coast coastline colors colours glistening glossy green greenery growing growth high-tide levels low tide mangrove-growth mangroves natural ocean ocean-edge ocean-waterline plants rocks rocky root-network Roots rough salt-resistant scrub security strength strong support tidal tide tides water waterline aerial aerial roots beach layers mangrove growth ocean edge ocean waterline pebbles receded receding receding tide root network sand dunes sand dunes builders' rubble color colored colour coloured dumped outcrop pollution rock formations rubble sea seashore seaside shade shadows shapes shore shoreline Sizes stones stony sunlight sunshine variety waste distance distant expanse footprints industrial activity industrial area Jetty people prints recreation relaxing sandy ships strolling waders wading