Larval Urchins Research Articles

Near future ocean acidification modulates the physiological impact of fluoxetine at environmental concentration on larval urchins

Pharmaceuticals found in human wastes are emergent pollutants that are continuously released into aquatic systems. While exposure to pharmaceuticals alone could adversely impact aquatic organisms, few studies have considered the interactive effects of pharmaceuticals and the future environmental conditions, such as decreasing pH due to ocean acidification. Given the bioavailability of many pharmaceuticals is dependent on these physical conditions, we investigated the effect of environmentally-relevant concentrations of fluoxetine (10 and 100 ng L−1) under ambient (pH 8.0) and reduced pH conditions (pH 7.7) on physiology, behavior, and DNA integrity of larval sea urchins (Heliocidaris crassispina). Notably, the negative impacts of fluoxetine exposure were attenuated by reduced pH. Larvae exposed to both reduced pH and fluoxetine exhibited lower levels of DNA damage compared to those exposed to only one of the stressors. Similar antagonistic interactions were observed at the organismal level: for example, fluoxetine exposure at 10 ng L−1 under ambient pH increased the percentage of embryos at later developmental stages, but such effects of fluoxetine were absent at pH 7.7. However, despite the modulation of fluoxetine impacts under ocean acidification, control larvae performed better than those exposed to either stressor, alone or in combination. We also observed that pH alone impacted organismal behaviors, as larvae swam slower at reduced pH regardless of fluoxetine exposure. Our findings highlight the need to consider multi-stressor interactions when determining future organismal performance and that multiple metrics are needed to paint a fuller picture of ecological risks.

Impacts of ocean acidification on survival, growth, and swimming behaviours differ between larval urchins and brittlestars

AbstractOcean acidification (OA) is widely recognized as an increasing threat to marine ecosystems. Many marine invertebrates have dual-phase life cycles in which planktonic larvae connect and sustain otherwise disconnected benthic adult populations. Many planktonic larvae are particularly sensitive to environmental stresses including OA. Here, we compared the developmental dynamics, survivorship, and swimming behaviours of plutei of two ecologically important echinoderm species that naturally experience variability in ambient pH: the purple urchin Strongylocentrotus purpuratus and the infaunal brittlestar Amphiura filiformis. Sensitivity to decreased pH differed between these two species and between maternal lineages. Larvae of both species experienced increased mortality and reduced growth rate under low pH conditions. However, larval brittlestars appeared more sensitive and experienced over 80% mortality after 7-d exposure to pH 7.7. Larval urchins from one maternal lineage underwent highly synchronized budding (release of blastula-like particles) at low pH. Observed budding temporarily increased numerical density and reduced individual size, leading to differences in growth and mortality rates between the two half-sibling groups and another population. Swimming speeds of larval brittlestars were reduced in decreased pH. In contrast, acidification had either no effect or positive effect on swimming speeds of larval urchins. The observed differences between species may be a reflection of pre-exposure in their natural habitats: larval brittlestars experience a relatively stable in situ pH environment, whereas larval urchins are occasionally exposed to low pH in upwelling regions. Urchins may therefore exhibit short-term compensatory responses such as budding and increased swimming speed. Natural selection could act upon the significant variations we observed between maternal lineages, resulting in more resilient populations confronting chronic exposure to OA.

Differential effects of suspended sediments on larval survival and settlement of New Zealand urchins Evechinus chloroticus and abalone Haliotis iris

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 314:149-158 (2006) - doi:10.3354/meps314149 Differential effects of suspended sediments on larval survival and settlement of New Zealand urchins Evechinus chloroticus and abalone Haliotis iris Nicole E. Phillips*, Jeffrey S. Shima School of Biological Sciences, PO Box 600, Victoria University of Wellington, Wellington 6001, New Zealand *Email: nicole.phillips@vuw.ac.nz ABSTRACT: Larvae of marine organisms play an important role in the dynamics of populations, are generally sensitive to environmental stressors, and vary dramatically among species in life history traits. We examined the effects of suspended sediments from terrestrial runoff on larval development, survival, and settlement of New Zealand sea urchins Evechinus chloroticus and abalone Haliotis iris. Larval urchins and abalone were reared under 5 suspended sediment regimes (variable concentrations and timing of exposure, benchmarked against nearby field conditions), and in the absence of sediments. Stage specific per capita mortality rates of urchin larvae increased with concentrations of suspended sediments, and generally, these rates (and the sensitivity of urchin larvae to sediments) decreased with age. Mortality rates of abalone similarly increased in response to sediment concentrations, although older larvae continued to incur high losses when exposed to sediments. Mortality rates of both abalone and urchins increased in response to acute exposure to sediments early in development. For urchins, this effect was immediate and coincident only with exposure to sediments, whereas elevated mortality rates persisted well after the removal of sediments for abalone. Cumulative survival to competency was similar among species and generally decreased with exposure time and/or concentration of sediments. Urchins were twice as likely to settle and metamorphose as abalone but patterns were not related to larval sediment regime for either species. The strong species specific responses to suspended sediments we observe may greatly alter patterns of larval connectivity in marine meta-communities. KEY WORDS: Suspended sediment · Runoff · Larval mortality · Recruitment · Settlement · Abalone · Urchins Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 314. Online publication date: May 22, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research.