How does rising atmospheric CO2 affect marine organisms?

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Volume 2 Number 11:  1 June 1999

Editorial
Frog Legs and Climate Change: Take frogs.  While some people eat their legs; others study them.  Back in 1995, for example, school children in Minnesota discovered a number of specimens that had more than their normal complement of hind appendages.  Further investigations revealed other abnormalities: missing limbs, twisted jaws and declining populations all around the globe.  Was it checkout time for toads?  The end of the world for amphibians?  A harbinger of even more terrible things about to descend on the rest of the biosphere?

Journal Reviews
Coral Bleaching Caused by Bacterial Infection: A laboratory study of a Mediterranean coral reveals that bleaching is induced when the coral is subjected to a certain bacterial strain.

Temperature, Bacterial Adhesion, and Coral Bleaching: The authors demonstrate a connection between elevated seawater temperatures and coral bleaching; but they cite numerous studies that suggest that other factors probably play a more basic role in the real world.

Effect of Temperature on Bacteria-Induced Coral Bleaching: In situ and laboratory studies reveal a close connection between seawater temperature and coral bleaching in the Mediterranean Sea, but not necessarily a cause and effect relationship.

Type II White-Band Disease: A bacterial infection is reported as causing coral bleaching in A. cervicornis.

Sediment Impact on Nearshore Coral Reefs: A study of coral bleaching and mortality caused by storm-induced increases in sedimentation rates highlights the exacerbating effect of coastal development activities on this bane of coral reefs.  It further implicates the simple phenomenon of growing human numbers in coastal areas as the prime cause of the seemingly increasing incidence of coral bleaching over the course of the past century or so.

Sediment Deposition on the Great Barrier Reef: A study of the impact of sediment load on corals suggests both direct and indirect negative effects on coral recruitment, survival and growth rates.

Coral Responses to Short-term Sediment Burial: Coral bleaching was the end result in an experiment exposing four coral taxon to varying lengths of full sediment burial.  However, most of the corals experienced full recovery within weeks after the stress was removed.

Effects of Elevated CO2 and Nitrogen Supply on Strawberry: Strawberry plants grown in glasshouses for nearly three months at 560 ppm CO2 displayed higher rates of net photosynthesis, greater flower and fruit numbers, and greater fruit weights and total plant biomass than plants grown at 390 ppm CO2, regardless of soil nitrogen supply.

Effects of Elevated CO2 Daily Exposure Duration on Soybean Growth: Soybeans grown in large pots displayed CO2-induced increases in growth and yield that were similar to those exhibited by plants rooted directly in the ground.  In addition, CO2-induced increases in growth and yield were similar for plants exposed to 12 or 24 hours of twice-ambient CO2 concentration.

Effects of Elevated CO2 and Root Zone Temperature on Soybean: Soybean plants grown in elevated CO2 for 21 days displayed significantly greater rates of whole plant net photosynthesis regardless of soil root zone temperature.  However, this stimulatory effect was reduced by nearly 50% over the course of the experiment due to photosynthetic acclimation.  Despite this phenomenon, plants grown in elevated CO2 exhibited total dry weight increases that averaged nearly 40% more than those measured at ambient CO2, irrespective of soil temperature.

Effects of Elevated CO2 and Temperature on Five Fast-Growing Annuals: In an open-top chamber study of 20-year old Scots pine, it was determined that elevated CO2 did not significantly affect starch accumulation in needles until the third year of treatment exposure, at which time it was significantly increased.  In addition, neither elevated CO2 or O3 had any effects on secondary metabolite production throughout the 3-year study.

Effects of Elevated CO2 on Growth and Fungal Colonization of Three Tree Species: As the air's CO2 content rises, saplings of paper birch, Eastern hemlock, and Eastern white pine will likely increase rates of photosynthesis and carbohydrate production to increase whole plant and root biomass.