_ECO Biology

_Impact of Algal Blooms

Impact of Algal Blooms
‘Phytoplankton’ and ‘algal blooms’ aren’t exactly household words—but too much of either can have a serious impact on the food chain and, more importantly, human life.

_Ling Ren

Ren is a scientist at the Academy, with research interests in Eutrophication, harmful algal blooms and the Barnegat Bay.

Academy of Natural Sciences of Drexel University scientist Ling Ren has spent the last few years studying blooms of phytoplankton, a type of algae that lives near the surface of water.

The green muck may seem harmless, but as it turns out, algae can play a massive role in the health of ecosystems.

Phytoplankton grows naturally when light, temperature and nutrients such as nitrogen and phosphorus are balanced. However, excessive nutrient inputs, warmer water temperatures and plenty of light can cause growth to occur too quickly, resulting in rapid expansion of massive phytoplankton populations. These “blooms” sink to the bottom of waters along the coast where they decompose and consume oxygen.

“Some forms of phytoplankton can also produce toxins, which may be accumulated in shellfish or fish via the food chain and eventually be harmful for human consumers,” Ren says.

In 2009, along with scientists from China’s Zhejiang Ocean University (ZJOU), Ren began a project to evaluate the ecology of the Zhoushan Fishery region of the East China Sea by re-examining how phytoplankton blooms affect fish resources. This information will eventually provide a scientific basis for future coastal management and ecological restoration.

During the three-year project, Ren set up small-scale experiments to study the nutrient inputs on phytoplankton by recreating the conditions that spur algal blooms. She also trained Chinese graduate students to carry out these experiments and will return to China this November to check their progress.

Ren recently received funding to focus her research closer to home, in New Jersey’s Barnegat Bay. This area has seen significant changes over the past few decades, mainly attributed to human activities in the area including population growth, and increases in industrial development and agriculture.
During this two-year project, Ren hopes to learn more about phytoplankton blooms, their relationships to human activity and how these blooms are affecting its grazers—such as aquatic insects, shellfish, fish—and the long-term ecology of the bay. There are also harmful phytoplankton that can bloom in Barnegat Bay, including “brown tide” blooms that can affect shellfish growth and reproduction.
Ren will collect and analyze water samples from the bay to determine phytoplankton species diversity and how it changes over time—an abundance of certain species can tell a story about the water quality of the bay.

Her project is one of many bay-wide monitoring studies currently being conducted by Academy scientists. Ren’s results will provide a better understanding of current water quality issues, which will contribute to better management and restoration of critical natural resources within the bay.

In Focus: Ling Ren

Ling Ren grew up in Zhoushan, one of China’s largest fishery areas in the East China Sea. Her work has taken her back to her birthplace on several occasions, and sadly, over the years she has seen her country’s rapid urbanization and dramatic population increases fundamentally change the face of this formerly peaceful fishing community.

More recently, her work has taken her to the marshes of New Jersey’s Barnegat Bay, where she continues her work exploring the potentially damaging impact of algae blooms.

EXEL Magazine spoke with Ren about her work both in China and here in the United States, how the two countries compare in terms of environmental awareness and education, and why her work is so important.

What was it like growing up in Zhoushan?

Zhoushan (Jo-Shan) translates to mean “boat island.” I grew up there in the 1970s and at that time, China was not as economically driven. It was the end of cultural revolution. I’ve always loved that place. I remember when I was in middle school, there were four or five of us girls who always climbed a mountain to see the whole area. It’s just beautiful.

Did your childhood there inspire your interest to go into marine studies?

Oh, definitely. The sea has always been a part of my life and I wanted to know more about it. Plus, the water in the area is within the Yangtze River plume. The water is very dynamic a lot of different currents. So, the water is very turbid and very yellow and muddy. As a child, we never really had a chance to travel too far everybody because there wasn’t a lot of money and transportation in Zhoushan is really not convenient. I wanted to see the kind of poetic blue, clear water that you read about in books. So, I went to China’s Ocean University in 1988 for my undergraduate studies. The city is located on the coast of the Yellow Sea, and the campus is only five minutes from a really beautiful beach. And, yes, the water there is blue.

What is your earliest memory of “pollution?”

Things are very different in China. I did not really learn about pollution until I was in graduate school in the mid to late 1990s. More and more people were talking about the reduction of fish species we’d been eating, and that fish prices were going up and that some species had gone extinct over the last 20-30 years. In my master’s program, I started to learn more about ecology and environmental issues like the relationship between nutrients and biology and algae growth and how humans play a part in all of this and it was then that I made the connection.

What are the biggest differences you see between Americans and the people of China when it comes to dealing with pollution and protecting the environment?
People in the U.S. are doing a much better job, I think. People here are more aware of the environment and how important it is to human beings. People here are more educated and the government is doing a better job to raise awareness of environmental issues.

In China, many people don’t care that much, the public is not getting as much education. Problems with the environment tend to be ignored because very few people realize the overall picture—that the environment and humans are all part of a whole ecosystem. They’re more in the line of thinking that the environment is a source that people can exploit.
Occasionally, if things get very bad, the government will issue a warning. But mostly people think that problems with the environment will just solve themselves. It’s very frustrating.

What was it like to go back to your birthplace, to Zhoushan, as an adult and as someone more educated about pollution and algal blooms?

When I went back to Zhousan during my master’s program, I saw a large algal bloom not far from the ferry I took. The water was just covered with reddish, patchy layers of algae. It was really shocking. It’s getting worse there every year. Over the last 10-15 years, there’s been an increase of blooms and a reduction in the fish resources. One type of fish, the large yellow croaker (Larimichthys crocea), used to be the major resource there back in the 1970s but now its natural population is nearly gone.

How are the people of Zhoushan dealing with the changes?

Now aquaculture is really developing there. But while it may support the economic development, it also has a negative impact on the environment. Very often in aquaculture, small wild fish are used to feed the farm-raised fish. This causes a reduction in those small wild fish population. On the other hand, any feed not consumed by farmed fish can enter the environment and pollute the water.

And, for the majority of the local people, because it’s so expensive and the supply is limited, they just cannot afford farm-raised fish.

Why is your work important?

Because it gives me a voice. In China, you’re not encouraged to speak up about the environment. When I was a child, we were not encouraged to have dreams about making change in the world. So, I’m still in the very early stages and I wonder if I’m brave enough, but if I could play a part in changing things, that would be my dream; to make noise and really do something.