Abstract:
Marine habitats are some of the largest habitats on earth which host a wide range of
organisms that can each play central roles in ecosystems. Soft sediment systems are
dynamic and subject to various amounts of change over time in response to
disturbances. As a result, it is important to develop cost-effective tools that can be used
to analyze the ecological state of soft sediment systems for optimal management. In this
study, sediment surface microtopography was used as an indicator of macrofauna
activity in the Whangateau Estuary as a way to assess ecosystem functionality. To
provide a uniform starting point to gauge the rates of change for microtopograhic
features, at each site surface features were gently flattened by smoothing the sediment
surface with a piece of wood, with one location being left unsmoothed to act as a
control. Laser scanning was then carried out on the smoothed locations to obtain a
range of images using an RGB device. To assess the rates of microtopographic
features, observations were carried out twice a day around 12 hours apart. Laboratory
analysis was carried out on sediment samples collected from the Whangateau estuary
to also investigate whether sediment organic or mud content had any significant impact
on rates of change across the sites. Overall sediment mud content showed some levels
of correlation with organism activity, however, the effects overall were insignificant.
