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Coral reefs are globally threatened by climate change-related ocean warming and ocean acidification (OA). To date, slow-response mechanisms such as genetic adaptation have been considered the major determinant of coral reef persistence, with little consideration of rapid-response acclimatizationmechanisms. These rapidmechanisms such as parental effects that can contribute to trans-generational acclimatization (e.g. epigenetics) have, however, been identified as important contributors to offspring response in other systems. We present the first evidence of parental effects in a cross-generational exposure to temperature and OA in reef-building corals. Here, we exposed adults to high (28.9°C, 805 µatm PCO2) or ambient (26.5°C, 417 µatm PCO2) temperature and OA treatments during the larval brooding period. Exposure to high treatment negatively affected adult performance, but their larvae exhibited size differences and metabolic acclimation when subsequently re-exposed, unlike larvae from parents exposed to ambient conditions. Understanding the innate capacity corals possess to respond to current and future climatic conditions is essential to reef protection and maintenance. Our results identify that parental effects may have an important role through (1) ameliorating the effects of stress through preconditioning and adaptive plasticity, and/or (2) amplifying the negative parental response through latent effects on future life stages. Whether the consequences of parental effects and the potential for transgenerational acclimatization are beneficial or maladaptive, our work identifies a critical need to expand currently proposed climate change outcomes for corals to further assess rapid response mechanisms that include non-genetic inheritance through parental contributions and classical epigenetic mechanisms. [ABSTRACT FROM AUTHOR]

Aurelia spp. are among the main blooming jellyfish species. The polyp stage plays an important role in its outbreaks. To determine how temperature and food conditions may affect the process of reproduction, we maintained Aurelia sp. 1 polyps in the laboratory at three temperatures (10-15°C) and four food concentrations (0-0.1 mg C l) to test their combined effects on the strobilation process and the production of buds and ephyrae. The length of the strobilation preparation period significantly decreased with increased temperature, but was not affected by food conditions. With sufficient food supply, the polyps that had already released ephyrae restart the strobilation process. Food condition positively affects both the production of buds and ephyrae. Temperature, however, had different effects: at the three temperatures tested, 13°C was most appropriate for polyps to release ephyrae, while bud production was highest at 15°C. These results suggest that eutrophication (as a proxy for food condition) would affect both the size of the Aurelia sp. 1 polyp population and juvenile medusa population, whereas temperature adjusts the reproductive energy distribution between budding and ephyra release to regulate the strobilation process. This temperature adjustment mechanism likely helps match the production of juvenile medusae with the peak of zooplankton biomass. [ABSTRACT FROM AUTHOR]

Blooms of the scyphozoan jellyfish Aurelia spp. are directly affected by the number, survival, and ontogenetic process of the ephyra stage. To determine the combined effect of temperature and food conditions on the production of ephyrae, the rising- and decreasing-temperature experiment was designed to simulate the warming from spring to summer and the cooling from fall to winter, respectively. Results showed that both temperature and prey concentrations significantly affected the ephyra production. Aurelia sp. 1 strobilation occurred from 8 to 17°C, while 13°C was the optimal temperature for ephyra production. At 8, 10, and 17°C, when the parental polyps had abundant food, the released ephyrae had a larger bell diameter and a better nutritional foundation. Abundant food conditions in the field would therefore elevate ephyrae survival rate, accelerate individual development, and thus ensure the population size of medusae. Our results indicate that a longer spring and a relatively higher zooplankton biomass may increase blooms of Aurelia sp. 1. However, the limited food conditions present in autumn and winter most likely mean that the Aurelia sp. 1 ephyrae released during these seasons are not the main source of the following year's medusa population. [ABSTRACT FROM AUTHOR]

Environmental factors such as temperature and food type affect the rate of asexual reproduction of jellyfish at the polyp stage. Combinations of three temperatures (10, 15, and 20°C) and four food treatments ( Prorocentrum donghaiense, Skeletonema costatum, Artemia sp. nauplii, and no food) were established to examine the asexual reproduction strategy of Aurelia sp.1. The results allowed us to reject two null hypotheses: no effect of temperature and no effect of food. A change from 20 to 15 or 10°C induced polyps to release ephyrae when food was present, while polyps without food did not strobilate. Polyps with Artemia sp. nauplii as prey produced more polyps through buds and podocysts, as well as more ephyrae through strobilation. At 20°C, the mortality rates of polyps exceeded 50%, except for those served by Artemia sp. nauplii. The number of polyps increased rapidly with Artemia sp. nauplii as prey. We conclude that when animal prey is limited, plants can serve as a nutrient source and satisfy the energy requirements for polyps at lower temperatures (10 or 15°C). Phytoplankton cannot provide adequate nutrition to polyps at higher temperature (20°). Abundant animal prey and suitable temperatures are essential conditions for polyps to strobilate and release ephyrae, leading to jellyfish blooms. [ABSTRACT FROM AUTHOR]

The scyphozoan Aurelia aurita (Linnaeus) s. l., is a cosmopolitan species-complex which blooms seasonally in a variety of coastal and shelf sea environments around the world. We hypothesized that ephyrae of Aurelia sp.1 are released from the inner part of the Jiaozhou Bay, China when water temperature is below 15°C in late autumn and winter. The seasonal occurrence, growth, and variation of the scyphomedusa Aurelia sp.1 were investigated in Jiaozhou Bay from January 2011 to December 2011. Ephyrae occurred from May through June with a peak abundance of 2.38 ± 0.56 ind/m in May, while the temperature during this period ranged from 12 to 18°C. The distribution of ephyrae was mainly restricted to the coastal area of the bay, and the abundance was higher in the dock of the bay than at the other inner bay stations. Young medusae derived from ephyrae with a median diameter of 9.74 ± 1.7 mm were present from May 22. Growth was rapid from May 22 to July 2 with a maximum daily growth rate of 39%. Median diameter of the medusae was 161.80 ± 18.39 mm at the beginning of July. In August, a high proportion of deteriorated specimens was observed and the median diameter decreased. The highest average abundance is 0.62 ± 1.06 ind/km in Jiaozhou Bay in August. The abundance of Aurelia sp.1 medusae was low from September and then decreased to zero. It is concluded that water temperature is the main driver regulating the life cycle of Aurelia sp.1 in Jiaozhou Bay. [ABSTRACT FROM AUTHOR]

Blooms of Nemopilema nomurai medusae have plagued East Asian coastal waters during the last decade. Recent studies indicate that the benthic polyp phase is important for reproductive potential and survival in scyphozoans. We investigated the effects of temperature and food on the development of N. nomurai polyps in the laboratory in Dalian, China. First, polyps were exposed to temperatures of 2.5-27.5°C in 2.5°C intervals. Next, we assessed the long-term cold tolerance by subjecting polyps to 0°C for 90 days. Third, we tested polyps in 16 combinations of temperature (8, 12, 16, and 20°C) and food supply (0.42, 1.25, 2.08, and 2.91 μg C polyp day). Our results showed that N. nomurai polyps can survive from 0 to 27.5°C and overwinter without feeding. Production and excystment of podocysts did not occur at temperatures below 10°C. Somatic growth, podocyst-formation, and excystment increased with increasing temperature and were dramatically affected by food supply at warmer temperatures. Thus, warm temperatures (15-27.5°C) and abundant plankton biomass during the previous season should result in high productivity of polyps and significantly contribute to blooms of N. nomurai the following year. [ABSTRACT FROM AUTHOR]

Frequent blooms of the giant jellyfish, Nemopilema nomurai, have occurred in the East Asian Marginal Seas since 2000 and have had a devastating effect on commercial fisheries. To determine the probability of future bloom development to permit effective countermeasures, it is essential to assess the influence of environmental factors on polyp development. In this study, the effects of salinity on the polyps of N. nomurai from the coastal waters of Dalian in the northern Yellow Sea were tested at salinities ranging from 2.5 to 45. The combined effects of salinity (15 and 32) and light intensity (800, 400, and 0 lux) in a 12-h light-12-h dark photoperiod were also assessed. The lower and upper salinity limits for N. nomurai polyp survival were 10 and 40, respectively. The salinity range of 20-27.5 was best for podocyst reproduction. Survival and somatic growth of polyps, and their asexual production of podocysts, were significantly greater at low to middle than at high salinities. Polyps survived, grew, and produced podocysts at all light intensities tested; however, differences in light intensity induced few statistically significant changes. These results indicated that N. nomurai polyps are adapted to survive, grow, and reproduce in estuaries and near-shore environments. [ABSTRACT FROM AUTHOR]

In recent decades, massive outbreaks of the giant jellyfish, Nemopilema nomurai have been appearing frequently in coastal seas of China. In the life cycle of N. nomurai, asexual reproduction by its benthic polyps may largely determine the jellyfish population size, and it was thought that asexual reproduction leading to medusae might be affected by differences in the duration at low winter temperature on different parts of the coast. To test this hypothesis, polyps were first stored at low temperature for two different durations, 5°C for either 40 or 117 days. They were then maintained at seven temperatures, (maintained at 5°C, and separately elevated to 10, 13, 16, 19, 22, 27°C) reached by raising the temperature 1°C every 2 days from 5°C, as well as a control temperature: 5°C. Polyps were fed with three frequencies (once per 5 days, once per 10 days, and unfed, prey concentration, 0.1 mgC l, being supplied once). The percentages of polyps strobilating, strobilation duration, ephyra and podocyst production were recorded. The results showed that longer duration at low temperature accelerated strobila formation at warmer temperature, as well as significantly enhancing podocyst production, but not for the strobilation percentage or ephyra production. Temperature had a marked influence on strobilation percentage, as well as on ephyra and podocyst production. The optimum temperature for strobilation by N. nomurai polyps ranged from 10 to 13°C. The maximum numbers of ephyrae appeared after polyps had been stored at longer low temperature then warmed to 10°C and fed once per 5 days, while the maximum production of podocysts occurred in polyps warmed to 27°C and fed once per 5 days. We conclude that longer duration at low temperature in winter, a continuous 10-13°C period in spring, and increasing food supply all accelerate the strobila formation, increase jellyfish production and are tend to increase blooms of N. nomurai medusae. [ABSTRACT FROM AUTHOR]

Cyanea nozakii and Nemopilema nomurai are two major giant jellyfish species frequently blooming in East Asian waters in recent decades. In order to inspect their asexual reproduction performance in climate regimes associated with global warming, variations of podocyst reproduction and strobilation were investigated at five different temperature regimes (approximate simulation of summer in warm years and cold years: temperature increased from 18 to 25°C and then decreased to 18 and 10°C in three months, respectively; approximate simulation of autumn in warm years and cold years: temperature decreased from 18 to 10°C in two and three months, respectively; control: constant 18°C), and three food frequencies (once per 3d, once per 6d, and unfed). Strobilation in C. nozakii occurred at warmer temperature (≥18°C) but lower temperature (≤18°C) in N. nomurai. More than 90% of ephyrae of C. nozakii and N. nomurai were released in the thermal ranges of 22-25°C and 10-13°C, respectively. Higher percentages of polyps produced podocysts, and increased podocyst production was observed at warmer temperature (>18°C) and more food supplies in both species. The numbers of ephyrae in C. nozakii and podocysts in N. nomurai were significantly increased by prolonged duration of 18-25°C in summer during warm years. Simultaneously, prolonged duration of 10-18°C significantly increased strobilation percentage, ephyra, and podocyst production in N. nomurai in the autumn. More polyps of N. nomurai strobilating in the autumn proved adverse to outbreaks of medusae in the following summer. The results of this study indicate that the response of asexual reproduction to ocean warming appears species specific. Increased ephyra production in C. nozakii but higher podocyst reproduction in N. nomurai is expected in summer and autumn during warm years. [ABSTRACT FROM AUTHOR]

Significant warming and acidification of the oceans is projected to occur by the end of the century. CO vents, areas of upwelling and downwelling, and potential leaks from carbon capture and storage facilities may also cause localised environmental changes, enhancing or depressing the effect of global climate change. Cold-water coral ecosystems are threatened by future changes in carbonate chemistry, yet our knowledge of the response of these corals to high temperature and high CO conditions is limited. Dimethylsulphoniopropionate (DMSP), and its breakdown product dimethylsulphide (DMS), are putative antioxidants that may be accumulated by invertebrates via their food or symbionts, although recent research suggests that some invertebrates may also be able to synthesise DMSP. This study provides the first information on the impact of high temperature (12 °C) and high CO (817 ppm) on intracellular DMSP in the cold-water coral Lophelia pertusa from the Mingulay Reef Complex, Scotland (56°49′N, 07°23′W), where in situ environmental conditions are meditated by tidally induced downwellings. An increase in intracellular DMSP under high CO conditions was observed, whilst water column particulate DMS + DMSP was reduced. In both high temperature treatments, intracellular DMSP was similar to the control treatment, whilst dissolved DMSP + DMS was not significantly different between any of the treatments. These results suggest that L. pertusa accumulates DMSP from the surrounding water column; uptake may be up-regulated under high CO conditions, but mediated by high temperature. These results provide new insight into the biotic control of deep-sea biogeochemistry and may impact our understanding of the global sulphur cycle, and the survival of cold-water corals under projected global change. [ABSTRACT FROM AUTHOR]