Flies of the genus Coelopa lay their eggs onto these organisms found decomposing at wrack zones. It’s not diatoms, but non-photochemical quenching in one clade of these organisms is facilitated by allenic pigments called fucoxanthins. The thallus of these organisms comprises the stipe and lamina, which are connected to gas-filled (*) pneumatocysts [new-MAT-uh-sists]. Carrageenans synthesized by these organisms are (10[1])harvested for use as food (-5[1])thickeners. Eel migration is speculated to be propagated by free-floating kinds of these organisms named after the Sargasso (10[2])Sea. Sea otters are a keystone species of these organisms’ namesake ecosystems. For 10 points, name these (-5[1])plant-like (10[1])algal organisms that form namesake underwater “forests.” (0[1])■END■