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some improvement for water quality. In addition, the results did show that the uppermost tidal <br /> reach of the Quashnet is a major nitrogen sink and the sediment should not be disturbed. The <br /> study also delimited areas where oysters can survive and grow. <br /> (3) Analysis of the total chlorophyll-a and particulate organic nitrogen. (PON) data indicate that <br /> the PON is directly related to the chlorophyll-a concentration (R2=0.96). This underscores the <br /> contention that the particulate matter in the water column of these estuaries in not "imported" but <br /> comprised of phytoplankton growing within the water column. This supports the management <br /> plan, which indicates that lowering the nitrogen levels within the estuaries will reduce <br /> phytoplankton biomass and improve water and habitat quality. <br /> (4) Oxygen depletion of bottom waters (Figures 9, 13)was variable but still evident within both <br /> systems in 2012-2014 and were generally consistent with historical data,following the <br /> distribution of nitrogen enrichment and elevated Chlorophyll-a levels. The large phytoplankton <br /> bloom in summer 2016 resulted in high total chlorophyll a levels and increased oxygen depletion <br /> in basins where the bloom was observed. The linkage of oxygen depletion to nitrogen <br /> enrichment is seen over the long term record and in 2016, with higher oxygen levels at lower <br /> levels of nitrogen enrichment and greater depletion in basins with higher nitrogen enrichment. In <br /> addition, oxygen data from 2016 supports the linkage between nitrogen enrichment,organic <br /> matter loading and oxygen depletion, with enhanced depletion likely due to meteorological <br /> forcing factors(wind, light intensity, temperature)as seen in other estuaries in throughout the <br /> region. <br /> (5) It appears that the monitoring program is becoming sufficiently robust to be able to detect <br /> changes within the estuaries in response to implementation of management alternatives, Also, <br /> the natural variation obscuring detection of year to year changes is overcome by continued <br /> long-term monitoring. <br /> Improvements: <br /> Because of the variability in the dissolved oxygen data, we have made some recommendations to <br /> strengthen the oxygen data base in the Waquoit and Popponesset systems. <br /> Because dissolved oxygen in the water column, especially bottom waters, are subject to periodic <br /> episodes of hypoxia/anoxia and because D.O. is such an important component in structuring <br /> aquatic ecosystems,we feel that two possible approaches can be taken to improve the oxygen <br /> data collection: <br /> 1) Continue of Winkler Titrations on water samples where meter readings of D.O. are< <br /> 5mg/L. Winkler titration is a more accurate and precise method for quantifying . <br /> dissolved oxygen concentrations in samples expected to have low DO levels, <br /> 2) Collect bottom water light records from Hamblin and Jehu Pond to refuie the level of <br /> improvement needed to restore eelgrass in these basins as shellfish are deployed by <br /> the Town in these basins. <br /> In addition, due to the habitat impairments related to accumulations of macroalgae, survey of <br /> macroalgal accumulations in both estuaries are needed to give insight into: (a)the areas of direct <br /> 22 <br />