Gschwend%20thesis.pdf

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revealing the variation of salinity at CD on an hourly timescale show
a range of salinities of about 0.20/00. These salinity data suggest that
pond water exiting to the Sound was diluted about iSO times with coastal
seawater by the time it reached CD.
During the period of this study, precipitation was spread quite
evenly throughout the year (figure 3-4).
The distributions of the nutrients in the waters off CD are shown
in figure 3-6. Nitrate, nitrite and ammonia showed an interesting
succession with the most reduced form, NH:, appearing at the end of August
and remaining until October. The N02 became important in November and
the beginning of December. Finally, NO; grew in while N02 was still
present and peaked in concentration in January. NH: may be introduced after
the breakdown of the seasonal thermocline in the nearby Oyster Pond in
the late summer with mixing of its anoxic bottom waters and spillage
into the Sound (see Emery, 1972). However, samples taken along an offshore
transec t on October 3 showed similar levels of NH: in all samples,
al though salinity increased offshore. Thus it is unlikely that mixing
+
of pond water into the Sound was the source of this NH4. Rather this
ammonia was probably part of the classical picture of fall-winter
remineralization of organic matter. The virtual absence of these nutri-
ents throughout the remainder of the year is indicative of the activity
of marine plants.
Phosphate demonstrated a more scattered distribution, as did
silicate. The simultaneous minima of these two nutrients in October
may reflect a fall bloom triggered by the sudden abundance of nitrogen
+
in the form of NH4. This was not indicated by the chlorophyll ~ measure-
ments although a fall diatom bloom is common in this region (Fish. 1925;