One-year experiment on the physiological response of the Mediterranean crustose coralline alga, Lithophyllum cabiochae, to elevated pCO2 and temperature

The response of respiration, photosynthesis, and calcification to elevated pCO₂ and temperature was investigated in isolation and in combination in the Mediterranean crustose coralline alga Lithophyllum cabiochae. Algae were maintained in aquaria during 1 year at near-ambient conditions of irradiance, at ambient or elevated temperature (+3°C), and at ambient (ca. 400 μatm) or elevated pCO₂ (ca. 700 μatm). Respiration, photosynthesis, and net calcification showed a strong seasonal pattern following the seasonal variations of temperature and irradiance, with higher rates in summer than in winter. Respiration was unaffected by pCO₂ but showed a general trend of increase at elevated temperature at all seasons, except in summer under elevated pCO₂. Conversely, photosynthesis was strongly affected by pCO₂ with a decline under elevated pCO₂ in summer, autumn, and winter. In particular, photosynthetic efficiency was reduced under elevated pCO₂. Net calcification showed different responses depending on the season. In summer, net calcification increased with rising temperature under ambient pCO₂ but decreased with rising temperature under elevated pCO₂. Surprisingly, the highest rates in summer were found under elevated pCO₂ and ambient temperature. In autumn, winter, and spring, net calcification exhibited a positive or no response at elevated temperature but was unaffected by pCO₂. The rate of calcification of L. cabiochae was thus maintained or even enhanced under increased pCO₂. However, there is likely a trade-off with other physiological processes. For example, photosynthesis declines in response to increased pCO₂ under ambient irradiance. The present study reports only on the physiological response of healthy specimens to ocean warming and acidification, however, these environmental changes may affect the vulnerability of coralline algae to other stresses such as pathogens and necroses that can cause major dissolution, which would have critical consequence for the sustainability of coralligenous habitats and the budgets of carbon and calcium carbonate in coastal Mediterranean ecosystems.

Application deadline coming up: ocean acidification methodologies

The application deadline is coming up for the summer course on Ocean Acidification Methodologies offered at the Friday Harbor Laboratories of the University of Washington. This course will be offered by Dr. Jon Havenhand, Dr. Andrew Dickson, and and Dr. Moose O’Donnell from July 22 – August 23, 2013. There is space available for 15 students.

Ocean acidification: the also increasing ‘other CO2 problem’

UI departments host talks on climate change

Scientists predict a 150 to 200 percent increase in ocean acidity by the year 2100, and the effects will be felt strongly by professional and recreational fishers in the Pacific Northwest.

The University of Idaho Sustainability Center and the Department of Fish and Wildlife Sciences began its Oceans, Ice and Climate Change event Thursday night with research ecologist Shallin Busch speaking about the effect of ocean acidification, also known as the “other CO2 problem.”

Businesses balk at dealing with ocean threat

They say the first-in-the-nation effort to reduce ocean acidification is premature. Environmental groups want to move forward.

Business interests say a proposal to deal with the rising acidity of Washington’s coastal waters is “not ready for prime time.”

The Association of Washington Business and the Washington Farm Bureau lined up Wednesday against a bill to create a council to advise the state government on how to tackle ocean acidification. The bill also calls for considering the acidity of water runoff in urban planning efforts.

What does ocean acidification mean for sea life?

Scientists take a closer look at the impact of carbon dioxide on marine ecosystems

The sky is low and dusky, and the rain comes in blustery gusts as we make our way out onto a spill of rocks that juts seaward from the shore just north of Boiler Bay on the Oregon coast. Low tide is just beginning; at times it looks as if we’ll be swamped by waves. It’s October 30 and in the late afternoon gloaming, my eyes take a few minutes to adjust so I can begin to differentiate mussels from rock and to spot the clutch of seals watching our progress.

To the scientists who make up the Ocean Margin Ecosystem Group for Acidification Studies, this spot is known as the Fogarty Creek Intertidal Long-Term Ecological Research Site. The obvious drama of this place comes from the waves and wind and charismatic whiskered marine mammals. But I’m here to witness a different kind of drama with Oregon State University graduate student Jeremy Rose, who specializes in marine ecology and is part of a team of scientists investigating the effects of ocean acidification on the small organisms that inhabit the rocky tide-pool landscape beneath our feet.