1. Analyzing the Trends of Water Quality Indicators Over Time in Jamaica Bay, NY
A.L. Lamb1, R.B. Boger2, and B.F. Branco1,2,3
1Department of Earth and Environmental Sciences, The Graduate Center, City University of New York, New York, NY, United States
2Department of Earth and Environmental Sciences, Brooklyn College (CUNY), Brooklyn, NY, United States
3Aquatic Research and Environmental Assessment Center, Brooklyn College (CUNY), United States
1. Jamaica Bay – The “Sewage Estuary” 2. The Problem Figure 2: Annesia Lamb on a sampling
Four municipal wastewater treatment plants servicing Brooklyn Multiple agencies, for example the New York City trip with the National Park Service in
and Queens (Fig. 1) contribute ~90% of the nitrogen load, or Department of Environmental Protection (NYCDEP) and Jamaica Bay during the summer of 2011
approximately 14,000 kg of nitrogen per day (Benotti et al. 2006). the National Park Service (NPS) collect similar monitoring
Nitrogen reduction programs are being implemented with the data, with little time given to coordination and in depth
goal of reducing WWTP loading by 50%. Restoration of oysters, analysis. Data sets are not easily accessible. Timely
eelgrass and the disappearing salt marsh islands is underway. analysis of data sets may improve management efforts Figure 3: NPS water quality monitoring
and help identify weaknesses in our understanding of the stations in Jamaica Bay. The yellow circles
Jamaica Bay system. indicate stations included in the below
analysis. Hydroqual models suggest strong
We are currently working with the National Park Service hydraulic connectivity between these
to create a georeferenced database of their monitoring stations.
data and to conduct an analysis of temporal trends and
relationships between water quality parameters. 1 mile
3. The NPS Dataset 4. The Approach
Dataset begins in 1966, but data set is sparse until 1995. Analyze along hydraulic flow paths (Fig 3). Hydroqual model results indicate a
1995 – 2009: Surface and bottom (when applicable) samples including nitrate, orthophosphate and chlorophyll at 13 stations. direct flow path from station 3 to station 9A via 5A, 6, and 6B. Transport
Our preliminary analysis only includes these years due to concerns about changes in sampling and analysis protocols around the southern channel is slower. Avoid spatial averaging because we
Summer values – Memorial Day (late May/early June) to Labor Day (late August/early September) want to see internal processes (changes along flow path). Check for
Weekly with some gaps (e.g. due to boat repairs) interannual trends at individual stations. Check for relationship between
Chlorophyll and nutrient data prior to 2001 are sparse and not used here precipitation and other variables.
During summer of 2011, Lamb participated in sampling and analysis to observe protocols and methods (Fig. 2).
Figure 1: Jamaica Bay, NY (from Benotti et al. 2006)
32 0.40
32 0.60 JB3
JB5A
6. Nutrient dynamics 20
40
35 0.35
JB3
JB5A
0.55 30
30 JB6
JB6B
The depletion of orthophosphate along the flow 2005 30 2006
JB6
JB6B
0.50 15 N:P = 4.0 25 N:P = 5.1 0.30
path appears to be conservative mixing (below). JB9A
nitrate (µM)
nitrate (µM)
28 JB9A 28
orthophosphate (mg/L)
0.45 20
10 0.25
0.40 Increase in nitrate (2001-2009)? The low N:P ratio of nutrient depletion along 15
Salinity (ppt)
26
Nitrate (mg/L)
Salinity (psu)
STN p-value 10 26
0.35 5 0.20
24
0.30
9A
6B
0.003
0.004
the flow path (right) suggests nitrogen 5
24
22 0.25
6
5A
0.008
0.042
limitation during the summer in spite of the 0
0 1 2 3 4 5 6 7
0
0 1 2 3 4 5 6 7
0.15
JB3 JB3
20 JB5A 0.20 3 0.200 high nitrogen loading. However, results should 40 orthophosphate (µM) 45 orthophosphate (µM)
22 JB5A
0.10
JB6 0.15 35 40 JB6
18 JB6B
0.10
be interpreted with caution because ammonia 30
2007 35 2008
20
JB6B
0.05
JB9A N:P = 5.1 30 JB9A
is not included in NPS measurements, and two 25 N:P = 4.3
nitrate (µM)
nitrate (µM)
16 0.05 25 0.00
20 May 20 Jun 3 Jun 17 Jul 1 Jul 15 Jul 29 Aug 12 Aug 26 May 20 Jun 3 Jun 17 Jul 1 Jul 15 Jul 29 Aug 12 Aug 26
1994 1996 1998 2000 2002 2004 2006 2008 2010 1994 1996 1998 2000 2002 2004 2006 2008 2010 WWTPs discharge along the flow path (Fig. 1). 15
20
15
10 10
5 5
4.0
1996 – 2009: Significant decrease in
Secchi Depth for JB6 (p=0.0007) and
JB9A (p=0.007)
JB3
JB5A 5. Interannual trends 0
0 1 2 3 4 5 6 7
0
0 1 2 3 4 5 6 7 8 9 7. Patterns during a typical 1.0 5/24/2007
JB6 1.0 2009 orthophosphate (µM) orthophosphate (µM) 8/15/2007
3.5 JB6B
JB9A
Strong east‐west gradients in salinity, 2008
2007
30
Along flowpath from East
summer season (2007): The saw 0.8
8/23/2007
Normalized orthophosphate
nutrients, chlorophyll and Secchi depth 25
tooth pattern for salinity and
Normalized orthophosphate
0.8 2006 to West, nitrate and ortho-
3.0 2005
2009
20 phosphate decrease at a molar
nitrate (µM)
persist every year (summer averages). N:P = 3.7
ratio of approximately 4 to 5 orthophosphate, particularly for western 0.6
Secchi Disk (m)
15
2.5 0.6
from 2005 to 2009. Note that
Nitrate appears to be increasing, 10
ammonia is not measured by
stations, suggests a strong tidal influence 0.4
2.0
particularly in easternmost portion of 0.4
Mixing line 5 NPS, but is included in the on water quality readings. The Mixing Line
0 NYC DEP monitoring program.
1.5 the Bay. The Bay also appears to be 0 1 2 3 4 5 6 7 8 9 orthophosphate exhibits strong 0.2
orthophosphate (µM)
1.0
getting saltier (perhaps decrease in 0.2
conservative behavior on some sampling 0.0
WWTP discharges) with decreasing 0.0
dates, though this pattern is not seen
0.5 0.0 0.2 0.4 0.6 0.8 1.0
1994 1996 1998 2000 2002 2004 2006 2008 2010 light penetration. 0.0 0.2 0.4 0.6 0.8 1.0
with nitrate and other parameters. Normalized salinity
Normalized salinity
8. Discussion 9. Conclusions
Results from monitoring programs are often presented in reports of annual Bay‐wide averages. Such averaging (e.g. all sampling stations The tides appear to be an important driver of water quality variations during summers and need to be considered during the analysis
over an entire season or year) obscures the spatial patterns that inform us of physical controls on water quality. Jamaica Bay (like most The NPS water quality monitoring should include other forms of nitrogen and phosphorus to allow more detailed analysis of nutrient
estuaries) is defined by strong gradients in salinity in spite of the distribution of WWTP outfalls and Combined Sewer Overflow discharge dynamics
points. These gradients are important to consider with respect to restoration efforts (oyster, eelgrass, marsh islands). No relationship The NPS, NYCDEP and other agencies should begin coordinating their monitoring efforts and evaluate the scientific value of their current
was found between precipitation and interannual or within summer variations in parameters, including salinity. Variations in WWTP sampling protocols and methods.
freshwater discharges may be controlling salinity. It is also interesting to note that the influence of the Coney Island WWTP and the 26th orthophosphate appears to behave conservatively in the Bay suggesting that nitrogen is limiting in spite of the high loading rates
Ward WWTP outfalls was not prominent along the hydraulic flow path presented here.
Acknowledgements: Mark Ringenary of the National Park Service collected all of the data used in this work. We would also like to acknowledge the collaboration
with Mark Christiano who was instrumental in starting the effort to compile these data into a user‐friendly database. Also, we thank the many undergraduates at
Brooklyn College who have volunteered their time to copy, past, and type data.