DOI: 10.5061/dryad.9ghx3ffqk
title: Ocean climate and hydrodynamics drive decadal shifts in Northeast Atlantic dinoflagellates

description: The abundance of large marine dinoflagellates has declined in the North
 Sea since 1958. Although hypotheses have been proposed to explain this
 diminution (increasing temperature and wind), the mechanisms behind this
 pattern have thus far remained elusive. In this article, we study the
 long-term changes in dinoflagellate biomass and biodiversity in relation
 to hydro-climatic conditions and circulation within the North-Atlantic.
 Our results show that the decline in biomass has paralleled an increase in
 biodiversity caused by a temperature-induced northward movement of
 subtropical taxa along the European shelf-edge, and facilitated by changes
 in oceanic circulation (subpolar gyre contraction). However, major changes
 in North Atlantic hydrodynamics in the 2010s (subpolar gyre expansion and
 low-salinity anomaly) stopped this movement, which triggered a
 biodiversity collapse in the North Sea. Further, North Sea dinoflagellate
 biomass remained low because of warming. Our results, therefore, reveal
 that regional climate warming and changes in oceanic circulation strongly
 influenced shifts in dinoflagellate biomass and biodiversity. The data
 provided here are the changes in dinoflagellates taxonomic richness and
 biomass in the Northeast Atlantic, the salinity and temperature optimums
 of each taxa and various hydroclimatic indices.
description: # Ocean climate and hydrodynamics drive decadal shifts in Northeast
 Atlantic dinoflagellates published in Global Change Biology. The content
 of each '.mat' file is described below:
 -Dino_north_sea_data_all.mat *yrs2 = a vector with the years from 1958 to
 2020 *dino_tot_yrs = a vector with the mean annual changes in
 dinoflagellates biomass in the North Sea *sp_rich_yrs = a vector with the
 annual changes in dinoflagellates taxonomic richness in the North Sea
 -Dino_north_sea_data_group.mat *dino_1_yrs = a vector with the mean annual
 changes in biomass of the Warm-haline assemblage in the North Sea
 *dino_2_yrs = a vector with the mean annual changes in biomass of the
 Psychrophilous assemblage in the North Sea *dino_3_yrs = a vector with the
 mean annual changes in biomass of the Temperate assemblage in the North
 Sea *dino_4_yrs = a vector with the mean annual changes in biomass of the
 Temperate-haline assemblage in the North Sea *dino_5_yrs = a vector with
 the mean annual changes in biomass of the Temperate hypohaline assemblage
 in the North Sea *sp_rich_yrs_grp1 = a vector with the annual changes in
 taxonomic richness of the Warm-haline assemblage in the North Sea
 *sp_rich_yrs_grp2 = a vector with the annual changes in taxonomic richness
 of the Psychrophilous assemblage in the North Sea *sp_rich_yrs_grp3 = a
 vector with the annual changes in taxonomic richness of the Temperate
 assemblage in the North Sea *sp_rich_yrs_grp4 = a vector with the annual
 changes in taxonomic richness of the Temperate-haline assemblage in the
 North Sea *sp_rich_yrs_grp5 = a vector with the annual changes in
 taxonomic richness of the Temperate hypohaline assemblage in the North Sea
 *ltc_dino_liss_grp1 = a matrice (63 years x 12 months) with the monthly
 changes in biomass of the Warm-haline assemblage in the North Sea
 *ltc_dino_liss_grp2 = a matrice (63 years x 12 months) with the monthly
 changes in biomass of the Psychrophilous assemblage in the North Sea
 *ltc_dino_liss_grp3 = a matrice (63 years x 12 months) with the monthly
 changes in biomass of the Temperate assemblage in the North Sea
 *ltc_dino_liss_grp4 = a matrice (63 years x 12 months) with the monthly
 changes in biomass of the Temperate-haline assemblage in the North Sea
 *ltc_dino_liss_grp5 = a matrice (63 years x 12 months) with the monthly
 changes in biomass of the Temperate hypohaline assemblage in the North Sea
 *yrs2 = a vector with the years from 1958 to 2020
 -rockall_trough_1958_2020.mat *sal_rt = a vector with annual salinity
 values in Rockall Trough *sal_rt_anom = a vector with annual salinity
 anomaliies in Rockall Trough *ssh_rt = a vector with annual sea surface
 height values in Rockall Trough *ssh_rt_anom = a vector with annual sea
 surface height anomaliies in Rockall Trough *sst_rt = a vector with annual
 sea surface temperature values in Rockall Trough *sst_rt_anom = a vector
 with annual sea surface temperature anomaliies in Rockall Trough *yrs = a
 vector with the years from 1958 to 2020 -enviro_1958_2020_NS.mat *AMO_yrs
 = Atlantic Multidecadal Oscillation index *gyre_ind = subpolar gyre index
 *inflow_yrs = oceanic inflow into the North Sea *MLD_yrs = changes in mean
 annual Mixed Layer Depth in the North Sea *NAO_yrs = North Atlantic
 Oscillation index *nb_yrs = number of year considered *netflow_yrs =
 netflow in the North Sea *NHT_yrs = Northern Hemisphere Temperature
 anomalies *outflow_yrs = North Sea outflow *precip_yrs = changes in mean
 annual precipitation above the North Sea *sal_yrs = changes in mean annual
 sea surface salinity in the North Sea *sst_yrs = changes in mean annual
 sea surface temperature in the North Sea *tot_wind_yrs = changes in mean
 annual total wind speed above the North Sea *u10_yrs = changes in mean
 annual 10m u wind component above the North Sea *v10_yrs = changes in mean
 annual 10m v wind component above the North Sea *yrs_gyre = a vector with
 the years from 1994 to 2020 *yrs_uniq = a vector with the years from 1958
 to 2020 -biomasse_dino_5_grps_v3.mat *carbon_dino_grp1_liss = changes in
 mean biomass of the Warm-haline assemblage in the Northeast Atlantic
 region, for the four annual periods corresponding to a persistent negative
 or positive NAO phase (smoothed data) *carbon_dino_grp2_liss = changes in
 mean biomass of the Psychrophilous assemblage in the Northeast Atlantic
 region, for the four annual periods corresponding to a persistent negative
 or positive NAO phase (smoothed data) *carbon_dino_grp3_liss = changes in
 mean biomass of the Temperate assemblage in the Northeast Atlantic region,
 for the four annual periods corresponding to a persistent negative or
 positive NAO phase (smoothed data) *carbon_dino_grp4_liss = changes in
 mean biomass of the Temperate-haline assemblage in the Northeast Atlantic
 region, for the four annual periods corresponding to a persistent negative
 or positive NAO phase (smoothed data) *carbon_dino_grp5_liss = changes in
 mean biomass of the Temperate hypohaline assemblage in the Northeast
 Atlantic region, for the four annual periods corresponding to a persistent
 negative or positive NAO phase (smoothed data) *carbon_dino_grp1_nonliss =
 changes in mean biomass of the Warm-haline assemblage in the Northeast
 Atlantic region, for the four annual periods corresponding to a persistent
 negative or positive NAO phase (unsmoothed data) *carbon_dino_grp2_nonliss
 = changes in mean biomass of the Psychrophilous assemblage in the
 Northeast Atlantic region, for the four annual periods corresponding to a
 persistent negative or positive NAO phase (unsmoothed data)
 *carbon_dino_grp3_nonliss = changes in mean biomass of the Temperate
 assemblage in the Northeast Atlantic region, for the four annual periods
 corresponding to a persistent negative or positive NAO phase (unsmoothed
 data) *carbon_dino_grp4_nonliss = changes in mean biomass of the
 Temperate-haline assemblage in the Northeast Atlantic region, for the four
 annual periods corresponding to a persistent negative or positive NAO
 phase (unsmoothed data) *carbon_dino_grp5_nonliss = changes in mean
 biomass of the Temperate hypohaline assemblage in the Northeast Atlantic
 region, for the four annual periods corresponding to a persistent negative
 or positive NAO phase (unsmoothed data) *carbon_dino_grp1 = changes in
 biomass of the Warm-haline assemblage in the Northeast Atlantic region,
 for each two months period between 1958 and 2020 *carbon_dino_grp2 =
 changes in biomass of the Psychrophilous assemblage in the Northeast
 Atlantic region, for each two months period between 1958 and 2020
 *carbon_dino_grp3 = changes in biomass of the Temperate assemblage in the
 Northeast Atlantic region, for each two months period between 1958 and
 2020 *carbon_dino_grp4 = changes in biomass of the Temperate haline
 assemblage in the Northeast Atlantic region, for each two months period
 between 1958 and 2020 *carbon_dino_grp5 = changes in biomass of the
 Temperate hypohaline assemblage in the Northeast Atlantic region, for each
 two months period between 1958 and 2020 *lat_def = latitude vector
 *lon_def = longitude vector *time_phyto = monthly time vector *yrs1 =
 annual time vector 1 *yrs2 = annual time vector 2 The content of each
 '.xlsx' file is discribed below:
 -list_dino_distrib_geo_carbon_v2.xlsx *Excel file with the carbon cell
 content and niche optimums (for sst, salinity, bathymetry and latitude) of
 each taxa. Niche optimums were estimated by means of the Species
 chromatogram method and with a weighted mean. Dinoflagellates names are
 displayed in the first column. Mean carbon cell content (in µC cell^-1)
 are displayed in the second column. SST optimums (in degree C) estimated
 by means of the weighted mean or the species chromatogram method are
 displayed in the third and fourth columns respectively. SSS optimums (in
 PSU) estimated by means of the weighted mean or the species chromatogram
 method are displayed in the fifth and sixth columns respectively.
 Bathymetry optimums (in m) estimated by means of the weighted mean or the
 species chromatogram method are displayed in the seventh and eighth
 columns respectively. Latitudes optimums (in degree N) estimated by means
 of the weighted mean or the species chromatogram method are displayed in
 the nineth and last columns respectively.