DOI: 10.5061/dryad.3xsj3txt2
title: Ice gliding diatoms establish record-low temperature limits for motility in a eukaryotic cell

description: Despite periods of permanent darkness and extensive ice coverage in polar
 environments, photosynthetic ice diatoms display a remarkable capability
 of living inside the ice matrix. How these organisms navigate such hostile
 conditions with limited light and extreme cold remains unknown. Using a
 custom sub-zero temperature microscope during an Arctic expedition, we
 present the discovery of motility at record-low temperatures in a
 Eukaryotic cell. By characterizing the gliding motility of several ice
 diatom species, collected from ice cores in the Chukchi Sea, we record
 that they retain motility at temperatures as low as –15 °C.
 Remarkably, ice diatoms can glide on ice substrates, a capability absent
 in temperate diatoms of the same genus. This unique ability arises from
 adaptations in extracellular mucilage that allow ice diatoms to adhere to
 ice, essential for gliding. Even on glass substrates where both cell types
 retain motility at freezing temperatures, ice diatoms move an order of
 magnitude faster, with their optimal motility shifting toward colder
 temperatures. Combining field and laboratory experiments with
 thermo-hydrodynamic modeling, we reveal adaptive strategies that enable
 gliding motility at extreme cold temperatures. These strategies involve
 increasing internal energy efficiency with minimal changes in heat
 capacity and activation enthalpy, and reducing external dissipation by
 minimizing the temperature sensitivity of mucilage viscosity. The
 discovery of diatoms' ice gliding motility opens new routes for
 understanding their survival within a harsh ecological niche and their
 migratory responses to rapid environmental changes. Our work highlights
 the robust adaptability of ice diatoms in one of Earth's most extreme
 settings.
description: # Ice gliding diatoms establish record-low temperature limits for motility
 in a eukaryotic cell Dataset DOI:
 [10.5061/dryad.3xsj3txt2](10.5061/dryad.3xsj3txt2) ## Description of the
 data and file structure These datasets contain measurements supporting the
 discovery of ice gliding motility of diatoms in the Arctic. Data were
 collected during a 45-day expedition in the Chukchi Sea and through
 subsequent laboratory experiments. The dataset is organized into three
 categories: 1. **Adhesion Strength Measurements:** Data from experiments
 measuring the adhesion force of diatoms on different surfaces. 2.
 **Gliding Motility Assays:** Video recordings and summary data of diatom
 motility across a wide range of temperatures. 3. **Particle-Image
 Velocimetry, Particle-Tracking Velocimetry and Traction-Force
 Microscopy:** Data used to visualize fluid flow, ventral region flow, and
 measure the physical forces exerted by diatoms. ## 1. Adhesion Strength
 Measurements This section contains data from experiments measuring the
 adhesion strength of diatoms. #### File Naming Convention: The ZIP
 archives for adhesion data follow this structure:
 `adhesion_[diatom_type]_on_[substrate]_exp[replicate_number].zip` *
 `[diatom_type]`: Specifies the diatom population used. * `ice_diatoms`:
 Arctic diatoms collected from the Chukchi Sea. * `temperate_diatoms`: A
 laboratory-cultured temperate diatom species. * `[substrate]`: The surface
 the diatoms were adhering to (`glass` or `ice`). * `[replicate_number]`:
 The experimental replicate number (e.g., `exp1`, `exp2`). #### Example
 Content (inside each .zip file): Each ZIP archive contains the image data
 for a single adhesion experiment. For example,
 `adhesion_ice_diatoms_on_glass_exp1.zip` would contain: * A series of
 image files (e.g., `.tiff` or `.png`) from a flow-cell experiment at
 different shear stress (noted as `[magnitude_of_shear_stress].png`). *
 These images document the number of diatoms remaining on the substrate
 after being subjected to a specific fluid flow. * The applied shear stress
 is annotated directly on the images for quantification of detachment
 forces. Below are the adhesion files: *
 adhesion_ice_diatoms_on_glass_exp1.zip *
 adhesion_ice_diatoms_on_glass_exp2.zip *
 adhesion_ice_diatoms_on_glass_exp3.zip *
 adhesion_ice_diatoms_on_ice_exp1.zip *
 adhesion_ice_diatoms_on_ice_exp2.zip *
 adhesion_ice_diatoms_on_ice_exp3.zip *
 adhesion_temperate_diatoms_on_glass_exp1.zip *
 adhesion_temperate_diatoms_on_glass_exp2.zip *
 adhesion_temperate_diatoms_on_glass_exp3.zip *
 adhesion_temperate_diatoms_on_ice_1mPa.zip ## 2. Gliding Assay Movies and
 Data This section includes video recordings of diatom (both temperate and
 ice) motility across a wide range of temperatures, a MATLAB script for
 analysis, and a summary spreadsheet. #### File Naming Convention for
 Movies (.mp4): The video files follow this structure:
 `[diatom_type]_[temperature]C_annotated_raw_movie_[species_number].mp4` *
 `[diatom_type]`: `ice_diatom` or `temperate_diatom`. * `[temperature]C`:
 The experimental temperature in degrees Celsius (e.g., `-10C`, `22C`). *
 `[species_number]`: For example, [1] refers to the first ice diatom
 species we explored, *Navicula sp.*. Full species names are noted in each
 movie. #### Description of Movie Files: These are raw video files from
 light microscopy showing diatom gliding motility. The videos are
 "annotated," meaning they have text overlays with key
 experimental parameters burned into the frames, typically including the
 temperature (°C), a micron scale bar, and a time scale. #### Associated
 Data and Code Files: * `temperature_dependent_speed_of_ice_diatoms.xlsx`:
 An Excel spreadsheet containing the summarized gliding speed data derived
 from the motility videos. The columns are as follows: * **temperature
 (°C)**: The temperature at which motility was measured. * **mean speed (μm
 s⁻¹) (movie-level mean)**: The mean gliding speed of diatoms. * **standard
 error over experimental replicates**: The standard error calculated across
 the different experiments. * **tracked cells**: The number of individual
 cells tracked. * **experiment replicates**: The number of experimental
 replicates performed. * **tracking time**: The duration over which the
 cells were tracked. * `velocity_speed.m`: A MATLAB script used to analyze
 diatom tracks from their X,Y coordinates over time to calculate the
 average gliding speed.\ Note on Usage: This script requires an input file
 (e.g., sum.xlsx) that users can generate by processing the raw .mp4 movie
 files with particle tracking software (ImageJ/Fiji with the TrackMate
 plugin). The files below are movies, code and excel data of gliding
 assays: * ice_diatom_-10C_annotated_raw_movie_1.mp4 *
 ice_diatom_-15C_annotated_raw_movie_1.mp4 *
 ice_diatom_-1C_annotated_raw_movie_1.mp4 *
 ice_diatom_-2C_annotated_raw_movie_2.mp4 *
 ice_diatom_-3C_annotated_raw_movie_1.mp4 *
 ice_diatom_-5C_annotated_raw_movie_1.mp4 *
 ice_diatom_-5C_annotated_raw_movie_2.mp4 *
 ice_diatom_-7C_annotated_raw_movie_1.mp4 *
 ice_diatom_-7C_annotated_raw_movie_2.mp4 *
 ice_diatom_-8C_annotated_raw_movie_1.mp4 *
 ice_diatom_0C_annotated_raw_movie_1.mp4 *
 ice_diatom_0C_annotated_raw_movie_2.mp4 *
 ice_diatom_10C_annotated_raw_movie_1.mp4 *
 ice_diatom_12C_annotated_raw_movie_1.mp4 *
 ice_diatom_12C_annotated_raw_movie_2.mp4 *
 ice_diatom_18C_annotated_raw_movie_1.mp4 *
 ice_diatom_1C_annotated_raw_movie_1.mp4 *
 ice_diatom_20C_annotated_raw_movie_1.mp4 *
 ice_diatom_22C_annotated_raw_movie_1.mp4 *
 ice_diatom_3C_annotated_raw_movie_1.mp4 *
 ice_diatom_3C_annotated_raw_movie_2.mp4 *
 ice_diatom_6C_annotated_raw_movie_1.mp4 *
 ice_diatom_6C_annotated_raw_movie_2.mp4 *
 temperate_diatom_-1C_annotated_raw_movie_1.mp4 *
 temperate_diatom_-1C_annotated_raw_movie_3.mp4 *
 temperate_diatom_-3C_annotated_raw_movie_3.mp4 *
 temperate_diatom_-5C_annotated_raw_movie_3.mp4 *
 temperate_diatom_0C_annotated_raw_movie_1.mp4 *
 temperate_diatom_0C_annotated_raw_movie_2.mp4 *
 temperate_diatom_0C_annotated_raw_movie_3.mp4 *
 temperate_diatom_12C_annotated_raw_movie_1.mp4 *
 temperate_diatom_12C_annotated_raw_movie_2.mp4 *
 temperate_diatom_12C_annotated_raw_movie_3.mp4 *
 temperate_diatom_15C_annotated_raw_movie_1.mp4 *
 temperate_diatom_17C_annotated_raw_movie_3.mp4 *
 temperate_diatom_18C_annotated_raw_movie_2.mp4 *
 temperate_diatom_1C_annotated_raw_movie_3.mp4 *
 temperate_diatom_20C_annotated_raw_movie_1.mp4 *
 temperate_diatom_20C_annotated_raw_movie_3.mp4 *
 temperate_diatom_22C_annotated_raw_movie_2.mp4 *
 temperate_diatom_25C_annotated_raw_movie_1.mp4 *
 temperate_diatom_25C_annotated_raw_movie_2.mp4 *
 temperate_diatom_25C_annotated_raw_movie_3.mp4 *
 temperate_diatom_28C_annotated_raw_movie_1.mp4 *
 temperate_diatom_28C_annotated_raw_movie_2.mp4 *
 temperate_diatom_30C_annotated_raw_movie_2.mp4 *
 temperate_diatom_30C_annotated_raw_movie_3.mp4 *
 temperate_diatom_32C_annotated_raw_movie_1.mp4 *
 temperate_diatom_34C_annotated_raw_movie_2.mp4 *
 temperate_diatom_36C_annotated_raw_movie_1.mp4 *
 temperate_diatom_38C_annotated_raw_movie_1.mp4 *
 temperate_diatom_3C_annotated_raw_movie_1.mp4 *
 temperate_diatom_3C_annotated_raw_movie_3.mp4 *
 temperate_diatom_42C_annotated_raw_movie_1.mp4 *
 temperate_diatom_6C_annotated_raw_movie_1.mp4 *
 temperate_diatom_6C_annotated_raw_movie_2.mp4 *
 temperate_diatom_6C_annotated_raw_movie_3.mp4 * velocity_speed.m *
 temperature_dependent_speed_of_ice_diatoms.xlsx ## 3. Particle-Image
 Velocimetry (PIV), Particle-Tracking Velocimetry (PTV) and Traction-Force
 Microscopy (TFM) This section includes data used to visualize the fluid
 flow generated by diatoms and to measure the forces they exert on their
 substrate. #### File Descriptions: * `images_for_PIV_40X_3.2fps.zip`: A
 ZIP archive containing a pair of two .`png` images. This image pair
 represents the start and end states for a single PIV displacement
 analysis. The images were captured at 40X magnification with a time
 interval corresponding to 3.2 frames per second. *
 `plottrajectoryoftracerparticles.m`: A MATLAB script that plots the
 trajectories of tracer particles in the ventral region (PTV). *
 `Tracer_particle_moving_in_ventral_region_1.mp4` & `..._2.mp4`: Videos
 showing the movement of fluorescent tracer beads in the fluid near the
 ventral (underside) region of a diatom, visualizing the flow field. *
 `Traction_force_microscopy_annotated_raw_movie.mp4`: A video showing a
 diatom on a flexible gel containing fluorescent beads. The displacement of
 the beads is used to calculate traction forces. Annotations include a
 scale bar and time scale. * `traction_forces.mat`: A MATLAB data file
 (`.mat`) containing the processed TFM data. When loaded into MATLAB, it
 creates a single variable named traction. * traction: This is a cell array
 where each cell corresponds to one frame of the analysis. Each cell
 contains a struct with the following four fields for that specific frame:
 * `tx`: An M x N matrix of the calculated traction force in the
 x-direction (in Pascals). * `ty`: An M x N matrix of the calculated
 traction force in the y-direction (in Pascals). * `X`: An M x N matrix of
 the corresponding x-coordinates of the grid (in meters). * `Y`: An M x N
 matrix of the corresponding y-coordinates of the grid (in meters). The
 datasets below are measurements of particle-image velocimetry (PIV),
 ventral flow and traction-force microscopy (TFM): *
 images_for_PIV_40X_3.2fps.zip * plottrajectoryoftracerparticles.m *
 Tracer_particle_moving_in_ventral_region_1.mp4 *
 Tracer_particle_moving_in_ventral_region_2.mp4 *
 Traction_force_microscopy_annotated_raw_movie.mp4 * traction_forces.mat