Primary production, an index of climate change in the ocean: Satellite-based estimates over two decades

© 2020 by the authors. Primary production by marine phytoplankton is one of the largest fluxes of carbon on our planet. In the past few decades, considerable progress has been made in estimating global primary production at high spatial and temporal scales by combining in situ measurements of primary production with remote-sensing observations of phytoplankton biomass. One of the major challenges in this approach lies in the assignment of the appropriate model parameters that define the photosynthetic response of phytoplankton to the light field. In the present study, a global database of in situ measurements of photosynthesis versus irradiance (P-I) parameters and a 20-year record of climate quality satellite observations were used to assess global primary production and its variability with seasons and locations as well as between years. In addition, the sensitivity of the computed primary production to potential changes in the photosynthetic response of phytoplankton cells under changing environmental conditions was investigated. Global annual primary production varied from 38.8 to 42.1 Gt C yr-1 over the period of 1998-2018. Inter-annual changes in global primary production did not follow a linear trend, and regional differences in the magnitude and direction of change in primary production were observed. Trends in primary production followed directly from changes in chlorophyll-a and were related to changes in the physico-chemical conditions of the water column due to inter-annual and multidecadal climate oscillations. Moreover, the sensitivity analysis in which P-I parameters were adjusted by ±1 standard deviation showed the importance of accurately assigning photosynthetic parameters in global and regional calculations of primary production. The assimilation number of the P-I curve showed strong relationships with environmental variables such as temperature and had a practically one-to-one relationship with the magnitude of change in primary production. In the future, such empirical relationships could potentially be used for a more dynamic assignment of photosynthetic rates in the estimation of global primary production. Relationships between the initial slope of the P-I curve and environmental variables were more elusive

In vivo genome editing using Staphylococcus aureus Cas9

The RNA-guided endonuclease Cas9 has emerged as a versatile genome-editing platform. However, the size of the commonly used Cas9 from Streptococcus pyogenes (SpCas9) limits its utility for basic research and therapeutic applications that employ the highly versatile adeno-associated virus (AAV) delivery vehicle. Here, we characterize six smaller Cas9 orthologs and show that Cas9 from Staphylococcus aureus (SaCas9) can edit the genome with efficiencies similar to those of SpCas9, while being >1kb shorter. We packaged SaCas9 and its sgRNA expression cassette into a single AAV vector and targeted the cholesterol regulatory gene Pcsk9 in the mouse liver. Within one week of injection, we observed >40% gene modification, accompanied by significant reductions in serum Pcsk9 and total cholesterol levels. We further demonstrate the power of using BLESS to assess the genome-wide targeting specificity of SaCas9 and SpCas9, and show that SaCas9 can mediate genome editing in vivo with high specificity

Lack of long-term acclimation in Antarctic encrusting species suggests vulnerability to warming

Marine encrusting communities play vital roles in benthic ecosystems and have major economic implications with regards to biofouling. However, their ability to persist under projected warming scenarios remains poorly understood and is difficult to study under realistic conditions. Here, using heated settlement panel technologies, we show that after 18 months Antarctic encrusting communities do not acclimate to either +1 °C or +2 °C above ambient temperatures. There is significant up-regulation of the cellular stress response in warmed animals, their upper lethal temperatures decline with increasing ambient temperature and population genetic analyses show little evidence of differential survival of genotypes with treatment. By contrast, biofilm bacterial communities show no significant differences in community structure with temperature. Thus, metazoan and bacterial responses differ dramatically, suggesting that ecosystem responses to future climate change are likely to be far more complex than previously anticipated

Increased Resection Rates and Survival Among Patients Aged 75 Years and Older with Esophageal Cancer: A Dutch Nationwide Population-Based Study

The incidence of esophageal cancer has grown over the recent decades and 30 % of esophageal cancer patients are now 75 years or older at the time of diagnosis. The aim of this study was to evaluate trends in management and survival of patients aged 75 years or older with esophageal cancer. In the Netherlands cancer registry, we identified all patients aged 75 years or older who were diagnosed with esophageal cancer between 1989 and 2008. Trends in management and survival were analyzed by time period (1989-2001 vs. 2002-2008), TNM stage, and age (75-79, 80-84, and 85+ years). chi(2) testing was used to analyze time trends in treatment, Kaplan-Meier analysis and log-rank testing to estimate survival, and Cox regression model to calculate hazard ratios for death. Some 7,253 patients were included in the study. The surgical resection rate increased over the 1989-2008 period from 8.9 to 12.6 % (p = 0.028), especially among patients aged 75-79 years (44.6 vs. 55.4 %, p < 0.001) and patients with TNM stage I disease (12.7 vs. 22.0 %, p < 0.001). The use of definitive chemoradiotherapy (CRT) also increased (0.19 vs. 2.20 %, p < 0.001). Whereas the use of chemotherapy as a single-modality treatment more than doubled (0.64 vs. 1.54 %, p = 0.004), that of radiot In patients of 75 years or older, surgical treatment and use of definitive CRT have increased between 1989 and 2008. Also, an increase in the use of chemotherapy as a single modality was noted. Overall 5 year survival for all cancer patients was stable but remained poor, while survival of patients who underwent esophagectomy improved significantly in the Netherlands since 1989

Changes in hospital variation in the probability of receiving treatment with curative intent for esophageal and gastric cancer

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Plant spore walls as a record of long-term changes in ultraviolet-B radiation

Stratospheric ozone screens the Earth’s surface from harmful ultraviolet-B radiation. Concentrations of stratospheric ozone are governed by a variety of natural and anthropogenic factors, including solar cycles, volcanic aerosols, ozone-depleting substances and climate change. However, assessing this variability before instrumental records has proved difficult owing to the lack of a well-constrained proxy. Here, we use microspectroscopy to analyse the chemical composition of herbarium samples of clubmoss (Lycophyta) spores originating from high- and low-latitude localities, where they were exposed to different ultraviolet-B histories. We show that the concentration of two ultraviolet-B-absorbing compounds in the walls of high-northern- and southern-latitude spores is strongly regulated by historical variations in ultraviolet-B radiation. Conversely, we find little change in the concentration of these compounds in spores originating fromtropical Ecuador, where ultraviolet levels have remained relatively stable. Using spores from Greenland, we reconstruct past (1907–1993) changes in ozone concentration and ultraviolet-B flux; we reveal strong similarities between spore-wall reconstructions, and independent instrumental records and model results. Our findings suggest that ultraviolet-B-absorbing compounds in plant spore walls have the potential to act as a proxy for past changes in terrestrial ultraviolet-B radiation and stratospheric ozone. The chemical signature of plant spore walls in herbaria, and possibly also in sedimentary and ice-core archives, may therefore prove valuable for reconstructing past variations in stratospheric ozone and their connections with changes in solar radiation and climate

Correction: Kulk et al. Primary production, an index of climate change in the ocean: Satellite-based estimates over two decades (Remote Sens., (2020), 12, (826), 10.3390/rs12050826)

This is the final version. Available from MDPI via the DOI in this record. Since the article “Primary Production, an Index of Climate Change in the Ocean: Satellite-Based Estimates over Two Decades” by Kulk et al. [1] was published, we discovered an error in the code of the primary production model, which crept in when the code was updated from the original version described by Platt and Sathyendranath (1988), Sathyendranath et al. (1995) and Longhurst et al. (1995) ([2,31,52] in [1]). The main error in the code led to a time interval for the integration of daily water-column primary production that was shorter than it should have been. As a consequence, daily surface irradiance and hence primary production were systematically underestimated by 20–25% for the entire time series. We also discovered that the Photosynthetic Active Radiation (PAR) products of the National Aeronautics and Space Administration (NASA) that were used to scale the daily light cycle were rounded down for 2003–2019 (MODIS years), which led to an additional but small underestimation of daily surface irradiance. In addition to addressing these errors, we have included a merged time series of the PAR product to remove inter-sensor biases (as described in the corrected text of Appendix B; see below). The main corrections increased our estimate of global annual primary production on average by +23.9% between 1998 and 2018, while the correction of the rounding error in the PAR products increased global annual primary production between 2003 and 2018 by +0.9%. Inclusion of the merged PAR product in the primary production model caused a −0.25% decrease in global annual primary production between 1998 and 2002 and a +0.08% increase between 2003 and 2010 (relative to the aforementioned +23.9% increase for the entire time series). Our estimate of global annual primary production between 1998 and 2018 now is 48.7 to 52.5 Gt C y−1 instead of the published estimate of 38.8 to 42.1 Gt C y−1 . Although this is a substantial increase in the estimate of primary production, the results of the sensitivity analysis in which the photosynthesis versus irradiance parameters were varied by ±1 standard deviation and, importantly, the observed trends in regional and global annual primary production are largely unchanged. We therefore consider the outcomes of the study still valid after the corrections. We also note that our corrected estimate of global annual primary production is still within the range of earlier reports (32.0–70.7 Gt C y−1 [5,104] in [1])