Past the Precipice? Projected Coral Habitability Under Global Heating.

Coral reefs are rapidly declining due to local environmental degradation and global climate change. In particular, corals are vulnerable to ocean heating. Anomalously hot sea surface temperatures (SSTs) create conditions for severe bleaching or direct thermal death. We use SST observations and CMIP6 model SST to project thermal conditions at reef locations at a resolution of 1 km, a 16-fold improvement over prior studies, under four climate emissions scenarios. We use a novel statistical downscaling method which is significantly more skillful than the standard method, especially at near-coastal pixels where many reefs are found. For each location we present projections of thermal departure (TD, the date after which a location with steadily increasing heat exceeds a given thermal metric) for severe bleaching recurs every 5 years (TD5Y) and every 10 years (TD10Y), accounting for a range of post-bleaching reef recovery/degradation. As of 2021, we find that over 91% and 79% of 1 km2 reefs have exceeded TD10Y and TD5Y, respectively, suggesting that widespread long-term coral degradation is no longer avoidable. We project 99% of 1 km2 reefs to exceed TD5Y by 2034, 2036, and 2040 under SSP5-8.5, SSP3-7.0, and SSP2-4.5 respectively. We project that 2%-5% of reef locations remain below TD5Y at 1.5°C of mean global heating, but 0% remain at 2.0°C. These results demonstrate the importance of further improving ecological projection capacity for climate-vulnerable marine and terrestrial species and ecosystems, including identifying refugia and guiding conservation efforts. Ultimately, saving coral reefs will require rapidly reducing and eliminating greenhouse gas emissions.

Efficacy of 5-day parenteral versus intramammary benzylpenicillin for treatment of clinical mastitis caused by gram-positive bacteria susceptible to penicillin in vitro.

The efficacy of parenteral (intramuscular) or intramammary (IMM) benzylpenicillin treatment for clinical mastitis caused by gram-positive bacteria susceptible to penicillin in vitro was investigated. Cows with clinical mastitis in 1 udder quarter were randomly placed into 2 treatment groups. The preliminary bacteriological diagnosis of intramammary infection (IMI) was based on on-farm culturing, and the bacteriological diagnoses were later confirmed by a quantitative PCR assay. Clinical mastitis caused by gram-positive bacteria susceptible to benzylpenicillin was treated with penicillin via either the parenteral route (20mg/kg) or IMM route (600mg) once per day for 5d. The outcome of the treatment was evaluated 3 to 4wk after the onset of the treatment. The affected quarter was examined to assess the clinical cure, and milk samples were collected from the affected quarter to determine the bacteriological cure and milk N-acetyl-ß-d-glucosaminidase activity. The survival and the composite milk somatic cell counts of the treated cows were followed up for 6 and 3mo after treatment, respectively. A total of 140 cows with clinical mastitis were included in the study, 61 being treated with benzylpenicillin parenterally and 79 via the IMM route. From all quarters treated, 108 of 140 (77.1%) were cured clinically and 77 of 140 (55.0%) were cured bacteriologically. The route of treatment did not significantly affect the outcome of the treatment; 80.3% of the quarters with parenteral treatment and 74.7% of the quarters with IMM treatment showed a clinical cure, and 54.1 and 55.7% a bacteriological cure, respectively. The milk N-acetyl-ß-d-glucosaminidase activity was significantly lower in the quarters with a clinical or bacteriological cure than in the quarters with no cure. The 6-mo survival and the proportion of cows with composite milk somatic cell counts <200,000/mL among the treated cows during the 3-mo follow-up period did not significantly differ between the treatment groups. In conclusion, the outcome of either parenteral or IMM benzylpenicillin treatment of clinical mastitis caused by penicillin-susceptible bacteria was similar.

Milk haptoglobin, milk amyloid A, and N-acetyl-ß-D-glucosaminidase activity in bovines with naturally occurring clinical mastitis diagnosed with a quantitative PCR test.

The associations between quantitative bacteriological results from a real-time PCR test and concentrations of acute-phase proteins (APP) and N-acetyl-ß-d-glucosaminidase (NAGase) activity in milk in naturally occurring clinical mastitis were investigated. Milk APP concentrations and NAGase activity in clinical mastitis caused by different udder pathogens were studied. The associations between the severity of the clinical signs and concentrations of APP and NAGase activity were estimated. Milk samples from 281 cases of clinical mastitis were collected from 3 Estonian dairy farms and analyzed by PCR to identify pathogens. Twenty-seven samples out of 281 (9.6%) were PCR negative. Milk samples containing 4 or more bacterial species (n=28) were considered possibly contaminated and excluded from all further analyses. In total, 443 bacterial identifications were made from the remaining 226 milk samples. A single bacterial species was detected in 68 samples (30.1%), 2 species were detected in 99 samples (43.8%), and 3 species were detected in 59 (26.1%) samples. To determine the inflammatory response in the udder, the concentrations of milk amyloid A (MAA) and haptoglobin (Hp) and NAGase activity in the milk were analyzed. A significant positive association was found between the severity of the clinical signs and inflammatory markers in the milk. Milk amyloid A and Hp concentrations and NAGase activity were significantly higher in samples with large quantities of bacterial DNA from Escherichia coli or Streptococcus dysgalactiae compared with milk samples not containing those species. Large quantities of bacterial DNA from Trueperella pyogenes or Streptococcus uberis in the milk were associated with elevated concentrations of Hp and high NAGase activity, but not with increased MAA concentrations. Milk samples containing Corynebacterium bovis and coagulase-negative staphylococci had significantly lower concentrations of MAA and Hp and lower NAGase activity compared with samples where these species were not detected. It can be concluded that concentrations of APP and NAGase activity in the milk were associated with the quantity of bacterial DNA in the milk samples.