ALBERT

Description: There is growing concern that modifications to the global environment such as ocean acidification and increased ultraviolet radiation may interact with anthropogenic pollutants to adversely affect the future marine environment. Despite this, little is known about the nature of the potential risks posed by such interactions. Here, we performed a multifactorial microcosm experiment to assess the impact of ocean acidification, ultraviolet B (UV-B) radiation and oil hydrocarbon contamination on sediment chemistry, the microbial community (composition and function) and biochemical marker response of selected indicator species. We found that increased ocean acidification and oil contamination in the absence of UV-B will significantly alter bacterial composition by, among other things, greatly reducing the relative abundance of Desulfobacterales, known to be important oil hydrocarbon degraders. Along with changes in bacterial composition, we identified concomitant shifts in the composition of oil hydrocarbons in the sediment and an increase in oxidative stress effects on our indicator species. Interestingly, our study identifies UV-B as a critical component in the interaction between these factors, as its presence alleviates harmful effects caused by the combination of reduced pH and oil pollution. The model system used here shows that the interactive effect of reduced pH and oil contamination can adversely affect the structure and functioning of sediment benthic communities, with the potential to exacerbate the toxicity of oil hydrocarbons in marine ecosystems.

Description: The wind-driven part of the South Atlantic Ocean is primarily ventilated through central and intermediate water formation. Through the water mass formation processes, anthropogenic carbon (C-ant) is introduced into the ocean's interior which in turn makes the South Atlantic region vulnerable to ocean acidification. C-ant and the accompanying acidification effects have been estimated for individual sections in the region since the 1980s but a comprehensive synthesis for the entire basin is still lacking. Here, we quantified the C-ant accumulation rates and examined the changes in the carbonate system properties for the South Atlantic using a modified extended multiple linear regression method applied to five hydrographic sections and data from the GLODAPv2.2021 product. From 1989 to 2019, a mean C-ant column inventory change of 0.94 +/- 0.39 mol C m(-2) yr(-1) was found. C-ant accumulation rates of 0.89 +/- 0.33 mu mol kg(-1) yr(-1) and 0.30 +/- 0.29 mu mol kg(-1) yr(-1) were observed in central and intermediate waters, accompanied by acidification rates of -0.0020 +/- 0.0007 pH units yr(-1) and -0.0009 +/- 0.0009 pH units yr(-1), respectively. Furthermore, increased remineralization was observed in intermediate waters, amplifying the acidification of this water mass, especially at the African coast along 25 degrees S. This increase in remineralization is likely related to circulation changes and increased biological activity nearshore. Assuming no changes in the observed trends, South Atlantic intermediate waters will become unsaturated with respect to aragonite in similar to 30 years, while the central water of the eastern margins will become unsaturated in similar to 10 years.

Description: Aquaculture has been one of the fastest-growing food production systems sectors for over three decades. With its growth, the demand for alternative, cheaper and high-quality feed ingredients is also increasing. Innovation investments on providing new functional feed alternatives have yielded several viable alternative raw materials. Considering all the current feed ingredients, their circular adaption in the aquafeed manufacturing industry is clearly of the utmost importance to achieve sustainable aquaculture in the near future. The use of terrestrial plant materials and animal by-products predominantly used in aquafeed ingredients puts a heavily reliance on terrestrial agroecosystems, which also has its own sustainability concerns. Therefore, the aquafeed industry needs to progress with functional and sustainable alternative raw materials for feed that must be more resilient and consistent, considering a circular perspective. In this review, we assess the current trends in using various marine organisms, ranging from microorganisms (including fungi, thraustochytrids, microalgae and bacteria) to macroalgae and macroinvertebrates as viable biological feed resources. This review focuses on the trend of circular use of resources and the development of new value chains. In this, we present a perspective of promoting novel circular economy value chains that promote the re-use of biological resources as valuable feed ingredients. Thus, we highlight some potentially important marine-derived resources that deserve further investigations for improving or addressing circular aquaculture.