scholarly journals Effects of ultraviolet (UV) radiation on larval settlement of the reef coral Pocillopora damicornis

2001 ◽  
Vol 217 ◽  
pp. 251-261 ◽  
Author(s):  
IB Kuffner
2017 ◽  
Author(s):  
Lei Jiang ◽  
You-Fang Sun ◽  
Yu-Yang Zhang ◽  
Guo-Wei Zhou ◽  
Xiu-Bao Li ◽  
...  

Abstract. Diurnal fluctuations in seawater temperature are ubiquitous on tropical reef flats. However, effects of such dynamic temperature variations on the early stages of corals are poorly understood. Here, we investigated the responses of larvae and new spats of Pocillopora damicornis to two constant temperature treatments (29 and 31 °C), and two diurnally fluctuating treatments (28–31 and 30–33 °C with daily means of 29 and 31 °C, respectively) simulating the 3 °C diel oscillations at 3 m depth on Luhuitou fringing reef (Sanya, China). Results showed that the thermal stress on settlement at 31 °C was almost negated by the fluctuating treatment. Further, temperature fluctuations did not exacerbate bleaching responses but alleviated the maximum excitation pressure over photosystem Ⅱ (PSⅡ). Although early growth and development were highly stimulated at 31 °C, oscillations of 3 °C had little effects on budding and lateral growth. Nevertheless, daytime encounters with the maximum temperature of 33 °C elicited a notable reduction in calcification. These results underscore the complexity in the effects caused by diel temperature fluctuations on early stages of corals, and suggest that the ecologically relevant temperature variability could buffer the warming stress on larval settlement and dampen the positive effects of increased temperatures on coral growth.


2017 ◽  
Vol 14 (24) ◽  
pp. 5741-5752 ◽  
Author(s):  
Lei Jiang ◽  
You-Fang Sun ◽  
Yu-Yang Zhang ◽  
Guo-Wei Zhou ◽  
Xiu-Bao Li ◽  
...  

Abstract. Diurnal fluctuations in seawater temperature are ubiquitous on tropical reef flats. However, the effects of such dynamic temperature variations on the early stages of corals are poorly understood. In this study, we investigated the responses of larvae and new recruits of Pocillopora damicornis to two constant temperature treatments (29 and 31 °C) and two diurnally fluctuating treatments (28–31 and 30–33 °C with daily means of 29 and 31 °C, respectively) simulating the 3 °C diel oscillations at 3 m depth on the Luhuitou fringing reef (Sanya, China). Results showed that the thermal stress on settlement at 31 °C was almost negated by the fluctuating treatment. Further, neither elevated temperature nor temperature fluctuations caused bleaching responses in recruits, while the maximum excitation pressure over photosystem II (PSII) was reduced under fluctuating temperatures. Although early growth and development were highly stimulated at 31 °C, oscillations of 3 °C had little effects on budding and lateral growth at either mean temperature. Nevertheless, daytime encounters with the maximum temperature of 33 °C in fluctuating 31 °C elicited a notable reduction in calcification compared to constant 31 °C. These results underscore the complexity of the effects caused by diel temperature fluctuations on early stages of corals and suggest that ecologically relevant temperature variability could buffer warming stress on larval settlement and dampen the positive effects of increased temperatures on coral growth.


mBio ◽  
2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Christophe Kopp ◽  
Isabelle Domart-Coulon ◽  
Stephane Escrig ◽  
Bruno M. Humbel ◽  
Michel Hignette ◽  
...  

ABSTRACT  Reef-building corals form essential, mutualistic endosymbiotic associations with photosynthetic Symbiodinium dinoflagellates, providing their animal host partner with photosynthetically derived nutrients that allow the coral to thrive in oligotrophic waters. However, little is known about the dynamics of these nutritional interactions at the (sub)cellular level. Here, we visualize with submicrometer spatial resolution the carbon and nitrogen fluxes in the intact coral-dinoflagellate association from the reef coral Pocillopora damicornis by combining nanoscale secondary ion mass spectrometry (NanoSIMS) and transmission electron microscopy with pulse-chase isotopic labeling using [13C]bicarbonate and [15N]nitrate. This allows us to observe that (i) through light-driven photosynthesis, dinoflagellates rapidly assimilate inorganic bicarbonate and nitrate, temporarily storing carbon within lipid droplets and starch granules for remobilization in nighttime, along with carbon and nitrogen incorporation into other subcellular compartments for dinoflagellate growth and maintenance, (ii) carbon-containing photosynthates are translocated to all four coral tissue layers, where they accumulate after only 15 min in coral lipid droplets from the oral gastroderm and within 6 h in glycogen granules from the oral epiderm, and (iii) the translocation of nitrogen-containing photosynthates is delayed by 3 h. IMPORTANCE  Our results provide detailed in situ subcellular visualization of the fate of photosynthesis-derived carbon and nitrogen in the coral-dinoflagellate endosymbiosis. We directly demonstrate that lipid droplets and glycogen granules in the coral tissue are sinks for translocated carbon photosynthates by dinoflagellates and confirm their key role in the trophic interactions within the coral-dinoflagellate association.


2020 ◽  
Vol 97 (1) ◽  
Author(s):  
Fangfang Yang ◽  
Jiahao Mo ◽  
Zhangliang Wei ◽  
Lijuan Long

ABSTRACT Calcified macroalgae play an important role in the settlement and metamorphosis of invertebrate larvae in coral reef ecosystems. However, little is known about the algal-associated bacterial communities and their effects on larval settlement. In this study, the responses of larvae of the coral Pocillopora damicornis to calcified algae (Porolithon onkodes, Halimeda cylindracea, Halimeda opuntia and Amphiroa fragilissima) were evaluated. The results revealed that Por. onkodes and H. cylindracea significantly enhanced the rates of settlement and metamorphosis, whereas fewer larvae settled on Am. fragilissima and H. opuntia. Amplicon pyrosequencing of the V3–V4 region of 16S rDNA was applied to investigate the relationship between algal bacterial community and larval settlement. Principal coordinates analysis demonstrated that the bacterial community composition of H. opuntia was more similar to that of Am. fragilissima, but clearly distinct from those of H. cylindracea and Por. onkodes. Furthermore, the relative abundances of bacteria were highly diverse among different algae. H. opuntia had higher percentages of Thalassobius, Pelagibius and SM1A02, whereas the abundances of Mycoplasma and Suttonella were significantly higher in H. cylindracea than other algae. Our results showed that larval settlement/metamorphosis was strongly correlated with the bacterial community composition and with the relative abundance of a few operational taxonomic units.


2018 ◽  
Vol 33 (1) ◽  
pp. 33-39 ◽  
Author(s):  
Munasik ◽  
Suharsono ◽  
J. Situmorang ◽  
H. N. Kamiso

Monthly larval release by the coral Pocillopora damicornis at Panjang Island, Central Java was investigated. Corals were collected from windward and leeward and maintained in outdoor, flow-trough system to quantify nightly release of larvae. Larval release of the coral occurs every month throughout the year, and its planulation increased during dry monsoon. Monthly planulation occurs from new moon to full moon and possesses in different pattern between single and paired colonies. Planulation in paired colonies occurred in single peak and more synchronized in each colony however single colonies planulated in double peaks and less synchronized in each colony. This study confirmed that planulation period of P. damicornis at Panjang Island over a range of lunar phases with shorter periods of peak release which predominantly controlling by tidal range rather than lunar cycle.


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