Climatide

Courtesy of Woods Hole Research Center

The Global Rivers Project currently studies six major rivers and their drainage basins, with an eye toward their chemical influence on coastal ocean ecology.

Bernhard Peucker-Ehrenbrink is a senior scientist in the Marine Chemistry and Geochemistry department at Woods Hole Oceanographic Institution (WHOI, pronounced hoo-ee). He’s an unassuming man with an office barely big enough for two chairs, but he sits at the center of an impressive global network of researchers and students collectively known as the Global Rivers Project.

www.whoi.edu

Bernhard Peucker-Ehrenbrink

“This is not just WHOI,” he emphasizes. “This is WHOI, Woods Hole Research Center, Univerisity of New Hampshire, University of the Fraser Valley, East China Normal University, Russian Science Station on the Kolyma, colleagues that we have on the Congo. They all contribute. So this is much bigger than just a few scientists at WHOI.”

As the name implies, the Global Rivers Project studies rivers – six of them, to be precise. The Congo in Africa, the Fraser in western Canada, the Yangtze in China, the Kolyma in Russia, and the Brahmaputra and Ganges which together feed the vast deltas of Bangladesh. The central question at the heart of the project is: what exactly are rivers carrying to the sea?

Bernhard says there are several possibilities. Nutrients – both naturally occurring and originating from agriculture – are important fertilizers for marine life in the coastal ocean. Then there are what Bernhard calls “dissolved constituents,” the major ions – calcium, magnesium, sodium, potassium, silica, and so on.

“But it’s also contaminants that are generated in the drainage basins by urban centers,” Bernhard says. “For instance, stormwater overflows, sewer overflow, contamination that’s released by industry, traffic, you know, a whole slew of activities we are conducting in drainage basins.”

The Global Rivers Project takes a uniquely comprehensive approach to studying river chemistry, crossing geopolitical and scientific boundaries in the process. They try to measure all the different elements, both dissolved in the water and attached to sand and silt being carried by the rivers. They also measure different forms of the same element that come from biological and non-biological sources, what scientists call organic or inorganic.

“And that has never been done in such a comprehensive way,” Bernhard explains, “because these two communities of scientists who do either inorganic or organic geochemistry, traditionally they are separate communities. They work differently, they use different instrumentation, they use different lab procedures. What’s clean for the inorganic geochemists is sometimes dirty for the organic chemists and vice versa.”

A central challenge for the Global Rivers Project is coming up with methods for sampling, storing, and analyzing river water for all the different chemicals, and then training scientists who are comfortable with the full range of techniques. Bernhard’s lab at WHOI is cluttered with bins full of bottles, syringes, and tubing used for collecting water. There are glass jars for collecting samples to measure organic carbon; jars with ground glass stoppers for capturing gases, like carbon dioxide – an inorganic form of carbon; and pre-cleaned plastic bottles for sampling rare, or trace, metals – iron, zinc, cobalt.

Some samples need to be analyzed as quickly as possible after collection: gases can escape, nutrients get used. To deal with the latter issue, Bernhard says they have a portable freezer that plugs into the cigarette lighter of a car. Nutrient samples are immediately frozen, then shipped back to the lab (still frozen) and kept frozen until moments before they are to be analyzed.

Heather Goldstone

Britta Voss, a graduate student in Bernhard Peucker-Ehrenbrink's lab, prepares sample tubes in the clean room's laminar flow hood.

But the technical challenges don’t end with the return to the lab. Here, the concern is contamination of precious river water samples with dust from the air. So all work happens in a so-called clean room that is pumped so full of filtered air that it flows out from under the door.

Bernhard gave me a tour of the facility and explained how it works: “The airflow in this entire laboratory has been carefully designed to make sure that the cleanest part of the lab is over-pressured the most, and then the prep lab is over-pressured slightly less, and the [main laboratory] room where we are standing in right now is over-pressured just slightly compared to the outside hallway. So there is an active airflow from the cleanest part out into the ambient environment.”

To enter the clean room, we have to go through an intermediate prep room and don full Tyvek suits, booties, gloves, hairnets and face shields. But even that isn’t enough. Once suited up and inside the cleanest room in the lab, Bernhard and his students take yet another precaution: they do all their work inside what’s called a laminar flow hood, an enclosed work bench with a glass sash on the front. Filtered air constantly flows down and out of the hood to ensure that no airborne contaminants (we’re in the clean room, remember) get into the samples while they’re open.

The near-paranoia about contamination extends to water in the lab as well, since researchers sometimes have to add water to samples before they’re analyzed. On one wall there’s a series of tanks and tubes that transforms Falmouth town water into something chemists like Bernhard considers usable.

Bernhard rattles off several water purification technologies: “It’s a combined reverse osmosis, ion exchange, activated charcoal filtration, UV radiation to kill organic matter, until the water comes out extremely clean and pure.”

All these precautions are necessary because the elements that scientists are trying to measure are often present in minute quantities, comparable to a sugar cube dissolved in an Olympic swimming pool. And yet, even those tiny amounts can be enough to shape the chemistry and biology of the coastal ocean where they end up. By measuring river chemistry over time, scientists hope to put together a picture of how natural cycles and human activities – especially carbon dioxide emissions – are affecting ocean ecology. But as we’re leaving the clean room, Bernhard reveals another benefit of the Global Rivers Project.

“Think about a researcher in 20 years,” he says with a new energy in his voice, “a student who has some bright idea a new analytical procedure and she wants to get a sample from the Mississippi River, 20 years from now. Who will have that sample? There’s no national or international archive for river samples available.”

Bernhard says that the Global Rivers Project has an opportunity to create a well-preserved and well-documented collection of river water samples that could be even more valuable than the data he and his colleagues are generating.

Bernhard Peucker-Ehrenbrink and Global Rivers co-leader Max Holmes of the Woods Hole Research Center will join Mindy Todd for a conversation about the Global Rivers Project on The Point tomorrow morning at 9:30am EST. You can listen on WCAI (90.1 or 94.3FM on Cape Cod, 91.1 on Nantucket, or streaming live at www.capeandislands.org).