You never know what horrors may be lurking at the bottom of a swamp. Bogs, meanwhile, sound comical. Marshes are pleasanter, although bring malaria to mind, while wetlands emanate wholesomeness but are also wet in the “meh” sense of take it or leave it. Yet, as Tom Blass explains, these words all refer to the same thing: a place where land and water have got into a tussle and can’t decide which has won. The result is not so much an equilibrium, although these states of semi-submersion can hold their nerve for millennia, more a temporary detente where both sides are too exhausted to declare an outcome. It is in search of these in-between places that Blass travels from Cyprus to Lapland, Romania to Virginia, eyes peeled and treading gingerly lest he fall into the murk that lies beneath. Early on, Blass reveals himself to be more ethnologist than naturalist. While he pays respectful attention to the fauna that he encounters as he tacks from the Romney Marshes to Louisiana’s bayous by way of the Danube delta, it is the people he is after. The Lipovans, Cajuns and Seminole are all ethnic groups that have moulded a culture from the sludge squelching between their toes and this is the true subject of Blass’s bracingly original work. Above all, he is scrupulous about avoiding cliches. There are, for instance, very few glorious sunsets in Swamp Songs or encounters with gnarly old locals acting as aquifers for ancient wisdom, small mercies for which the reader should be grateful. This desire to skewer the cliches of his chosen genre starts early on, when Blass makes a trip to Dungeness, which in summer “is overrun by sea kale, psycho-geographers and, dammit, by people like me”. What people like him tend to be after, of course, is Prospect Cottage, the isolated clapperboard dwelling in which the film director Derek Jarman spent his last years cultivating his garden, a Shintoesque, salt-blown wonder in the lee of the looming nuclear power station. Even here, Blass can’t resist undercutting the conventions of his chosen genre, which may, indeed, be psycho-geography. “‘That’s it,’ they say. ‘That’s Derek Jarman’s house.’ And they move on, because really, there isn’t a great deal to see.” Such deadpanning is much in evidence too when Blass heads for the Great Dismal Swamp of Virginia’s coastal plane. The very name of the place is tautologous, since from the 17th century the word “dismal” was a catch-all term for a quagmire. “In other words, all swamps were dismal by dint of being swampy,” he writes. Still, Dismal does seem to live up to the modern usage, offering the visiting Blass nothing but a series of guarded, misfiring interactions with the inhabitants who are doing their favourite thing of fishing for bowfin and bullheads while giving nothing away. The only clue as to what may lie behind this persistent sense of Dismal’s menace is the fact that in the domestic front yards you can see Confederate flags alongside the more usual stars and stripes. The year is 2016, and as Blass drives round the edge of the swamp the US presidential election is only a few weeks away. Everywhere he sees placards that bear the slogans “Lock Her Up” and “Make America Great Again”. Most chilling of all, though, is the exhortation to “Drain the Swamp”. Blass discovers that historically the Dismal was the last redoubt of Black people running away from the plantations, fugitive Native Americans, English and Irish indentured labourers. Seen in this context, to “drain the swamp” is to recast a cluster of oppressed and vulnerable people as bogeymen. Before Britons feel too smug, Blass finds this dynamic alive and well closer to home. Back at the Romney Marshes, near to where he lives, he explores the local romance of smuggling, which has endured over centuries thanks to the watery inlets that allow small boats to drift quietly ashore and unload well away from the customs officer’s gaze. But Blass turns his binoculars sharply round and, before we know it, we are confronting the fact that every month refugees are smuggled across the Channel to land at nearby Dover. They are greeted, if not as swamp monsters exactly, then certainly as creatures from the deep to be swiftly dealt with and dispatched. Swamp Songs: Journeys Through Marsh, Meadow and Other Wetlands by Tom Blass is published by Bloomsbury (£20). To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply.