CellTracker Green labelling vs. rose bengal staining: CTG wins by points in distinguishing living from dead anoxia-impacted copepods and nematodes

Author(s)
Mateja Grego, Michael Stachowitsch, Marleen De Troch, Bettina Riedel
Abstract

Hypoxia and anoxia have become a key threat to shallow coastal seas. Much is known about their impact on macrofauna, less on meiofauna. In an attempt to shed more light on the latter group, in particular from a process-oriented view, we experimentally induced short-term anoxia (1 week) in the northern Adriatic Sea (Mediterranean) and examined the two most abundant meiofauna taxa – harpacticoid copepods and nematodes. Both taxa also represent different ends of the tolerance spectrum, with copepods being the most sensitive and nematodes among the most tolerant. We compared two methods: CellTracker Green (CTG) – new labelling approach for meiofauna – with the traditional rose bengal (RB) staining method. CTG binds to active enzymes and therefore colours live organisms only. The two methods show considerable differences in the number of living and dead individuals of both meiofauna taxa. Generally, RB will stain dead but not yet decomposed copepods and nematodes equally as it does live ones. Specifically, RB significantly overestimated the number of living copepods in all sediment layers in anoxic samples, but not in any normoxic samples. In contrast, for nematodes, the methods did not show such a clear difference between anoxia and normoxia. RB overestimated the number of living nematodes in the top sediment layer of normoxic samples, which implies an overestimation of the overall live nematofauna. For monitoring and biodiversity studies, the RB method might be sufficient, but for more precise quantification of community degradation, especially after an oxygen depletion event, CTG labelling is a better tool. Moreover, it clearly highlights the surviving species within the copepod or nematode community. As already accepted for foraminiferal research, we demonstrate that the CTG labelling is also valid for other meiofauna groups.

Organisation(s)
Functional and Evolutionary Ecology, Department of Palaeontology
External organisation(s)
National Institute of Biology, Ghent University
Journal
Biogeosciences
Volume
10
Pages
4565-4575
No. of pages
11
ISSN
1726-4170
DOI
https://doi.org/10.5194/bg-10-4565-2013
Publication date
2013
Peer reviewed
Yes
Austrian Fields of Science 2012
106054 Zoology, 106020 Limnology
Portal url
https://ucrisportal.univie.ac.at/en/publications/fc2f4c72-4a7f-498d-ae06-f61f60a29aa3