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 harvested for (10[1])use as food (10[2])thickeners. Eel migration is speculated to be propagated by free-floating kinds of these (10[2])organisms named after the Sargasso (-5[1])Sea. (10[1])Sea (-5[2])otters are a keystone species of these organisms’ namesake (10[1])ecosystems. For 10 points, name these plant-like algal organisms that form namesake underwater “forests.” (10[2]0[1])■END■