The Lower Hudson Raritan Estuary
is Surprisingly Clean Except
for a Few Hotspots!

Abstract

The lower Hudson Raritan Estuary is a complex urban tidal water body that includes Raritan Bay, Sandy Hook Bay, Navesink River, Shrewsbury River and faces a great influence by the Hudson River plume. The aim of this research was to collect spatially-explicit phytoplankton and water quality data from the lower Hudson Raritan Estuary to identify areas of disproportionate phytoplankton abundance or other parameters that may indicate poor ecosystem conditions. It was hypothesized that clear phytoplankton hotspots would arise and be sustained in near shore locations. Eight different water quality parameters were collected over ten weeks and all data was processed using R Studio. Implementation of underway data flow sampling was integral to the project as it allowed for the creation of maps that display real time, georeferenced water quality and phytoplankton data that do not exist elsewhere. Maps produced in this project suggest a system that is of predominantly good ecological status except for a few ‘hot spots’ that may be cause for concern. 

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Objectives

The goal of this project was to collect and represent phytoplankton and water quality data from within the HRE in a unique manner, create a tool to be used in future research and to identify specific areas of concern.

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Methods

Data collection was divided into two separate transects, one of Raritan and Sandy Hook Bay and the other of the Navesink and Shrewsbury Rivers. A biweekly sampling rotation was implemented.

 

At the heart of this project was the data flow, a simple pump system that continually collects surface water and records eight different water quality parameters every six seconds. Monmouth University’s Parker Boat Works 1801 center console known, as “Little Hawk”, was the vessel of choice. Water is pulled through the intake pipe of the data flow and fills a canister containing a multi parameter data sond. A data cable is then run to a handheld display that is tied into Little Hawk’s integrated GPS system. The GPS and data sond work together to provide vast amounts of georeferenced data.  

 

In addition to this surface water and bottom water samples were taken at predetermined stations within Raritan in Sandy Hook Bay. Only surface samples were collected within the river transect due the shallow bathymetry of the system. A 21 micron plankton net was towed at each station and plankton samples where preserved for later analysis.

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Results

Data analysis indicates a system of good ecological status with a few clear hotspots. Namely Atlantic Highlands Municipal Harbor, Keyport Marina and Branchport Creek. These areas display poor water quality conditions and large spikes in phytoplankton abundance when compared to the rest of the HRE.

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Future Research 

It is best to look at this as a multi-phase project and our geospatial representation of water quality is phase one. The vast amounts of data collected here provide the “big picture” and allow for a look at general condition throughout the system. Phase two will include identification of dominant phytoplankton species and will look for possible favorable conditions. As well as the driving factors that create the hotspots identified in phase one. Phase three will include combining the results of phase one and two to create a comprehensive report on the phytoplankton communities within the lower Hudson Raritan Estuary. Additionally, the R Studio scripts used in our data analysis will be refined to allow for streamlined data analysis in the years to come.

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Acknowledgments 

A special thank you The Urban Coast Institute for providing the funding for this project and Capt. Jim Nickels for keeping Little Hawk seaworthy. Thank you to Dr. Jason Adolf and the rest of the PHAB Lab team for making this project possible!