No abstract

Preserved and archived organic material offers huge potential for the conduct of retrospective and long-term historical ecosystem reconstructions using stable isotope analyses, but because of isotopic exchange with preservatives the obtained values require validation. The Continuous Plankton Recorder (CPR) Survey is the most extensive long-term monitoring program for plankton communities worldwide and has utilised ships of opportunity to collect samples since 1931. To keep the samples intact for subsequent analysis, they are collected and preserved in formalin; however, previous studies have found that this may alter stable carbon and nitrogen isotope ratios in zooplankton. A maximum ~0.9‰ increase of δ(15) N and a time dependent maximum ~1.0‰ decrease of δ(13) C were observed when the copepod, Calanus helgolandicus, was experimentally exposed to two formalin preservatives for 12 months. Applying specific correction factors to δ(15) N and δ(13) C values for similarly preserved Calanoid species collected by the CPR Survey within 12 months of analysis may be appropriate to enable their use in stable isotope studies. The isotope values of samples stored frozen did not differ significantly from those of controls. Although the impact of formalin preservation was relatively small in this and other studies of marine zooplankton, changes in isotope signatures are not consistent across taxa, especially for δ(15) N, indicating that species-specific studies may be required.

Aim Demographic linkage between subpopulations plays a critical role in population processes. Metapopulation dynamics, however, remains one of the most poorly understood aspects of population biology. This is especially true for small, pelagic seabirds because their discrete subpopulations are located on offshore islands, separated by vast areas of open ocean, making monitoring logistically challenging. Seabird populations often contain large numbers of immature pre‐breeders that may be important for subpopulation connectivity and demography, but are poorly studied. Here we provide evidence for intercolony movement of pre‐breeding Leach's storm‐petrels Oceanodroma leucorhoa among three colonies spanning the North Atlantic Ocean. We discuss their influence on metapopulation dynamics and the extinction risk of a subpopulation under threat from extreme predation. Location North Atlantic Ocean Islands (Scotland, Canada & Iceland). Methods We use a novel application of Bayesian stable isotope mixing models to infer recent movement of pre‐breeding birds between three major breeding populations in the North Atlantic. Carbon and nitrogen stable isotope values from breeding birds (central place foragers) sampled at each colony were used as model sources and pre‐breeding birds as model mixtures. Results Of 134 pre‐breeding Leach's storm‐petrels sampled at three colonies across the North Atlantic, five had isotope mixing model estimates dissimilar (< 25%) to their colony of capture and were instead isotopically similar to another breeding region. Nineteen further pre‐breeders had highly mixed signatures (< 50% for the colony of capture), indicating possible recent movement between colonies. Main conclusions Our findings provide evidence for interpopulation connectivity of pre‐breeding Leach's storm‐petrels among colonies spanning the North Atlantic. These results highlight the significance of cryptic young age‐classes in metapopulation dynamics and the demographic processes. Moreover, they provide us with a better understanding of how one subpopulation remains extant, despite experiencing extreme predation rates.

This study represents an adaptive learning partnership among The University of Central Florida, Colorado Technical University, and the platform provider Realizeit.  A thirteen-variable learning domain for students forms the basis of a component invariance study. The results show that four dimensions: knowledge acquisition, engagement activities, communication and growth remain constant in nursing and mathematics courses across the two universities, indicating that the adaptive modality stabilizes learning organization in multiple disciplines. The authors contend that similar collaborative partnerships among universities and vendors is an important next step in the research process.