Hemispheric asymmetry in ocean change and the productivity of ecosystem sentinels.

Climate change and other human activities are causing profound effects on marine ecosystem productivity. We show that the breeding success of seabirds is tracking hemispheric differences in ocean warming and human impacts, with the strongest effects on fish-eating, surface-foraging species in the north. Hemispheric asymmetry suggests the need for ocean management at hemispheric scales. For the north, tactical, climate-based recovery plans for forage fish resources are needed to recover seabird breeding productivity. In the south, lower-magnitude change in seabird productivity presents opportunities for strategic management approaches such as large marine protected areas to sustain food webs and maintain predator productivity. Global monitoring of seabird productivity enables the detection of ecosystem change in remote regions and contributes to our understanding of marine climate impacts on ecosystems.

Immune function and organochlorine pollutants in Arctic breeding glaucous gulls.

Organochlorine contaminants (OCs) are known to affect the immune systems of wildlife, and in this study we assessed the relationship between blood concentration of different OCs and measurements relevant to immune status and function in arctic breeding glaucous gulls (Larus hyperboreus). In 1997 and 2001, we counted white blood cells (heterophils and lymphocytes) from blood smears, and in 2000 and 2001 we injected two novel nonpathogenic antigens (diphtheria and tetanus toxoids) into the pectoral muscle of gulls and measured the primary antibody responses. We then related these measurements to the blood concentrations of three pesticides (hexachlorobenzene [HCB], oxychlordane, and p,p'-dichlorodiphenyldichloroethylene) and seven different polychlorinated biphenyl congeners (PCB 101, 99, 118, 153, 138, 180, and 170). There were significant or near significant positive relationships (0.1 > p > 0.001) between most persistent OCs and the levels of heterophils in the blood for both sexes in 1997 and for male gulls in 2001. Similarly, levels of all persistent OCs and lymphocytes were positively related (0.1 > p > 0.001) in both sexes in 1997. This suggests that OCs are causing alterations to immune systems, which may decrease their efficiency and make the birds more susceptible to parasites and diseases. In female gulls, the antibody response to the diphtheria toxoid was significant and negative for HCB (p < 0.01) and weaker, but significant, for oxychlordane (p < 0.05), suggesting that OCs were causing an impairment of the humoral immunity. Various OCs have been linked to negative effects in our study population, including decreased survival and reproduction, and this study suggests that such compounds also affect immune status and function.

Whole blood concentrations of organochlorines as a dose metric for studies of the glaucous gull (Larus hyperboreus).

In order to examine if whole blood concentrations of organochlorines (OCs) is an appropriate dosimetric parameter for use in ecotoxicological studies of free-living birds, a number of incubating glaucous gulls (Larus hyperboreus) were repeatedly sampled within and between subsequent breeding seasons. The wet weight concentrations of selected OCs, differing in persistence and fat solubility, were compared and it was assessed to what extent present concentrations could be predicted from concentrations previously measured in the individuals. There were only a few significant differences in the blood concentrations of the selected OCs within and between seasons. The most persistent compound, polychlorinated biphenyl (PCB)-153, showed a low interindividual variability, and between seasons, 70% of the variance could be explained by the level in the previous year, while changes in body condition and blood lipid percentage were of less importance. For PCB-101, the predictability of the present blood concentration from the previous concentration was lower than for PCB-153, and changes in body condition and blood lipid percentage explained a higher proportion of the variance. The present level of alpha-hexachlorocyclohexane (HCH) could not be predicted from the previous level. Sex did not explain any significant proportion of the variance in OC concentrations when previous level and changes in body mass and blood lipid were included in the statistical models. Thus, for the most persistent OCs, concentration in the blood of incubating glaucous gulls is representative for the interindividual differences over time and whole blood concentrations of OCs appear adequate as a dose metric in ecotoxicological studies.

Phylogeny and evolution of the auks (subfamily Alcinae) based on mitochondrial DNA sequences.

The genetic divergence and phylogeny of the auks was assessed by mitochondrial DNA sequence comparisons in a study using 19 of the 22 auk species and two outgroup representatives. We compared more than 500 nucleotides from each of two mitochondrial genes encoding 12S rRNA and the NADH dehydrogenase subunit 6. Divergence times were estimated from transversional substitutions. The dovekie (Alle alle) is related to the razorbill (Alca torda) and the murres (Uria spp). Furthermore, the Xantus's murrelet (Synthliboramphus hypoleucus) and the ancient (Synthliboramphus antiquus) and Japanese murrelets (Synthliboramphus wumizusume) are genetically distinct members of the same main lineage, whereas brachyramphine and synthliboramphine murrelets are not closely related. An early adaptive radiation of six main species groups of auks seems to trace back to Middle Miocene. Later speciation probably involved ecological differentiations and geographical isolations.