Description
Marine invertebrates have a complex life cycle consisting of both a dispersive larval and adult benthic phase. For these organisms, larval transport is crucial in ensuring settlement and recruitment into adulthood. In waters off the coast of La Jolla, CA, bryozoan Membranipora membranacea live in a planktonic larval stage called cyphonautes. With physical processes impacting larval transport, we hypothesized that cyphonautes distribution would vary based on changes in annual and seasonal thermal stratification. We analyzed the distribution of cyphonautes larvae off the coast of La Jolla, CA from May 2014 to September 2016 in response to annual and season thermal stratification. By collecting samples from seven different stations with depths ranging from 4m to 14m in 2m increments, this allowed us to examine the vertical distribution and cross-shore distribution of the larvae. We found that the concentration of cyphonautes was highest in 2016, but cyphonautes had the deepest distribution during 2014. This is possibly in response to differences in the temperature of the water, as large-scale oceanic disturbances impacted southern California in 2014 (?The Blob?) and El-Nino (2015) bringing excessively warm water to the region. This study provides insight on how larval dispersal might be impacted by environmental conditions.
The Distribution of Bryozoan Larvae in the Near Shore
Marine invertebrates have a complex life cycle consisting of both a dispersive larval and adult benthic phase. For these organisms, larval transport is crucial in ensuring settlement and recruitment into adulthood. In waters off the coast of La Jolla, CA, bryozoan Membranipora membranacea live in a planktonic larval stage called cyphonautes. With physical processes impacting larval transport, we hypothesized that cyphonautes distribution would vary based on changes in annual and seasonal thermal stratification. We analyzed the distribution of cyphonautes larvae off the coast of La Jolla, CA from May 2014 to September 2016 in response to annual and season thermal stratification. By collecting samples from seven different stations with depths ranging from 4m to 14m in 2m increments, this allowed us to examine the vertical distribution and cross-shore distribution of the larvae. We found that the concentration of cyphonautes was highest in 2016, but cyphonautes had the deepest distribution during 2014. This is possibly in response to differences in the temperature of the water, as large-scale oceanic disturbances impacted southern California in 2014 (?The Blob?) and El-Nino (2015) bringing excessively warm water to the region. This study provides insight on how larval dispersal might be impacted by environmental conditions.