Response of the upper ocean to tropical cyclone in the Northwest Pacific observed by gliders during fall 2018

The evolution of thermohaline structure at the upper ocean during three tropical cyclones(TCs)in the Northwest Pacific was studied in this study based on successive observation by two new-style underwater gliders during fall 2018.These remote-controllable gliders with CTD sensor enabled us to explore high frequency responses of temperature,salinity,mixed and barrier layers in the upper ocean to severe TCs in this area.Results showed that three significant cooling-to-warming and stratification destructing-to-reconstructing processes at the mixed layer occurred during the lives of three TCs.The maximal cooling of SST all reached≥0.5℃although TCs with different intensities had different minimal distances to the observed area.Under potential impacts of solar radiation,tide and inertial motions,the mixed layer depth possessed significant high-frequency fluctuations during TC periods.In addition,barrier layers appeared and vanished quickly during TCs,accompanied with varied temperature inversion processes.

Physical structure and phytoplankton community off the eastern Hainan coast during summer 2015

Based on satellite remote sensing dataset and survey data during upwelling season of 2015,the spatial structures of phytoplankton biomass and community for the first time in the eastern Hainan upwelling(EHU)and its adjacent area,the eastern Leizhou Peninsula upwelling(ELPU)were illustrated.It is found that a significant cold tongue with high salinity and low temperature along the eastern Hainan coast driven by upwelling-favorable summer monsoon.The ELPU was relative weaker than the EHU because of its wide and gentle continental slope.Due to mixing by tides and waves,DO concentration with high value(>6.0 mg/L)were almost homogenous from surface to 30 m depth at the EHU.Beneath that,low DO water(<6.0 mg/L,anoxia)were pumped upward from bottom by the upwelling.The ELPU has worse DO condition compared with the EHU where bottom DO were lower than 3.5 mg/L owing to abundant DO consumption.The phytoplankton biomass reached maximal value about 1.5 mg/m3 at 30 m depth layer rather than surface layer at the EHU indicating the impact limit of upwelling on phytoplankton growth and DO distribution.Nourished by rich nutrient input,the phytoplankton biomass at the ELPU were much higher than the EHU where the maximal value can reach about 4.0 mg/m3.The phytoplankton biomass were reduced to about 0.2–0.3 mg/m3 at the offshore areas of the EHU and ELPU which were close to the value at open sea.At the inshore of the EHU,the phytoplankton community was dominated by diatom which accounted for about 50%of phytoplankton biomass.And prokaryotes(about 40%),green algae(about 20%)and prochlorococcus(about 20%)became main species at the offshore of the EHU.At the ELPU,diatom accounted for about 80%of phytoplankton biomass followed by green algae,indicating a different ecosystem at this region compared with the EHU.

Bacterioplankton, Picoeukaryotes and Synechococcus Distribution Associated with Seagrass in South Coast of Hainan Island, China

Seagrass ecosystem is a potential bank for carbon sink. In the paper, we compared the distribution of bacterioplankton, picoeukaryotes and Synechococcus in seagrass ecosystem in Xincun Bay and coral ecosystem in Sanya Bay and found that quantity of bacterioplankton was higher in seagrass ecosystem, and picoeukaryotes had similar distribution pattern with that of bacterioplankton. However, quantity of Synechococcus distribution was higher in coral ecosystem and higher in Sanya Bay. Comparing the unit of quantity of bacterioplankton, picoeukaryotes and Synechococcus in Xincun Bay with that of Sanya Bay, open sea of the South China Sea and Indian Ocean, results showed that the highest quantity of bacterioplankton was in Xincun Bay, and the lowest was in open sea of the South China Sea. The quantity of picoeukaryotes had the similar pattern with that of bacterioplankton. Pattern of Synechococcus quantity was different, which was the highest in Sanya Bay. These results indicated that seagrass ecosystem was more suitable for bacterioplankton and picoeukaryotes growth.

Metabolic strategy of macrophages under homeostasis or immune stress in Drosophila

Macrophages are well known for their phagocytic functions in innate immunity across species.In mammals,they rapidly consume a large amount of energy by shifting their metabolism from mitochondrial oxidative phosphorylation toward aerobic glycolysis,to perform the effective bactericidal function upon infection.Meanwhile,they strive for sufficient energy resources by restricting systemic metabolism.In contrast,under nutrient deprivation,the macrophage population is down-regulated to save energy for survival.Drosophila melanogaster possesses a highly conserved and comparatively simple innate immune system.Intriguingly,recent studies have shown that Drosophila plasmatocytes,the macrophage-like blood cells,adopt comparable metabolic remodeling and signaling pathways to achieve energy reassignment when challenged by pathogens,indicating the conservation of such metabolic strategies between insects and mammals.Here,focusing on Drosophila macrophages(plasmatocytes),we review recent advances regarding their comprehensive roles in local or systemic metabolism under homeostasis or stress,emphasizing macrophages as critical players in the crosstalk between the immune system and organic metabolism from a Drosophila perspective.