Scarla Weeks (Biophysical Oceanography Group, School of Geography, Planning and Environmental Management, University of Queensland, St Lucia, Australia) and colleagues writing in the journal Marine Ecology Progress Series have looked at effects of increasing sea-surface temperature on seabirds foraging in the Great Barrier Reef, including the Wedge-tailed Shearwater Puffinus pacificus.

The paper’s abstract follows:

“Previously we have demonstrated that prey availability to seabirds of the Great Barrier Reef (GBR) decreases in direct association with within-season increases in sea-surface temperature, independent of prevailing El Niño conditions.  These negative impacts occur throughout the GBR and affect multiple seabird species.  Currently, the oceanic processes driving these impacts or the potential for them to occur in other marine systems are unknown. Here, we use satellite andin situ data obtained during a thermal stress event to identify the within-season links between ocean dynamics and seabird foraging success on the southern GBR.  In February 2006, a major mesoscale eddy formed coastward of the East Australian Current flow, adjacent to our study site.  In mid-February, strengthening of this eddy caused an intrusion of cool, dense waters at depth across the GBR shelf.  This intrusion intensified vertical stratification and caused a pronounced warming of sea-surface layers.  Prey availability to seabirds significantly decreased during this period and remained low until eddy intensity decreased and surface waters cooled.  Prey availability increased following this episode, clearly indicating that loss of prey was associated with a short-term vertical and/or horizontal redistribution of forage-fish, or subsurface predators, rather than an overall decrease in productivity linked to seasonal-scale El Niño processes.”

Wedge-tailed Shearwater, photographed by Alan Burger

Reference:

Weeks, S.J., Steinberg, C. & Congdon, B.C.  2013.  Oceanography and seabird foraging: within-season impacts of increasing sea-surface temperature on the Great Barrier Reef.  Marine Ecology Progress Series 490:247-254.

John Cooper, ACAP Information Officer, 12 November 2013