Recruitment And Symbiont Interactions In Anthropogenically Altered Habitats: The Porifera Of Maunalua Bay, Oʻahu

Abstract

Marine ecosystems around the world are affected by anthropogenically-induced disturbances, impacting the competition for benthic space by sessile invertebrates. To investigate the recruitment of Porifera in Maunalua Bay, Oʻahu, Hawaiʻi, Porifera abundances were compared to two earlier studies, Coles et al. (2002) and Longenecker et al. (2011), to understand changes through time. Cyanobacterial symbiont interactions were tested by determining chlorophyll concentration in the sponge holobiont. There has been a significant increase in Porifera since 2011 and Porifera are now more prevalent in areas where the invasive alga, Gracilaria salicornia, is dominant compared to nearby native sea grass beds. Recruitment of Porifera to the invasive algal mats was not explained by resource partitioning facilitated by cyanobacterial symbionts. Over time and through successional regimes, endemic, native, and non-native Porifera have become established in invasive algal mats and the new niche space that they provide.