| Summary: | Dissolution of shell and photosynthesis by macrophytes have potential to raise local pH and therefore improve conditions for shell-forming organisms, but habitat-specific performance could also derive from altered water flow or food web dynamics. This study involved a split plot design to examine two habitat treatments (macrophytes, shell) on (1) juvenile Venerupis philippinarum settlement, survival, and growth and (2) local water chemistry at Fidalgo Bay and Skokomish Delta, Washington. Results show no macrophyte or shell hash treatment effect on V. philippinarum settlement or survival. A significant macrophyte treatment effect was detected on clam growth, with mean length higher when macrophytes were absent regardless of the presence or absence of shell hash. Additionally, there was no significant difference in porewater pH between the habitat treatments. However, the macrophyte treatment had an unexpected correlation with pH in the overlaying water, where pH was higher outside of macrophyte beds than inside. Although these results do not support the use of either treatment as an ocean acidification adaptation strategy, the mixed results reported in the literature for both treatments highlight the nascent nature of this research and the need to continue studying the effectiveness of potential strategies in the field. Such research could help guide local adaptation actions, especially among resource-dependent communities that rely on sustainable fisheries for their health and well-being.
|
|---|