Can geophysical systems adapt to changing environmental conditions or to disturbances, in a way broadly analogous to biological adaptation, but independently of any biological components? Yes, according to my analysis using the example of hydrological systems. Just published in Ecohydrology, https://doi.org/10.1002/eco.2567 and attached here. 

Just published, in Geomorphology (Vol. 403, article no. 108666): Landscape Change and Climate Attribution, With an Example From Estuarine Marshes.

Climate change and related effects such as rising sea-levels and increased frequency and severity of severe storms and fires is resulting in geomorphological, hydrological, ecological, and pedological change. But landscape change is influenced not only by climate and severe meteorological events, but also by a host of other environmental factors, not least human impacts. How can we sort out the effects of recent and ongoing anthropically-driven climate change amidst all the other signals (and noise)?

A recent article in Coastal Review (a service of the North Carolina Coastal Federation) about the possibility of “farming carbon” in peatlands of northeastern North Carolina via carbon sequestration and trading and carbon trading markets caused me to revisit some work from my younger days—a frequent diversion for old codgers like me. Many of the pocosin wetlands were artificially drained by ditches and canals sometime between the 18^thcentury and the 1980s, and the key to maximizing carbon sequestration there is restoring the wetland hydrology. Back in the 1980s I did some work on artificially drained peatlands in the region, and in the 1990s on other artificially drained farmland in eastern N.C. One of the bottom lines was that this is a case where passive restoration works. In other words, if you simply don’t maintain the ditches and canals, they rapidly lose conveyance capacity and essentially become linear ponds. In some contract work I did for the Croatan National Forest in N.C. in 1997, in fact, I recommended passive restoration—there was no need to fill in canals or remove water control structures, etc.

In the lower reaches of some coastal plain rivers there is a transition from mineral to organic alluvial soils, which appears to mark the leading edge of effects of sea-level rise. This post is part of project to address the question of how a river, swamp, or floodplain undergoes a transition--apparently relatively suddenly in some cases, judging from stratigraphy--from a muddy or sandy, mineral-dominated state to one that is overwhelmingly composed of organic matter? For background, see this previous post. 

As rivers flowing across the coastal plains of the Carolinas approach the coast and their estuaries they widen, split into multiple channels, and flows can slow or reverse as astronomical tides, wind tides, and storm surges downstream have their effects. And on their floodplain swamps, the sandy and muddy soils and sediments give way to organic mucks or peats.

Area of organic muck soils, Thorofare Island, Waccamaw River, S.C.

Fluvial (river or stream) terraces are former active floodplain or channel surfaces that become isolated from regular flow or inundation by downcutting (incision) of the channel. Alluvial terraces start as predominantly depositional floodplains, but as the river incises, they eventually become isolated from flooding and deposition in all but the largest, rarest floods. Strath terraces are erosional surfaces associated with former channel positions; again, separated from river flows by downcutting of the channel.

Polly’s Bend, Kentucky. The T1, T2, T3 areas are strath terraces in oldest-youngest order. Base map is shaded relief based on 1.5 m resolution digital elevation model. Area shown is about 2.7 km (north-south) by 2.5 km (east-west). Coordinates at center are 37.8022° N, 84.6472° W (Fig. 2 from Phillips, 2018).

Tupelo gum and bald cypress (Nyssa aquatica and Taxodium distichum) are the main trees you are likely to find in perennially flooded deepwater swamps and stream channels in the southeastern U.S.A. Once established, they can grow in sites that are always inundated. However, they cannot germinate from seeds and establish seedlings in standing water. The substrate must be exposed at least once, at the right time of year, for that to happen. 

So how come you can find cypress and tupelo growing in perennially flooded areas, in standing water, that apparently never dry out? How do they get a start on the bottom of a stream or lake?

Pinetree Creek, an anabranch of the lower Neuse River, N.C.

The obvious answer is that they (or their parents, if they grew from stump sprouts or nurse logs) got their start when the site was not flooded, or always inundated, or that they got their start on some raised spot within the water that is no longer evident.

Last year, I wrote about how the warnings about human-accelerated climate change we’ve been hearing (and those of us in the business have been sending) for decades are, unfortunately, coming true. Almost daily, our news feeds remind us of this, or provide new evidence that Earth’s climate, and the environmental systems affected by it, are approaching unknown territory. We are seeing ocean temperatures, ice loss from the great Antarctic and Greenland ice sheets, storm and flood regimes, heat waves, and fires that are unprecedented in human history and in some cases unprecedented in Earth history, period. 

National Weather Service heat warnings for California

As much as we’d like to think otherwise, the facts (data, analyses, results, observations) do not speak for themselves. As scientists and educators, we are obliged to explain and interpret the facts; to attach meaning to them. As things have come to pass in the scientific world, we are obliged to speak for the facts in English. 

This post was inspired by a discussion posted on researchgate.net by Alejandro Bortolus of the Centro Nacional Patagonico (Argentina): Is the use of English in scientific articles a real need for an international working language, or a sign of long-lasting Colonialism? The lively discussion can be accessed here.

You can’t rely on me for a comprehensive and coherent summary of the comments and reactions, but some key themes are:

•The (obvious) advantages of having a single lingua franca to support global scientific communication. 

Spoiler alert--the answer is: maybe, but I’m not sure.

Argillic horizons are subsoil layers that are enriched in silicate clays. I have long been interested in soil morphology as it relates to argillic horizons. First, it was with respect to soil erosion. As these horizons are by definition formed below the surface, their exposure at or near the ground surface indicates removal of overlying soil. To the extent soils have a characteristic depth, or range of depths, to the top of the argillic horizon, then variations in DTA (depth to argillic) can indicate erosion or deposition. I used this to study soil erosion in the North Carolina coastal plain and piedmont in the late 1980s and 1990s, and in the Ouachita Mountains of Arkansas in the 2000s and 2010s.

Multiple argillic horizons in a Kandiustult in Zambia (source: https://www.uidaho.edu/cals/soil-orders/ultisols).