As our research continues, we are beginning to recognize we may be entering some uncharted territory for Georgica Pond, as least in recent memory. Specifically, while the inlet or cut in Georgica Pond has been traditionally opened to the ocean twice annually, in the spring and fall and closing shortly thereafter, this year it has been more or less open all year. Specifically, the Trustees opened the cut in January and it remains open today.
Since January, the cut to the ocean has meandered, shrunk, closed temporarily, and re-opened several times. The most recent iteration of this metamorphic process occurred in late May and was recorded by our water quality buoy. Specifically, with the cut temporarily closed, the salinity of the Pond was dropping below 20 and a microalgae bloom was developing in the Pond as chlorophyll levels were rising (see buoy figure below). During a series of storms that occurred on June 2nd and 3rd, the cut re-opened, causing the microalgae to be flushed out of the Pond by ocean water (see buoy figure below). This version of the inlet permitted strong flushing of the Pond this month as, according to our buoy, the salinity in the southern extent of the Pond is the same as the ocean (31), there is no accumulation of microalgae, and oxygen levels in the Pond are high (see buoy figure below). Then, suddenly this weekend, the cut closed again, and the salinity is now dropping once again (see figure). While this closure could remain through the fall, only time will tell if this is indeed the case. Given that two of the problems that have plagued Georgica Pond, microalgae (blue-green algae) blooms and low oxygen, have been in check this year, having the cut open has had benefits. As I am sure many of you have seen, there is a downside to this ‘inlet open’ status, specifically the Pond is so shallow as to be partly unnavigable for boats and the current conditions have been favorable for the proliferation of macroalgae (seaweeds) which are presently wide-spread through much of the Pond. In 2014, the growth of macroalgae increased through the early summer and began to dissipate in July. Because of the extended ‘inlet open’ status and higher salinity this year, it is difficult to know if the macroalgae patterns will parallel 2014. As was done last year, we are surveying the macroalgae on a regular basis. Later this week, we will review what we know about the macroalgae in Georgica Pond.