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The seas you’re in: fish urine contributes nutrients to coastal waters - The Red and Black : Ugalife

The seas you’re in: fish urine contributes nutrients to coastal waters

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Posted: Wednesday, January 30, 2013 10:00 am | Updated: 1:48 pm, Thu Sep 5, 2013.

Originally, when he was invited to research how fish affect the nutrient cycle in the Bahamas, Jake Allgeier didn’t want to go.

“I said ‘H--- no, I don’t want to go there because it’s not my kind of thing,’” said Allgeier, a doctoral student in the Odum School of Ecology. “I’m a jungle junky. I love the jungle. And then it was just amazing there. You can see. At that point I was used to swimming around in muddy waters with caiman [relations of alligators] everywhere. And then you go to this place and you can see far and it’s beautiful.”

Now Allgeier does most of his research off the coast of Abaco Island in the Bahamas, looking at how fish contribute huge amounts of nitrogen and phosphorus to coral reef, mangrove forest, and sea grass bed ecosystems.

“Coral reef ecosystems are among the most nutrient poor, but the most productive ecosystems in the world. So that’s kind of a conundrum in just general ecology,” he said. “[How animals contribute to their environment has] been this thing that’s widely overlooked, really, in coastal marine systems. I’m not really sure why because they do a pretty good job of it in the freshwater world.”

In order to study this system, Allgeier and his colleague Craig Layman, an associate professor at Florida International University, constructed artificial cinder block reefs in a bay in Abaco to create controlled environments to monitor how nutrient contribution worked. While Allgeier said they knew fish were contributing to the growth of sea grass and algae through the nutrient cycle, it wasn’t until they started the study that they understood just how much.

“A funny comparison is if you take the biggest ungulate herd — so that would be bison, antelope, deer and elk — in Yellow Stone National Park, per meter squared — so per unit area — the fish on one of the reefs that I look at...they actually pee more than three times more [than that herd],” he said.

Fish urine even dwarfs fertilizer-heavy golf course runoff — per meter squared — in nutrient content.

Luke Joseph, a freshman biology major from Augusta, said he wouldn’t have guessed fish pee had so much to do with nutrient cycling.

“That’s pretty cool,” he said. “I guess that means aquaponics might be a good way to grow things.”

Allgeier and Layman have now constructed 36 different artificial reefs to study everything from how different types of fish — such as herbivores and predators — contribute different types and amounts of nutrients and how overfishing and human nutrient contribution affect growth.

“One of the kind of crux arguments we’re making are these fish are important so if you take them away through overfishing you lose this really important process,” Allgeier said. “A counter argument to that is where you take them away you have humans — because they’re overfishing — but where you have humans you have nutrients coming into the ecosystem. So maybe those nutrients could supplant the nutrients lost by the fish.”

For the past two years, Allgeier has been testing that counter argument by mimicking overfishing and nutrient contribution by humans at the artificial reefs in Abaco.

He also models the phenomenally large amounts of phosphorus and nitrogen numbers released in urine during spawning aggregations of grouper — which can reach 10,000 fish in a hectare.

Allgeier got his undergraduate degree from Centre College in Kentucky, taking five years off before graduate school to travel and do research in South America, Africa and Asia. He met Layman in Venezuela.

Layman said Allgeier was hilarious to work with in the field and brought a sense of humor to sometimes ridiculous situations.

“We were both helping a research group from Cornell on a project in a small river system there,” Layman wrote in an email from the Bahamas. “I recognized Jake’s enthusiasm and his passion right away, so I asked him to help with some of my on-going projects later that spring.  He worked with me over a 2 year period in Venezuela, but the political situation began to deteriorate rapidly. So we shifted over to The Bahamas where we continue our research today.”

A new grant from the National Science Foundation will allow Allgeier and Layman to expand their work from the Bahamas to Haiti, the Dominican Republic and Grenada — which will involve different geological regions with different nutrients, changing how fish affect them.

“For me it really just kind of bangs home the point that these fish are doing something that, interestingly, fishermen always notice,” Allgeier said. “Every time I’ve presented to a fisherman down there, they’re like ‘yeah.’ But once we actually quantified it — put the numbers to it — then it’s like everybody’s like ‘whoa.’”

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1 comment:

  • ugamd posted at 9:48 pm on Thu, Jan 31, 2013.

    ugamd Posts: 13

    When you got to go, you got to go!