The final Great Decisions lecture will be at 6:30 p.m. Wednesday at the Cumming library, 585 Dahlonega Road. Anna Rulska, NGCSU assistant professor of political science, will discuss energy geopolitics.
Buying sustainable seafood is one way people can help protect the oceans, a North Georgia College & State University professor told an audience Thursday.
Nancy Dalman, interim head of the university’s biology department, presented a discussion on the state of the world’s oceans as part of the Great Decisions lecture series at the Cumming library.
Dalman said ocean ecosystems face many challenges.
Some of the worst threats, she said, are climate change, pollution, over-hunting and invasive species.
Dalman said pollution from machinery that produces greenhouse gases is leading to global warming.
“Many different scientists have all reached the same conclusion that the general trend over the last 50 years is warmer temperatures,” she said.
She noted that while history shows that the earth has gone through many natural cycles of warmer and cooler temperatures, the process has been greatly increased over the past 60 years or so.
According to Dalman, a major impact of global warming on the oceans comes from increased melting of the polar ice cap.
She showed photos of the Arctic taken from space in 1979 and in 2007 to demonstrate how much the ice cap has melted.
“The last three decades have been the warmest on record,” she said. “During that time period, as you can see, there has been about a 34 percent decrease in the ice cap.”
The increase of melted fresh water can have impacts on species ranging from polar bears and fish to micro-organisms, she said.
Dalman also said trash in the oceans is a major problem.
She said there are several large areas known as trash vortexes, where currents move garbage into central locations.
“One of the largest vortexes in the north Pacific is the double the size of Texas,” Dalman said.
Due to their massive size and distance from shore, Dalman said it would be difficult to clean up the vortexes.
Other problems facing the oceans are over-hunting by predators and humans, and invasive species that are introduced to non-native areas by humans.
Dalman said various research groups are trying to develop better fishing practices for many species that have been over-harvested.
Aquaculture, or farming of fish and other ocean species, is also a viable option to increasing species.
Dalman encouraged residents to purchase seafood with seals deeming it certified sustainable or certified as using best aquaculture practices.
She said they could also download a pocket guide of the most environmentally sustainable types of seafood to purchase from the Monterey Bay Aquarium’s Web site at www.montereybayaquarium.org.
Dalman ended her presentation on a positive note.
“It’s important to know the reality of what’s going on, but a lot of organizations are feeling some optimism since there is an increasing public awareness and people are making changes,” she said.