FIGURES AND TABLES

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Figure 1A. Saltwater stations sampled by the Three Bays Preservation Monitoring Program throughout 1999. Sampling is within the basins from small boats.

Figure 1B. Freshwater stations sampled by the Three Bays Preservation Monitoring Program and the Barnstable Land Trust during 1999. Sampling is from along shore in the River and from small boats in the ponds.

Figure 2. Rainfall measured at the Long Pond Falmouth Gauging Station during 1999. Arrows represent sampling dates in the Three Bays System.

Figure 3. Depth of light penetration (Secchi Depth) and proportion of water column above Secchi Depth. Stations with values >70% may support bottom plants. Diamonds = % above Secchi Depth; Solid boxes = Secchi Disk Depth in meters.
Graph Label Abbreviations
MR-B = Marstons Mills River, Station B
MR-C thru MR-4 = Marstons Mills River, Station C thru Station 4
PC2 and PC3 = Prince Cove, Station 2 and Station 3
NB5 thru NB7 = North Bay, Station 5 thru Station 7
WB8 and WB9 = West Bay, Station 8 and Station 9
ER10 = Eel River, Station 10
CB12 and CB13 = Cotuit Bay, Station 12 and Station 13
SR11 = Seapuit River, Station 11
NS14 = Nantucket Sound, Station 14

Figure 4. Average nitrogen concentration by nitrogen species and as total nitrogen for each monitoring station over the study period, May - November. Note that the estuary is dominated by organic nitrogen forms, with little inorganic nitrogen. In contrast, the freshwaters have high inorganic nitrogen due to watershed inputs. Horizontal line indicates 0.35 mg N/L.

Figure 5. (Top) Inorganic nitrogen versus phosphorus ratio (N/P) as the geometric mean and maximum and minimum values from May - November 1999. Horizontal bar represents the Redfield Ratio, where values above the bar suggest plant growth limited by phosphorus availability and below the bar growth limited by inorganic nitrogen availability. (Bottom) Inorganic nitrogen versus phosphorus ratios for each station on each of the 7 samplings in 1999.

Figure 6. Relationship of phytoplankton chlorophyll a to water column particulate organic carbon concentration throughout the fresh and salt water systems. The direct relationship within the estuary suggests that the predominant source of organic matter is from phytoplankton production as opposed to import via runoff from the watershed. Stations MR-D and MR-E are within the Marstons Mills River System (cf. Figure 1B).

Figure 7. Minimum bottom water dissolved oxygen concentrations sampled during the 1999 field season. Although all values are >4 mg/L, the levels in Prince Cove support the contention that this system periodically has low DO. and is showing nutrient related water quality decline. Continuous DO. measurements are to be undertaken during the 2000 monitoring season.

Figure 8. Eutrophication Index calculated for each monitoring station within the Three Bays System based upon average water quality conditions, May - November 1999. The Index is based upon chlorophyll a, dissolved inorganic nitrogen, total organic nitrogen, Secchi depth, and the 20% lowest dissolved oxygen values for each station. The Index has been calibrated using Buzzards Bay and Falmouth Pond Watch long-term estuarine monitoring data.

Figure 9. Fecal coliform densities within the upper estuary and Middle Pond and the Marstons Mills River in 1999. Numbers above the bars indicate the amount of rainfall (inches) during the 5 days prior to sampling. Note that all high fecal coliform values are not associated with rain events.

Figure 10. (Top) Percent of samples having fecal coliform levels which exceed the limit for shellfish harvest, June - September, versus average station salinity. (Bottom) Geometric mean and maximum fecal coliform densities and average station salinity, June - November 1999.

Figure 11. Summary of Fecal Coliform data collected by Massachusetts Division of Marine Fisheries, 1985 - 1998. Station ID's are as in column 2 of Table 2. The values above the bars indicate the total number of samples collected. Note that significant numbers of samples were found to contain fecal coliform levels >14 FC/100 mL in the Marstons Mills River Mouth (MMR), Prince Cove (PC), North Bay Upper (NB1, NB2) and Mid (NB4, NB5), the Marina & Marsh in West Bay (LIM), the Little River and boat landing in Cotuit Bay (LR, BL), and the bird area associated with Sampson's Island at the western end of the Seapuit River.

Table 1. Physical Characteristics of Component Aquatic Systems of the Three Bays Complex.

Table 2. Fecal Coliform data collected by Massachusetts Division of Marine Fisheries, 1985 - 1998. Sampling stations have been grouped into functional spacial units. Shellfishing limit is geometric mean of 15 sets of 14 FC per 100 mL or 10% samples >29 FC per 100 mL. Beach limit is 200 FC per 100 mL, DMF assay typically cannot determine over 50-64 FC/100 mL or <1.4-2 FC/100 mL.