Novel method to concurrently sample the planktobenthos and benthos

Abstract

The planktobenthos is an important area with unique environmental conditions that represents the immediate link between the benthos and the water column, yet it has never been deliberately sampled concurrently with the benthos. We have developed a new sampling method to allow concurrent collection of benthic and planktobenthic specimens. The Mounted Assembly for Planktobenthic Sampling (MAPS) uses a novel trilayered net with a seafloor-triggered opening and closing mechanism attached to an epibenthic sled. The MAPS was deployed on the Carnarvon Shelf off Western Australia and was successful at separately sampling both benthic and planktobenthic fauna. A wide variety of epibenthic and infaunal animals were collected from the sled, and planktobenthic animals such as mysids were identified from all three nets. The trilayered net was particularly effective at collecting a broad range of planktobenthic organisms, including smaller fragile larvae and adults that may have otherwise been destroyed during collection in a single net or grab. The number of species in planktobenthic and benthic samples was correlated, although the strength and significance of this relationship varied among taxonomic groups, suggesting that rich benthic assemblages are linked to rich planktobenthic assemblages. Importantly, the MAPS is a value-adding method, collecting two sample sets for the cost of one, and can be modified for use on a wide variety of benthic sleds to target a range of organisms. The concurrent collection of planktobenthic and benthic biota will contribute to a range of research areas, including larval ecology, nutrient cycling, and surrogacy research for habitat mapping.