Posts Tagged 'echinoderms'

Impact on fertility rate and embryo-larval development due to the association acidification, ocean warming and lead contamination of a sea urchin Echinometra lucunter (echinodermata: echinoidea)

Ocean warming and acidification can cause deleterious effects on marine biota, which may be potentialized when associated with metal pollution. Thus, the aim of this work was to evaluate the effects of pH decrease, temperature increase and lead contamination on fertility rate and embryo-larval development of Echinometra lucunter. Gametes and embryos were exposed at pH 8.2 (control) and 7.5; at 26°C (control) and 28°C; and at lead concentrations of 0 (control), 125, 250 and 500 μg/L. These conditions were tested individually and in combination. The fertilization rate of E. lucunter was only significantly reduced in the treatments where temperature was increased and in the treatment where pH decreased. However, the development rate of the pluteus larvae was significantly affected in the majority of treatments: metal contamination in the higher concentration; decreased pH in all metal concentrations; increased temperature in the highest metal concentration; decreased pH and increased temperature and all variables combined, which is decreased pH, increased temperature and metal contamination in relation to the control group (C). The development test was shown to be more sensitive than the fertilization test in all the studied scenarios. In general, the present study suggests that pH decrease, temperature increase and metal pollution may have a significant impact on E. lucunter reproductive cycle.

Caetano L. S., Pereira T. M., Envangelista J. D., Cabral D. S., Coppo G. C., Alves de Souza L., Anderson A. B., Heringer O. A. & Chippari-Gomes A. R., in press. Impact on fertility rate and embryo-larval development due to the association acidification, ocean warming and lead contamination of a sea urchin Echinometra lucunter (echinodermata: echinoidea). Bulletin of Environmental Contamination and Toxicology. Article (subscription required).

Cross‐generational response of a tropical sea urchin to global change and a selection event in a 43‐month mesocosm study

Long‐term experimental investigations of transgenerational plasticity (TGP) and transgenerational acclimatization to global change are sparse in marine invertebrates. Here, we test the effect of ocean warming and acidification over a 25‐month period of Echinometra sp. A sea urchins whose parents were acclimatized at ambient or one of two near‐future (projected mid‐ and end‐ of the 21st century) climate scenarios for 18 months. Several parameters linked to performance exhibited strong effects of future ocean conditions at 9 months of age. The Ambient‐Ambient group (A‐A, both F0 and F1 at ambient conditions) was significantly larger (21%) and faster in righting response (31%) compared to other groups. A second set of contrasts revealed near‐future scenarios caused significant negative parental carryover effects. Respiration at 9 months was depressed by 59% when parents were from near‐future climate conditions, and righting response was slowed by 28%. At ten months, a selective pathogenic mortality event lead to significantly higher survival rates of A‐A urchins. Differences in size and respiration measured prior to the mortality were absent after the event, while a negative parental effect on righting (29% reduction) remained. The capacity to spawn at the end of the experiment was higher in individuals with ambient parents (50%) compared to other groups (21%) suggesting persistent parental effects. Obtaining different results at different points in time illustrates the importance of longer‐term and multi‐generation studies to investigate effects of climate change. Given some animals in all groups survived the pathogenic event and that effects on physiology (but not behavior) among groups were eliminated after the mortality, we suggest that similar events could constitute selective sweeps, allowing genetic adaptation. However, given the observed negative parental effects and reduced potential for population replenishment it remains to be determined if selection would be sufficiently rapid to rescue this species from climate change effects.

Continue reading ‘Cross‐generational response of a tropical sea urchin to global change and a selection event in a 43‐month mesocosm study’

Impacts of plastic-made packaging on marine key species: effects following water acidification and ecological implications

This study evaluates the impacts of 16 different leachates of plastic-made packaging on marine species of different trophic levels (bacteria, algae, echinoderms). Standard ecotoxicological endpoints (inhibition of bioluminescence, inhibition of growth, embryo-toxicity) and alterations of ecologically significant parameters (i.e., echinoderms’ body-size) were measured following exposure under different pH water conditions: marine standard (pH 8.1) and two increasingly acidic conditions (pH 7.8 and 7.5) in order to evaluate possible variations induced by ocean acidification. The results obtained in this study evidence that the tested doses are not able to significantly affect bacteria (Vibrio fischeri) and algae (Phaeodactylum tricornutum). On the contrary, Paracentrotus lividus larvae were significantly affected by several packaging types (13 out of 16) with meaningless differences between pH conditions.

Continue reading ‘Impacts of plastic-made packaging on marine key species: effects following water acidification and ecological implications’

The effects on low pH on sea urchin larval survivorship and development

In recent decades, increasing atmospheric CO2 levels have contributed to the acidification of the world’s oceans. Seawater absorbs CO2 from the atmosphere, which, through a series of chemical reactions, causes an increase in free hydrogen ions and a subsequent decrease in carbonate ions. This adversely affects marine organisms, including sea urchins, since carbonate is critical for building calcium carbonate structures such as shells, without which organisms can die. Declines in urchin populations can have ecological and economic effects, as urchins play critical roles in maintaining ecological balance in marine habitats and are important commercially harvested invertebrates. Larval marine organisms are particularly vulnerable, and increased deformities and mortality are expected in more acidic environments. Therefore, we exposed green sea urchin (Lytechinus variegatus) larvae to different pH levels and examined the effects on development and mortality. Fertilized eggs were reared in seawater with environmentally realistic pH values ranging from pH 7.8 to pH 8.2 (normal seawater), and a larval sample from each treatment was collected every 24 hours for 7 – 10 days. Mortality was documented by counting dead larvae, and development was assessed by comparing morphology among the control and treatment groups. In general, both mortality and morphological abnormalities showed inverse correlations with pH, with the highest mortality rate and most severe abnormalities occurring in larvae exposed to the lowest pH seawater. Larval development was also somewhat delayed in urchin larvae exposed to low pH seawater. These results suggest that acidic seawater, at pH values currently found in the world’s oceans, can adversely affect sea urchin larval development, which can, in turn, have negative ecological and economic consequences.

Continue reading ‘The effects on low pH on sea urchin larval survivorship and development’

Combined effect of microplastics and global warming factors on early growth and development of the sea urchin (Paracentrotus lividus)

Highlights

  • This work focusses on the effect of a multi-stressor environment in sea urchin.
  • Embryo-larval bioassays were used to determine growth and morphometric parameters.
  • A lower water pH (7.6) reduced larval growth and caused deformities.
  • Microplastics aggravate the effect of water acidification in sea urchin larvae.
  • High temperatures caused an additional stress and reduced larvae stomach volume.

Abstract

The aim of this work was to estimate the potential risk of the combined effect of global change factors (acidification, temperature increase) and microplastic (MP) pollution on the growth and development of the sea urchin P. lividus. Embryo-larval bioassays were conducted to determine growth and morphology after 48 h of incubation with MP (1000 and 3000 particles/mL); with filtered sea water at pH = 7.6; and with their combinations. A second experiment was conducted to study the effect of pH and MP in combination with a temperature increase of 4 °C compared to control (20 °C). We found that the inhibition of growth in embryos reared at pH = 7.6 was around 75%. Larvae incubated at 3000 MP particles/mL showed a 20% decrease in growth compared to controls. The exposure to MP also induced an increase in the postoral arm separation or rounded vertices. The combined exposure to a pH 7.6 and MP caused a significant decrease of larval growth compared to control, to MP and to pH 7.6 treatments. Morphological alterations were observed in these treatments, including the development of only two arms. Increasing the temperature resulted in an increased growth in control, in pH 7.6 and pH 7.6 + MP3000 treatments, but the relative stomach volume decreased. However, when growth parameters were expressed per Degree-Days the lower growth provoked by the thermal stress was evidenced in all treatments. In this work we demonstrated that MP could aggravate the effect of a decreased pH and that an increase in water temperature generated an additional stress on P. lividus larvae, manifested in a lower growth and an altered development. Therefore, the combined stress caused by ocean warming, ocean acidification, and microplastic pollution, could threaten sea urchin populations leading to a potential impact on coastal ecosystems.

Continue reading ‘Combined effect of microplastics and global warming factors on early growth and development of the sea urchin (Paracentrotus lividus)’

Partner preference in the intertidal: possible benefits of ocean acidification to sea anemone-algal symbiosis

Ocean acidification (OA) threatens many marine species and is projected to become more severe over the next 50 years. Areas of the Salish Sea and Puget Sound that experience seasonal upwelling of low pH water are particularly susceptible to even lower pH conditions. While ocean acidification literature often describes negative impacts to calcifying organisms, including economically important shellfish, and zooplankton, not all marine species appear to be
threatened by OA. Photosynthesizing organisms, in particular, may benefit from increased levels of CO2. The aggregating anemone (Anthopleura elegantissima), a common intertidal organism throughout the northeast Pacific, hosts two photosynthetic symbionts: Symbiodinium muscatinei (a dinoflagellate) and Elliptochloris marina (a chlorophyte). The holobiont, therefore, consists of both a cnidarian host and a photosymbiont that could be affected differently by the changing levels of environmental CO2. To determine the effects of OA on this important marine organism, A. elegantissima in each of four symbiotic conditions (hosting S. muscatinei, hosting E. marina, hosting mixed symbiont assemblages, or symbiont free) were subjected to one of three pCO2 levels (800 ppm, 1200 ppm, or 1800 ppm) of OA for 10 weeks. At regular intervals, gross photosynthesis and density of the symbionts, respiration rate of the hosts, levels of reactive oxygen species (ROS) in the host, and percent of organic carbon received by the host from the symbiont (CZAR) were measured. Over the 10-week period of the experiment, the densities of symbionts responded differently to an increase in pCO2, increasing in anemones hosting S. muscatinei but decreasing for those hosting E. marina. Similarly, anemones of mixed symbiont complement that started with approximately 50% of each symbiont type shifted toward a higher percentage of S. muscatinei with higher pCO2. Both gross photosynthesis and dark respiration were significantly affected by pCO2 and symbiont state, though we cannot say that the symbiontsv responded differently to increased OA. Symbiont state was a significant predictor for ROS concentration, with greatest levels seen in anemones hosting E. marina and for CZAR score, with greatest levels in anemones hosting S. muscatinei, our linear models did not reveal pCO2 as a significant factor in these responses. Together, these results suggest that S. muscatinei may benefit from elevated pCO2 levels and that A. elegantissima hosting that symbiont may have a competitive advantage under some future scenarios of ocean acidification.

Continue reading ‘Partner preference in the intertidal: possible benefits of ocean acidification to sea anemone-algal symbiosis’

Experimental assessment of the impacts of ocean acidification and urchin grazing on benthic kelp forest assemblages

Ocean acidification (OA) is likely to differentially affect the biology and physiology of calcifying and non-calcifying taxa, thereby potentially altering key ecological interactions (e.g., facilitation, competition, predation) in ways that are difficult to predict from single-species experiments. We used a two-factor experimental design to investigate how multispecies benthic assemblages in southern California kelp forests respond to OA and grazing by the purple sea urchinStrongylocentrotus purpuratus. Settlement tiles accrued natural mixed assemblages of algae and invertebrates in a kelp forest off San Diego, CA for one year before being exposed to OA and grazing in a laboratory experiment for two months. Space occupying organisms were identified and pooled into six functional groups: calcified invertebrates, non-calcified invertebrates, calcified algae, fleshy algae, sediment, and bare space for subsequent analyses of community structure. Interestingly, communities that developed on separate tile racks were unique, despite being deployed close in space, and further changes in community structure in response to OA and grazing depended on this initial community state. On Rack 1, we found significant effects of both pCO2 and grazing with elevated pCO2 increasing cover of fleshy algae, but sea urchin grazers decreasing cover of fleshy algae. On Rack 2, we found a ~ 35% higher percent cover of sediment on tiles reared in ambient pCO2 but observed ~27% higher cover of bare space in the high pCO2 conditions. On Rack 3, we found an average of 45% lower percent cover of calcified sessile invertebrates at ambient pCO2 than in high pCO2 treatments on Rack 3. Net community calcification was 137% lower in elevated pCO2 treatments. Kelp sporophyte densities on tiles without urchins were 74% higher than on tiles with urchins and kelp densities were highest in the elevated pCO2 treatment. Urchin growth and grazing rates were 49% and 126% higher under ambient than high pCO2 conditions. This study highlights consistent negative impacts of OA on community processes such as calcification and grazing rates, even though impacts on community structure were highly context-dependent.

Continue reading ‘Experimental assessment of the impacts of ocean acidification and urchin grazing on benthic kelp forest assemblages’

Effect of CO2 driven ocean acidification on calcification, physiology and ovarian cells of tropical sea urchin Salmacis virgulata – a microcosm approach

In the present study, we depict the structural modification of test minerals, physiological response and ovarian damage in the tropical sea urchin Salmacis virgulata using microcosm CO2 (Carbon dioxide) perturbation experiment. S. virgulata were exposed to hypercapnic conditions with four different pH levels using CO2 gas bubbling method that reflects ambient level (pH 8.2) and elevated pCO2 scenarios (pH 8.0, 7.8 and 7.6). The variations in physical strength and mechanical properties of S. virgulata test were evaluated by thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction analysis and scanned electron microscopy analysis. Biomarker enzymes such as glutathione-S-transferase, catalase, acetylcholine esterase, lipid peroxidase and reduced glutathione showed physiological stress and highly significant (p < 0.01) towards pH 7.6 and 7.8 treatments. Ovarian cells were highly damaged at pH 7.6 and 7.8 treatments. This study proved that the pH level 7.6 and 7.8 drastically affect calcification, physiological response and ovarian cells in S. virgulata.

Continue reading ‘Effect of CO2 driven ocean acidification on calcification, physiology and ovarian cells of tropical sea urchin Salmacis virgulata – a microcosm approach’

Ocean acidification may slow the pace of tropicalization of temperate fish communities

Poleward range extensions by warm-adapted sea urchins are switching temperate marine ecosystems from kelp-dominated to barren-dominated systems that favour the establishment of range-extending tropical fishes. Yet, such tropicalization may be buffered by ocean acidification, which reduces urchin grazing performance and the urchin barrens that tropical range-extending fishes prefer. Using ecosystems experiencing natural warming and acidification, we show that ocean acidification could buffer warming-facilitated tropicalization by reducing urchin populations (by 87%) and inhibiting the formation of barrens. This buffering effect of CO2 enrichment was observed at natural CO2 vents that are associated with a shift from a barren-dominated to a turf-dominated state, which we found is less favourable to tropical fishes. Together, these observations suggest that ocean acidification may buffer the tropicalization effect of ocean warming against urchin barren formation via multiple processes (fewer urchins and barrens) and consequently slow the increasing rate of tropicalization of temperate fish communities.

Continue reading ‘Ocean acidification may slow the pace of tropicalization of temperate fish communities’

A review and meta-analysis of potential impacts of ocean acidification on marine calcifiers from the southern Ocean

Understanding the vulnerability of marine calcifiers to ocean acidification is a critical issue, especially in the Southern Ocean (SO), which is likely to be the one of the first, and most severely affected regions. Since the industrial revolution, ~30% of anthropogenic CO2 has been absorbed by the global oceans. Average surface seawater pH levels have already decreased by 0.1 and are projected to decline by ~0.3 by the year 2100. This process, known as ocean acidification (OA), is shallowing the saturation horizon, which is the depth below which calcium carbonate (CaCO3) dissolves, likely increasing the vulnerability of many resident marine calcifiers to dissolution. The negative impact of OA may be seen first in species depositing more soluble CaCO3 mineral phases such as aragonite and high-Mg calcite (HMC). Ocean warming could further exacerbate the effects of OA in these particular species. Here we combine a review and a quantitative meta-analysis to provide an overview of the current state of knowledge about skeletal mineralogy of major taxonomic groups of SO marine calcifiers and to make projections about how OA might affect a broad range of SO taxa. We consider a species’ geographic range, skeletal mineralogy, biological traits, and potential strategies to overcome OA. The meta-analysis of studies investigating the effects of the OA on a range of biological responses such as shell state, development and growth rate illustrates that the response variation is largely dependent on mineralogical composition. Species-specific responses due to mineralogical composition indicate that taxa with calcitic, aragonitic, and HMC skeletons, could be at greater risk to expected future carbonate chemistry alterations, and low-Mg calcite (LMC) species could be mostly resilient to these changes. Environmental and biological control on the calcification process and/or Mg content in calcite, biological traits, and physiological processes are also expected to influence species-specific responses.

Continue reading ‘A review and meta-analysis of potential impacts of ocean acidification on marine calcifiers from the southern Ocean’

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Ocean acidification in the IPCC AR5 WG II

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