Aurelia aurita

About: Aurelia aurita is a research topic. Over the lifetime, 503 publications have been published within this topic receiving 15489 citations. The topic is also known as: Common jellyfish.

Reproduction and life history strategies of the common jellyfish, Aurelia aurita, in relation to its ambient environment

Abstract: The scyphozoan Aurelia aurita (Linnaeus) is a cosmopolitan species, having been reported from a variety of coastal and shelf sea environments around the world. It has been extensively studied over the last 100 years or so, and examination of the literature reveals three striking features: (1) the presence of populations in a wide range of environmental conditions; (2) large inter-population differences in abundance and life history patterns over large and small spatial scales; and (3) inter-annual variability in various aspects of its population dynamics. A. aurita is clearly a highly flexible species that can adapt to a wide range of environmental conditions. While various physiological and behavioural characteristics explain how A. aurita populations can take advantage of their surrounding environment, they do not explain what governs the observed temporal and spatial patterns of abundance, and the longevity or lifespan of populations. Understanding these features is necessary to predict how bloom populations might form. In a given habitat, the distribution and abundance of benthic marine invertebrates have been found to be maintained by four factors: larval recruitment (sexual reproduction), migration, mortality and asexual reproduction. The aims of this review are to determine the role of reproduction and life history strategies of the benthic and pelagic phases of A. aurita in governing populations of medusae, with special attention given to the dynamic interaction between A. aurita and its surrounding physical and biological environment.

Molecular Evidence for Cryptic Species of Aurelia aurita (Cnidaria, Scyphozoa)

Abstract: Morphological taxonomy suggests that marine faunas are species poor compared to terrestrial and freshwater faunas (1). This dichotomy has been attributed to the unique potential of marine plankters for distant dispersal across homogenous oceans with few barriers to gene flow (2). The relative scarcity of opportunities for allopatric divergence has resulted in depauperate marine faunas characterized by a high proportion of widespread or cosmopolitan species. Aurelia aurita (Linnaeus) has been considered a good example of such a cosmopolite (3, 4, 5, 6). However, recent molecular studies have revealed cryptic species in many marine taxa (7), suggesting that marine biodiversity is higher and opportunities for speciation have been more frequent than generally recognized. Here, we present nuclear and mitochondrial DNA sequence evidence of seven sibling species of Aurelia aurita and two additional species, A. limbata Brandt and A. labiata Chamisso & Eysenhardt. These sequence data indicate speciation events as early as the late Cretaceous or early Tertiary, consistent with the formation of well-recognized biogeographic barriers to gene flow in the seas. Traditionally, the genus Aurelia comprises two species: A. limbata, a polar species, and A. aurita, a common inhabitant of nearshore waters circumglobally between about 50 °N and 55 °S (3, 4, 5; Fig. 1). Perhaps due to its ubiquity, A. aurita has become a popular research organism for studies as diverse as protein chemistry, development, ecology, ethology, and hydrodynamics (6). A. aurita also is economically important because worldwide it preys on or competes with larvae of commercial fisheries and because swarms of medusae may impede trawling or block power-plant intakes (8). Furthermore, this “pest” has been introduced at least into San Francisco Bay (9) and possibly many other places (10). A. aurita is also familiar to nonspecialists because it is the most commonly displayed medusa in public aquaria. The systematics of A. aurita therefore is of considerable scientific, economic, and general interest. Aurelia has a typical bipartite scyphozoan life history in which benthic scyphopolyps asexually strobilate ephyrae that grow into sexual medusae, the females of which brood larvae that settle into the shallow coastal benthos within a few days of being released. Of these life stages, the medusa probably is the principal dispersal phase because only the medusa is both long-lived (several months to more than one year; 11) and planktonic (6). The potential of medusae for distant dispersal is consistent with the current classification of A. aurita as a circumglobal, almost cosmopolitan, species (4, 5). However, A. aurita medusae in Saanich Inlet, British Columbia, and perhaps elsewhere, migrate directionally (12), maintaining breeding aggregations within isolated inlets and probably limiting gene flow among populations. Consistent with limited gene flow, allozyme differences have been found between populations of A. aurita in the eastern and western Atlantic Ocean, the Gulf of Mexico, and the eastern and western Pacific Ocean (9, 13). In addition, one species, A. labiata, was recently recognized as native to Pacific North America and distinct from A. aurita (10). Novel DNA sequence data from nuclear internal transcribed spacer one (ITS-1) and mitochondrial cytochrome oxidase c subunit I (COI) reveal highly structured gene genealogies and at least nine distinct clades of Aurelia (Figs. 1, 2). Several lines of argument suggest that these clades warrant recognition as distinct species. First, the length of ITS-1 varies from 240 nucleotides (Charlestown, RI) to 360 nucleotides (Cananeia, Brazil). Such length variation is comparable to that found among congeneric species of Received 7 August 2000; accepted 19 October 2000. * To whom correspondence should be addressed at Coral Reef Research Foundation, Box 1765, Koror, PW 96940, Palau. Reference: Biol. Bull. 200: 92–96. (February 2001)

Seasonal variation in δ13C and δ15N of size-fractionated plankton at a coastal station in the northern Baltic proper

Abstract: Seasonal cycles of δ 13 C and δ 15 N in dissolved organic carbon and size-fractionated plankton, ranging from bacteria to the jellyfish Aurelia aurita, were studied during a 1 yr cycle at a coastal station in the Baltic Sea. The observed isotopic changes were found with time lags in all size-fractions of plankton. The δ 13 C showed a bimodal cycle with 2 local maxima, the first coinciding with the spring bloom and the second with the autumn bloom. In δ 15 N, the annual cycle was trimodal with 3 local maxima. The first occurred in connection with the spring bloom, the second in mid-summer and the third was a broad autumn-to-winter maximum. The causes of these patterns are discussed in relation to measured oceanographic variables. In the summer, a depleted nitrogen isotopic signal was propagated through all size-classes of plankton, indicating direct or secondary utilisation of fixed nitrogen from cyanobacteria. The strength of the signal indicated that nitrogen-fixing cyanobacteria are more ecologically important as instantaneous nitrogen sources in the Baltic than previously assumed. Enrichment of δ 15 N in size-classes of plankton was found to be a linear function of logarithmic organism size from 20 to 500 μm, reflecting size-related consumption patterns of marine plankton food-webs. The explanatory power of the linear regression and the enrichment per unit size were stronger in spring and autumn than in the summer, reflecting time lags and diversity in the zooplankton community. The size-specific approach was found to be a simpler and more appropriate way of analysing trophic isotope enrichment in plankton food-webs than the assumption of a general enrichment factor per trophic level.

Pelagic coelenterates and eutrophication: a review

Abstract: Although eutrophication is a widespread problem in marine waters, its effects are often difficult to separate from normal fluctuations of pelagic coelenterate populations and from other anthropogenic changes due to industrial pollution, construction, introductions, global warming and overfishing The least complex situations are in small coastal water bodies such as the Caribbean lagoons and Scandinavian fjords Typically, the diversity of pelagic coelenterates decreases, but the biomass of a small number of species (such as the hydromedusae Aglantha digitale and Rathkea octopunctata and the scyphomedusae Aurelia aurita and Cassiopea spp) may increase Adaptations that may allow these species to survive under eutrophic conditions are discussed