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An Eelgrass Meadow Grows in Sunset Park!

By admin
December 20, 2013

“Billion Oyster Project…it’s not all about the oyster” People should know this and spread the word far and wide. Oysters are only one of at least three major engineering species that were historically present in the estuary. All three of these species – oysters, sea grass, and marsh grass – are needed together to restore the ecology of the NY Harbor. While the name of our project may imply otherwise, the ultimate goal of our work is comprehensive ecological restoration – of habitat, not only individual species. Just as the Great Ape could not live in a forest devoid of trees, understory, or insects, nor can the oyster make a comeback in an estuary devoid of marshland and submerged aquatic vegetation.

Eelgrass (Zostera Marina) is historically the most widely distributed genus of sea grass or submerged aquatic vegetation (SAV) in the North Atlantic bight. The historical Hudson Raritan Estuary was teaming with these underwater meadows. Like the oyster reefs that surrounded them, eelgrass meadows supported countless other species of fish, crustaceans, mollusks, and benthic dwelling invertebrates of all shapes and sizes. Seagrass meadows are the subtidal analog of upland and intertidal salt marsh (spartina alterniflora and spartina patens). The healthy estuary consists of all three habitat types: sea grass, marsh grass, and oyster reef. But unlike oysters, Eelgrass has a relatively narrow tolerance range for factors like dissolved oxygen and sunlight. When these become limited due to excessive sedimentation, dredging, and nitrogen loading (raw sewage) the sensitive fronds of eelgrass quickly die back. Eelgrass also needs a sandy bottom. The anoxic mud (black mayonnaise) that now covers vast areas of the Harbor bottom makes Eelgrass restoration efforts near impossible…

Enter the promised land: the Sunset Park Industrial Waterfront and the 120-year old Bush Terminals Piers. Once the busiest and most productive stretch of industrial waterfront in NYC, employing some 27,000 people in its heyday in the mid 1920s, Bush Terminals is now at the leading edge of the ecological revival of New York City’s post-industrial shoreline. Starting in the 1960s Terminals 1 through 5 were abandoned and became unused for the more than 35 years. The piers themselves collapsed and began a process of decay and reintegration with nature. Today Terminals 1 through 4 have been converted into the newest NYC Park site with ball fields, beachfront, mature cottonwood trees and two habitat-enhanced tidal lagoons. Pier 5 is the remaining collapsed/derelict pier and has evolved naturally with little to no human intervention. Slabs of collapsed concrete are surrounded by self colonizing grasses (mostly phragmites) and clean sandy bottom. Large stretches of native blue mussel beds coat the cracks and crevices between the slabs and old monolithic pilings. Oysters are a few and far between but at last count three hardy colonizers had been identified alongside 15 or so bottom shell remnants.  In summary nature is recolonizing the upland and intertidal surfaces of the collapsed pier. It is truly an amazing process to witness.

Natural restoration of subtidal (submerged) bottom is a slower process, but the Pier 5 site shows extraordinary potential for human assisted restoration. The subtidal bottom is sandy and visibility is high, allowing plenty of light and oxygen to reach benthic dwelling plants and animals. The embayment is largely protected and the shoreline shallows are easily accessible from the Pier. In summary Pier 5 is the perfect site in the Upper NY Bay for an eelgrass restoration pilot. The small pilot project (footprint: 10 ft by 100 ft.) is led by site manager Bart Chezar and Harbor School marine biology research students (Nicolle Martinez et al). The plantings were established in the Fall of 2012, with assistance of Cornell Coopertive Extension, just weeks before Superstorm Sandy struck. Not only have all the plantings survived but 75% of the burlap bases show expanded footprints. As of the most recent monitoring on 12/14, new shoots are evident on 8 of the 10 original planting bases. Underwater video of the 12/14 monitoring will soon be posted on the MBRP Harbor SEALs Eelgrass project page.