pituitary LH/FSH stores. The magnitude of the effect of EB on the LRH-responsiveness is LRH dependent: it is very weak (almost zero) in LRH-pretreated rats, but strong in rats not exposed to LRH as well as in rats of which the LRH-pretreatment was stopped 4 days previously. Similarly, the effect of EB on the pituitary LH and FSH stores is LRH-dependent: in the absence of LRH, EB has no influence on the contents of these stores, but EB can potentiate the depleting effect of LRH on the LH/FSH-stores. Also this effect disappear after cessation of the LRH-pretreatment.

Sign in / Sign up

Export Citation Format

Share Document