KAWAI NUI MARSH

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TRANSECT A

The mat penetration wells along Transect A were deployed on an eastward course between Na Pohaku o Hauwahine and the central "great pond" of Kawai Nui Marsh (see MAP). This part of the marsh is thought to be near the boundary between what has previously been described as an upper wet meadowland (upper part) and the "floating mat" dominated marsh (lower part). Most of this area is characterized by para grass (Brachiaria mutica), with some small areas of cattails (Typha latifolia), a large, circular patch of papyrus (Cyperus papyrus), and, between the papyrus and the margin of the pond, an area of mixed wetland plants with an abundance of arrowhead plant (Sagittaria latifolia). The trail ends at water quality Station 005.

In our hypothesis, Transect A crosses a part of Kawai Nui Marsh characterized by a vegetation mat (or organic soil) overlying a layer of sediment. Water in this part of the marsh saturates the sediment and soil layers to a depth that will vary seasonally, with flooding of the surface occurring in the wet season.

Individual descriptions of each of the well locations on Transect A with graphical presentations of data, are presented as follows:

Well A1 ("ponds 2")
Well A2 ("maile pilau")
Well A3 ("para grass")
Well A4 ("papyrus") NEW
Well A5 ("arrowhead")

TRANSECT B

The mat penetration wells along Transect B were deployed on a more or less north by northeast course between Na Pohaku o Hauwahine and the man-made "channel" in the middle of Kawai Nui Marsh (see MAP). This area just reaches the edge of the sawgrass (Cladium jamaicense), first crossing what was known to be a pond 20-25 years ago and is now "thin" vegetation mat dominated my cattail. Plant assemblages along this transect include the area of cattails, extensive areas of bulrush (Schoenoplectus spp.), and smaller areas covered by neke fern (Cyclosorus interruptus). Para grass dominates some areas, and encroaches on others. Invasive trees, such as fiddlewood (Citharexylum caudatum), octopus tree (Schefflera actinophylla), and Moluccan albizia (Falcataria moluccana), are sparsely scattered over this part of the marsh, although the density of trees is increasing slowly.

In our hypothesis, Transect B crosses a part of Kawai Nui Marsh characterized by a floating vegetation mat. We anticipate that data from each well on this transect will describe a mat physically buoyed up by the organic peat in which the vegetation is rooted and below which will be found water or a water-sediment mixture that is mostly water. The space below the mat may be separated into two or more layers: a water layer over a denser sediment suspension layer or layers. The relative thickness of the layers may vary seasonally and/or in response to inputs of rainfall and run-off. The aquatic environment will be anoxic and reducing below the mat, supporting only microbial life. This description comprises our "Standard Floating Mat Model."

Individual descriptions of each of the well locations on Transect B with graphical presentations of data obtained, are presented at the following links:

Well B1 ("ponds")
Well B2 ("cattail")
Well B3 ("fern 1")
Well B4 ("fern 2")
Well B5 ("fiddlewood")
Well B6 ("bulrush")
Well B7 ("albizia")

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