MEPS 486:13-22 (2013)  -  DOI: https://doi.org/10.3354/meps10374

ABSTRACT: Mapping survey sites is essential when studying the spatio-temporal distribution of sessile assemblages in submarine or semi-submerged marine caves. Acquiring the necessary topographic measurements is challenging, given that underwater mapping is performed in restricted spaces and with limited time or visibility. This study presents a rapid and cost-effective method for the 3-dimensional mapping and visualization of simple marine caves, where ‘simple’ mainly refers to the absence of a complex dendritic network of conduits. The method can be implemented by 2 divers using a regular dive line, an inexpensive handheld echosounder, and standard diving equipment. Source data are particularly compact and designed for ease of underwater acquisition, and post-survey processing is automatically performed by the accompanying customized software. The output is a scaled 3-dimensional model of the surveyed cave, which can be viewed from any particular orientation. It can be sliced to depict the horizontal zonation patterns of benthic assemblages, or used to extract approximate estimates of passage cross-sectional area. The method can assist the sampling design of ecological studies with minimum allocation of mapping resources and help the evaluation of topographic features that may affect the spatial distribution of marine biota.

KEY WORDS: Marine caves · Mapping · Topography · Zonation · Benthos