The shift in marine resource management from a compartmentalized approach of dealing with resources on a species basis to an approach based on management of spatially defined ecosystems requires an ...accurate accounting of energy flow. The flow of energy from primary production through the food web will ultimately limit upper trophic-level fishery yields. In this work, we examine the relationship between yield and several metrics including net primary production, chlorophyll concentration, particle-export ratio, and the ratio of secondary to primary production. We also evaluate the relationship between yield and two additional rate measures that describe the export of energy from the pelagic food web, particle export flux and mesozooplankton productivity. We found primary production is a poor predictor of global fishery yields for a sample of 52 large marine ecosystems. However, chlorophyll concentration, particle-export ratio, and the ratio of secondary to primary production were positively associated with yields. The latter two measures provide greater mechanistic insight into factors controlling fishery production than chlorophyll concentration alone. Particle export flux and mesozooplankton productivity were also significantly related to yield on a global basis. Collectively, our analyses suggest that factors related to the export of energy from pelagic food webs are critical to defining patterns of fishery yields. Such trophic patterns are associated with temperature and latitude and hence greater yields are associated with colder, high latitude ecosystems.
Controllable concomitant production of CO and H2 (syngas) during electrochemical CO2 reduction reactions (CO2RR) is expected to improve the commercial feasibility of the technology to mitigate CO2 ...emissions as the generated syngas can be converted into useful chemicals using the commercial Fischer–Tropsch (FT) process. Herein, we demonstrate the ability of a Co single-atom-decorated N-doped graphitic carbon shell-encapsulated cobalt nanoparticle electrocatalyst (referred as Co@CoNC-900) to controllably produce syngas at low overpotentials during CO2RR. Through the engineering and modulation of dual active sites for CO2RR (modified carbon shell with encapsulated Co) and hydrogen evolution reaction (Co–N4 moieties) within Co@CoNC by varying the annealing temperature, we are able to tune the H2: CO ratio from 1: 2 to 1: 1 to 3: 2 over a wide range of applied potentials (−0.5 V to −0.8 V versus reversible hydrogen electrode, RHE). This versatile control of H2: CO ratio in CO2RR reaction brings up significant opportunity of using CO2 and H2O and renewable energy for producing a range of chemicals.
Literature review and synthesis of growth rates of aquatic protists focused on the role of temperature in the formation of massive annual algal blooms in high-latitude ecosystems. Maximal growth ...rates of herbivorous protists equaled or exceeded maximal growth rates of phototrophic protists at temperatures above 15°C. Maximal growth rates of herbivorous protists declined more rapidly with decreasing temperature than did those of phototrophic protists, and at the very low temperatures common to high-latitude ecosystems, the maximal growth rates of herbivorous protists were less than half the maximal growth rates of phototrophic protists. Growth rates of herbivorous protists were consistently lower than those of bacterivorous protists and were unrelated to differences in cell volume between the two groups. Linear equations describing the relationship of the natural log of maximal growth rates of bacterivorous and herbivorous protists to temperature were generated and compared to published information for maximal growth rates of phototrophic protists and copepods. The three heterotrophic groups had similar slopes (0.12 for bacterivorous protists, 0.10 for herbivorous protists, and 0.13 for copepods) that were approximately double that of phototrophic protists (0.06). The massive annual algal blooms observed in high latitudes are due in part to a fundamental difference in the relationship between growth and temperature for phototrophic protists and their grazers.
Microbes have central roles in ocean food webs and global biogeochemical processes, yet specific ecological relationships among these taxa are largely unknown. This is in part due to the dilute, ...microscopic nature of the planktonic microbial community, which prevents direct observation of their interactions. Here, we use a holistic (that is, microbial system-wide) approach to investigate time-dependent variations among taxa from all three domains of life in a marine microbial community. We investigated the community composition of bacteria, archaea and protists through cultivation-independent methods, along with total bacterial and viral abundance, and physico-chemical observations. Samples and observations were collected monthly over 3 years at a well-described ocean time-series site of southern California. To find associations among these organisms, we calculated time-dependent rank correlations (that is, local similarity correlations) among relative abundances of bacteria, archaea, protists, total abundance of bacteria and viruses and physico-chemical parameters. We used a network generated from these statistical correlations to visualize and identify time-dependent associations among ecologically important taxa, for example, the SAR11 cluster, stramenopiles, alveolates, cyanobacteria and ammonia-oxidizing archaea. Negative correlations, perhaps suggesting competition or predation, were also common. The analysis revealed a progression of microbial communities through time, and also a group of unknown eukaryotes that were highly correlated with dinoflagellates, indicating possible symbioses or parasitism. Possible 'keystone' species were evident. The network has statistical features similar to previously described ecological networks, and in network parlance has non-random, small world properties (that is, highly interconnected nodes). This approach provides new insights into the natural history of microbes.
It remains unclear how often and under what circumstances intimate partner violence (IPV) precedes suicide. Available research on IPV and suicide focuses largely on homicide-suicide, which is a rare ...event (<2% of suicides). We focus instead on single suicides (i.e., suicides unconnected to other violent deaths), which are the most common type of fatal violence in the US.
Unfortunately, information about IPV circumstances is often unavailable for suicides. To address this gap, we sought to identify the proportion of single suicides that were preceded by IPV in North Carolina (NC), to describe the prevalence of IPV victimization and perpetration as precursors to suicide, and to explore how IPV-related suicides differ from other suicides. We used data from the NC Violent Death Reporting System (2010–2017, n = 9682 single suicides) and hand-reviewed textual data for a subset of cases (n = 2440) to document IPV circumstances.
We had robust inter-rater reliability (Kappa: 0.73) and identified n = 439 IPV-related suicides. Most were males who had perpetrated nonfatal IPV (n = 319, 72.7%) prior to dying by suicide. Our findings suggest that IPV was a precursor for at least 4.5% of single suicides.
Next, we conducted logistic regression analyses by sex comparing IPV-related suicides to other suicides. For both men and women, IPV was more common when the person who died by suicide had recently disclosed suicidal intent, was younger, used a firearm, and was involved with the criminal legal system, even after controlling for covariates. We also found sex-specific correlates for IPV circumstances in suicide.
Combined with homicide-suicide data (reported elsewhere), IPV is likely associated with 6.1% or more of suicides overall. Results suggest clear missed opportunities to intervene for this unique subpopulation, such as suicide screening and referral in IPV settings (e.g., batterer intervention programs, Family Justice Centers) that is tailored by sex.
•Intimate partner violence is a precipitating factor for 4.5% of single suicides.•Most IPV-related single suicides were of men who perpetrated nonfatal IPV.•Decedents in IPV-related suicides often used a firearm and disclosed intent.•Integrated prevention strategies to target both IPV and suicide may be appropriate.•When combined with homicide-suicide data, IPV influences 6.1% of suicides overall.
Enhancement of shellfish populations has long been discussed as a potential nutrient reduction tool, and eastern oyster aquaculture was recently approved as a nutrient reduction best management ...practice (BMP) in Chesapeake Bay, USA. This study addressed BMP-identified data gaps involving variation in nutrient concentration related to ploidy, effects of reproductive development, and a paucity of phosphorus concentration data. Diploid and triploid oysters were collected from farms in Maryland and Virginia across the typical local reproductive cycle. The nutrient concentration of tissue and shell was consistent with the currently implemented BMP. Minor variation observed in nitrogen and phosphorus concentration was within the previously reported range, for farm location, ploidy, and reproductive cycle timing. Ploidy-based differences in tissue dry weight were not observed at either farm, which contrasts with current nutrient reduction estimates. These results suggest separate crediting values for diploids and triploids may need further investigation and potential re-evaluation.
•Nitrogen (N) & phosphorus (P) in tissue and shell was consistent with prior studies.•Only minor variation in tissue N & P was observed in association with reproduction.•Ploidy-based differences in tissue dry weight were inconsistent with prior studies.•N & P reductions can be predicted with high confidence for nutrient management.
The Eastern Oyster (
Crassostrea virginica
) is a commercially important aquaculture species and food resource along the Atlantic and Gulf coasts of the USA. In addition to its economic value, oyster ...aquaculture provides ecological value such as water quality improvement. Oyster filtration is highly variable as filtration behavior is influenced by environmental conditions, oyster size, and oyster energetic demands. However, average rates generated in laboratory experiments are often used to estimate the ecological impact of oyster filtration, and there is a need for field-based, farm-specific estimates of filtration that account for this variation. In this study, field experiments were conducted between September 2020 and September 2021 to estimate seasonal oyster filtration physiology at oyster farms in three different bays in the Mid-Atlantic (Barnegat Bay and Delaware Bay in New Jersey and Rehoboth Bay in Delaware). The physiological activity of oysters at each farm varied such that oysters at Barnegat Bay were the most active and oysters at Rehoboth Bay were the least active. Seasonal physiological trends were observed such that filtration behavior generally increased in warmer months. An increase in physiological activity across all farms was associated with an increase in salinity and temperature, but physiological activity at each farm was associated with a different suite of environmental variables including total particulate matter and the organic content of seston. This study provides a robust dataset which can be incorporated into models estimating ecological filtration rates in the Mid-Atlantic and adds to the growing body of evidence supporting bivalve aquaculture as a nutrient reduction strategy.
Excess nutrients in the coastal environment have been linked to a host of environmental problems, and nitrogen reduction efforts have been a top priority of resource managers for decades. The use of ...shellfish for coastal nitrogen remediation has been proposed, but formal incorporation into nitrogen management programs is lagging. Including shellfish aquaculture in existing nitrogen management programs makes sense from environmental, economic, and social perspectives, but challenges must be overcome for large-scale implementation to be possible.
•Model estimates of nitrogen removal by shellfish farms were compiled.•Information was summarized for 7 species and 14 locations around the world.•Removal range was 105–1356lbsacre−1 year−1, average ...520lbsacre−1year−1.•Estimates compare favorably to agricultural BMPs and stormwater control measures.•Individual removal estimates are site-specific, not transferable to other locations.
The use of shellfish aquaculture for nutrient removal and reduction of coastal eutrophication has been proposed. Published literature has indicated that nitrogen contained in harvested shellfish can be accurately estimated from shell length:nitrogen content ratios. The range of nitrogen that could be removed by a typical farm in a specific estuarine or coastal setting is also of interest to regulators and planners. Farm Aquaculture Resource Management (FARM) model outputs of nitrogen removal at the shellfish farm scale have been summarized here, from 14 locations in 9 countries across 4 continents. Modeled nitrogen removal ranged from 105lbsacre−1year−1 (12gm−2year−1) to 1356lbsacre−1year−1 (152gm−2year−1). Mean nitrogen removal was 520lbsacre−1year−1 (58gm−2year−1). These model results are site-specific in nature, but compare favorably to reported nitrogen removal effectiveness of agricultural best management practices and stormwater control measures.
PDF
