L o o k d e e p i n t o n a t u re , a n d t h e n y everything better. ~A ou will understand l b e r t E i n s te i n
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A DELICATE BALANCE:
Our Marshes and Sea Level By Dr. Lenore Tedesco, Executive Director of The Wetlands Institute
Sunny-day marsh flooding during full-moon tides is now more frequent.
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oastal marshes, tidal creeks, and bays are the cradles of life. They host a phenomenal diversity of wildlife, and their intrinsic beauty is a balm for the soul. They are the foundations of a complex web that is the building block for commercial and recreational fisheries, supports local economies, and sustains the coastal way of life. Marshes and tidal creeks are critical nursery grounds for fish and shellfish. More than 75% of the commercially and recreationally important species like blue crabs, oysters, clams, striped bass, flounder, and many others rely on marshes during at least part of their life cycles. Marshes are the kidneys of our coastal waters, naturally improving the quality of water passing through them by trapping sediments and converting dissolved chemicals into harmless compounds. They are also crucial to coastal resiliency, offering protection against damage to property and infrastructure and reducing loss of life during storm surge and flooding – providing our coastal communities concrete and immediate benefits. Research from
the insurance industry showed that marshes directly prevented more than $625 million in flood damages during Superstorm Sandy in 2012, further underscoring their value. If you have either lived near the coast or visited it over many years, you have probably noticed the changes in water levels in our marshes. It used to be a really big deal when the meadows were flooded, because it didn’t happen very often. Times have changed. Now, they flood numerous times every month – even on calm, sunny days. What causes this, and what does it mean for our marshes and the wildlife that depend on them? It is well-established fact: The sea level in our area is rising – and doing so too fast to sustain healthy marshes. The rate of sea-level rise is also accelerating dramatically. For the past 100 years or so, scientists directly measured this through local tide gauges that record how high the water level rises and falls each day. More recently, they have been using satellite technology as well. We are fortunate to have sev-
eral gauges in the area that have relatively long records, so we can see how sea level has changed. Averaged over long periods, sea-level measurements taken in both Atlantic City and Cape May show that sea level is rising at a rate of about 4.2 millimeters (or 0.16 inches) per year. This may not seem like much, but from 1911 to 2023 that is a change of more than 1½ feet. Due to a complex set of reasons – most importantly because southern New Jersey is also sinking – sea level has risen here at more than twice the global average. Long-term averages only tell us part of the story, though, and downplay the increasing rate of sea-level rise. To really understand what is happening today to our marshes, we need to look more closely at the record. Over the past 15 years, the rate of sea-level rise measured right here on the 96th Street bridge into Stone Harbor is more than 6 millimeters (or a quarter-inch) per year. Simply put, the water is rising higher each year and we see it now more dramatically because it’s
Barrier island street flooding has become a normal part of island life.
Extensive tidal marshes of Seven Mile Beach enrich our lives.
Many open-water areas at The Wetlands Institute are drowned marshes, seen here during a very high tide. continued on page 64
Seven Mile Times August 2023
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