Trait-based approach revealed the seasonal variation of mesozooplankton functional groups in the South Yellow Sea.

Functional traits determine the fitness of organisms and mirror their ecological functions. Although trait-based approaches provide ecological insights, it is underexploited for marine zooplankton, particularly with respect to seasonal variation. Here, based on four major functional traits, including body length, feeding type, trophic group, and reproduction mode, we quantified the seasonal variations of mesozooplankton functional groups in the South Yellow Sea (SYS) in the spring, summer, and autumn of 2018. Strong seasonal dynamics were identified for all traits but patterns varied among traits. Small zooplankton (47.7-88.6%), omnivores-herbivores (81.3-97.6%), and free spawners (54.8-92.5%) dominated in three seasons, while ambush feeders and current feeders dominated in spring (45.7%), and autumn (73.4%), respectively. Cluster analysis of the functional traits showed that the mesozooplankton in the SYS can be classified into eight functional groups. The biogeographic and seasonal variations of functional groups can be partially explained by environmental drivers. Group 1, represented by omnivores-herbivores, was the most dominant functional group, the abundance of which peaked in spring and was positively correlated with chlorophyll a concentration, indicating its close association with phytoplankton dynamics. The contribution of giant, active ambush carnivores, passive ambush carnivore jellyfish, current omnivores-detritivores, and parthenogenetic cladocerans increased with sea surface temperature. The proportion of giant, active ambush carnivores and active ambush omnivore-carnivore copepods decreased with salinity in autumn. This study presents a new perspective for understanding the dynamics of zooplankton and paves the way for further research on the functional diversity of zooplankton in the SYS. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-022-00156-9.

Latitudinal transition of epipelagic mesozooplankton in the northwestern Pacific in winter.

The northwestern Pacific (NWP) is a hotspot of marine biodiversity study, and zooplankton is a crucial secondary producer in the marine ecosystem. It is of utmost importance to do extensive study on the distribution of zooplankton community in the NWP. The distribution of epipelagic zooplankton community in the 143-146°E section between the equator and 36°N in winter was examined in this study. The findings indicated that the Kuroshio extension, the North Pacific Subtropical Gyre, the North Equatorial Current and the North Equatorial Countercurrent were the four main ocean currents in the NWP that regulated the latitudinal transition of epipelagic mesozooplankton and split the sample section into four station groups. The key factors influencing zooplankton's geographic distribution were temperature, primary productivity, and current movement. In general, as latitude increased, zooplankton abundance and biomass first decreased and subsequently flourished in the NWP. Diversity indexes and indicator species also revealed the difference across the communities in four station groups. The body length of zooplankton declined gradually from north to south under the combined influence of temperature and primary production, with the minimum in the oligotrophic subtropical zone and a sub-peak in the high primary production area near the equator. Additionally, the abundance of zooplankton was higher in the winter than in the summer due to seasonal fluctuations in the properties of the ocean currents. This study elucidated the control effects of ocean currents on the latitudinal distribution of zooplankton, supplemented records of the geographic distribution and body length characteristics of zooplankton communities in the NWP, and provided the basis for further research on the ecological role of zooplankton communities and the global changes of marine ecosystems.

Effects of Prorocentrum donghaiense bloom on zooplankton functional groups in the coastal waters of the East China Sea.

Blooms of the non-toxic dinoflagellate Prorocentrum donghaiense are common in the East China Sea; however, the in situ impacts of these blooms on zooplankton community functions have not yet been conducted in this area. Using functional trait-based methods, we found that P. donghaiense bloom significantly changed the zooplankton community structure and functions in the coastal water of the East China Sea. Zooplankton species richness and biodiversity increased after the bloom. Based on body length, feeding type, trophic group and reproductive mode, we categorized zooplankton into four functional groups and characterized their dynamics. Before and after the bloom, the zooplankton community was dominated by herbivorous- and free-spawner- lineages represented by copepods and tunicates, while during the bloom, the zooplankton community was dominated by carnivorous- and egg-brooding- lineages represented by small jellyfish, chaetognaths and copepods.

An embryonic stem cell-like gene expression signature in poorly differentiated aggressive human tumors.

Cancer cells possess traits reminiscent of those ascribed to normal stem cells. It is unclear, however, whether these phenotypic similarities reflect the activity of common molecular pathways. Here, we analyze the enrichment patterns of gene sets associated with embryonic stem (ES) cell identity in the expression profiles of various human tumor types. We find that histologically poorly differentiated tumors show preferential overexpression of genes normally enriched in ES cells, combined with preferential repression of Polycomb-regulated genes. Moreover, activation targets of Nanog, Oct4, Sox2 and c-Myc are more frequently overexpressed in poorly differentiated tumors than in well-differentiated tumors. In breast cancers, this ES-like signature is associated with high-grade estrogen receptor (ER)-negative tumors, often of the basal-like subtype, and with poor clinical outcome. The ES signature is also present in poorly differentiated glioblastomas and bladder carcinomas. We identify a subset of ES cell-associated transcription regulators that are highly expressed in poorly differentiated tumors. Our results reveal a previously unknown link between genes associated with ES cell identity and the histopathological traits of tumors and support the possibility that these genes contribute to stem cell-like phenotypes shown by many tumors.