The fog of science – TIDE 2011 begins

by kate.

As of May 25th, twenty-four different people have seen our TIDE creeks so far in 2011, we’ve had one sunny field day, and have only just accomplished our second tank fill for the season. More scientists, sunshine, and fertilizer are due any day. We’ve already lost track of how many batteries and pumps we’ve lugged out onto the Spartina marsh.

We first ventured out into the low pressure system that was late April for a round of shear vaning at all six creeks with our dear geomorphologists Carol and Zoe from Boston University. We were measuring the resistance of the sediment to torque applied with a specially designed vane in order to understand if the fractures, slumping, and sliding we see at our fertilized creek are related to decreased soil strength. The monotony of six hundred shear strength measurements was occasionally broken by an especially squishy or strong layer of mud, a shift in the weather from rain to merely fog-rain, or a traditional Welsh ballad. We do extend our thanks to Zoe for spending so many hours peering at the dial of the shear vane

and to both Zoe and Carol for making light work of the Sweeney dripper platform construction, bringing us a victorious end to an otherwise rugged day.

For the next couple of weeks we left the marsh to its own devices: getting its chlorophyll mojo working, apparently, as it started to turn intensely green. Then we introduced it to the new Plum Island LTER postdoc Jimmy, who helped build the Clubhead dripper platform within hours of arriving from Florida.

Jimmy quickly showed the marsh who’s boss by carrying double the fertilizer of any other researcher and fixing water pumps that otherwise refused to start. We filled both tanks with fertilizer and allowed the marsh to ponder its fate over the weekend before the ides of May would once again flood Clubhead and Sweeney with good old sodium nitrate. Our target date for beginning the year’s nutrient addition is always May 15th. Since it fell on a Sunday this year, we decided to give the marsh a day of rest and turn on the drippers shortly thereafter.

The week of the 16th brought big tides of water and of people. Linda, Bruce, and Rich came up for a visit, and even Skyler and Xi stopped by.

We all had a bit of a scramble to install equipment, sample pre-fertilizer sediment porewater, and turn on the fertilizer drippers before MBL’s eight Science Journalism fellows and their leader, Chris, arrived at the end of the week. In the gathering gloom of Wednesday evening, enough of the pieces were in place, and it was go time. David and Jimmy flipped the switch at Clubhead, and Linda did the honors at Sweeney while Bruce and Kate wandered in the mist nearby. We all met halfway between the tanks for a foggy cheers to the beginning of another season of TIDE…

…Only to find out the next day that when it’s May in New England and the temperature lingers in the 40s, the pumps disagree with the whole idea. While dinner for fourteen set off the smoke detector—twice—bringing visitors from the Byfield Fire Department, Linda became a pinch-hitter and gave the presentation David had prepared for the journalists because he and Jimmy were on a nighttime safari to Sweeney to try to persuade the dripper to drip. They concluded that our coastal nutrient addition is meant to be a summer endeavor: in weather like this, the guaranteed-to-be-the-best tubing in the peristaltic dripper pumps is cold enough to lose all of its pliability, and the pumps give up.

Nutrients or none, sunshine or none, the journalists crammed a season’s worth of field work into two days with trips to Sweeney, West, and Plum Island Sound and measurements of geomorphology, nutrient flux, soil respiration, and invertebrate abundance.


A little more persuasion and slightly higher temperatures have allowed the pumps to cross some tides off their to-do lists. Austin and Meghan have arrived. We have continued our usual schtick by filling the tanks, checking in on the instruments, and sampling chlorophyll, curiously in the absence of David, who is rubbing elbows with some freshwater ecologists at the annual meeting of the North American Benthological Society and even hosting an invited session there on the connections between watersheds and estuaries.

As we have visited our fertilized creeks, we’ve been amazed to see some dramatic changes in their shape.Peat blocks we knew and loved last summer have been sheared away, and more than a few chunks of the marsh surface—we can recognize them by their Spartina patens vegetation—are now in the bottom of the creek. The last few weeks have also brought some changes to the local landscape that aren’t caused by nutrient additions. Ipswich has a new windmill, conveniently placed near Sweeney Creek to allow us to precisely gauge rain-fog intensity by counting the number of blades visible. As we were building the Clubhead platform, the Murphys from Newburyport were here tearing down the ell of the barn and the fondly-remembered goat shed .


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