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Lake ice melting and breakup form a fast, nonlinear process with important mechanical, chemical, and biological consequences. The process is difficult to study in the field due to safety issues, and therefore relatively little is known about its details. In the present work, ice monitoring was based on foot, hydrocopter, and boat to get a full time-series of the evolution of ice structure and geochemical properties through the melting period. The field observations were made in Lake Pääjärvi during the ice decay periods in 2018 and 2022. In 2022, the maximum thickness of ice was 55 cm with 60 % snow-ice, and based on the data and heat budget analysis, the ice melted by 33 cm from the surface and 22 cm from the bottom while porosity increased to 40–50 % at breakup. In 2018, the snow-ice layer was small and bottom and internal melting dominated during the decay. Due to global warming, the ice breakup date became earlier. The mean melting rates were 1.31 cm d–1 in 2022 and 1.55 cm d–1 in 2018. In 2022 the electrical conductivity (EC) in ice was 11.4±5.79 S cm–1, one order of magnitude lower than in the lake water, and ice pH was 6.44±0.28, lower by 0.4 than in water. pH and EC of ice and lake water decreased along the ice decay except slight increases in ice due to flushing by lake water. Chlorophyll a was less than 0.5 g L–1 in porous ice, approximately one-third of that in the lake water. These results are important for further development of numerical models and understanding the process of ice decay with consequences to lake ecology and to safety of ice cover for human activities.

Analysis of migration and marriage patterns of a population of forced refugees from WW II Finland

A research on renewal rate, allocation and bioconverting capabilities of fatty acids in P.quadrispinosa.

Water browning or brownification refers to increasing water color, often related to increasing dissolved organic matter (DOM) and carbon (DOC) content in freshwaters. Browning has been recognized as a significant physicochemical phe-nomenon altering boreal lakes, but our understanding of its ecological consequences in different freshwater habitats and regions is limited. Here, we review the consequences of browning on different freshwater habitats, food webs and aquatic-terrestrial habitat coupling. We examine global trends of browning and DOM/DOC, and the use of remote sensing as a tool to investigate browning from local to global scales. Studies have focused on lakes and rivers while sel-dom addressing effects at the catchment scale. Other freshwater habitats such as small and temporary waterbodies have been overlooked, making the study of the entire network of the catchment incomplete. While past research inves-tigated the response of primary producers, aquatic invertebrates and fishes, the effects of browning on macrophytes, invasive species, and food webs have been understudied. Research has focused on freshwater habitats without consid-ering the fluxes between aquatic and terrestrial habitats. We highlight the importance of understanding how the changes in one habitat may cascade to another. Browning is a broader phenomenon than the heretofore concentration on the boreal region. Overall, we propose that future studies improve the ecological understanding of browning through the following research actions: 1) increasing our knowledge of ecological processes of browning in other wetland types than lakes and rivers, 2) assessing the impact of browning on aquatic food webs at multiple scales, 3) examining the effects of browning on aquatic-terrestrial habitat coupling, 4) expanding our knowledge of browning from the local to global scale, and 5) using remote sensing to examine browning and its ecological consequences.

Demographers argue that human migration patterns are shaped by people moving to better environments. More recently, however, evolutionary theorists have argued that people move to similar environments to which they are culturally adapted. While previous studies analysing which factors affect migration patterns have focused almost exclusively on successful migrations, here we take advantage of a natural experiment during World War II in which an entire population was forcibly displaced but were then allowed to return home to compare successful with unsuccessful migrations. We test two competing hypotheses: (1) individuals who relocate to environments that are superior to their place of origin will be more likely to remain-The Better Environment Hypothesis or (2) individuals who relocate to environments that are similar to their place of origin will be more likely to remain-The Similar Environment Hypothesis. Using detailed records recording the social, cultural, linguistic and ecological conditions of the origin and destination locations, we find that cultural similarity (e.g. linguistic similarity and marrying within one's own minority ethnic group)-rather than ecological differences-are the best predictors of successful migrations. These results suggest that social relationships, empowered by cultural similarity with the host population, play a critical role in successful migrations and provide limited support for the similar environment hypothesis. Overall, these results demonstrate the importance of comparing unsuccessful with successful migrations in efforts understand the engines of human dispersal and suggest that the primary obstacles to human migrations and successful range expansion are sociocultural rather than ecological.

The conditions that propel humans to make sacrifices for groups of unrelated, and often unknown, individuals has received considerable attention across scientific disciplines. Evolutionary explanations for this type of sacrifice have focused on how men form strategic coalitions organized around kin networks and reciprocity when faced with out-group threats. Few studies, however, have analyzed how women respond to external threats. Using data from one of the largest female paramilitary organizations in history we show that women who have more brothers, women whose husbands serve in the military and women without children are more likely to volunteer. These results provide qualified support for the hypothesis that women are more likely to sacrifice for their country when members of their family are at risk. Overall, our analysis suggests that self-sacrifice and intense bonding with an imagined community of unknown individuals, such as the nation state, may arise out of a suite of psychological adaptations designed to facilitate cooperation among kin (i.e. kin psychology). These results can be interpreted within the framework of kin selection showing how individuals come to view unrelated group members as family. They may also shed light on various theories of group alignment, such as ‘identity fusion’ – whereby individuals align their personal identity and interests with those of the group – and on our understanding of evolutionary adaptations that cause women to direct altruism toward in-groups.

Gammarid amphipods are a crucial link connecting primary producers with secondary consumers, but little is known about their nutritional ecology. Here we asked how starvation and subsequent feeding on different nutritional quality algae influences fatty acid retention, compound-specific isotopic carbon fractionation, and biosynthesis of omega-3 and omega-6 polyunsaturated fatty acids (PUFA) in the relict gammarid amphipod Pallaseopsis quadrispinosa. The fatty acid profiles of P. quadrispinosa closely matched with those of the dietary green algae after only seven days of refeeding, whereas fatty acid patterns of P. quadrispinosa were less consistent with those of the diatom diet. This was mainly due to P. quadrispinosa suffering energy limitation in the diatom treatment which initiated the metabolization of 16:1 omega 7 and partly 18:1 omega 9 for energy, but retained high levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) similar to those found in wild-caught organisms. Moreover, alpha-linolenic acid (ALA) from green algae was mainly stored and not allocated to membranes at high levels nor biosynthesized to EPA. The arachidonic acid (ARA) content in membrane was much lower than EPA and P. quadrispinosa was able to biosynthesize long-chain omega-6 PUFA from linoleic acid (LA). Our experiment revealed that diet quality has a great impact on fatty acid biosynthesis, retention and turnover in this consumer.