Nature Notes: Georgica in the Crosshairs

Seapoosed ponds have two distinct habitats at different times of the year — one tidal, one brackish

 Of the 15 coastal ponds situated behind the Atlantic Ocean between the hamlet of Amagansett and the eastern terminus of Shinnecock Bay, Georgica Pond in East Hampton is the second largest after Mecox Bay. Before the 1938 hurricane, Shinnecock Bay was the largest coastal pond on the South Fork. The 100-year coastal cyclone opened the bay to the ocean, after which a permanent inlet was created, bounded by two rock jetties.

Georgica, Mecox, and Sagg Pond, the third largest in that area, all drain to the ocean when opened by heavy equipment.

Of the three, Georgica is the only one opened both in the spring and the fall, according to a schedule maintained generation after generation by the East Hampton Town Trustees. Opening each pond allows the much saltier ocean water and a host of ocean sea life to enter the ponds. Occasionally, a pond will stay tidal for several weeks, or even a month, but in most cases the temporary inlet closes up after one or two weeks. It is an annual practice gleaned from the habits of the local Native Americans, who opened these ponds regularly for centuries using primitive digging sticks and wooden spades. Once a pond is full to the gills, opening a small channel from pond to ocean, especially during a full moon low tide, was all that it took to create a strong flow from a trickle out into the ocean.

Coastal ponds in Rhode Island and Massachusetts were periodically opened in the same manner by the Indians and later by local colonial and post-colonial officials.

Thus, these seapoosed ponds have two distinct habitats at different times of the year — one tidal, one brackish. The volume of seawater accumulated during the tidal period is such that some salt remains even when the inlet is closed for long periods. Many “euryhaline” fishes — those that can tolerate both low and high salinities, such as white perch, herring, alewives, striped bass, and killifishes — do well in these coastal ponds whatever the salt content, low or high.

Oysters also can thrive in such habitats. The Great South Bay, Moriches Bay, and Shinnecock Bay were once more renowned for their oysters than their hard clams. Predators of oysters such as starfish don’t do well in low saline waters and so the oysters were not bothered by them. Mecox Bay has a large oyster population augmented by periodic stocking under the auspices of the Southampton Town Trustees.

All of these oceanic coastal ponds, those on the South Fork, but also those to the west all the way to Queens and Brooklyn, were once interconnected behind one long barrier beach. As the barrier beaches migrated shoreward under the influence of coastal storms and rising seas well after the end of the last glaciation, this big body of water was pinched off in places, resulting in several smaller bays. The ones like Georgica that were eventually cut off from the ocean by a coastal bar became fresher and fresher as they were mostly fed by the fresh groundwater from the upper glacial aquifer as it drained to the ocean.

Hook Pond in the Village of East Hampton used to be open to the ocean on occasions so that it received salt water from time to time, especially during large storms. Now it tests almost completely fresh, has a weir keeping the freshwater level up, and drains into the ocean through large pipes. Hook Pond once had a thriving alewife population, but alewives have been absent for more than 30 years running. It is nigh impossible to pass through the weir. During Superstorm Sandy some saltwater shot up the outflow pipes and entered the pond, but such a happening is a great rarity.

The three largest ponds are very rich in wildlife, both aquatic and surficial; many ducks, swans, and geese populate them, as well as many shore birds such as the piping plovers that feed at their edges. Lately, however, because they have houses with septic systems near their shores, runoff from roads, and because they are fed by water coming from the top of the glacial aquifer — which is becoming more enriched with fertilizers and other chemicals as density increases to the north — they are all experiencing blue-green algae (or cyanobacteria) blooms. Such blooms thrive on the eutrophic and dystrophic conditions that result from nitrogen, phosphorous, and other anthropomorphic additives, but also from uric acid in the excretions of waterfowl.

Georgica Pond, which has been suffering from such unhealthy conditions more than the other two, is immediately down-gradient of the much higher-than-sea-level elevations of the aquifer to the north, say, in the vicinity of the East Hampton Airport. When it is let out, it is mostly refilled by groundwater emanating from the top of that aquifer. The water under the airport has indeed been sullied over time, but it is hard to tell to what degree merely from test-well readings. But should we make it more sullied?

What is even more perplexing is the recent leasing of large East Hampton Airport parcels to two private landscaping outfits. Two of the parcels have recently been completely cleared of pitch pine, oaks, and other pine-barren-type vegetation. The potential problem, as I see it, having co-authored two East Hampton Town conservation plans, is that the sandy porous soils comprising these parcels are not much good for agriculture but excellent in terms of passing rainwater down to the aquifer below. They will need a lot of fertilizer and irrigation to grow plants other than cacti and a few grasses like bluestem. Thus, in order to turn a profit, even if they  entail large greenhouses, they will further contribute to Georgica Pond’s deterioration over time.

With these parcels as little as 4,000 feet away from the pond’s upper edges, it will take about 10 years at the most before the groundwater under them reaches Georgica Pond, but even so, it will almost certainly ensure Georgica Pond’s continuing run toward complete dystrophy. I guess we’ll have to wait and see, won’t we?


Larry Penny can be reached via email at Larrypenny9@gmail.com.