Continuous observations of the surface energy budget and meteorology over the Arctic sea ice during MOSAiC.

The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) was a yearlong expedition supported by the icebreaker R/V Polarstern, following the Transpolar Drift from October 2019 to October 2020. The campaign documented an annual cycle of physical, biological, and chemical processes impacting the atmosphere-ice-ocean system. Of central importance were measurements of the thermodynamic and dynamic evolution of the sea ice. A multi-agency international team led by the University of Colorado/CIRES and NOAA-PSL observed meteorology and surface-atmosphere energy exchanges, including radiation; turbulent momentum flux; turbulent latent and sensible heat flux; and snow conductive flux. There were four stations on the ice, a 10 m micrometeorological tower paired with a 23/30 m mast and radiation station and three autonomous Atmospheric Surface Flux Stations. Collectively, the four stations acquired ~928 days of data. This manuscript documents the acquisition and post-processing of those measurements and provides a guide for researchers to access and use the data products.

Single nucleus RNA-sequencing: how it's done, applications and limitations.

Single nuclei RNA-sequencing (sNuc-Seq) is a methodology which uses isolated nuclei instead of whole cells to profile gene expression. By using droplet microfluidic technologies, users are able to profile thousands of single transcriptomes at high throughput from their chosen tissue. This article aims to introduce sNuc-Seq as a method and its utility in multiple tissue types. Furthermore, we discuss the risks associated with the use of nuclei, which must be considered before committing to a methodology.

A Go-type opsin mediates the shadow reflex in the annelid Platynereis dumerilii.

BACKGROUND: The presence of photoreceptive molecules outside the eye is widespread among animals, yet their functions in the periphery are less well understood. Marine organisms, such as annelid worms, exhibit a 'shadow reflex', a defensive withdrawal behaviour triggered by a decrease in illumination. Herein, we examine the cellular and molecular underpinnings of this response, identifying a role for a photoreceptor molecule of the Go-opsin class in the shadow response of the marine bristle worm Platynereis dumerilii. RESULTS: We found Pdu-Go-opsin1 expression in single specialised cells located in adult Platynereis head and trunk appendages, known as cirri. Using gene knock-out technology and ablation approaches, we show that the presence of Go-opsin1 and the cirri is necessary for the shadow reflex. Consistently, quantification of the shadow reflex reveals a chromatic dependence upon light of approximately 500 nm in wavelength, matching the photoexcitation characteristics of the Platynereis Go-opsin1. However, the loss of Go-opsin1 does not abolish the shadow reflex completely, suggesting the existence of a compensatory mechanism, possibly acting through a ciliary-type opsin, Pdu-c-opsin2, with a Lambdamax of approximately 490 nm. CONCLUSIONS: We show that a Go-opsin is necessary for the shadow reflex in a marine annelid, describing a functional example for a peripherally expressed photoreceptor, and suggesting that, in different species, distinct opsins contribute to varying degrees to the shadow reflex.