Why do plankton matter? 91��ɫ biology Professor Norman Yan, the study’s senior author, says these tiny creatures are critical to our survival. “Without plankton, humans would be quite hungry and perhaps even dead. Much of the world's photosynthesis, the basis of all of our food, comes from the ocean's plankton. The oxygen in every other breath we take is a product of phytoplankton photosynthesis,” says Yan.

Norman Yan

Yan together with the study's lead author Howard Riessen, a professor of biology at SUNY College at Buffalo studied the effect of changes in water chemistry on plankton prey defenses. Specifically, they examined how lower calcium concentrations affect Daphnia (water flea) exoskeleton development. These low calcium levels are caused by loss of calcium from forest soils, a consequence of decades of acid rain and multiple cycles of logging and forest growth. The results are published this week in the Proceedings of the National Academy of Sciences.

Daphnia pulex

“At low calcium levels the organisms grow slower and cannot build their armour,” says Riessen. “Without suitable armour, they are vulnerable to ambush by predators,” he says.

“Calcium is a critical element for Daphnia and many other crustaceans,” Riessen says. “Daphnia build their exoskeletons, which include some defensive spines, with calcium to protect themselves from predators. Where calcium levels are low, the Daphnia have softer, smaller, exoskeletons with fewer defensive spines, making them an easy snack.”

This phenomenon of reduced calcium is also playing out on a much larger scale in the world’s oceans, notes Yan. “Increases in ocean acidity are complicating calcium acquisition by marine life, which is an under-reported effect of global carbon dioxide emissions. Thus marine plankton may also find themselves more vulnerable to predators,” he says.

Howard Riessen

The public is used to stories about changes in water chemistry that lead to large-scale fish kills, says Riessen. “These changes are more insidious. Daphnia might not be a household name, but they are food for fish, and they help keep our lakes clean. Changing the balance between Daphnia and their predators marks a major change in lake systems.”

Republished courtesy of YFile– 91��ɫ’s daily e-bulletin.

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Blow by Blow: The Second Annual Donald Sanderson Memorial Symposium on Sport Concussion is open to the public – athletes, coaches, parents, researchers and anyone interested in the physical and psychological impact head injuries can have on individuals and their families.

91��ɫ’s School of Kinesiology & Health Science will host the two-hour evening event, which will bring sports medicine and brain researchers together with athletes to discuss an injury that continues to impair the careers and health of both amateur and professional athletes − most recently, hockey champion Sidney Crosby.

The symposium is held in honour of Donald Sanderson, the 91��ɫ kinesiology student and promising hockey player who died Jan. 2, 2009 as a result of a head injury during a Whitby Dunlops game. 

     Right: Matt Dunigan

"Educating our student athletes about head injuries is critical,” says Cindy Hughes, manager of the Gorman/Shore Sport Injury Clinic in 91��ɫ’s School of Kinesiology & Health Science, who helped organize the symposium. “They need to understand the importance of reporting a possible concussion right away so they can receive the proper care."

, a game analyst with TSN since 1996, played football for 14 years on five Canadian teams and was inducted into the Canadian Football Hall of Fame in 2006. He retired from football in 1996 after suffering at least a dozen diagnosed concussions, and continues to struggle with the long-term effects of those concussions. He will speak about the post-concussive symptoms he has experienced since retirement and the effect of concussion on himself and his family, as well as the importance of reporting concussion and taking it seriously. A champion of research on sport concussion, Dunigan announced last spring that upon his death his brain will be donated to Toronto’s Krembil Neuroscience Centre.

Dahna Sanderson, who established the Donald Sanderson Memorial Trust Fund in memory of her son, will also speak during the symposium. A sports mom and fan for 20 years, she coached professional figure skating and is passionate about sports and sports safety. 

is a primary care sport medicine specialist, certified in family and sports medicine in Canada and the US. Currently practising in Burlington, he has been a junior hockey team physician for the past decade in Canada and the US. He is a research chair of the Hockey Neurotrauma and Concussion Initiative Research Committee and is primary investigator of the Hockey Concussion Education Project. 

Lauren Sergio is a professor in the School of Kinesiology & Health Science in 91��ɫ’s Faculty of Health. A neuroscientist, she studies the effects of age, sex, neurological disease, head injury and experience (élite versus non-élite athletes) on the brain’s control of complex movement. She works with a wide range of adults, from NHL draft prospects to Alzheimer’s disease patients, using behavioural and brain imaging techniques. 

Left: Lauren Sergio

Roy McMurtry, 91��ɫ chancellor and former chair and chief executive officer of the Canadian Football League, will deliver opening remarks. Award-winning CBC sports reporter Teddy Katz will MC the event. 

The symposium takes place in the Price Family Cinema, Accolade East Building, from 7 to 9pm. Admission is free, but registration is required. To register and for more information on speakers, visit the symposium website.

Republished courtesy of YFile– 91��ɫ’s daily e-bulletin.

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