​The problem with Long Pond is not new. 
​A 2008 study conducted by the U Mass Dartmouth School of Marine Science and Technology for
the Town of Barnstable revealed that, while not one of the most impaired ponds in town,
Long Pond Marstons Mills was considered unhealthy as many as 15 years ago.
This is evident  in the high phosphorus concentrations and low Secchi (water clarity) depths shown in the two graphs below.

​The above graph shows average total phosphorus concentrations between June and September 2008 for Barnstable ponds that have depths between 2.1 and 8.6 meters. Pond names have the depths in meters at which readings were collected (e.g., “Eagle0.5 m” is Eagle Pond readings collected at 0.5 m). 
The red line is the Cape Cod threshold for healthy pond ecosystems (10 micrograms per liter of TP from Eichner, et al., 2003); bars for ponds with an average TP concentration less than 10 µg/l are colored light blue. 

In the graph below, ponds with red bars have average Secchi depths that are less than the state safe swimming clarity limit of four feet, while ponds with yellow bars have shallowest recorded readings that are less than the four-foot limit.​