Three-quarters of Octocorallia species are found in deep waters. These cold- water octocoral colonies can form a major constituent of structurally complex habitats. The global distribution and the habitat requirements of deep-sea octocorals are poorly understood given the expense and difficulties of sampling at depth. Habitat suitability models are useful tools to extrapolate distributions and provide an understanding of ecological requirements. Here, we present global habitat suitability models and distribution maps for seven suborders of Octocorallia: Alcyoniina, Calcaxonia, Holaxonia, Scleraxonia, Sessiliflorae, Stolonifera and Subselliflorae. Reference: Yesson C, Taylor ML, Tittensor DP, Davies AJ, Guinotte J, Baco A, Black J, Hall-Spencer JM, Rogers AD (2012) Global habitat suitability of cold-water octocorals. Journal of Biogeography 39:1278–1292.

30-year trends in alpha diversity of benthic macroinvertebrates in the stony littoral zones (1 m depth) of two Scandinavian Arctic/alpine lakes: Lake Abiskojaure (upper panel) and Lake Stor-Tjulträsk (lower panel). State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 71- Figure 4-35

Results of circumpolar assessment of river benthic macroinvertebrates, indicating (a) the location of river benthic macroinvertebrate stations, underlain by circumpolar ecoregions; (b) ecoregions with many river benthic macroinvertebrate stations, colored on the basis of alpha diversity rarefied to 100 stations; (c) all ecoregions with river benthic macroinvertebrate stations, colored on the basis of alpha diversity rarefied to 10 stations; (d) ecoregions with at least two stations in a hydrobasin, colored on the basis of the dominant component of beta diversity (species turnover, nestedness, approximately equal contribution, or no diversity) when averaged across hydrobasins in each ecoregion. State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 67 - Figure 4-30

Long-term monitoring programs on benthic fauna are missing for large areas of the Arctic. In areas where repeated monitoring has occurred, it is difficult to compare data due to different sampling approaches and different targets of monitoring efforts. There is a need for an international standardization of long- term benthic monitoring. The CBMP Benthos Expert Network has identified potential ways to improve benthic monitoring coverage, and has come up with a map showing a Pan Arctic station map.

Results of circumpolar assessment of lake littoral benthic macroinvertebrates, indicating (a) the location of littoral benthic macroinvertebrate stations, underlain by circumpolar ecoregions; (b) ecoregions with many littoral benthic macroinvertebrate stations, colored on the basis of alpha diversity rarefied to 80 stations; (c) all ecoregions with littoral benthic macroinvertebrate stations, colored on the basis of alpha diversity rarefied to 10 stations; (d) ecoregions with at least two stations in a hydrobasin, colored on the basis of the dominant component of beta diversity (species turnover, nestedness, approximately equal contribution, or no diversity) when averaged across hydrobasins in each ecoregion. State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 65 - Figure 4-29

Figure 4-16 Map showing the magnitude of change in diatom assemblages for downcore samples, with beta diversity used as a measure of the compositional differences between samples at different depths along the core. Boundaries for the beta diversity categories are based on distribution quartiles (0-0.1, 0.1-1.24, 1.24-1.5, >1.5), where the lowest values (blue dots) represent the lowest degree of change in diatom assemblage composition along the length of the core in each lake. State of the Arctic Freshwater Biodiversity Report - Chapter 2 - Page 15 - Figure 2-1

Estimation of diatom assemblage changes over a period of about 200 years (top versus bottom sediment cores). State of the Arctic Freshwater Biodiversity Report - Chapter 4 - Page 41 - Figure 4-14

Map of the Arctic Ocean with superimposed stacked bars representing species numbers of macrozoobenthos from different shelf sea areas: Crustacea+Mollusca+Echinodermata (blue) and Annelida (black). Compiled by Piepenburg et al. (2011). Conservation of Arctic Flora and Fauna, CAFF 2013 - Akureyri . Arctic Biodiversity Assessment. Status and Trends in Arctic biodiversity. - Marine Invertebrates(Chapter 8) page 282