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Considerable uncertainty remains over how increasing atmospheric CO2 and anthropogenic climate changes are affecting open‐ocean marine ecosystems from phytoplankton to top predators. Biological time series data are thus urgently needed for the world's oceans. Here, we use the carbon stable isotope composition of tuna to provide a first insight into the existence of global trends in complex ecosystem dynamics and changes in the oceanic carbon cycle. From 2000 to 2015, considerable declines in δ13C values of 0.8‰–2.5‰ were observed across three tuna species sampled globally, with more substantial changes in the Pacific Ocean compared to the Atlantic and Indian Oceans. Tuna recorded not only the Suess effect, that is, fossil fuel‐derived and isotopically light carbon being incorporated into marine ecosystems, but also recorded profound changes at the base of marine food webs. We suggest a global shift in phytoplankton community structure, for example, a reduction in 13C‐rich phytoplankton such as diatoms, and/or a change in phytoplankton physiology during this period, although this does not rule out other concomitant changes at higher levels in the food webs. Our study establishes tuna δ13C values as a candidate essential ocean variable to assess complex ecosystem responses to climate change at regional to global scales and over decadal timescales. Finally, this time series will be invaluable in calibrating and validating global earth system models to project changes in marine biota.Anthropogenic climate change is expected to alter open‐ocean marine ecosystems from phytoplankton to top predators. Our study revealed that changes in the marine carbon cycle can be traced in the tissues of marine top predators. We detected a worldwide decrease in tuna δ13C values over the 2000–2015 period. Our analysis suggests a widespread shift in marine phytoplankton community structure or a change in phytoplankton physiology, while this does not exclude other factors that may act in synergy (Suess effect, productivity, trophic fractionation factor). [ABSTRACT FROM AUTHOR]

Lakes are among the most seasonally forced ecosystems on Earth. Seasonal variation in temperature and light produce cyclic patterns in water column mixing, nutrient supply and phytoplankton biomass. Diet responses of consumers to these patterns have rarely been quantified. Moreover, pelagic-littoral coupling of dietary resources by mobile consumers is commonly considered to be static over annual cycles., This study quantifies littoral-pelagic diet responses of multiple consumers to a strong shift in pelagic phytoplankton abundance over an annual cycle (September 2014 to August 2015) in a large (area 614 km2), oligotrophic, monomictic lake (Lake Taupō, New Zealand). Intra-annual patterns in pelagic phytoplankton (chlorophyll a) and zooplankton were determined over multiple years. Major resource and consumer δ13C and δ15N were then collected over an annual cycle. Temporal patterns in food-web structure were examined using convex hulls as a proxy of community trophic niche size. Diet was quantified using mixing models for zooplankton, meso-predatory zooplanktivorous common smelt ( Retropinna retropinna) and benthivorous common bullies ( Gobiomorphus cotidianus), as well as the top-predator rainbow trout ( Oncorhynchus mykiss). Trophic structure patterns for smelt, bullies and trout were then independently examined using compound-specific amino acid δ15N analyses ( CSIA- AA)., Lake Taupō demonstrated similar food-web patterns to other lakes globally. Phytoplankton and zooplankton demonstrated strong seasonal oscillations of abundance driven by both bottom-up (nutrient supply) and top-down (stable limit cycle) drivers. The food web demonstrated the typical nested structure. It responded to seasonally low and high pelagic resource availability periods by expansion and contraction, respectively, of trophic niche space. In response to lower pelagic phytoplankton abundance during summer stratification, and phytoplankton accumulation at a deep chlorophyll maximum ( DCM), zooplankton abundance reduced and their diet became dominated by phytoplankton from below the thermocline (i.e. the hypolimnion and DCM). This change may have been prompted by the combined drivers of avoidance of predation and depauperate food supply in surface waters., The diet of smelt and bullies switched from predominantly zooplankton to benthic macroinvertebrates, synchronous with the decline in pelagic zooplankton. Trout diet, inferred from comparison of isotopic signatures of tissues with different turnover rates, also increased littoral resource reliance over the stratified period. Smelt, bully and trout CSIA- AA data confirmed estimates of trophic position and indicated a greater degree of trophic complexity in the littoral than the pelagic food chain., Food webs in large, deep lakes such as Taupō are expected to be primarily pelagic. This study demonstrates the need to re-examine this expectation due to seasonal variations in productivity. The relatively small littoral areas in large lakes, combined with meso-predators' highly seasonally variable littoral resource use, may drive strong seasonal top-down effects on littoral macroinvertebrate prey. Our study supports the notion that food-web interactions are highly dynamic and responsive to seasonal forcing. By linking food-web dynamics to dynamic environmental conditions, this study provides a framework for future studies research on understanding lake food-web responses to a range of annual/seasonal and global environmental change drivers. [ABSTRACT FROM AUTHOR]

The Eastside Illicit Drinkers Group for Education has been supportive of research dedicated to establishing the effectiveness of Managed Alcohol Programs since its inception. Dedicated funding for MAPs in Vancouver, British Columbia is contingent on the research demonstrating that alcohol-related harms are reduced while participating in a Managed Alcohol Program. The Eastside Illicit Drinkers Group for Education understands the need for evidence-based research but we are critical of how much research is needed before sustainable funding can be established for these innovative programs. [ABSTRACT FROM AUTHOR]

Rationale: Billfishes, such as marlin, are top pelagic predators that play an important role in maintaining the stability of marine food webs. Notwithstanding the importance of these species, there remain gaps in our knowledge on their movements, foraging, and trophic status in the early stage of life. METHODS: We measured the δ13C and δ15N values in each annual growth band deposited in the dorsal spine from striped marlin caught off Cabo San Lucas, Mexico, to produce retrospective isotopic profiles that would enable us to detect any significant isotopic changes across development. The samples were analyzed using an elemental analyzer coupled to an isotope ratio mass spectrometer. RESULTS: There was no relationship between the size of striped marlin and the δ15N values. Differences in δ15N mean values across different age classes were not significant and the variation in δ15N values through the marlins' life cycle was less than 2%. However, the mean δ15N values between individuals varied by up to 6%. The δ13C values increased as a function of age, and the mean δ13C values varied significantly between age classes. CONCLUSIONS: Fin spines can be used to construct retrospective isotopic histories for the investigation of trophic dynamics and migratory histories in billfishes, for which population dynamics are often poorly known. Copyright© 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Nitrogen and carbon stable isotope data sets are commonly used to assess complex population to ecosystem responses to natural or anthropogenic changes at regional to global spatial scales, and monthly to decadal timescales. Measured in the tissues of consumers, nitrogen isotopes (δ15N) are primarily used to estimate trophic position while carbon isotopes (δ13C) describe habitat associations and feeding pathways. Models of both δ15N and δ13C values and their associated variance can be used to estimate likely dietary contributions and niche width and provide inferences about consumer movement and migration. Stable isotope data have added utility when used in combination with other empirical data sets (e.g., stomach content, movement tracking, bioregionalization, contaminant, or fisheries data) and are increasingly relied upon in food web and ecosystem models. While numerous regional studies publish tables of mean δ15N and δ13C values, limited individual records have been made available for wider use. Such a deficiency has impeded full utility of the data, which otherwise would facilitate identification of macroscale patterns. The data provided here consist of 4,498 records of individuals of three tuna species, Thunnus alalunga, T. obesus, and T. albacares sampled from all major ocean basins from 2000 to 2015. For each individual tuna, we provide a record of the following: species name, sampling date, sampling location, tuna length, muscle bulk and baseline corrected δ15N values, and muscle bulk and, where available, lipid corrected δ13C values. We provide these individual records to support comparative studies and more robust modeling projects seeking to improve understanding of complex marine ecosystem dynamics and their responses to a changing environment. There are no copyright restrictions for research and/or teaching purposes. Users are requested to acknowledge their use of the data in publications, research proposals, websites, and other outlets following the citation instructions in Class III, Section B. [ABSTRACT FROM AUTHOR]