Last week the Ecosystems Lab spent a wonderful day in the New Forest, hosted by two expert guides Jonathan Spencer (Forest Enterprise Head of Environment, England and former Senior Ecologist in the New Forest) and Jane Smith (Head of Planning and Environment in FE South District).

The New Forest is neither new (it was established by the Norman William the Conqueror as a royal hunting forest in around 1079), nor a forest in the modern sense of the word, as it has many areas of open, treeless heath. In the Norman sense a forest was an area for hunting by the elite declared to be outside (Latin foris) the common law of the land, i.e. local people were restricted from farming it or hunting on it.

The region is fascinating ecologically and hydrologically. There is forest, open heathlands, and wetlands (bogs and mires). Jane Smith taught us about how meandering streams (see photo) had been channelised in Victorian times (mid 1800s) to improve drainage from the forest. This affected the natural ability of the bog to regulate water flow. The New Forest National Park Authority are now rehabilitating the streams to their original meandering state. Restoration of the original meandering stream improves the health of the wetland and helps to prevent flooding. See the youtube video for full details.

At another location in New Forest we saw a man-made river knickpoint - a break in slope causing an increase in erosion to occur upslope to level out the channel - in a man-made stream. Originally, only overland surface flow would occur in this location. This forever altered the water flow patterns. Over time, the small man-made channel has deepened and widened substantially, with gullies and knickpoints forming. Erosion upslope of the river knickpoint is causing a loss in peat soil and vegetation. Additionally, the entrenched channels cause an increased water loss from the precious wetland in its headwaters. Starting in the headwaters, they are filling in the gullies, with the aim to eliminate the knickpoints. Complete removal of the knickpoints would take substantial amounts of sediment and rehabilitation efforts.

There are related posts by Yadvinder Malhi and Ben Blonder on this visit.

Global carbon cycling to a new level! The New Scientist published an article entitled: Cryptic river: The Torrents that flow beneath the seabed. It came out a couple months ago and it really caught my attention as a terrestrial river organic carbon geochemist. Below is a summary of what I got out of the article:

    River geochemistry doesn’t end once it hits the ocean as underwater rivers travel thousands of kilometres beneath the ocean creating deep criss-crossing channels burying vast quantities of terrestrial organic carbon and delivering oxygen and sediment to the ocean depths. Quantification of how much carbon is transported and buried in these deposits and how that affects the global carbon cycle is a hot area in research.

Terrestrial river flow paths are dependent on the features of the surrounding geology and geomorphology.  Underwater river flow paths, on the other hand, are dependent on other factors such a weakened gravitational force due to the water body itself pushing upwards and due to the Coriolis force which causesflow to be influenced by the rotation of the earth. For example, underwater rivers near the equator “wiggle” but near the poles underground rivers are much straighter. Often unnoticed at the ocean surface, these underwater rivers form abyssal channels and can be hundreds of meters deep and kilometres across. Telecommunications cables, which cross the oceans or seas, are snapped as huge sediment loads rush down the river like a pyroclastic cloud or an avalanche. This can cause communication blackouts to large regions. Unfortunately, mapping of these rivers and understanding where they are, why they’re there, and how fast they flow is a challenge. We actually know more about the channels on Mars and Venus than we do about the underwater channels in our own oceans. As the study of underwater rivers in the ocean is of key importance to improving telecommunications, the exploration of oil, and the understanding of global carbon cycling this area is ever growing.

Here is a video of my river geochemistry work in the Andes. It's taken by Matt Wainwright on a trip I took with Cape Farewell in 2009. We went on an expedition from the Andes to the Amazon with several artists and scientists. The aim of the trip was to promote linkages between artists and scientists on the subject of climate change.

The picture below taken by Anthony Santoro of Andriane Colburn, Yann Martel and me. We are off to study the Kosñipata River in Peru.