Global Carbon Cycling on a Heterogeneous Seafloor

Diverse biological communities mediate the transformation, transport, and storage of elements fundamental to life on Earth, including carbon, nitrogen, and oxygen. However, global biogeochemical model outcomes can vary by orders of magnitude, compromising capacity to project realistic ecosystem responses to planetary changes, including ocean productivity and climate. Here, we compare global carbon turnover rates estimated using models grounded in biological versus geochemical theory and argue that the turnover estimates based on each perspective yield divergent outcomes. Importantly, empirical studies that include sedimentary biological activity vary less than those that ignore it. Improving the relevance of model projections and reducing uncertainty associated with the anticipated consequences of global change requires reconciliation of these perspectives, enabling better societal decisions on mitigation and adaptation.Peer reviewe

Challenging the paradigms of deep-sea ecology

Deep-sea ecosystems represent Earth's major ecological research frontier. Focusing on seafloor ecosystems, we demonstrate how new technologies underpin discoveries that challenge major ecological hypotheses and paradigms, illuminating new deep-sea geosphere–biosphere interactions. We now recognize greater habitat complexity, new ecological interactions and the importance of ‘dark energy’, and chemosynthetic production in fuelling biodiversity. We also acknowledge functional hotspots that contradict a food-poor, metabolically inactive, and minor component of global carbon cycles. Symbioses appear widespread, revealing novel adaptations. Populations show complex spatial structure and evolutionary histories. These new findings redefine deep-sea ecology and the role of Earth's largest biome in global biosphere functioning. Indeed, deep-sea exploration can open new perspectives in ecological research to help mitigate exploitation impacts.<br/

The deep-sea under global change

The deep ocean encompasses 95% of the oceans’ volume and is the largest and least explored biome of Earth’s Biosphere. New life forms are continuously being discovered. The physiological mechanisms allowing organisms to adapt to extreme conditions of the deep ocean (high pressures, from very low to very high temperatures, food shortage, lack of solar light) are still largely unknown. Some deep-sea species have very long life-spans, whereas others can tolerate toxic compounds at high concentrations; these characteristics offer an opportunity to explore the specialized biochemical and physiological mechanisms associated with these responses. Widespread symbiotic relationships play fundamental roles in driving host functions, nutrition, health, and evolution. Deep-sea organisms communicate and interact through sound emissions, chemical signals and bioluminescence. Several giants of the oceans hunt exclusively at depth, and new studies reveal a tight connection between processes in the shallow water and some deep-sea species. Limited biological knowledge of the deep-sea limits our capacity to predict future response of deep-sea organisms subject to increasing human pressure and changing global environmental conditions. Molecular tools, sensor-tagged animals, in situ and laboratory experiments, and new technologies can enable unprecedented advancement of deep-sea biology, and facilitate the sustainable management of deep ocean use under global change

Experimental evidence for concentration-dependence and intra-specific variation of movement behaviour in American lobster (Homarus americanus) larvae

Predicting dispersal paths of marine larvae with extended pelagic durations, such as American lobster (Homarus americanus (Milne Edwards, 1837)), requires understanding the cues to which larvae respond, and how that response reflects changes in larval behaviour. If larvae respond to conspecific presence by varying their movement, this behaviour can bias laboratory estimates of environmental responses. We tested whether larvae actively decreased their local intraspecific density by measuring how the vertical distribution of larvae changed under high versus low concentrations of conspecifics. We observed weak increases in vertical dispersion at higher concentrations in both newly-hatched larvae and in post-larvae, but not in intermediate larval stages. We also tested for differences in horizontal swimming behaviour in high and low concentrations, by fitting a novel random walk model that allowed us to model both larval interactions and persistent turning behaviours. We showed substantial reduction in diffusive behaviour under high concentration conditions resulting from more frequent turns by each larva, but no evidence for consistent avoidance of conspecifics. Our study is the first to demonstrate concentration-dependent behaviours in lobster larvae.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Larval connectivity of northern shrimp (Pandalus borealis) in the Northwest Atlantic

Northern shrimp (Pandalus borealis) represents one of the most important fisheries in the Northwest Atlantic Ocean, but few studies have considered connectivity among different management units (i.e., stocks). Using a biophysical model, we investigated potential larval dispersal among North Atlantic Fisheries Organization (NAFO) divisions and its interannual variability during the long pelagic larval phase of P. borealis (∼3 months). Overall, we found a largely stable, stream-like larval connectivity system driven by the main currents that flow over both the Greenland and Canadian continental shelves, with a relatively low but consistent exchange of larvae between Greenland and Canada across the Baffin Island continental shelf. We observed highest potential settlement densities on the northwestern Greenland and Newfoundland shelves, representing retention areas that correspond to highest abundances of adult shrimp. Intermittent and variable larval exchanges of lower magnitude also occurred between populations less obviously associated with the major circulation features. Our study improves understanding of northern shrimp stock–recruitment relationships at the metapopulation level, which could help determine the appropriate spatial scale to improve management strategies.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Data from: Identifying patterns of dispersal, connectivity, and selection in the sea scallop, Placopecten magellanicus, using RAD-seq derived SNPs

Understanding patterns of dispersal and connectivity among marine populations can directly inform fisheries conservation and management. Advances in high-throughput sequencing offer new opportunities for estimating marine connectivity. We used Restriction-site Associated DNA sequencing to examine dispersal and realized connectivity in the sea scallop Placopecten magellanicus, an economically important marine bivalve. Based on 245 individuals sampled range-wide at 12 locations from Newfoundland to the Mid-Atlantic Bight we identified and genotyped 7163 Single Nucleotide Polymorphisms; 112 (1.6%) were identified as outliers potentially under directional selection. Bayesian clustering revealed a discontinuity between northern and southern samples and latitudinal clines in allele frequencies were observed in 42.9% of the outlier loci and in 24.6% of neutral loci. Dispersal estimates derived using these clines and estimates of linkage disequilibrium imply limited dispersal; 373.1 ± 407.0 km (mean ± SD) for outlier loci and 641.0 ± 544.6 km (mean ± SD) for neutral loci. Our analysis suggests restricted dispersal compared to the species range (>2000 km) and that dispersal and effective connectivity differ. These observations support the hypothesis that limited effective dispersal structures scallop populations along eastern North America. These findings can help refine the appropriate scale of management and conservation in this commercially valuable species

Data from: Season and site fidelity determine home range of dispersing and resident juvenile Greenland cod (Gadus ogac) in a Newfoundland fjord. A Canadian Healthy Oceans Network Population Connectivity, PC-03

Acoustic telemetry data was collected from October 2010 - October 2011 for 42 individual age 1+ Gadus ogac individuals tagged with Vemco Ltd™ V7-4L coded acoustic tags, programmed to emit a signal at a randomized average delay of every 240 ± 70 s, and a nominal tag life of 415 days. A receiver network comprised of 26 Vemco™ VR2W and VR2 hydrophones allowed for continual detection throughout Newman Sound over a full year. The data presented have been filtered to eliminate spurious detections using both a single detection filter (eliminating lone detections for a single fish over 24 hours) and a conservative speed filter (eliminating detections > 2 body lengths/second apart which could indicate ingestion by a predator). Using known positions of the acoustic receivers, we calculated position estimates in hourly time intervals using a weighted arithmetic mean to increase precision from a presence/absence dataset to a position-based dataset. Therefore the beginning of each hour time interval is indicated in the "Date" and "Time" field. Positions are indicated in decimal degrees in the "COA_Lat" and "COA_Lon" fields of the CSV files. Also included are the ArcGIS defined "POINT_X" and "POINT_Y" fields using a NAD_1983_UTM_Zone_21N projection. Individual fish IDs are included in the "Tag" field. The "Transplant" field indicates whether the individual was in the control group (site of capture = site of release) or the transplant group (site of capture ≠ site of release). Site of capture is indicated by the "Cove" field (HC = Heffern's Cove; BC= Buckley's Cove)

Season and site fidelity determine home range of dispersing and resident juvenile Greenland cod (Gadus ogac) in a Newfoundland fjord (Year 2). A Canadian Healthy Oceans Network Population Connectivity, PC-03

Acoustic telemetry data was collected from November 2011 - November 2012 for 42 individual age 1+ Gadus ogac individuals tagged with Vemco Ltd™ V7-4L coded acoustic tags, programmed to emit a signal at a randomized average delay of every 240 ± 70 s, and a nominal tag life of 415 days. A receiver network comprised of 32 Vemco™ VR2W and VR2 hydrophones allowed for continual detection throughout Newman Sound over a full year. The data presented have been filtered to eliminate spurious detections using both a single detection filter (eliminating lone detections for a single fish over 24 hours) and a conservative speed filter (eliminating detections > 2 body lengths/second apart which could indicate ingestion by a predator). Using known positions of the acoustic receivers, we calculated position estimates in hourly time intervals using a weighted arithmetic mean to increase precision from a presence/absence dataset to a position-based dataset. Therefore the beginning of each hour time interval is indicated in the "Date" and "Time" field. Positions are indicated in decimal degrees in the "COA_Lat" and "COA_Lon" fields of the CSV files. Also included are the ArcGIS defined "POINT_X" and "POINT_Y" fields using a NAD_1983_UTM_Zone_21N projection. Individual fish IDs are included in the "Tag" field. The "Transplant" field indicates whether the individual was in the control group (site of capture = site of release) or the transplant group (site of capture ≠ site of release). Site of capture is indicated by the "Cove" field (HC = Heffern's Cove; BC= Buckley's Cove)

VanWyngaardenM_etal_GeogDistMatrix

This file contains matrices of pairwise geographic distances (km; shortest distance and estimated ocean current-based distance) between 12 populations of the sea scallop, Placopecten magellanicus, used along with 7163 RAD-seq derived SNPs to estimate isolation-by-distance and dispersal distances among populations. Population names and geographic coordinates can be found in Table 1 of the associated publication