Complex life cycles have evolved independently numerous times in marine animals as well as in disparate algae. Such life histories typically involve a dispersive immature stage followed by settlement and metamorphosis to an adult stage on the sea floor. One commonality among animals exhibiting transitions of this type is that their larvae pass through a ‘precompetent’ period in which they do not respond to localized settlement cues, before entering a ‘competent’ period, during which cues can induce settlement. Despite the widespread existence of these two phases, relatively little is known about how larvae transition between them. Moreover, recent studies have blurred the distinction between the phases by demonstrating that fluid turbulence can spark precocious activation of competence. Here, we further investigate this phenomenon by exploring how larval interactions with turbulence change across ontogeny, focusing on offspring of the sand dollar Dendraster excentricus (Eschscholtz). Our data indicate that larvae exhibit increased responsiveness to turbulence as they get older. We also demonstrate a likely cost to precocious competence: the resulting juveniles are smaller. Based upon these findings, we outline a new, testable conception of competence that has the potential to reshape our understanding of larval dispersal and connectivity among marine populations.

We used a metagenomic approach to identify viruses that may be involved in the ecology of Daphnia spp. in Oneida and Cayuga lakes (upstate New York). We identified several highly represented, putative eukaryotic, circular, single-stranded deoxyribonucleic acid (DNA) viral genomes. Among these, we discovered a genotype similar in both sequence and genomic architecture to a virus previously reported from a hyperthermal lake that shares characteristics of both single-stranded ribonucleic acid (RNA) and single-stranded DNA viruses. We used quantitative polymerase chain reactions to study the prevalence and viral load of both positive-sense and negative-sense strands of the Daphnia mendotae-associated (Cladocera) hybrid virus (DMClaHV) over a summer season in Oneida and Cayuga lakes. DMClaHV had high prevalence within Daphnia populations, where viral load and the proportion of virus-positive individuals were higher preceding host population decline. DMClaHV viral load was different between two species of Daphnia (D. mendotae and D. retrocurva), and the dynamics between viruses and their hosts varied between the two lakes. We detected DMClaHV in eggs (ephippia) retrieved from Oneida Lake sediments with an estimated age of 30 yr. Using transmission electron microscopy, we observed small (20 nm diameter) virus-like particles in Daphnia that were well away from gut tissues and not associated with intracellular parasites. Because Daphnia plays a critical role in many lake ecosystems, DMClaHV may have important effects on herbivory and thus carbon flow through the lake ecosystem.

Dispersal of benthic species in the sea is mediated primarily through small, vulnerable larvae that must survive minutes to months as members of the plankton community while being transported by strong, dynamic currents. As climate change alters ocean conditions, the dispersal of these larvae will be affected, with pervasive ecological and evolutionary consequences. We review the impacts of oceanic changes on larval transport, physiology, and behavior. We then discuss the implications for population connectivity and recruitment and evaluate life history strategies that will affect susceptibility to the effects of climate change on their dispersal patterns, with implications for understanding selective regimes in a future ocean. We find that physical oceanographic changes will impact dispersal by transporting larvae in different directions or inhibiting their movements while changing environmental factors, such as temperature, pH, salinity, oxygen, ultraviolet radiation, and turbidity, will affect the survival of larvae and alter their behavior. Reduced dispersal distance may make local adaptation more likely in well‐connected populations with high genetic variation while reduced dispersal success will lower recruitment with implications for fishery stocks. Increased dispersal may spur adaptation by increasing genetic diversity among previously disconnected populations as well as increasing the likelihood of range expansions. We hypothesize that species with planktotrophic (feeding), calcifying, or weakly swimming larvae with specialized adult habitats will be most affected by climate change. We also propose that the adaptive value of retentive larval behaviors may decrease where transport trajectories follow changing climate envelopes and increase where transport trajectories drive larvae toward increasingly unsuitable conditions. Our holistic framework, combined with knowledge of regional ocean conditions and larval traits, can be used to produce powerful predictions of expected impacts on larval dispersal as well as the consequences for connectivity, range expansion, or recruitment. Based on our findings, we recommend that future studies take a holistic view of dispersal incorporating biological and oceanographic impacts of climate change rather than solely focusing on oceanography or physiology. Genetic and paleontological techniques can be used to examine evolutionary impacts of altered dispersal in a future ocean, while museum collections and expedition records can inform modern‐day range shifts.

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Marine debris is a global environmental problem especially apparent on small islands throughout the world. We implemented an educational outreach program to engage primary and secondary students in the scientific process using the tangible issue of marine debris on a typical small island in Indonesia (Barrang Lompo, Spermonde Islands, South Sulawesi). Over a 3-year period, students conducted systematic sampling of debris on their island's beaches. They quantified the enormity of the debris problem, discussed data, and compared experiences with partner schools in California. The program inspired a unique, local perspective on marine debris that includes greater awareness of human health impacts as well as a need for realistic solutions to this problem faced by small islands.