Publications by authors named "Wilhelm Hagen"

Species identification is pivotal in biodiversity assessments and proteomic fingerprinting by MALDI-TOF mass spectrometry has already been shown to reliably identify calanoid copepods to species level. However, MALDI-TOF data may contain more information beyond mere species identification. In this study, we investigated different ontogenetic stages (copepodids C1-C6 females) of three co-occurring Calanus species from the Arctic Fram Strait, which cannot be identified to species level based on morphological characters alone.

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Background: Trophic interactions are key processes, which determine the ecological function and performance of organisms. Many decapod crustaceans feed on plant material as a source for essential nutrients, e.g.

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The brown shrimp Crangon crangon is a key component of the North Atlantic coastal food web and an important target species for the fishery economy. As the brown shrimp contains large amounts of protein and essential fatty acids, its consumption makes it a beneficial choice for humans. Commercially harvested crustaceans like C.

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The brown shrimp, Crangon crangon, is well adapted to the variable environmental conditions in the southern North Sea. It is very abundant, has high reproduction rates, and holds a key position in coastal ecosystems. This species has very low lipid deposits in the midgut gland, suggesting that the main function of the midgut gland is metabolic turnover rather than energy storage.

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The study revealed species- and stage-specific differences in lipid accumulation of the dominant Antarctic copepods, the primarily herbivorous (copepodite stage V (CV), females) and the more omnivorous (females) storing wax esters and triacylglycerols, respectively, which were collected in summer (end of December). Feeding carbon-labelled diatoms to these copepods, C elucidated assimilation and turnover rates of copepod total lipids as well as specific fatty acids and alcohols. The C incorporation was monitored by compound-specific stable isotope analysis (CSIA).

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Hyperiid amphipods are predatory pelagic crustaceans that are particularly prevalent in high-latitude oceans. Many species are likely to have co-evolved with soft-bodied zooplankton groups such as salps and medusae, using them as substrate, for food, shelter or reproduction. Compared to other pelagic groups, such as fish, euphausiids and soft-bodied zooplankton, hyperiid amphipods are poorly studied especially in terms of their distribution and ecology.

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Tolerance of organisms towards heterogeneous and variable environments is highly related to physiological flexibility. An effective strategy to enhance physiological flexibility is the expression of polymorphic enzymes. This seems to be the case in the brown shrimp Crangon crangon.

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Article Synopsis
  • - The study focuses on how giant kelp (Macrocystis pyrifera) adapts to varying light and temperature conditions at different depths of water, specifically looking at long-term and short-term acclimation strategies across different seasons.
  • - Researchers found that the kelp adjusts its pigment composition, chlorophyll fluorescence, and fatty acid profiles when moving between depth levels, illustrating its physiological adaptability to changing environmental conditions.
  • - Key findings highlight that phlorotannins are important for long-term adaptation, while antioxidants are crucial for quick adjustments; however, more research is necessary to fully understand how different environmental factors contribute to these physiological changes.
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Long-term data sets are essential to understand climate-induced variability in marine ecosystems. This study provides the first comprehensive analysis of longer-term temporal and spatial variations in zooplankton abundance and copepod community structure in the northern Benguela upwelling system from 2005 to 2011. Samples were collected from the upper 200 m along a transect at 20 °S perpendicular to the coast of Namibia to 70 nm offshore.

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Oxygen minimum zones (OMZs) affect distribution patterns, community structure and metabolic processes of marine organisms. Due to the prominent role of zooplankton, especially copepods, in the marine carbon cycle and the predicted intensification and expansion of OMZs, it is essential to understand the effects of hypoxia on zooplankton distribution and ecophysiology. For this study, calanoid copepods were sampled from different depths (0-1800 m) at eight stations in the eastern tropical Atlantic (3 °47'N to 18 °S) during three expeditions in 2010 and 2011.

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Both Engaeus sericatus and Cherax destructor are omnivorous crayfishes consuming a variety of food items. Materials identified in the faeces of both E. sericatus and C.

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Fatty acids have been used as qualitative markers to trace or confirm predator-prey relationships in the marine environment for more than thirty years. More recently, they have also been used to identify key processes impacting the dynamics of some of the world's major ecosystems. The fatty acid trophic marker (FATM) concept is based on the observation that marine primary producers lay down certain fatty acid patterns that may be transferred conservatively to, and hence can be recognized in, primary consumers.

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