b'SUBTLE BUT SIGNIFICANTTides flow in. Tides flow out. It seems simple enough, but the UGA team\'s research"Can we discern any difference between the on Little St. Simons Island is full of mysteries andaltered and reference sites?" Sutter asks. "Are these nuance. The altered marsh has a single openingcreeksheds serving as sources or sinks of particular through which water enters and exits the wetland,nutrients or sediment?" and is crossed by straightened "mosquito ditches" to speed water flow in and out of the parcel in an effort toAnswering those questions demands highly accurate reduce mosquito breeding. and adaptable instruments, capable of precise measurements even in extremely shallow water. The comparison wetland, the "reference" marsh, has more natural, sinuous channels. The reference marshThe difference between low and high tide in the is complicated by the fact that it has a main portal onmarshes on Little St. Simons Island is about 5 feet (1.5 the north side and a smaller inlet on the south side thatmeters) on an average day, raising the water depth in could play an important role in the movement of waterthe tidal channel for about three hours, then draining and nutrients, Sutter notes.again for about nine hours. From the perspective of measuring water volume and current, that\'s a "That\'s the hole in the bucket; the back door," she says.challenging range. Comparing the altered marsh with the referenceComplicating the issue further are the narrow tidal marsh could provide valuable insights on the rolecreekswhich drain completely on some occasions and of hydrological modificationfor instance, thecontinue flowing on othersand the fact that the water straightened ditches that are common in the region.experiences bidirectional flow during the tidal cycle. Running transects with the RS5 gives the team a bigger picture of narrow tidal creeks.54 MISSION: WATER'