Sunday, September 21, 2014

“Super-Moon”, High Tides and Visiting Osprey at Rocky Point Marsh.

Salt marshes depend on external forces to flush them and provide an exchange of nutrients. The ocean’s tides are the prime means to do so, with rising tides bringing more new water in; receding tides then drain it out. Tidal dynamics on the East Coast of North America cause “spring tides” to predominate. These types of tides are caused when the sun and the mood exert gravitational force at the same time, from the same direction. August and September saw the so-called “Super-Moon” cause these high tides to be as much as 6.9-feet in Jamaica Bay, which fronts Rocky Point. Several visits to the marsh by Tony and I resulted in the photographs seen here.

First in order of appearance are these three images made by Tony. They show an inundated marsh as the result of a 6.3-foot morning high tide, which occurred at 0941, on August 12, 2014. The image files are time-coded between 0931 and 0933. These images were made looking westwards (top), then slightly north of west (middle). The bottom image depicts a detail on the marsh’s western verges.

August 13th saw clouds subsiding as recently deposited rainwater dripped from marsh vegetation. The high tide, again 6.3-feet, was due at 1035.

Various fixed reference points were photographed in order to convey the visual impression of the rising of the tides in a still photography medium. Here are the twin culverts on the inner edge of the marsh. Time: 0932.

Vegetation has been inundated, with the direction of water-flow clearly indicated as their stalks are pushed towards the right of the image, or into, the marsh. Time: 0939.

The surface of the marsh is covered in water, as the tide continues to rise. At center, background, are the twin culverts; note also the branch in the water to the left. Both items were used as measuring instruments. Time: 0942.

Just a couple of minutes have passed as more of the branch is submerged. Time: 0944.
By far the most visually dynamic event of this high tide was the foaming, bursting seawater, as it flooded into the marsh’s entry. It should be noted that this breach was made when Super-storm Sandy crashed through the area in October of 2012. As the beach naturally migrates inland, and vertical growth takes place, the original entrance to the marsh has become much less efficient at admitting water. So, in a sense, Sandy may have extended the natural life of the marsh. Time: 0948.

A mere four minutes later, the camera pivots 180-degrees, towards the area where the marsh’s original entry point lies. While the new entry is admitting copious amounts of seawater, barely a trickle has made its way through the original entrance. Some of the water is detoured by the sand-bar; the remainder by the depth and steepness of the migrating beach. Inland, the direction of migration, is to the right. Time: 0952.

This is the western-most extent of the inundated marsh, looking east. The new entrance is to the left, the old to the right. The flow of the water could be seen to come from left-to-right, further evidence that little water comes in via the old entrance. Time: 1014.

The twin culverts are now almost completely under water. The time of this photo was 1037, two minutes after high tide.

Compare this image to the one taken at 0952, above. Note how the sandbar has been covered and how some water is entering the marsh via the old entrance at the far left. Time: 1042
Turning the camera 180-degrees again, the new marsh entrance, just above the vegetation at right, is level with the sea. Time: 1043.

Our old friend, the tree branch, is fading fast, as is the vegetation above it. Note also that the sand-spit visible in the photo above at 0944, has gone underwater. Also to consider is this: the tide began receding 13 minutes prior to this photo, which was made at 1048.

The water-flow within the marsh has reversed to right-to-left as the tide recedes, as indicated by the direction in which the inundated vegetation points. Time: 1057.

Still under threatening skies, the camera takes in an overall view of the shore-line, looking east. Note how the sand-bar begins to re-emerge as the tide continues to recede. Time: 1133.

One would think that the marsh in this condition presents a perfect opportunity for wading birds to get a meal; that would be correct. Seen here is a Great Egret on the prowl. Time: 0937.

The smaller cousin of the Great Egret, this Snowy Egret also made continued life a precarious prospect for the local fish. Time: 1053.

The marsh is also home to an extraordinary variety of creatures, such as mammals, insects, fish, crustaceans and birds. An Osprey nesting box was installed in the hopes that one of these predators would take up residence. Although this has not happened, recent observations have seen an apparent up-tick in visits by these birds; I have observed five appearances in four visits. The good hunting in the area, as well as the ready availability of a custom-built home may yet see the Osprey choose to settle at Rocky Point.

The morning of August 9, 2014 saw two Osprey perched on the upper-most branches of a dead tree. One eventually flew off, while the other stayed, but only a bit longer.

The same tree on August 30, hosted an Osprey. Note that the tree is located within just a few dozen feet of the water’s edge, making it an ideal perch for an avian hunter who may wish to conserve precious energy, while still searching the waters below for prey.

On September 16, two separate Osprey sightings were recorded. This was the second one, at 1425. Like the first sighting earlier, this fellow flew from west-to-east, with a slight detour above the marsh. The most recent sighting was on the morning of September 20; a single Osprey was spotted perched in the usual tree.

Speaking of the Osprey, this particular one, part of a trio seen on September 20, is flown by the US Marine Corps as part of the presidential air transport fleet.

Except where noted, all photos and text are by Frank V. De Sisto. Special Thanks to NPS Ranger Tony Luscombe for the use of his photographs.

Published works consulted for this posting include the following:

 “Salt Marshes, A Natural and Unnatural History”, by J.S. Weiss & C.A. Butler. 2009, Rutgers University Press, ISBN 9780813545707.
The go-to book on the subject of the salt marsh, this title is a must for students of the subject. Among its many nuggets is a small schematic drawing that accompanies a brief description of what causes tides.

 “Field Guide to the Water’s Edge” National Geographic, by S. Leatherman & J. Williams. ISBN 9781426208683.
A broad, basic and well-illustrated guide to our nation’s beaches, shorelines and riverbanks, this book also details the various flora and fauna that populate such places. Aside from a concise fully-illustrated section describing the workings of tides, it also has a section on marshlands.

Tony also recommended this web-site to find local tide information. For locations, heights and times of the tides see:
An excellent, easily-accessed resource for precise locations, dates and times of tides. Click on “Tides” in the header bar. Fill in the required fields. Note the red dots in Jamaica Bay. For Rocky Point Marsh, click on the left-most one, “Barron Island-Rockaway Inlet”.

“Clouds and Weather”, Peterson First Guides, by J.A. Day & V.J. Schaefer. ISBN 9780395906637.
It’s nice to know how to “read” the sky when in the field. This compact booklet is packed with 128 pages of text, diagrams, excellent color photography and a handy index.

 Rocky Point Marsh needs your help. To volunteer for service contact National Park Services Ranger Tony Luscombe at:

 For more photos of Rocky Point as well as other locations within the Gateway NRA complex, visit:



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