Abstract:
Drift algal material exported from kelp beds plays a significant role in nearby
ecosystems. Phenotypic traits such as gonad index and jaw diameter can be indicators of
diet consistency and nutrient uptake and thus can be used to assess the possible role of
exported kelp. In this study, individuals of an herbivorous (Strongylocentrotus
droebachiensis) and a filter feeding (Balanus nubilus) species were sampled from near
the kelp beds in the shallow subtidal photic environment (SSPE) and far from the kelp
beds in the deep subtidal environment (DSE). Urchins in the DSE had significantly larger
gonads and jaws in comparison to individuals in the SSPE. I conclude that urchins in the
DSE were getting better fed, whether through quantity or quality of food, suggesting that
drift algae was being exported from nearby kelp beds. There was no significant difference
between barnacle gonad indices with depth suggesting that their particulate organic
matter food was equal at both depths. Future studies could examine gut contents to
determine if there are diet differences between the two depths.
