Slow Community Development Enhances Abiotic Limitation of Benthic Community Structure in a High Arctic Kelp Bed

We examined the patterns of propagule recruitment to assess timescale and trajectory succession possible roles physical factors in controlling benthic community structure a shallow High Arctic kelp bed Beaufort Sea, Alaska. Spatial differences established epilithic assemblages were evaluated against static habitat attributes (depth, distance from river inputs) environmental (temperature, salinity, current speed, underwater light) collected continuously over 2–6 years. Our measurements revealed that bottom waters remained below freezing (mean winter temperatures ∼−1.8°C) saline (33–36) with negligible light levels for 8–9 months. In contrast, summer open water period was characterized by variable salinities (22–36), higher (up 8–9°C) measurable irradiance (1–8 mol photons m –2 day –1 ). An inshore, near-river site experienced strong, acute, springtime drops salinity nearly 0 some The dominated foliose red algae (47–79%), prostrate kelps (2–19%), crustose coralline (0–19%). Strong spatial distinctions among sites included positive correlation between cover inputs, but we found no significant relationships multi-year means functional groups. Low rates colonization very slow growth recruits are main contribute prolonged development, which augments influence low-frequency events local structure. Mortality during early largely determines algal invertebrate prevalence community, while seem be recruitment-limited. On scales > 1 m, varies bathymetry exposure freshwater intrusion, regulate frequency primary physiological disturbance. Colonization (means 3.3–69.9 ind. 100 cm year ) much lower than studies other habitats, likely reflect nature truly environment. results suggest development nearshore Sea occurs decades, is affected combinations limitation, disturbance, abiotic stressors. While seasonality exerts strong on systems, characteristics determine ecosystem integrating seasonal interannual variability timescales longer most ecological studies.