MEPS 552:71-79 (2016)  -  DOI: https://doi.org/10.3354/meps11769

Improving the estimation of deep-sea megabenthos biomass: dimension to wet weight conversions for abyssal invertebrates

Jennifer M. Durden1,2,*, Brian J. Bett1, Tammy Horton1, Amanda Serpell-Stevens1, Kirsty J. Morris1, David S. M. Billett1, Henry A. Ruhl1

1National Oceanography Centre, European Way, Southampton SO14 3ZH, UK
2Ocean and Earth Science, University of Southampton, National Oceanography Centre Southampton, European Way, Southampton SO14 3ZH, UK
*Corresponding author:

ABSTRACT: Deep-sea megafaunal biomass has typically been assessed by sampling with benthic sledges and trawls, but non-destructive methods, particularly photography, are becoming increasingly common. Estimation of individual wet weight in seabed photographs has been achieved using equations obtained from measured trawl-caught specimens for a limited number of taxa. However, a lack of appropriate conversion factors has limited estimation across taxa encompassing whole communities. Here we compile relationships between measured body dimensions and preserved wet weights for a comprehensive catalogue of abyssal epibenthic megafauna, using ~47000 specimens from the Porcupine Abyssal Plain (NE Atlantic) housed in the Discovery Collections (National Oceanography Centre, Southampton, UK). The practical application of the method is demonstrated using an extremely large dataset of specimen measurements from seabed photographs taken in the same location. We also collate corresponding field data on fresh wet weight, to estimate the impact of fixation in formalin and preservation in industrial denatured alcohol on the apparent biomass. Taxa with substantial proportions of soft tissues lose 35 to 60% of their wet weight during preservation, while those with greater proportions of hard tissues lose 10 to 20%. Our total estimated fresh wet weight biomass of holothurians and cnidarians in the photographic survey was ~20 times the previous estimates of total invertebrate biomass based on trawl catches. This dramatic uplift in megabenthic biomass has significant implications for studies of standing stocks, community metabolism, and numerical modelling of benthic carbon flows.


KEY WORDS: Biomass · Invertebrate · Preservation · Wet weight · Photograph · Deep sea · Porcupine Abyssal Plain


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Cite this article as: Durden JM, Bett BJ, Horton T, Serpell-Stevens A, Morris KJ, Billett DSM, Ruhl HA (2016) Improving the estimation of deep-sea megabenthos biomass: dimension to wet weight conversions for abyssal invertebrates. Mar Ecol Prog Ser 552:71-79. https://doi.org/10.3354/meps11769

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