The current debate should focus interest not solely on the old Wild West dead-or-alive issue but also on the rich biology in these habitats and the importance of obtaining new samples from the sediments in question and similar habitats. Indeed, there is no debate about the ability of unicellular eukaryotes to survive in the anoxic brine, nor is there debate about animals living on the margins of the anoxic zone . The issue is the ability of metazoans (multicellular eukaryotes) to survive in the strictly anaeorbic zone. Ideally, one would like to see some evidence for actively transcribed genes in loriciferans from these habitats. That would also tell us a lot about how they are growing with respect to core carbon and energy metabolism. In particular, one would want to know whether these animals harbor and express any of the genes that protists use to survive in anaerobic environments, such as [FeFe]-hydrogenase, pyruvate:ferredoxin oxidoreductase, bifunctional alcohol dehydrogenase E (ADHE), acetyl-CoA synthase (ADP forming), and the like , or whether they have some other means of surviving without oxygen. It is perhaps more likely that they use strategies more similar to those found in the anaerobic mitochondria of parasitic animals, for example, malate dismutation with the involvement of rhodoquinone .
As a long shot alternative, if the animals are alive, it is even imaginable that they have acquired genes via lateral gene transfer (LGT) for a new strategy to survive anoxia. Indeed, some camps argue that all eukaryotes are ancestrally strict aerobes and that the ability of eukaryotes to survive anoxia is always the result of lateral gene transfer . We do not agree with that view, mainly for three reasons. First, the eukaryotic anaerobes studied so far always have the same basic carbon and energy metabolic backbone  and if LGT was behind eukaryote anaerobiosis, then eukaryotic anaerobes should be as physiologically diverse as prokaryotic anaerobes, which is definitely not the case; energy metabolism based on sulfate reduction , which is lacking in eukaryotes, is a strong case in point. Second, the Earth sciences tell us that anaerobic habitats are ancient and that aerobic habitats are recent . So, if anything, we should be seeing LGT as a means of improving mitochondrial function in aerobic habitats. For example, aerobic methane oxidation is a very widespread form of energy metabolism in prokaryotes but we don’t see eukaryotes that have acquired genes to do that; rather, eukaryotes possess one ancestrally present stock of enzymes . Third, it is often proposed that one lineage of eukaryotes acquires one or the other anaerobic enzyme via LGT from prokaryotes and then passes it around via eukaryote to eukaryote LGT in order to account for the monophyly of the eukaryote enzymes involved. That idea has been specifically tested at the whole-genome level, and rejected, whereby the “patchy gene distributions” that are often seen as the hallmark of LGT are actually better explained by differential loss than they are by LGT .
Of course it might also turn out that the loriciferans from the habitats in question do not show vital signs of gene expression. It might be that they are dead, not alive. There is only one way to find out: biologists will have to go back out to those deep environments and get new samples.