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: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.
Project description:Many species of micronekton perform diel vertical migrations (DVMs), which ultimately contributes to carbon export to the deep sea. However, not all micronekton species perform DVM, and the nonmigrators, which are often understudied, have different energetic requirements that might be reflected in their trophic ecology. We analyze bulk tissue and whole animal stable nitrogen isotopic compositions (? 15N values) of micronekton species collected seasonally between 0 and 1250?m depth to explore differences in the trophic ecology of vertically migrating and nonmigrating micronekton in the central North Pacific. Nonmigrating species exhibit depth-related increases in ? 15N values mirroring their main prey, zooplankton. Higher variance in ? 15N values of bathypelagic species points to the increasing reliance of deeper dwelling micronekton on microbially reworked, very small suspended particles. Migrators have higher ? 15N values than nonmigrators inhabiting the epipelagic zone, suggesting the consumption of material during the day at depth, not only at night when they migrate closer to the surface. Migrating species also appear to eat larger prey and exhibit a higher range of variation in ? 15N values seasonally than nonmigrators, likely because of their higher energy needs. The dependence on material at depth enriched in 15N relative to surface particles is higher in migratory fish that ascend only to the lower epipelagic zone. Our results confirm that stark differences in the food habits and dietary sources of micronekton species are driven by vertical migrations.