scholarly journals Planktonic stages of the ecologically important sea urchin, Diadema africanum: larval performance under near future ocean conditions

2020 ◽  
Vol 42 (3) ◽  
pp. 286-304
Author(s):  
José Carlos Hernández ◽  
Sabrina Clemente ◽  
Eliseba García ◽  
Justin S McAlister

Abstract Diadema africanum is a recently described sea urchin from the Eastern Atlantic archipelagos, and adults play a major ecological role mediating the transition between two alternative ecosystem states: macroalgal beds and urchin barrens. The aim of this study was to describe for the first time the egg characteristics, fertilization and larval development. To determine basic life-history characteristics for this species, we reared larvae through to metamorphic competence under an energy shortage experiment and temperature–pH experiments to characterize the morphological plasticity of larval responses to actual and future oceanic conditions. D. africanum produces eggs that are larger both in diameter (82.7 μm) and volume (0.30 nl) than the eggs of both Diadema antillarum (70.0 μm, 0.18 nl) and Diadema mexicanum (68.0 μm, 0.16 nl). Larval development is similar to other species within the Family Diadematidae, with a Echinopluteus transversus larval type morphology. The combined effects of the climate change-related environmental factors resulted in a reduction in fitness of D. africanum at the warmer limit of its thermal range when combined with low pH. Results suggest that the egg and larval life-history characteristics of D. africanum may have evolved to facilitate long-distance oceanic transport; however, near-future oceanic conditions may compromise larval survival.

2011 ◽  
Vol 69 (3) ◽  
pp. 460-464 ◽  
Author(s):  
Steve S. Doo ◽  
Symon A. Dworjanyn ◽  
Shawna A. Foo ◽  
Natalie A. Soars ◽  
Maria Byrne

Abstract Doo, S. S., Dworjanyn, S. A., Foo, S. A., Soars, N. A., and Byrne, M. 2012. Impacts of ocean acidification on development of the meroplanktonic larval stage of the sea urchin Centrostephanus rodgersii. – ICES Journal of Marine Science, 69: 460–464. The effects of near-future ocean acidification/hypercapnia on larval development were investigated in the sea urchin Centrostephanus rodgersii, a habitat-modifying species from eastern Australia. Decreased pH (−0.3 to −0.5 pH units) or increased pCO2 significantly reduced the percentage of normal larvae. Larval growth was negatively impacted with smaller larvae in the pH 7.6/1800 ppm treatments. The impact of acidification on development was similar on days 3 and 5, indicating deleterious effects early in development. On day 3, increased abnormalities in the pH 7.6/1600 ppm treatment were seen in aberrant prism stage larvae and arrested/dead embryos. By day 5, echinoplutei in this treatment had smaller arm rods. Observations of smaller larvae in C. rodgersii have significant implications for this species because larval success may be a potential bottleneck for persistence in a changing ocean.


Author(s):  
Jan Kuper

The life-history and behaviour of the chironomid Metriocnemus (Inermipupa) carmencitabertarum was studied for three years and a comparison was made between two populations in the Netherlands. Key life-history characteristics are reported, including the number of generations (2-5 generations) and duration of larval development (19-55 days). Life-history characteristics differed between the two populations and between generations within a population. These differences were likely related to differences in competitors (mainly Chironomus riparius Meigen) and thermal characteristics of the habitat from variations in water volume and ambient temperature. Results suggested a diapause in summer, when water levels dropped, and not in winter. A clear seasonal pattern in body size was found with pupal length increasing steeply at the beginning of the summer. The increase in body size was positively correlated with mean ambient temperature during larval development. This correlation is in contrast with the Temperature-Size Rule (TSR) in ectotherms, which postulates a negative correlation between temperature and adult body size. The chance of ectotherm predators being present in the habitat is low, which may explain this feature. Life history characteristics supported a recent northward range expansionfor M. (I.) carmencitabertarum due to warmer winters. If correct, it is predicted that the species will be found in Scotland and northern Germany and/or southern Denmark in the near future.


2020 ◽  
Author(s):  
Alon Silberbush

AbstractSeveral species of mosquitoes respond to the presence of kairomones released by larval predators during oviposition habitat selection and larval development. These responses may differ among mosquito species and do not always correlate with larval survival. This study examined the responses of the mosquito Culiseta longiareolata Macquart to kairomones released by three species of fish during oviposition, Gambusia affinis Baird and Girard, Aphanius mento Heckel and Garra rufa Heckel. In addition, the study examined the effects of kairomones released by G. affinis on larval development. Results show that ovipositing female avoided cues from larvivorous, but not algivorous fish. In addition, developing larvae metamorphosed slower and showed increased mortality when exposed to fish-released kairomones. Results suggest that the responses of this mosquito species to fish-released kairomones may be explained by its competitive ability.


2020 ◽  
Vol 8 (9) ◽  
pp. 661
Author(s):  
Davide Asnicar ◽  
Costanza Cappelli ◽  
Ahmad Safuan Sallehuddin ◽  
Nur Atiqah Maznan ◽  
Maria Gabriella Marin

Despite the widespread use of herbicide glyphosate in cultivation, its extensive runoff into rivers and to coastal areas, and the persistence of this chemical and its main degradation product (aminomethylphosphonic acid, AMPA) in the environment, there is still little information on the potential negative effects of glyphosate, its commercial formulation Roundup® and AMPA on marine species. This study was conducted with the aim of providing a comparative evaluation of the effects of glyphosate-based and its derived chemicals on the larval development of the sea urchin Paracentrotus lividus, thus providing new data to describe the potential ecotoxicity of these contaminants. In particular, the effects on larval development, growth and metabolism were assessed during 48 h of exposure from the time of egg fertilization. The results confirm that AMPA and its parent compound, glyphosate have similar toxicity, as observed in other marine invertebrates. However, interestingly, the Roundup® formulation seemed to be less toxic than the glyphosate alone.


2008 ◽  
Vol 24 (2) ◽  
pp. 213-217 ◽  
Author(s):  
I. D. Leonardos ◽  
A. C. Tsikliras ◽  
V. Eleftheriou ◽  
Y. Cladas ◽  
I. Kagalou ◽  
...  

2012 ◽  
Vol 96 (10-11) ◽  
pp. 1187-1226 ◽  
Author(s):  
Jennifer L. Nielsen ◽  
Gregory T. Ruggerone ◽  
Christian E. Zimmerman

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