Zostera marina (eelgrass) growth and survival along a gradient of nutrients and turbidity in the lower Chesapeake Bay

Surv~val of transplanted Zostera marina L (eelgrass). Z mar111a growth, and envlronmental c o n d ~ t ~ o n s were studled concurrently at a number ot sltes In a southwestern tnbutary of the Chesapeake Bay to e luc~da te the factors l im~ting niacrophyte d~strlbution In thls region Cons~stent differences In surv~val of the tlansplants were observed, wlth no long-term survlval at any of the sites that were formerly vegetated w ~ t h t h ~ s pecles but that currently renialn unvegetated Therefore the current d l s t r~bu t~on f Z manna l~kely lepresents the extent of sultable env~ronmenta l cond~tions in the reglon, and the lack of recoxrry Into h~stor~cally veqetated s ~ t e s IS not solely due to lack of propagules Poor long-term survlval \vds reldted to seasonally h ~ g h levels of watel column l ~ g h t a t tenuat~on Fall transplants d ~ e d by the end of summer follow~ng exposure to levels of h ~ g h sprlng t u r b ~ d ~ t y (K, > 3 0) Accumulat~on of an e p ~ p h y t e ma t r~v durlng the late sprlng (0 36 to 1 14 g g ' dry cvt) may also have contributed to thls stress Differences In water column nutnent levels among sltes durlng the fall and wlnter (10 to 15 pM dissolved lnorqanic nltrogen and 1 pM dissolved inorganic phosphates) had no observable effect on e p ~ p h y t e accumulation or macrophyte growth Sallnlty effects were nnnor and there were no symptoms ot dlsease Although summertime cond~tions resulted In depress~ons In growth they d ~ d not alone 11m1t long-term surv~val It 1s suggested that water qua l~ ty condltlons enhancing adequate seagrass growth during the sprlng may be key to long-term Z manna surv~val and successful recolonizat~on in thls reglon