boat coast ebbs harbour port sea sky stones beach ebb flow meander meandering nature ripples sand tides water waves golden memory rock rocks seashore shore sunset tide wave melancholy ocean dark landscape light low natural river rural stream wet wild accumulations algae attached clinging coastline color colour covered ebb-and-flood ebb-and-flow filamentous green holdfasts layers levels low-tide pounding rocky rough seaside seaweed shadows shapes shoreline slimy slippery spray sticking stony stuck sunlight sunshine surf surge surging tidal velvety bed bottom fjord floor HDR island lake Nyberg stone summer beyond boulder distance distant far flats horizon Spain