A new method for acquiring images of meiobenthic images using the FlowCAM

Tomo Kitahashi,Hiromi Kayama Watanabe,Masashi Tsuchiya,Hideyuki Yamamoto,Hiroyuki Yamamoto

doi:10.1016/j.mex.2018.10.012

Tomo Kitahashi, Hiromi Kayama Watanabe + Show 3 more

Open Access

https://doi.org/10.1016/j.mex.2018.10.012

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Abstract

The purpose of this study was to develop a new method for investigating sediment-inhabiting meiobenthos using the Flow Cytometer And Microscope (FlowCAM). Meiobenthos are widely recognized as a useful indicator for assessing the effects of anthropogenic and natural disturbances in both shallow and deep ocean ecosystems. These small benthic invertebrates are traditionally investigated by individually counting and identifying specimens under a microscope, which is labor intensive and time consuming. However, FlowCAM, which was originally developed to semiautomatically analyze microplankton, has the potential to resolve these challenges. Meiobenthic specimens were extracted from sediment using the centrifugal separation method and were then pipetted into the FlowCAM system and imaged. The images were then used to classify and count the specimens at high taxonomic levels to verify the effectiveness of this method compared with traditional methods. We found that FlowCAM system:•Enabled sufficient meiobenthic images to be obtained to allow the identification and classification of specimens at high taxonomic levels.•Obtained comparable numbers of individuals to traditional methods.•Has the potential to rapidly process large the volumes of meiobenthos samples that are required when monitoring seasonal and spatial variation in ocean ecosystems and conducting long-term environmental impact assessments.

Highlights

Meiobenthos are small benthic invertebrates that pass through a 500–1000 mm sieve and are retained on a 32–63 mm sieve
These animals are important components of deep-sea benthic ecosystems because they are more abundant than larger macro- and megabenthos [1] and have a considerable influence on sediment nutrient cycling and stability, making them good biological indicators of anthropogenic and natural disturbances [2,3]
Nematodes and copepods are the first and second most dominant taxa in deep-sea metazoan meiobenthic assemblages (e.g., [2]), and the latter are more sensitive to environmental stress than nematodes, resulting the nematode-to-copepod ratio (N/C index) tending to increase under polluted conditions. This N/C index has been used to measure a range of environmental impacts, including the impacts of pollution [4], anthropogenic activities on sandy beaches [5], the Deepwater Horizon oil spill in the northern Gulf of Mexico in 2010 [6], deep-sea mining for manganese nodules in the central Indian Ocean [7], and fish farming [8]

Summary

Method Article

Tomo Kitahashia,*, Hiromi Kayama Watanabea, Masashi Tsuchiyaa, Hideyuki Yamamotob, Hiroyuki Yamamotoa a Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 2370061, Japan b Am-Lab Inc., Venture Plaza Funabashi 216, 1-17-25 Kitahon-cho, Funabashi, Chiba, 273-0864, Japan

Method details

Findings

Method validation