**4. Discussion**

In this study, we investigated the dynamics of the flow and environmental (hydrography, carbonate chemistry, and inorganic nutrients) conditions around three *L. pertusa*dominated wall reefs and two bank reefs in a narrow fjord on diurnal, seasonal, and annual time scales. Our results suggest that both hydrodynamics and hydro-biogeochemistry regulate the distribution and health of the reefs in Langenuen and that the fjord is likely to be in a state of change that has been ongoing since the 1980s.
