. ▁Also , ▁marine ▁de br is ▁such ▁as ▁fish ing ▁g ear ▁or ▁n ets ▁may ▁risk ▁human ▁life ▁on ▁the ▁be aches . ▁Such ▁poll ut ants ▁may ▁be ▁a ▁trap ▁for ▁beach ▁users ▁and ▁cause ▁very ▁serious ▁inj uries ▁or ▁d row ning ▁acc idents ▁for ▁tour ists . ▁ ▁E col ogy ▁▁ ▁Research es ▁on ▁marine ▁de br is ▁have ▁substantial ly ▁increased ▁our ▁knowledge ▁of ▁the ▁amount ▁and ▁composition ▁of ▁marine ▁de br is ▁as ▁well ▁as ▁its ▁impact s ▁on ▁the ▁marine ▁environment , ▁aqu atic ▁life ▁and ▁people . ▁Marine ▁de br is ▁is ▁very ▁harm ful ▁to ▁marine ▁organ isms ▁such ▁as ▁plants , ▁in verte br ates , ▁fish , ▁se ab ird s , ▁sea ▁t urt les ▁and ▁other ▁large ▁marine ▁m amm als . ▁Marine ▁de br is ▁contains ▁pl astic ▁lit ers ▁that ▁are ▁composed ▁of ▁industrial ▁chemical s ▁or ▁to x ins . ▁These ▁chemical s ▁can ▁be ▁destruct ive ▁to ▁aqu atic ▁organ isms ▁because ▁to x ins ▁accum ulate ▁in ▁the ▁t issues ▁of ▁marine ▁organ isms ▁and ▁they ▁cause ▁specific ▁effects ▁such ▁as ▁behavior al ▁changes ▁and ▁alter ations ▁in ▁met abol ic ▁processes . ▁Also , ▁a ▁combination ▁of ▁pl astic ▁and ▁se aw ater ▁materials ▁such ▁as ▁poly cyc lic ▁a rom atic ▁hydro car b ons ▁( PA H s ), ▁poly - ch lor in ated ▁bi phen yl s ▁( PC B s ) ▁and ▁heavy ▁met als ▁can ▁be