Project description:Metagenomic, Metatranscriptomic and Metviriomic analysis of samples collected at four time points during a single day at the Gulf of Aqaba in the Red Sea.
Project description:EMG produced TPA metagenomics assembly of the Metagenomic, Metatranscriptomic and Metviriomic analysis of samples collected at four time points during a single day at the Gulf of Aqaba in the Red Sea. (Red Sea Diel) data set
Project description:This project characterizes the metabolic consequences of the daily physiological rhythms and diel vertical migration for the model subtropical copepod, Pleuromamma xiphias. P. xiphias were collected near the Bermuda Atlantic Time Series in plankton tows at different times of day, representing different parts of their daily vertical migration. Single copepods were isolated from the tows and flash-frozen for proteomics analysis.
Project description:BackgroundThe diel vertical migration (DVM) of fish provides an active transport of labile dissolved organic matter (DOM) to the deep ocean, fueling the metabolism of heterotrophic bacteria and archaea. We studied the impact of DVM on the mesopelagic prokaryotic diversity of the Red Sea focusing on the mesopelagic deep scattering layer (DSL) between 450-600 m.ResultsDespite the general consensus of homogeneous conditions in the mesopelagic layer, we observed variability in physico-chemical variables (oxygen, inorganic nutrients, DOC) in the depth profiles. We also identified distinct seasonal indicator prokaryotes inhabiting the DSL, representing between 2% (in spring) to over 10% (in winter) of total 16S rRNA gene sequences. The dominant indicator groups were Alteromonadales in winter, Vibrionales in spring and Microtrichales in summer. Using multidimensional scaling analysis, the DSL samples showed divergence from the surrounding mesopelagic layers and were distributed according to depth (47% of variance explained). We identified the sources of diversity that contribute to the DSL by analyzing the detailed profiles of spring, where 3 depths were sampled in the mesopelagic. On average, 7% was related to the epipelagic, 34% was common among the other mesopelagic waters and 38% was attributable to the DSL, with 21% of species being unique to this layer.ConclusionsWe conclude that the mesopelagic physico-chemical properties shape a rather uniform prokaryotic community, but that the 200 m deep DSL contributes uniquely and in a high proportion to the diversity of the Red Sea mesopelagic.
Project description:One of the greatest cyclical patterns in the pelagic ecosystem is the daily vertical migration of various zooplankton and fish to depth, a process referred to as diel vertical migration (DVM). DVM is considered to be energetically costly as tiny plankton migrate hundreds of meters in a 24 hour period. To study the metabolic demands of DVM, the copepod Pleuromamma xiphias was collected during upwards and downwards migration off of Bermuda. Data-dependent acquisition on the Q-Exactive detected >1600 proteins, 180 of which were differentially abundant between the two sampling periods.
Project description:High-latitude environments show extreme seasonal variation in physical and biological variables. The classic paradigm of Arctic marine ecosystems holds that most biological processes slow down or cease during the polar night. One key process that is generally assumed to cease during winter is diel vertical migration (DVM) of zooplankton. DVM constitutes the largest synchronized movement of biomass on the planet, and is of paramount importance for marine ecosystem function and carbon cycling. Here we present acoustic data that demonstrate a synchronized DVM behaviour of zooplankton that continues throughout the Arctic winter, in both open and ice-covered waters. We argue that even during the polar night, DVM is regulated by diel variations in solar and lunar illumination, which are at intensities far below the threshold of human perception. We also demonstrate that winter DVM is stronger in open waters compared with ice-covered waters. This suggests that the biologically mediated vertical flux of carbon will increase if there is a continued retreat of the Arctic winter sea ice cover.
Project description:Diel vertical migration (DVM) of zooplankton is a global phenomenon, characteristic of both marine and limnic environments. At high latitudes, patterns of DVM have been documented, but rather little knowledge exists regarding which species perform this ecologically important behaviour. Also, in the Arctic, the vertically migrating components of the zooplankton community are usually regarded as a single sound scattering layer (SSL) performing synchronized patterns of migration directly controlled by ambient light. Here, we present evidence for hitherto unknown complexity of Arctic marine systems, where zooplankton form multiple aggregations through the water column seen via acoustics as distinct SSLs. We show that while the initiation of DVM during the autumnal equinox is light mediated, the vertical positioning of the migrants during day is linked more to the thermal characteristics of water masses than to irradiance. During night, phytoplankton biomass is shown to be the most important factor determining the vertical positioning of all migrating taxa. Further, we develop a novel way of representing acoustic data in the form of a Sound Image (SI) that enables a direct comparison of the relative importance of each potential scatterer based upon the theoretical contribution of their backscatter. Based on our comparison of locations with contrasting hydrography, we conclude that a continued warming of the Arctic is likely to result in more complex ecotones across the Arctic marine system.