Physical Parameters of the Great Bay-Mullica River Estuary (With a List of Research Publications)

Technical Report Physical Parameters of the Great Bay-Mullica River Estuary (with a list of research publications) K.W. Able, R. Roden, D. Witting, and J.B. Durand April1992 Marine Field Station Institute of Marine and Coastal Sciences Rutgers, The State University of New Jersey Tuckerton, New Jersey 08087 Contribution 92-06 INTRODUCTION Numerous authors have recently reemphasized the importance of long-term measurements in marine environments (Heip et al. 1987, Wiebe et al. 1987, Wolfe et al. 1987, Steele et al. 1989). Such measurements are especially valuable in relatively unaltered systems and may serve as baselines for comparison to those that have be~n impacted. The Great Bay - Mullica River estuary in southern New Jersey (Fig. 1) is just such an unaltered system. In fact, this estu~ is probably the cleanest in the Boston to Washington, D.C., megalopolis and will remain so because of the protection afforded by the Pinelands National Reserve (Good and Good 1984) and large holdings in federal and state wildlife refuge and management areas throughout the drainage basin. In this report, we summarize long-term observations of atmospheric and hydrographic conditions at a single location in Great Bay, New Jersey from 1976-1990 as a means of providing baseline physical parameters for this unaltered system. In addition, we include a list of published research in the Great Bay - Mullica River estuarine system. S'l'UDY SITE Environmental data were recorded at the Marine Field Station of the Institute of Marine and Coastal Sciences, Rutgers University on Great Bay (Fig. 1). The station is adjacent to Shooting Thorofare and is located approximately 3 km from Little Egg Inlet and 20 km north-northeast of Atlantic City, New Jersey. Tidal currents at this location, based on drogue studies (Charlesworth 1968), flow past the station in Shooting Thorofare into Great Bay on flood tides at average speeds of 90.5 em/second and back toward the inlet at average speeds of 70.1 em/second on ebb tides. · METHODS Environmental data of two distinct types were collected (Table 1). The first includes atmospheric parameters: air temperature, wind direction and speed, cloud cover and rainfall. ~he second category relates to water characteristics, and ~ncludes water temperature, salinity, turbidity and the times and heights of the local tides. All data were monitored at the same time each day, between 1200 and 1300 hours EST. 1 The air temperature data were collected with a mercury thermometer mounted on the parking deck at the station (4.0 m above the marsh surface) • It is positioned so that the thermometer is shaded at all times, but is still exposed to the elements. Wind speed and direction are measured by instruments that are mounted on the station meteorological tower (8 m above the marsh surface). Between 1976 and 1980, a Climet Instrument Inc. wind speed transmitter (model 011-1) and wind direction transmitter (Model 012-10) were mounted at the eight-meter level of the tower and were hard-wired into a Model 060-20 translator. The signal was then fed to Esterline Angus Co. Model 601-C chart recorders. From 1980 through 1990, wind instruments were supplied by the Department of Commerce Weather Bureau. Wind speed transmitters (Model F-420C-TS) and wind direction transmitters (Model F-420C-TD, Electronic Speed Indicators Co.) and data are recorded by reading a gauge at the station. The percent cloud cover is estimated; 10 signifies 100% cloud cover; 0 signifies no clouds. Rainfall was recorded from a 20-cm diameter Clear-Vue rain gauge mounted at the end of the boat dock (2.0 m above the marsh surface). All surface water samples were taken by bucket from Shooting Thorofare near the meteorological tower (Fig 1). The water depth ( 13 m) and the thorough mixing of the water column at this site minimizes atmospheric effects on water temperature. Water temperatures were measured with a mercury thermometer. Salinities were either titrated with AgN03 according to an abbreviated method (Harvey 1955) or determined with an American Optical refractometer. Turbidity samples were read immediately on a H.F. Scientific, Inc. turbidimeter (Model No. DTR-15B). A Metercraft Corp. gas-purged tide gauge, located on a piling in the boat basin was used to measure tidal stage. Times and heights of the tide are taken from the continuous chart recorder at any time or tidal stage desired. All times and heights of high and low water are included in this report. RESULTS Physical Parameters An array of atmospheric (air temperature, wind speed/direction, cloud cover, rainfall) and hydrographic (water temperature, salinity, turbidity and tide level) data have been recorded nearly daily beginning in 1976 at the Rutgers Marine Field Station ·(Table 1). Over this period, salinity ranged from 23.6- 34.5 ppt with minor increases in mean monthly values during July-October (Table 2). Mean monthly salinities over the same period are shown in Fig. 2. The high values are the result of the proximity of the Marine Field Station to Little Egg Inlet and the Atlantic Ocean. 2 water temperature varied seasonally, ranging from -0.1 to 25.2oC with the lowest temperatures in January and highest in July and August (Table 3). Weekly mean temperatures are depicted i~ Fig. 3. In an attempt to have access to temperature data pr~or to 1976 we determined if there was a correlation between water temperature at the Marine Field Station in Great Bay and a similar measurement in the surf in the vicinity of Atlantic City, where a more extensive time series. is available. ~he relationship, based on comparisons dur1ng 1989-91 var~ed seasonally. In general, during fall and winter months (August -March, r 2 = .97), surf temperatures near Atlantic City were a better predictor of Marine Field Station temperatures than late spring and summer temperature (April July, r 2 = .84). Regressions for both of these time periods (August - March and April - July) were highly significant ( RUMFS Temp = -0. 17 + 1.056*surf temperature; RUMFS temp = 3.26 + .947*surf temperature, respectively.) A covariance found significant differences between both slopes and intercepts. Based on these analyses, we feel that we can accurately estimate temperatures at the Marine Field Station based on surf temperatures near Atlantic City, which date back to the late 1800s. Turbidity, as indicated by mean monthly values, ranged from 4.9 - 17.9 Nephelometric Turbidity Units (NTU) but no apparent monthly or seasonal trends were evident (Table 4). Atmospheric parameters, including cloud cover (Table 5), air temperature (Table 6), wind speed (Table 7), rainfall (Table 8) and tide heights (Tables 9 and 10), are also summarized across months and years for the period from 1976-1990. Individuals interested in access to this data should contact the Director, Marine Field Station, Institute of Marine and Coastal Sciences, Great Bay Boulevard, Tuckerton, NJ 08087. Other Long-Term Studies We would like to call attention to other long-term or extensive studies in this estuarine system. During 1957-1986, extensive monitoring of nitrogen, phosphorus and carbon, as well as chlorophyll and standard hydrographic measurements occurred throughout the Great Bay - Mullica River estuary and into the adjacent Atlantic Ocean (Table 11). These data are summarized (Durand 1988, Yol. I) and presented in raw form elsewhere (Durand 1988, Vol. II). Air quality (visibility), based on 35 mm color photographs three times per day, has been documented since 1987. The camera is mounted on the main Marine Field Station building at 7. 5 m above the marsh surface. The Showboat Casino in Atlantic City is the distant target. These data are recorded and interpreted by NJDEPE Division of Environmental Quality, and are not presented here. An extensive survey of the biota (benthic invertebrates, zooplankton, fish) in the Great 3 I Bay - Mullica River and the adjacent Atlantic Ocean was conducted in the 1970's as part of an environmental impact study relative to a proposed offshore nuclear power plant (M1lstein and Thomas 1977). A summary of research in the freshwater and terrestrial portions of the Mullica River drainage basin can be found in Buckholz and Good (1982). Appendix I lists all of the known publications, theses, dissertations and technical reports for the Great Bay - Mullica River estuary that we are aware of to date. ACKNOWLEDGEMENTS We would like to thank Paula J. Halupa and Ralph E. Good for assistance in data compilation. Susan C. Kaiser prepared Fig. 1, and Barbara Zlotnik typed the manuscript. This is Rutgers University Institute of Marine and Coastal Sciences Contribution 92-06. LITERATURE CITED Buckholz, K. and R.E. Good. 1982. Compendium of New Jersey Pine Barrens literature. Center for Coastal and Environmental Studies, Rutgers University. Charlesworth, L.J. Jr. 1968. Bay, inlet and nearshore marine sedimentation: Beach Haven - Little Egg Inlet region, New Jersey. Ph.D. dissertation, University of ~chigan. Durand, J.B. and R.J. Nadeau. 1972 Water resources development in the Mullica River basin: Part I. Biological evaluation of the Mullica River Great Bay Estuary. Rutgers University Water Resource Research Institute. Durand, J.B. 1988. Field studies in the Mullica River - Great Bay estuarine system. Vol. I. Center for Coastal and Environmental Studies, Rutgers University, New Brunswick, NJ, Tech Rept. Durand, J.B. 1988. Field studies in the Mullica River - Great Bay estuarine system. Vol. II. Center for Coastal and Environmental Studies, Rutgers University, New Brunswick, NJ; Tech. Rept. I Good, R.E. and N.F. Good. 1984. The Pinelands National Reserve: an ecosystem approach to management. Bioscience 34(3): 169-173. Harvey, H.W. 1955. The chemistry and fertility of sea waters. Cambridge, London, England. 224 pp. 4 Heip, C., B.F.

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