Latitudinal gradients in sea ice and primary production determine Arctic seabird colony size in Greenland

Abstract

Sea ice loss will indirectly alter energy transfer through the pelagic food web and ultimately impact apex predators. We quantified spring-time trends in sea ice recession around each of 46 thick-billed murre (Uria lomvia) colonies in west Greenland across 208 of latitude and investigated the magnitude and timing of the associated spring-time primary production. A geographical information system was used to extract satellite-based observations of sea ice concentration from the Nimbus-7 scanning multichannel microwave radiometer (SMMR, 1979(SMMR, -1987 and the Defence Meteorological Satellite Programs Special Sensor Microwave/Imager (SSMI, 1987(SSMI, -2004, and satellite-based observations of chlorophyll a from the moderate resolution imaging spectroradiometer (MODIS: EOS-Terra satellite) in weekly intervals in circular buffers around each colony site (150 km in radius). Rapid recession of high Arctic seasonal ice cover created a temporally predictable primary production bloom and associated trophic cascade in water gradually exposed to solar radiation. This pattern was largely absent from lower latitudes where little to no sea ice resulted in a temporally variable primary production bloom driven by nutrient cycling and upwelling uncoupled to ice. The relationship between the rate and variability of sea ice recession and colony size of thick-billed murres shows that periodical confinement of the trophic cascade at high latitudes determines the carrying capacity for Arctic seabirds during the breeding period.

Physical controls and interannual variability of the Labrador Sea spring phytoplankton bloom in distinct regions

“…Labrador Sea food chains tend to be short, enabling a description of the relationship between higher consumers such as cod, whale and bird populations to primary production (Conover et al, 1995;Laidre et al, 2007Laidre et al, , 2008. Recruitment of copepods, the most abundant mezozooplankton in the region, depends on the supply of food (Head et al, 2000).…”

The Significance of the North Water Polynya to Arctic Top Predators

“…The lack of sea ice during the 2009 survey affected the whales and seals differently by allowing the whales access to a larger proportion of the region but providing fewer opportunities for The CV is given in parentheses (Karnovsky et al 2008). Longer flight routes have probably elevated energetic costs but could be compensated by higher copepod densities due to more strict timing of spring bloom development (Laidre et al 2008). Guillemots rely more on polar cod and Themisto libellula, and their distribution from colonies was not significantly different between 2009 and 2010 as they could probably maintain their feeding in leads and cracks in the denser ice coverage in 2010.…”

“…The timing of sea ice formation and recession plays a major role in triggering and shaping the trophic cascade in the North Water. The large colonies of guillemots rely on the strict schedule of primary production where the predictable peak offers reliable and abundant ice-related foraging opportunities when the birds arrive at their breeding colonies (Laidre et al 2008). Sea ice is also an important substrate for the haul-out of seals and walruses and it provides predation opportunities for polar bears.…”

Quantifying habitat use and preferences of pelagic seabirds using individual movement data: a review

“…Although there may be enough information in some studies to determine likely lag times and/or distances a priori, potentially based on the relative timing of life history events and seasonal peaks in primary production (e.g. Laidre et al 2008), it may be more pragmatic to investigate such effects on a studyby-study basis, by comparing the strength of relationships between spatial usage and biophysical covariates lagged at a range of plausible distances (e.g. Littaye et al 2004, Croll et al 2005.…”