We mapped tidal wetland gross primary production (GPP) with unprecedented detail for multiple wetland types across the continental United States (CONUS) at 16‐day intervals for the years 2000–2019. ...To accomplish this task, we developed the spatially explicit Blue Carbon (BC) model, which combined tidal wetland cover and field‐based eddy covariance tower data into a single Bayesian framework, and used a super computer network and remote sensing imagery (Moderate Resolution Imaging Spectroradiometer Enhanced Vegetation Index). We found a strong fit between the BC model and eddy covariance data from 10 different towers (r2 = 0.83, p < 0.001, root‐mean‐square error = 1.22 g C/m2/day, average error was 7% with a mean bias of nearly zero). When compared with NASA's MOD17 GPP product, which uses a generalized terrestrial algorithm, the BC model reduced error by approximately half (MOD17 had r2 = 0.45, p < 0.001, root‐mean‐square error of 3.38 g C/m2/day, average error of 15%). The BC model also included mixed pixels in areas not covered by MOD17, which comprised approximately 16.8% of CONUS tidal wetland GPP. Results showed that across CONUS between 2000 and 2019, the average daily GPP per m2 was 4.32 ± 2.45 g C/m2/day. The total annual GPP for the CONUS was 39.65 ± 0.89 Tg C/year. GPP for the Gulf Coast was nearly double that of the Atlantic and Pacific Coasts combined. Louisiana alone accounted for 15.78 ± 0.75 Tg C/year, with its Atchafalaya/Vermillion Bay basin at 4.72 ± 0.14 Tg C/year. The BC model provides a robust platform for integrating data from disparate sources and exploring regional trends in GPP across tidal wetlands.
Key Points
We created the Blue Carbon (BC) model, which mapped the Gross Primary Production (GPP) of all tidal wetlands within the continental United States
The BC model provides maps of tidal wetland GPP at sub‐250 m scales and at 16‐day intervals for the years 2000‐2019
The average daily GPP per m2 was 4.32 ± 2.45 g C/m2/day, and the total annual GPP for the continental United States was 39.65 ± 0.89 Tg C/year
Many point mutations in human Cu,Zn superoxide dismutase (SOD) cause familial amyotrophic lateral sclerosis (FALS), a fatal neurodegenerative disorder in heterozygotes. Here we show that these ...mutations cluster in protein regions influencing architectural integrity. Furthermore, crystal structures of SOD wild-type and FALS mutant H43R proteins uncover resulting local framework defects. Characterizations of β-barrel (H43R) and dimer interface (A4V) FALS mutants reveal reduced stability and drastically increased aggregation propensity. Moreover, electron and atomic force microscopy indicate that these defects promote the formation of filamentous aggregates. The filaments resemble those seen in neurons of FALS patients and bind both Congo red and thioflavin T, suggesting the presence of amyloid-like, stacked β-sheet interactions. These results support free-cysteine-independent aggregation of FALS mutant SOD as an integral part of FALS pathology. They furthermore provide a molecular basis for the single FALS disease phenotype resulting from mutations of diverse side-chains throughout the protein: many FALS mutations reduce structural integrity, lowering the energy barrier for fibrous aggregation.
Coastal dunes are often the first and only line of physical defense for communities subjected to damaging storms and waves. Planting vegetation on them has been proposed as one way to increase their ...protective capacity, but it is unknown how dune plant architecture reduces erosion. We conducted wave flume and field experiments to address this question and found that dune plants primarily reduced erosion by attenuating wave swash and run up bores with their stems and leaves, while their roots initially enhanced erosion through uprooting. After excavation, the roots also attenuated waves and reduced erosion. We then sampled the biophysical attributes of a broad distribution of plants, and found that herbaceous non-Graminoid (non-grass) species that inhabited the lowest latitudes and most seaward zones had the most efficient structures for erosion reduction. Our results suggest that there is a fundamental tradeoff in the ability of dune plant species to respond to hydrodynamic versus Aeolian processes, based on the relative allocation of aboveground versus belowground biomass. Through the combination of flume experiments, field survey, and meta-analysis, our findings show that vegetation provides on average ∼1.6 factor of safety over bare sand across a wide range of latitudes in the northern hemisphere - translating into a reduction of wave run up erosion by approximately 40% for dunes.
The present study quantified the vertical and horizontal distribution of sub-adult Chinook salmon Oncorhynchus tshawytscha in nearshore marine environments. Depth-specific hook and line sampling was ...conducted along the Pacific Ocean coast of Washington, USA. Our analysis, based on 187 Chinook salmon from 1299 sampling deployments and 6616 hooks, revealed a wide distribution of salmon in nearshore marine waters, with distinct patterns associated with fish size and age. Chinook salmon that spent one winter in marine waters were more likely to be caught at greater depths than those in their first year at sea, and larger fish were found at greater depths than smaller fish. The probability of Chinook salmon capture varied with depth, showing a higher likelihood of capture at midwater (>15 m from the surface and >5 m from the bottom) and near (<5 m) the bottom compared to near (<15 m) the surface. Additionally, environmental variables such as sea surface temperature, sea surface chlorophyll a , minutes to low tide, and boat speed unimodally influenced capture probability. Our study contributes valuable insights into the spatiotemporal ecology of Chinook salmon, offering a more mechanistic perspective for their management and conservation. The identified relationships between environmental covariates and Chinook salmon distribution can be used to inform life cycle models used to manage and protect this at-risk species and the ecosystem processes that depend on them, particularly in the context of changing oceanic conditions and their role as both predator and prey in marine ecosystems.
Proventriculitis was studied by experimentally reproducing the disease in broiler chickens. One-day-old infectious bursal disease virus (IBDV) and infectious bronchitis virus (IBV) antibody positive ...commercial broilers and 1-day-old antibody negative specific-pathogen-free (SPF) broilers were orally gavaged with proventricular homogenates produced from the proventriculi of broilers with proventriculitis. At 7 and 14 days, both commercial and SPF broilers had enlargement of the proventriculus with necrosis of the glandular epithelium and lymphocytic infiltrates in the proventricular glands. SPF broilers exposed to the proventricular homogenates developed infectious bursal disease, and IBDV was detected by reverse transcriptase–polymerase chain reaction (RT-PCR). They also were positive by RT-PCR to IBV and developed nephritis. Commercial broilers developed mild nephritis but not bursal disease and were negative for IBDV and positive for IBV by RT-PCR. Both homogenate-inoculated commercial and SPF chickens were negative for reovirus and Newcastle disease virus by RT-PCR and variably positive for adenovirus by PCR. Bacteria were not identified in histologic sections, nor were they isolated from affected proventriculi. Indirect fluorescent antibody assay using convalescent sera detected intracytoplasmic staining in the proventricular glandular epithelial cells. Examination of thin sections of proventriculi using electron microscopy identified virus-like particles approximately 120 nm in diameter within the cytoplasm of these cells at 7 days after inoculation. Passage of proventricular homogenate filtrates in chicken embryos for virus isolation caused stunting, and allantoic fluid from these eggs was positive for IBV by RT-PCR.
Broiler chickens with transmissible proventriculitis have severe lymphocytic infiltration of the proventricular glands. The distribution of T cells and B cells in these infiltrates was studied ...histopathologically, and their identity was confirmed immunohistochemically (CD3, CD4, CD8, and B cells). To reproduce this disease, 1-day-old commercial broilers were orally gavaged with homogenized proventriculi from broilers with proventriculitis. Resulting lesions were examined at both acute (7 days postinoculation dpi) and chronic (14 and 21 dpi) time points. Lymphocytic infiltrates in the proventricular glands and the mucosal lamina propria were present at all time points and were most prominent and demarcated at 14 dpi. T and B lymphocytes were present during acute and chronic proventriculitis, but their distribution varied within the glands. Lymphocytic infiltrates in the proventricular glands and in the lamina propria were predominantly CD3+ T cells, and most of these were also CD8+. B cells and CD4+ T cells formed aggregates in chronic proventriculitis. Thus, both cell-mediated and humoral immune responses are induced during transmissible proventriculitis, and the cell-mediated immune response is morphologically greater.
Proventriculitis in broilers causes carcass condemnation when swollen proventriculi tear during evisceration. The cause of this proventriculitis is unknown, but several infectious agents have been ...associated with it. One such agent, infectious bursal disease virus (IBDV), has been implicated as a cause of proventriculitis, but a direct effect of this virus on the proventriculus has not been proven. The role of IBDV in proventriculitis may be indirect as a result of its ability to cause immunosuppression. The objective of this study was to understand how immunosuppression affects the incidence of proventriculitis in broiler chickens. Immunosuppression was induced in commercial and specific-pathogen-free broiler chickens using chemicals (cyclophosphamide and cyclosporin) or virus (IBDV). All groups were then exposed to a proventricular homogenate produced from diseased birds. At 7 and 14 days postinoculation, the incidence of proventriculitis in these groups was compared to that produced by homogenate exposure in immunocompetent broilers. All birds exposed to the proventricular homogenate from diseased birds developed proventriculitis. Cyclophosphamide and IBDV, both B cell suppressors, did not significantly affect the incidence or characteristics of the proventriculitis observed, although they did have an effect on the size of the proventriculus at 7 days postinoculation. Chickens immunosuppressed with cyclosporin, a T cell suppressor, developed more severe lesions and had a higher incidence of proventriculitis. These findings indicate that both B and T cells are involved in the immune response against proventriculitis, but cell-mediated immunity appears to have a more important role in controlling the disease. IBDV affects both humoral and cellular immunity in the chicken, so although under experimental conditions it didn't have a major effect on proventriculitis, it may explain why control of IBDV in the field seems to reduce the incidence of proventriculitis.
1 USDA-ARS Animal Disease Research Unit, Bustad 337, WSU, Pullman, Washington 99164-7030
2 Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington ...99164-7040
3 908 South Third Street, Hamilton, Montana 59840-2924, U.S.A.
4 Central Veterinary Laboratory, New Haw, Addlestone, Surrey KT15 3NB, U.K.
and 5 Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison, Wisconsin 53706, U.S.A.
To determine whether the aetiological agent of bovine spongiform encephalopathy (BSE) is pathogenic for mink, standard dark mink were inoculated with coded homogenates of bovine brain from the U.K. Two homogenates were from cows affected with BSE. The third was from a cow that came from a farm with no history of having had BSE or having been fed ruminant-derived, rendered by-products, the proposed vehicle for introduction of the BSE agent. Each homogenate was inoculated intracerebrally into separate groups of mink and a pool of the three was fed to a fourth group. Signs of neurological disease appeared in mink an average of 12 months after intracerebral inoculation and 15 months after feeding. Decreased appetite, lethargy and mild to moderate pelvic limb ataxia were the predominant clinical signs, quite unlike the classic clinical picture of transmissible mink encephalopathy (TME). Microscopic changes in brain sections of most affected mink were those of a scrapie-like spongiform encephalopathy. Vacuolar change in grey matter neuropil was accompanied by prominent astrocytosis. Varying greatly in severity from one mink to another, the degenerative changes occurred in the cerebral cortex, dorsolateral gyri of the frontal lobe, corpus striatum, diencephalon and brainstem. Although resembling TME, the encephalopathy was distinguishable from it by less extensive changes in the cerebral cortex, by more severe changes in the caudal brainstem and by sparing of the hippocampus. The results of this study extend the experimental host range of the BSE agent and demonstrate for the first time the experimental oral infection of mink with a transmissible spongiform encephalopathy agent from a naturally infected ruminant species.
Received 25 February 1994;
accepted 20 April 1994.
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