Pass

3 out of 3 indicators were rated as PASS.

All three indicators must pass for the bay to be rated as PASS.

Learn more about how this report is created

Summary:

The overall health of Palma Sola Bay continued to be very good in 2017. Levels of chlorophyll a and nitrogen improved, with both being below their desired target values and earning them "Excellent" ratings. However, phosphorus concentration again rose, with high levels above the threshold early in the year, eventually dropping below the target value in late 2017. The average for the year was only slightly higher than in 2016, but enough to cause Palma Sola Bay's rating for phosphorus to be downgraded from "Excellent" to "Good".

Water Quality: Palma Sola Bay retained its 2016 “Pass” rating as all three water quality indicators (chlorophyll a, nitrogen, and phosphorus) were below established thresholds. The mean concentration for chlorophyll a dropped slightly, to 0.0067 mg/l, well below the target value. Mean nitrogen concentration dropped as well, to 0.6218 mg/l which is below the target value and caused the rating for nitrogen to be upgraded from "Good" to "Excellent". Phosphorus concentrations rose to 0.1422 mg/l, above the target value and downgrading the phosphorus rating to "Good". The mean for chlorophyll a was calculated as an arithmetic mean and the means for nitrogen and phosphorus were calculated as geometric means (per the Numeric Nutrient Criteria outlined in the Florida Administrative Code, section 62-302.532).

Biotic Indicator: Measurement of the biotic indicator, seagrass, was last performed in 2016 by the Southwest Florida Water Management District. The total area of seagrass in Palm Sola Bay increased very slightly from the 2014 assessment and is now estimated to be 1,569 acres, one and a half times the target acreage of 1,031 acres.

Palma Sola Bay

Palma Sola Bay

Water Chemistry Ratings

Total nitrogen, total phosphorus, and chlorophyll a levels are monitored carefully by water resource managers and used by regulatory authorities to determine whether a bay meets the water quality standards mandated by the Clean Water Act. The trend graphs for these indicators are shown below, along with their target and threshold values. A target value is a desirable goal to be attained, while a threshold is an undesirable level which is to be avoided. An individual indicator receives an "Excellent" rating if its mean value is below the target, a "Good" rating if its mean value is above the target but does not exceed the threshold, and a "Caution" rating if the mean value exceeds the threshold. Learn More about these ratings and how they are calculated »

The Five-year Rolling Average Graphs below illustrate the general trend of water quality parameters. They show a six-month running average, which moderates high and low values in the data.

Chart Legend
  • Trend Line
  • Annual Mean
  • Target
  • Threshold
Excellent

Chlorophyll a

Score: Excellent How was this determined?
Units: mg/l Year
2017
Historical
period of record
High 0.027 0.079
Mean 0.007 0.007 0.00694153 0.0085000000
Low 0.001 0.001
No. of Samples 36 627

Five-year Rolling Average

  • Annual Mean
Excellent

Nitrogen, Total

Score: Excellent How was this determined?
Units: mg/l Year
2017
Historical
period of record
High 1.295 2.510
Mean 0.622 0.582 0.38747536 0.7400000000
Low 0.186 0.030
No. of Samples 35 560

Five-year Rolling Average

  • Annual Mean
Good

Phosphorus, Total

Units: mg/l Year
2017
Historical
period of record
High 1.120 1.610
Mean 0.142 0.111 0.18795331 0.1300000000
Low 0.019 0.008
No. of Samples 36 658

Five-year Rolling Average

  • Annual Mean

Dissolved Oxygen

Units: mg/l Year
2017
Historical
period of record
High 9.49 11.00
Mean 7.33 6.81 1.39391
Low 4.49 2.20
No. of Samples 37 962

Five-year Rolling Average

  • Annual Mean

Apparent Color

Note: The latest available sample for this parameter is from September 2012
Units: PCU Year
2017
Historical
period of record
High 140.00
Mean 31.71 25.73546
Low 1.00
No. of Samples 0 529

Five-year Rolling Average

  • Annual Mean

BOD, Biochemical oxygen demand

Note: The latest available sample for this parameter is from May 2008
Units: mg/l Year
2017
Historical
period of record
High 3.90
Mean 2.80 0.56889
Low 2.00
No. of Samples 0 23

Five-year Rolling Average

  • Annual Mean

Dissolved oxygen saturation

Units: percent (%) Year
2017
Historical
period of record
High 135.20 176.60
Mean 101.62 96.32 18.34122
Low 66.00 7.90
No. of Samples 37 730

Five-year Rolling Average

  • Annual Mean

Light Attenuation

Units: K(1/m) Year
2017
Historical
period of record
High 2.33 2.33
Mean 1.08 1.01 0.41105
Low 0.53 0.02
No. of Samples 21 103

Five-year Rolling Average

  • Annual Mean

Nitrogen, Kjeldahl

Units: ug/l Year
2017
Historical
period of record
High 1080.00 2060.00
Mean 620.69 568.20 347.36318
Low 180.00 0.01
No. of Samples 36 688

Five-year Rolling Average

  • Annual Mean

Nitrogen, Nitrite + Nitrate as N

Units: ug/l Year
2017
Historical
period of record
High 330.00 610.00
Mean 73.89 75.88 108.8474
Low 6.00 1.00
No. of Samples 35 596

Five-year Rolling Average

  • Annual Mean

pH

Units: None Year
2017
Historical
period of record
High 8.42 9.59
Mean 8.03 8.01 0.38807
Low 7.27 6.30
No. of Samples 39 941

Five-year Rolling Average

  • Annual Mean

Salinity

Units: PSS Year
2017
Historical
period of record
High 36.53 41.50
Mean 25.10 28.74 8.72284
Low 1.23 0.20
No. of Samples 36 970

Five-year Rolling Average

  • Annual Mean

Specific conductance

Units: umho Year
2017
Historical
period of record
High 55310.00 61680.00
Mean 38592.31 39756.38 17399.64013
Low 2390.00 37.80
No. of Samples 36 643

Five-year Rolling Average

  • Annual Mean

Temperature, water

Units: deg F Year
2017
Historical
period of record
High 92.05 93.20
Mean 76.43 76.28 9.52205
Low 61.83 46.76
No. of Samples 38 1031

Five-year Rolling Average

  • Annual Mean

Turbidity

Units: NTU Year
2017
Historical
period of record
High 4.90 28.60
Mean 2.16 2.50 2.20468
Low 0.60 0.01
No. of Samples 35 1000

Five-year Rolling Average

  • Annual Mean

Other Measures of Bay Health

In addition to nutrient levels and chlorophyll concentration, dissolved oxygen levels, and water clarity are also objective indicators of bay health. These have complex interactive cycles which are affected by rainfall, temperature, and tidal action, as well as other factors. High nutrient levels (nitrogen and phosphorus) can stimulate excessive growth of marine algae (indicated by chlorophyll a level), resulting in reduced water clarity (and increased light attenuation) and depleted oxygen levels. Both plants and animals in a bay need oxygen to survive, and the seagrasses which provide food and cover for bay creatures need light for photosynthesis.

Bay Contour Maps (2017)

Contour mapping is one of the best ways to visualize spatial differences in coastal water quality. The interactive map shown below presents monthly data for one selected water quality indicator atop an aerial view of the bay. Choose a different water quality parameter from the list at the top to change the map. Learn More about Water Quality Contour Mapping »

Showing 2017 Monthly Contour Maps for: January
Loading interactive contour map viewer...
Contour Visibility:

Visit the Water Quality Contour Mapping Tool to view and compare monthly water quality contour maps for ten different water quality indicators. In addition, you can generate your own custom maps.

Contour Legend:

  • Less than 1 mg/l
  • 1.0 - 5.9 mg/l
  • 6.0 - 10.9 mg/l
  • 11.0 - 17.9 mg/l
  • Greater than 18 mg/l

Seagrasses

Among the most important habitats in Florida's estuarine environments, seagrass beds are indispensable for the role they play in cycling nutrients, supplying food for wildlife, stabilizing sediments, and providing habitat for juvenile and adult finfish and shellfish. Use the interactive map below to observe the size, density and location of seagrass beds from year to year. The graph shows how the total amount of seagrass in the bay has changed over time.
Learn More about Seagrasses »

Showing Seagrass Coverage for :
Loading interactive seagrass coverage viewer...
Loading interactive chart...
  • Target 1,031 acres

Visit our Seagrass page to discover the beauty and importance of seagrass habitats, and sign up to help monitor their health.

Impervious Features

Palma Sola Bay is located within the Sarasota Bay Watershed. View details about the Sarasota Bay Watershed »

Rain that falls on land that is in a natural state is absorbed and filtered by soils and vegetation as it makes it way into underground aquifers. However, in developed areas, "impervious surfaces" impede this process and contribute to polluted urban runoff entering surface waters. These surfaces include human infrastructure like roads, sidewalks, driveways and parking lots that are covered by impenetrable materials such as asphalt, concrete, brick and stone, as well as buildings and other permanent structures. Soils that have been disturbed and compacted by urban development are often impervious as well. Learn more about Impervious Features »

The Sarasota County Stormwater Environmental Utility (SEU) mapped impervious surfaces in the County in 2014. A map showing impervious surfaces can be viewed using the interactive Sarasota NPDES Viewer.

19% of the land area within the Sarasota Bay Watershed is covered by impervious surfaces

Impervious Surface Coverage by Type

Land Use / Land Cover

Land use within a bay's watershed has a major effect on its water quality. In general, less development means better water quality. Land Cover/Land Use classifications categorize land in terms of its observed physical surface characteristics (upland or wetland, e.g.), and also reflect the types of activity that are taking place on it (agriculture, urban/built-up, utilities, etc.). Florida uses as its standard a set of statewide classifications which were developed by the Florida Department of Transportation. Learn More about Land Use and Land Cover »

Palma Sola Bay is located within the Sarasota Bay Watershed. The chart below shows the land use / land cover characteristics for Sarasota Bay Watershed within the boundary of this Water Atlas. View details about the Sarasota Bay Watershed »

Acreage and Percentage within each Land Use / Land Cover Category for Sarasota Bay Watershed
Land Use Classification 1990 2005 2014 Trend
Urban & Built-up 32,90853.3% 37,84461.3% 37,98761.6%
Agriculture 6,33810.3% 2,4974% 2,3093.7%
Rangeland 5470.9% 1990.3% 4300.7%
Upland Forests 3,5885.8% 2,1093.4% 1,9233.1%
Water 13,35021.6% 14,22723.1% 14,13122.9%
Wetlands 2,8704.7% 2,2273.6% 2,3723.8%
Barren Land 290% 90% 1090.2%
Transportation and Utilities 1,8453% 2,6024.2% 2,4534%
Land Use Chart

Data Sources

The data sources listed below provided water quality data used to create the report on this page. Not all data sources provided data for every bay, and not every Bay Conditions Report used data from all listed data sources. While some data sources have no data for the scored year, they provided period-of-record (historical high, mean, low) data. Click on a data source name to review its metadata.