El Niño-Southern Oscillation (ENSO) and Southern Annular Mode (SAM) indirectly affect tooth growth of marine mammals, through changes in prey abundance, availability, and composition. This is reflected as variation in the dentine deposition, which determines the formation of annual layers, called growth layer groups (GLGs). The aim of this work was to study potential effects of ENSO and SAM on South American sea lion (Otaria byronia) of Patagonia, by examining interannual variability of GLG width. Adapting dendrochronological techniques, we analyzed 97 individuals (60 females and 37 males) and built six chronologies (three for each sex) by using cubic splines with different rigidity. Chronologies were correlated with MEI (Multivariate ENSO Index) and SAM index time series, considering lags in the biological response. The chronologies of females spanned 39 years and only two of these chronologies showed negative correlation with 1 year lagged SAM events. The chronologies of males spanned 23 years, but none showed significant correlation with these indexes. Our results did not indicate any ENSO effects on this species, while positive SAM events could reduce the abundance or availability of South American sea lion's prey, affecting the nutritional status of females and generating thinner GLGs during the next year.

中文翻译：

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气候异常影响南美海狮的牙齿生长模式

厄尔尼诺-南方涛动 (ENSO) 和南方环形模式 (SAM) 通过猎物丰度、可用性和组成的变化间接影响海洋哺乳动物的牙齿生长。这反映为牙本质沉积的变化，它决定了年层的形成，称为生长层组 (GLG)。这项工作的目的是研究 ENSO 和 SAM 对南美海狮 ( Otaria byronia ) 的潜在影响。) 的巴塔哥尼亚，通过检查 GLG 宽度的年际变化。采用树木年代学技术，我们分析了 97 个人（60 名女性和 37 名男性）并通过使用具有不同刚度的三次样条建立了六个年表（每种性别三个）。考虑到生物反应的滞后，年表与 MEI（多变量 ENSO 指数）和 SAM 指数时间序列相关。女性的年表跨越 39 年，其中只有两个年表与 1 年滞后的 SAM 事件呈负相关。男性的年表跨越了 23 年，但没有一个与这些指标有显着相关性。我们的结果并未表明 ENSO 对该物种有任何影响，而积极的 SAM 事件可能会减少南美海狮猎物的丰度或可用性，