Topic
Odontaster validus
About: Odontaster validus is a research topic. Over the lifetime, 93 publications have been published within this topic receiving 3914 citations. The topic is also known as: Sea star.
Papers published on a yearly basis
Papers
TL;DR: Data from the field surveys and the energetics studies suggest that Mycale is prevented from dominating the space resource by the predation of two asteroids.
Abstract: Studies of the benthos between 30 and 60 m at Cape Armitage, McMurdo Sound. Antarctica, reveal an epifaunal community in which sponges and their asteroid and nudibranch predators predominate. Field experiments demonstrated that, with the exception of Mycale accrata, the growth rates of the sponges are too slow to measure in one year. Mycale, however, was observed to increase its mass as much as 67%. Because of its more rapid growth rate, Mycale appears to be the potential dominant in competition for substratum space, the resource potentially limiting to the sessile species. This conclusion is supported by observations of Mycale growing over and, in some cases, apparently having smothered many other sessile species representing at least three phyla. The densities and size frequency distributions of all the predators were measured; numerous feeding observations allowed an accurate appraisal of dietary compositions. Because of the predators' very slow consumption rates, however, direct measures of ingestion and its impact on prey populations were not possible. Estimates of the ingestion rates were derived from measurements of predator respiration rates, growth rates, and gonad growth. Data from the field surveys and the energetics studies suggest that Mycale is prevented from dominating the space resource by the predation of two asteroids. Perknaster fuscus antarcticus and Acodontaster conspicuus. Adult Perknaster specialize on Mycale, and the sponge provides a small proportion of the diet of A. conspicuus. Acodontaster conspicuus and the dorid nudibranch Austrodoris memurdensis are the most important predators on three species of rossellid sponges (Rossella racovitzae, R. nuda, and Scolymastra joubini). Despite this relatively heavy consumption and despite the fact that none of these sponges has a refuge in growth from potential mortality from A. conspicuus, very large standing crops of the rossellid sponges have accumulated. This accumulation appears to result from predation on larval and young A. conspicuus and Austrodoris by Odontaster validus, which is primarily a detrital feeder and apparently acts as a filter against the settlement and survival of the A. conspicuus and Austrodoris larvae. In addition, predation upon adult A. conspicuus by O. validus and the actinian urticinopsis antarcticus annually kills approximately 3.5% of the A. conspicuus population. This mortality exceeds the apparent rate at which A. conspicuus escape the larval filter.
740 citations
14 Mar 2013
190 citations
TL;DR: A window of optimal temperature is proposed for development time and embryo viability in this population of Sterechinus neumayeri, Antarctica, after Spawning trials and field observations of larvae indicated that the time of gamete release and periods of larval development in S. neumayersi coincided with austral summer sea temperatures in the same window.
Abstract: The effects of temperature on development and viability were measured at 14 levels between -2?C and +3?C on embryos of two asteroids (Odontaster val- idus and Odontaster meridionalis) and an echinoid (Sterechinus neumayeri) from Signy Island, Antarctica. Development rates were 2 to 10 times slower than those for temperate or tropical echinoderms, with times to hatching up to 240 h. Development rates for the two asteroids differed by 1.15 x, and rates for both species approximately doubled over the experimental tempera- ture range. In 0. validus, embryo viability was indepen- dent of temperature, but in 0. meridionalis viability declined with increasing temperature. Development rates for S. neumayeri were little affected by tempera- ture above +0.2?C, but declined rapidly at lower tem- peratures. Conversely, the number of nonviable eggs was low and constant below + 1.7?C, but rose rapidly at higher temperatures. A window of optimal temperature, between +0.2?C and +1.7?C, has therefore been pro- posed for development time and embryo viability in this population of S. neumayeri. Spawning trials and field observations of larvae indicated that the time of gamete release and periods of larval development in S. neumay- eri coincided with austral summer sea temperatures in the same window. Embryos of 0. meridionalis and 0. validus are released in winter, when temperatures are constantly below -1.6?C. Comparison of the different strategies suggests that larval food supply and predation during planktonic phases are not the dominant ecologi- cal factors for these species.
152 citations
TL;DR: Compared to their metabolic rates, antarctic larvae have larger energy stores and planktotrophic larvae have higher nutrient transport capacities when compared to larvae from temperate regions, which allow antarctica larvae to survive for long periods without particulate food.
Abstract: The rates of oxygen consumption by embryos of antarctic echinoderms (Acodontaster hodgsoni, Odontaster validus, Psilaster charcoti, and Sterechinus neumayeri) were compared to the biomas (ash-free dry organic weight) of the egg of each species. These species could survive for months to years (range: 10 months to 5 years) by relying solely on the reserves present in the egg. However, certain species did not use any of the egg's reserves during early development. Embryonic stages of O. validus (a species with planktotrophic larvae) did not decrease in lipid, protein, or total biomass during the first 35 days of development. During the first 42 days of development, embryos of A. hodgsoni (a species with lecithotrophic development) used protein as an energy source. For both species lipid composed 40 to 50% of egg biomass, but was not used as an energy reserve. Larvae of O. validus have a high-affinity transport system for amino acids dissolved in seawater (K1 = 1.3 {mu}M for alanine). The rate of alanine transport from a low concentration (50 nM) could supply 32% of the larva's metabolic needs. This is a 10-fold higher input to metabolism than was determined (3% at 50 nM) for larvae of a temperate asteroid, Asterina miniata. Larvae of antarctic echinoderms live in an environment where the food supply is low for most of the year. Relative to their metabolic rates, antarctic larvae have larger energy stores and planktotrophic larvae have higher nutrient transport capacities when compared to larvae from temperate regions. These physiological differences allow antarctic larvae to survive for long periods without particulate food.
141 citations
TL;DR: Concentrations of essential and non-essential metals in birds were highest in liver followed by muscle and eggs, and concentrations of Cadmium and mercury levels in muscle of southern elephant seals were above the detection limit, whereas in Antarctic fur seals they were below it.
Abstract: To evaluate levels of essential (zinc and copper) and non-essential (mercury and cadmium) heavy metals, 34 species of organisms from different areas close to the Antarctic Peninsula were analysed. These included algae, filter-feeders, omnivorous invertebrates and vertebrates. Mercury was not detected, while cadmium was found in the majority of organisms analysed (detection limit was 0.05 ppm for both metals). The highest cadmium concentration was observed in the starfish Odontaster validus. Anthozoans, sipunculids and nudibranchs showed maximum levels of zinc, while the highest copper level was found in the gastropod Trophon brevispira. Mercury and cadmium levels in fishes were below the detection limit. Concentrations of essential and non-essential metals in birds were highest in liver followed by muscle and eggs. Cadmium and mercury levels in muscle of southern elephant seals were above the detection limit, whereas in Antarctic fur seals they were below it. The objective of the study was to gather baseline information for metals in Antarctic Ocean biota that may be needed to detect, measure and monitor future environmental changes.
131 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 2 |
| 2020 | 1 |
| 2019 | 3 |
| 2018 | 5 |
| 2017 | 3 |
| 2016 | 1 |