Diving

The Bounty of the Sea

Greetings from New England!Each Monday we write about the New England environment and way of life seen through our local perspective. Previous posts

By Phil Colarusso

Thousands of silver fish flashed around my head in every direction. The school of pollock seemed to be everywhere at once and their sheer abundance was disorienting. It’s easy to understand how difficult it must be for a predator to pick out individual fish in this incredible moving mass of life.

I’ve only had the pleasure of being enveloped by large schools of fish a few times in my diving career. Even so, today’s schools are typically small compared to historical accounts of fish abundance. Mariners in the 19th century and earlier reported schools streaming past their boats for hours at a time, so they probably had millions of fish. In 2013, it’s rare to find these massive congregations.

We used to believe the bounty of the seas was endless. We’ve since learned that fish, like other natural resources, are finite. Slow declines in abundance can go undetected by fishermen, scientists and the public. But, if these changes continue over a long time, lower levels of abundance become the new normal state.

Scientists have coined the term “shifting baselines” to describe this phenomenon. Each generation of scientists regards the state of the natural world during their career as the normal state, but in reality, small changes over multiple generations result in dramatic differences. The ocean that I swim in now is a very different place than the ocean of Jacques Cousteau in the 1960s.

The logical question to ask is: “Where did the bounty go?” Unquestionably, a large percentage of it went into fishermen’s nets to feed the world’s growing human population, but that’s not the only thing that’s going on. The oceans are part of a system with a large number of interlocking components involved in an elaborate balancing act. A significant change in one piece inevitably has implications (both positive and negative) for others. For example, in New England, the overfishing of cod resulted in skate and dogfish populations exploding. Simply stopping the fishing of cod may not be sufficient to restore populations to their historic levels: cod fishing ended on the Canadian side of Georges Bank more than a decade ago with little population recovery.

However, while my oceans are different than the oceans of Cousteau, they’re still special places. As I was surrounded by pollock, it was impossible not to be filled with hope.

More information about the work of EPA’s scientific divers.

About the author: Phil Colarusso is a marine biologist in the Coastal and Ocean Protection Section of EPA New England, and is an avid diver. He’s living the dream in Wenham with wife JoAnn, two kids, dog and white picket fence.

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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Flexing Freshwater Mussels in the Delaware

Reposted from Healthy Waters for EPA’s Mid-Atlantic Region

By Matt Colip

It takes more than the brute strength of legislation to clean up America’s waterways.  The complex process of aquatic ecosystem cleanup requires many tools, including one of nature’s most powerful muscles: her freshwater mussels.

That’s what the Partnership for the Delaware Estuary (PDE) – assisted by the Philadelphia Academy of Natural Sciences, and the U.S. Environmental Protection Agency’s (EPA) Scientific Dive Unit – set out to assess during a late summer freshwater mussel survey in a tidal section of the Delaware River near Philadelphia.

Freshwater mussels are bivalves similar to oysters and clams.  But, unlike oysters and clams, freshwater mussels live in inland streams, and provide valuable benefits including strengthening streambeds by keeping soils in place and providing food and habitat needed by other animals and plants.  As filter-feeders, mussels also clean the water in which they live by sucking water in and trapping solids such as dirt, algae and other pollutants, then releasing the clean filtered water back into the environment.

Being in the tidal area of the Delaware River as a scientific diver was an interesting experience. The water was not clear and flow rates were very high due to tidal fluctuation.  In these conditions, I couldn’t help but think, “There’s no way there are mussels down here.”  Despite my suspicions, when I reached the river bottom, sure enough, there were mussels everywhere, thriving and filtering the ambient water!

Freshwater mussel survey

Recording data during the freshwater mussel survey.

Ultimately, the survey, in addition to confirming the existence of an abundant freshwater mussel population in a very urbanized section of the Delaware River and providing valuable scientific data, gave me a newfound appreciation for what I used to only consider a tasty added protein to a pasta dish at a restaurant.*

For more information about freshwater mussels in the Delaware River, please visit the PDE’s website.  Read more about EPA scientific diving at facebook.com/EPADivers.

About the Author: Matt Colip works in the region’s NPDES Enforcement Branch and focuses primarily on enforcing wastewater and stormwater regulations. Originally from Texas, Matt graduated from Franklin & Marshall College in Lancaster, Pa., with an interdisciplinary BA in Public Health and has a MS from Saint Joseph’s University that focused on environmental protection policy and management. In addition to SCUBA diving, Matt is an avid bicyclist and enjoys riding with friends and colleagues.

*EPA is not endorsing the consumption of oysters, clams and mussels in the wild.   Please refer to the National Shellfish Sanitation Program guidelines associated with regulating the handling, processing and distribution of mussels prior to consumption.

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.

Flexing Freshwater Mussels in the Delaware

By Matt Colip

It takes more than the brute strength of legislation to clean up America’s waterways.  The complex process of aquatic ecosystem cleanup requires many tools, including one of nature’s most powerful muscles: her freshwater mussels.

That’s what the Partnership for the Delaware Estuary (PDE) – assisted by the Philadelphia Academy of Natural Sciences, and the U.S. Environmental Protection Agency’s (EPA) Scientific Dive Unit – set out to assess during a late summer freshwater mussel survey in a tidal section of the Delaware River near Philadelphia.

Freshwater mussels are bivalves similar to oysters and clams.  But, unlike oysters and clams, freshwater mussels live in inland streams, and provide valuable benefits including strengthening streambeds by keeping soils in place and providing food and habitat needed by other animals and plants.  As filter-feeders, mussels also clean the water in which they live by sucking water in and trapping solids such as dirt, algae and other pollutants, then releasing the clean filtered water back into the environment.

Being in the tidal area of the Delaware River as a scientific diver was an interesting experience. The water was not clear and flow rates were very high due to tidal fluctuation.  In these conditions, I couldn’t help but think, “There’s no way there are mussels down here.”  Despite my suspicions, when I reached the river bottom, sure enough, there were mussels everywhere, thriving and filtering the ambient water!

Recording data during the freshwater mussel survey

Recording data during the freshwater mussel survey

Ultimately, the survey, in addition to confirming the existence of an abundant freshwater mussel population in a very urbanized section of the Delaware River and providing valuable scientific data, gave me a newfound appreciation for what I used to only consider a tasty added protein to a pasta dish at a restaurant.

For more information about freshwater mussels in the Delaware River, please visit the PDE’s website.  Read more about the latest in EPA scientific diving at facebook.com/EPADivers.

 

About the Author: Matt Colip works in the region’s NPDES Enforcement Branch and focuses primarily on enforcing wastewater and stormwater regulations. Originally from Texas, Matt graduated from Franklin & Marshall College in Lancaster, Pa., with an interdisciplinary BA in Public Health and has a MS from Saint Joseph’s University that focused on environmental protection policy and management. In addition to SCUBA diving, Matt is an avid bicyclist and enjoys riding with friends and colleagues.

*EPA is not endorsing the consumption of oysters, clams and mussels in the wild.   Please refer to the National Shellfish Sanitation Program guidelines associated with regulating the handling, processing and distribution of mussels prior to consumption.

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.

Ebb and Flow: Feeling Like a Yo-yo

By Sean Sheldrake

My previous blog posts have featured how EPA diving scientists support cleanups in the nation’s waterways.  In this post, I talk about how our divers study the connection between groundwater and our waterways to support EPA cleanups.  (Hint: it’s not a one way street!)  Understanding which way groundwater is flowing is critical to implementing a successful cleanup—and protecting our nation’s waterways and oceans.

Groundwater: coming or going? 

We all know storm drains connect to our waterways, but how about groundwater? In a given stretch of a stream, lake,  river,  or the seafloor, groundwater may be feeding the waterway—or the opposite—that stream, lake,  river, or ocean could be losing water into groundwater in that location.  The direction of the flow can change by the hour, day, season, and conditions (such as drought)—a reality of the interconnectedness of water in the environment.

Gaining or losing? Mapping out the flow to get the cleanup right

Determining whether a river loses or gains water from the ground is a big deal when devising the best course of action to take during cleanup activities, as we need to follow the contaminated water to wherever it goes.  With this information, we can decide on important details, such as where to install caps in a riverbed to stop the flow of contaminated discharge, or how many and how fast pumping wells should be employed to move contaminated groundwater to a treatment plant.

Seepage meter installed by an EPA scientific diver near a Superfund Site in Lake Washington. Photo: Rob Pedersen, USEPA.

Seepage meter installed by an EPA scientific diver near a Superfund Site in Lake Washington. Photo: Rob Pedersen, USEPA.

Making such a determination is an ongoing process. For example, in an estuarine river (the part of a river that is near the sea), this may take a lot of monitoring locations over time to know we’re choosing the right kind of cleanup. A lot of factors also need to be considered, including the location, direction, and volume of local ship traffic.  EPA divers often must check various locations in the sediment near an active cleanup to determine where groundwater is discharging into the river—and vice versa.

Low-tech goes underwater

At some sites near marine environments, we use conductivity mapping to determine where groundwater discharge is occurring.  Because salt water conducts electricity better than fresh water, we tow an array of electrical cables that measure electrical fields to produce a map of where fresh ground water is discharging into salt water.  In other sites, we can use a more low-tech approach.

The photo above shows one such technique. Here, we use a five-gallon bucket, cut in half, stuck into the lake bottom. We then outfitted it with a sampling bag filled half way with water.  We use this simple device to determine the direction of the water flow by noting what happens to the sampling bag. If it begins to empty we know the direction of water is OUT of the lake (and bag) and into the ground, and if it fills up, we know the water is flowing in the other direction: from the ground into the river.   We can also seal the bag and bring it to our lab for analysis, getting and even better understanding of the rate of contaminant discharge into a lake or stream.  Over time, divers come back to visit the site to map the wonderful complexity of water’s connections.  The map allows us to understand the movement of historical pollution and to determine how to best conduct a clean up.

Read more about the latest in EPA scientific diving at facebook.com/EPADivers.

About the author:  Sean Sheldrake is part of the Seattle EPA Dive unit and is also a project manager working on the Portland Harbor cleanup in Oregon.  Sean Sheldrake serves on the EPA diving safety board, responsible for setting EPA diving policy requirements. 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.