Description: Optic technologies and methods/procedures are established across all areas and scales in limnic and marine research in Germany and develop further continuously. The working group “Aquatic Optic Technologies” (AOT) constitutes a common platform for knowledge transfer among scientists and users, provides a synergistic environment for the national developer community and will enhance the international visibility of the German activities in this field. This document summarizes the AOT-procedures and -techniques applied by national research institutions. We expect to initiate a trend towards harmonization across institutes. This will facilitate the establishment of open standards, provide better access to documentation, and render technical assistance for systems integration. The document consists of the parts: Platforms and carrier systems outlines the main application areas and the used technologies. Focus parameters specifies the parameters measured by means of optical methods/techniques and indicates to which extent these parameters have a socio-political dimension. Methods presents the individual optical sensors and their underlying physical methods. Similarities denominates the common space of AOT-techniques and applications. National developments lists projects and developer groups in Germany designing optical high-technologies for limnic and marine scientific purposes.

Description: I developed a new model for estimating annual production-to-biomass ratio P/B and production P of macrobenthic populations in marine and freshwater habitats. Self-learning artificial neural networks (ANN) were used to model the relationships between P/B and twenty easy-to-measure abiotic and biotic parameters in 1252 data sets of population production. Based on log-transformed data, the final predictive model estimates log(P/B) with reasonable accuracy and precision (r2 = 0.801; residual mean square RMS = 0.083). Body mass and water temperature contributed most to the explanatory power of the model. However, as with all least squares models using nonlinearly transformed data, back-transformation to natural scale introduces a bias in the model predictions, i.e., an underestimation of P/B (and P). When estimating production of assemblages of populations by adding up population estimates, accuracy decreases but precision increases with the number of populations in the assemblage.

Description: Optic technologies and methods/procedures are established across all areas and scales in limnic and marine research in Germany and develop further continuously. The working group “Aquatic Optic Technologies” (AOT) constitutes a common platform for knowledge transfer among scientists and users, provides a synergistic environment for the national developer community and will enhance the international visibility of the German activities in this field. This document summarizes the AOT-procedures and -techniques applied by national research institutions. We expect to initiate a trend towards harmonization across institutes. This will facilitate the establishment of open standards, provide better access to documentation, and render technical assistance for systems integration. The document consists of the parts: Platforms and carrier systems outlines the main application areas and the used technologies. Focus parameters specifies the parameters measured by means of optical methods/techniques and indicates to which extent these parameters have a socio-political dimension. Methods presents the individual optical sensors and their underlying physical methods. Similarities denominates the common space of AOT-techniques and applications. National developments lists projects and developer groups in Germany designing optical hightechnologies for limnic and marine scientific purposes.

Description: Biodiversity is seen as a core-service of marine ecosystems, and rare and endangered species play a crucial role in maintaining biodiversity. In shallow shelf seas such as the North Sea, benthic organisms contribute significantly to overall biodiversity. Hence, knowledge of biological characteristics and spatial distribution of benthic biodiversity and of benthic rare species is essential for sustainable ecosystem management and for the conservation of endangered species. In 2013, the status of endangered species was revised and published via the new “red list”. Regarding the marine benthic species on this list, the evidence used to judge them “endangered” is quite often scientifically unsatisfying by insufficient data and an imperfectly picture on their spatial occurrence. We use an extensive information system on benthic invertebrates in the German EEZ of the North Sea (〉9000 stations x 〉740 species) for a high-resolution and large-scale analysis of occurrence and spatial distribution of “red list” species. For the first time, we evaluate the functional role of endangered species by means of their biological traits and analyse their spatial distribution in the EEZ. Finally, we identify potentially sensitive areas where endangered species cluster. This information constitutes a sound scientific base for a sustainable ecosystem management.

Description: Biological hard parts and skeletons of aquatic organisms often archive information of past environmental conditions. Deciphering such information forms an essential contribution to our understanding of past climate conditions and thus our ability to mitigate the climatic, ecological, and social impacts of a rapidly changing environment. Several established techniques enable the visualization and reliable use of the information stored in anatomical features of such biogenic archives, i.e., its growth patterns. Here, we test whether confocal Raman microscopy (CRM) is a suitable method to reliably identify growth patterns in the commonly used archive Arctica islandica and the extinct species Pygocardia rustica (both Bivalvia). A modern A. islandica specimen from Norway has been investigated to verify the general feasibility of CRM, resulting in highly correlated standardized growth indices (r〉0.96; p〈0.0001) between CRM-derived measurements and measurements derived from the established methods of fluorescence microscopy and Mutvei’s solution staining. This demonstrates the general suitability of CRM as a method for growth pattern evaluation and cross-dating applications. Moreover, CRM may be of particular interest for paleoenvironmental reconstructions, as it yielded superior results in the analysis of fossil shell specimens (A. islandica and P. rustica) compared to both Mutvei staining and fluorescence microscopy. CRM is a reliable and valuable tool to visualize internal growth patterns in both modern and fossil calcium carbonate shells that notably also facilitates the assessment of possible diagenetic alteration prior to geochemical analysis without geochemically compromising the sample. We strongly recommend the CRM approach for the visualization of growth patterns in fossil biogenic archives, where conventional methods fail to produce useful results.

Description: Understanding the climate of the past is essential for anticipating future climate change. Palaeoclimatic archives are the key to the past, but few marine archives (including tropical corals) combine long recording times (decades to centuries) with high temporal resolution (decadal to intra-annual). In temperate and polar regions carbonate shells can perform the equivalent function as a proxy archive as corals do in the tropics. The bivalve Arctica islandica is a particularly unique bio-archive owing to its wide distribution throughout the North Atlantic and its extreme longevity (up to 500 years). This paper exemplifies how information at intra-annual and decadal scales is derived from A. islandica shells and combined into a detailed picture of past conditions. Oxygen isotope analysis (δ18O) provides information on the intra-annual temperature cycle while frequency analysis of shell growth records identifies decadal variability such as a distinct 5-year signal, which might be linked to the North Atlantic Oscillation.

Description: The shift towards a seasonally ice-free Arctic Ocean raises many questions related to the future of productivity and function of Arctic ecosystems. The highly productive marginal ice zone is dragged closer towards the center of the Arctic, and the ongoing thinning of sea ice and increased light penetration to the surface ocean may change spatio-temporal patterns of under- ice productivity. As under-ice processes are hard to monitor we study the dynamics on (and in) the Arctic seafloor, particularly the macrobenthos, as a proxy for pelagic change. We use biological trait analysis (BTA) to study the benthic functions and responses as this method links species, environment and ecosystem processes (Bremner 2005). Although benthos data from the Arctic and especially from the Arctic deep sea are scarce, international cooperation enables us to compile a dataset ranging over the past twenty years up to today. Based on this dataset we show that benthic functional traits like secondary production are correlated to Arctic sea ice and its associated dynamics. We give a regional example where benthic community functions have changed already over the last twenty years and highlight the areas of the Arctic Ocean that are most prone to these effects. Finally we want to stress the importance of international cooperation in the process of integrating existing data and knowledge to build up a spatially explicit Arctic trait database. Such a database would provide the scientific base to classify the Arctic into clearly defined “eco-function” regions. This functional atlas can then be used by the scientific community to correlate observed environmental trends and predict upcoming changes in ecosystem functioning accordingly.