Branko GlamuzinaLorenzo VilizziMarina PiriaAnte Žuljević...
143-154页
查看更多>>摘要：Globally,marine bioinvasions threaten marine ecosystem structure and function,with the Mediterranean Sea being one of the most affected regions.Such invasions are expected to increase due to climate change.We conducted a risk screening of marine organisms(37 fishes,38 invertebrates,and 9 plants),both extant and'horizon'(i.e.,not present in the area but likely to enter it).Based on expert knowledge for the Eastern Adriatic Sea coasts of Slovenia,Croatia,and Montenegro,screenings were conducted under both current and predicted climate conditions indicating with an increase in sea surface temperature and salinity of the Adriatic Sea together with changes in precipitation regime.Our aims were to:(1)identify non-native extant and horizon marine species that may pose threats to native biodiversity and(2)evaluate the risk of invasiveness of the selected species under current and predicted climate conditions.Of the 84 species screened,there was an increase in those ranked as'high risk'from 33(39.3％)under current climate conditions and to 47(56.0％)under global warming scenarios.Forthose ranked as'very high'risk,the increase was from 6(7.1％)to 21(25.0％).Amongst the screened species,the already established high-risk species Pacific oyster Magallana gigas and Atlantic blue crab Callinectes sapidus represent a threat to ecosystem services.Given the under-representation of marine species in the current European Union List,the species we have ranked as high to very high risk should be included.
查看更多>>摘要：Coral fluorescence phenotypes have been suggested as an adaptation to a broad range of environmental conditions,yet the mechanisms linking thermal bleaching tolerance in reef-building coral populations,associated with fluorescence phenotypes due to GFP-like proteins,remains unclear.In this study,the relationship between the thermal sensitivity and phenotypic plasticity of corals was investigated using two phenotypes of Galaxea fascicularis,green and brown.The results reveal that brown G.fascicularis was more susceptible to bleaching than green G.fascicularis when exposed to a higher growth tem-perature of 32 ℃.Both phenotypes of G.fascicularis were associated with the thermotolerant Symbiodiniaceae symbiont,Durusdinium trenchii.However,the brown G.fascicularis showed a significant decrease in Symbiodiniaceae cell density and a significant increase in pathogenic bacteria abundance when the growth temperature was raised from 29 to 32 ℃.The physiological traits and transcriptomic profiles of Symbiodiniaceae were not notably affected,but there were differences in the transcriptional levels of certain genes between the two phenotype hosts of G.fascicularis.Under heat stress of 32 ℃,the gene encoding green fluorescent protein(GFP)-like and chromosome-associated proteins,as well as genes related to oxidative phosphorylation,cell growth and death showed lower transcriptional levels in the brown G.fascicularis compared to the green G.fascicularis.Overall,the results demonstrate that the green form of G.fascicularis is better able to tolerate ocean warming and defend against pathogenic bacteria,likely due to higher gene transcription levels and defense ability.
查看更多>>摘要：Hadal trenches are characterized by enhanced and infrequent high-rate episodic sedimentation events that likely introduce not only labile organic carbon and key nutrients but also new microbes that significantly alter the subseafloor microbiosphere.Currently,the role of high-rate episodic sedimentation in controlling the composition of the hadal subseafloor microbio-sphere is unknown.Here,analyses of carbon isotope composition in a～750 cm long sediment core from the Challenger Deep revealed noncontinuous deposition,with anomalous 14C ages likely caused by seismically driven mass transport and the funneling effect of trench geomorphology.Microbial community composition and diverse enzyme activities in the upper～27 cm differed from those at lower depths,probably due to sudden sediment deposition and differences in redox condition and organic matter availability.At lower depths,microbial population numbers,and composition remained rela-tively constant,except at some discrete depths with altered enzyme activity and microbial phyla abundance,possibly due to additional sudden sedimentation events of different magnitude.Evidence is provided of a unique role for high-rate episodic sedimentation events in controlling the subsurface microbiosphere in Earth's deepest ocean floor and highlight the need to perform thorough analysis over a large depth range to characterize hadal benthic populations.Such depositional processes are likely crucial in shaping deep-water geochemical environments and thereby the deep subseafloor biosphere.
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