Publications by authors named "D A Wolf-Gladrow"

The redox speciation of iron was determined during the iron fertilization LOHAFEX and for the first time, the chemiluminescence assay of filtered and unfiltered samples was systematically compared. We hypothesize that higher chemiluminescence in unfiltered samples was caused by Fe(II) adsorbed onto biological particles. Dissolved and particulate Fe(II) increased in the mixed layer steadily 6-fold during the first two weeks and decreased back to initial levels by the end of LOHAFEX.

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A quantitative analysis of any environment older than the instrumental record relies on proxies. Uncertainties associated with proxy reconstructions are often underestimated, which can lead to artificial conflict between different proxies, and between data and models. In this paper, using ordinary least squares linear regression as a common example, we describe a simple, robust and generalizable method for quantifying uncertainty in proxy reconstructions.

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In the marine realm, microorganisms are responsible for the bulk of primary production, thereby sustaining marine life across all trophic levels. Longhurst provinces have distinct microbial fingerprints; however, little is known about how microbial diversity and primary productivity change at finer spatial scales. Here, we sampled the Atlantic Ocean from south to north (~50°S-50°N), every ~0.

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Article Synopsis
  • Lake eutrophication, driven by nutrient over-enrichment from agriculture and urban areas, leads to excessive phytoplankton growth, self-shading, and light limitation, yet the role of carbon limitation is often overlooked.
  • A study found that carbon dioxide (CO) undersaturation happens significantly more often in eutrophic lakes than in deeper, forested lakes, with annual occurrences around 34% and summer instances up to 44%.
  • The research showed that high light levels and shallow depths contribute to CO depletion, revealing that conditions of carbon limitation at the whole-lake scale are key for understanding phytoplankton biomass, emphasizing the need for new strategies to tackle both eutrophication and carbon depletion together.
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In this article, we analyze the impacts of climate change on Antarctic marine ecosystems. Observations demonstrate large-scale changes in the physical variables and circulation of the Southern Ocean driven by warming, stratospheric ozone depletion, and a positive Southern Annular Mode. Alterations in the physical environment are driving change through all levels of Antarctic marine food webs, which differ regionally.

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