Middle to Late Holocene Variations in Salinity and Primary Productivity in the Central Baltic Sea: A Multiproxy Study From the Landsort Deep

Anthropogenic forcing has led to an increased extent of hypoxic bottom areas in the Baltic Sea during recent decades. The Baltic Sea ecosystem is naturally prone to the development of hypoxic conditions due to its geographical, hydrographical, geological, and climate features. Besides the current spreading of hypoxia, the Baltic Sea has experienced two extensive periods of hypoxic conditions during the Holocene, caused by changing climate conditions during the Holocene Thermal Maximum (HTM; 8–4.8 cal ka BP) and the Medieval Climate Anomaly (MCA; 1–0.7 cal ka BP). We studied the variations in surface and bottom water salinity and primary productivity and their relative importance for the development and termination of hypoxia by using microfossil and geochemical data from a sediment core retrieved from the Landsort Deep during IODP Expedition 347 (Site M0063). Our findings demonstrate that increased salinity was of major importance for the development of hypoxic conditions during the HTM. In contrast, we could not clearly relate the termination of this hypoxic period to salinity changes. The reconstructed high primary productivity associated with the hypoxic period during the MCA is not accompanied by considerable increases in salinity. Our proxies for salinity show a decreasing trend before, during and after the MCA. Therefore, we suggest that this period of hypoxia is primarily driven by increasing temperatures due to the warmer climate. These results highlight the importance of natural climate driven changes in salinity and primary productivity for the development of hypoxia during a warming climate

Semantic processing of adjectives and nouns in American Sign Language: effects of reference ambiguity and word order across development

When processing spoken language sentences, listeners continuously make and revise predictions about the upcoming linguistic signal. In contrast, during comprehension of American Sign Language (ASL), signers must simultaneously attend to the unfolding linguistic signal and the surrounding scene via the visual modality. This may affect how signers activate potential lexical candidates and allocate visual attention as a sentence unfolds. To determine how signers resolve referential ambiguity during real-time comprehension of ASL adjectives and nouns, we presented deaf adults (n = 18, 19–61 years) and deaf children (n = 20, 4–8 years) with videos of ASL sentences in a visual world paradigm. Sentences had either an adjective-noun (e.g., “SEE YELLOW WHAT? FLOWER”) or a noun-adjective (e.g., “SEE FLOWER WHICH? YELLOW”) structure. The degree of ambiguity in the visual scene was manipulated at the adjective and noun levels (e.g., including one or more yellow items and one or more flowers in the visual array). We investigated effects of ambiguity and word order on target looking at early and late points in the sentence. Analysis revealed that adults and children made anticipatory looks to a target when it could be identified early in the sentence. Further, signers looked more to potential lexical candidates than to unrelated competitors in the early window, and more to matched than unrelated competitors in the late window. Children’s gaze patterns largely aligned with those of adults, although they made fewer anticipatory fixations to the target in the early window and were more susceptible to competitors in the late window. Together, these findings suggest that signers allocate referential attention strategically based on the amount and type of ambiguity at different points in the sentence when processing adjectives and nouns in ASL.Accepted manuscript2020-12-0