@misc{weidlich_safe_applications_2026, 
author={Weidlich, Sabine,Keuter, Sabine,Aires, Tania,Engelen, Aschwin,Kunzmann, Andreas},
title={Safe applications of ozone in tropical marine RAS: Determining impacts of elevated total residual oxidants (TRO) on Stylophora pistillata and Xenia sp. holobionts},
year={2026},
howpublished = {journal article},
doi = {https://doi.org/10.1016/j.aquaculture.2025.743369},
abstract = {Ozone-aided treatment of seawater creates secondary oxidants, which can be toxic for aquaculture animals. We aimed to define safe limits of ozonation-derived total residual oxidants (TRO) for Stylophora pistillata and Xenia sp. by conducting a 96 h acute toxicity experiment. In a chronic exposure experiment we then determined the impacts of three sub-lethal levels of TRO on animal health over four weeks by monitoring respiration, net photosynthesis, photosynthetic efficiency, and three oxidative stress biomarkers (CAT, SOD, LPO). We further documented the changes in coral surface microbiomes exposed to elevated TRO with 16S rRNA amplicon gene sequence analysis. We showed that Xenia sp. is more susceptible to elevated TRO, with first mortalities occurring within 24 h at 0.188 mg L-1 and higher. In Stylophora, mortalities were observable within 24 h at 1.272 mg L−1 and after 72 h at 0.353 mg L−1 TRO. Sub-lethal TRO levels caused higher respiration and lower photosynthetic efficiency in Xenia, and increased catalase activity by 29–42 % in Stylophora and by 38–45 % in Xenia, while not impacting lipid peroxidation or superoxide dismutase activity. Microbiomes displayed TRO-induced changes in both species, with a decline in Saprospiraceae as a potential indicator for ozone-inflicted mucus layer degradation. Vibrionaceae fully disappeared from Stylophora pistillata microbiomes after 26 days of exposure to 0.131 mg L-1 TRO, suggesting ozonation as a potential tool to treat pathogens in coral aquaculture. Our study represents the first analysis of ozonation-induced impacts on coral holobionts, thereby providing a guideline for the safe application of ozone in coral cultivation.},
note = {Online available at: \url{https://doi.org/10.1016/j.aquaculture.2025.743369} (DOI). Weidlich, S.; Keuter, S.; Aires, T.; Engelen, A.; Kunzmann, A.: Safe applications of ozone in tropical marine RAS: Determining impacts of elevated total residual oxidants (TRO) on Stylophora pistillata and Xenia sp. holobionts. Aquaculture. 2026. vol. 613, Part 1, 743369. DOI: 10.1016/j.aquaculture.2025.743369}}
@misc{keuter_phosphorus_limitation_2026, 
author={Keuter, Sabine,Koplovitz, Gil,Ben Yehuda, Maayan,Klaiman, Sivan,Frada, Miguel J.},
title={Phosphorus limitation drives seasonal enlargement of the coccosphere size in two coccolithophores},
year={2026},
howpublished = {journal article},
doi = {https://doi.org/10.1002/lno.70323},
abstract = {Coccolithophores are abundant marine microalgae that produce a cell cover (coccosphere) composed of calcium carbonate platelets (coccoliths) and play a unique role in global carbon cycle. Gephyrocapsa huxleyi is the most prevalent coccolithophore in the oceans. Experiments in vitro indicate that the coccosphere size and coccolith length in G. huxleyi increase or decrease during phosphorus (P) or nitrogen (N) deprived growth, respectively. To test whether coccosphere size variations occur in native populations and relate to specific macronutrient availability, we examined communities in the Gulf of Aqaba (GoA) in the northern Red Sea and the Eastern Mediterranean Sea (EMS).  In the GoA, G. huxleyi coccospheres were in average larger during the stratified, oligotrophic season (~39.5 µm2), and they were in average smaller during the mesotrophic winter (~30.9 µm2), and also along the DCM and the subeuphotic zone during stratified periods (~31.9 µm2). A weak correlation was found between coccosphere size and coccolith length (attached to coccospheres as well as free coccoliths). Similar seasonal coccosphere size were detected for the sister species Gephyrocapsa ericsonii. Complementary bioassays indicate that during the stratified period, cells were primarily P-limited, while P or N limitation was absent or weak in winter. The seasonal pattern in G. huxleyi size was the opposite in the EMS. Larger coccospheres were detected in winter and smaller ones during summer. However, this pattern coincided with the prevalent patterns of inorganic macronutrient availability, supporting phosphorus limitation as a key driver for coccospheres size increase. Macronutrient availability is a major regulator of coccolithophore size in the oceans.},
note = {Online available at: \url{https://doi.org/10.1002/lno.70323} (DOI). Keuter, S.; Koplovitz, G.; Ben Yehuda, M.; Klaiman, S.; Frada, M.: Phosphorus limitation drives seasonal enlargement of the coccosphere size in two coccolithophores. Limnology and Oceanography. 2026. vol. 71, no. 1, e70323. DOI: 10.1002/lno.70323}}
@misc{heydtmann_polychaetes_as_2026, 
author={Heydtmann, Arne Valentin,von Waldthausen, Constanze,Keuter, Sabine,Kunzmann, Andreas,Stuthmann, Lara},
title={Polychaetes as aquaculture feed: feeding experiments and nutritional value analysis of Eurythoe spp.},
year={2026},
howpublished = {journal article},
doi = {https://doi.org/10.1007/s10499-025-02407-9},
abstract = {Aquaculture needs more environmentally friendly alternatives to fishmeal-based feed. Polychaetes could be part of a solution, since they are comparatively easy to cultivate. Eurythoe sp. and especially the species complex Eurythoe complanata is widely distributed across tropical coasts and aquaria. However, studies on the biology, needed for a targeted cultivation, are rare. In order to evaluate the species’ potential as an aquaculture species, an understanding especially of their feeding preferences and proximate composition, namely lipid, carbohydrate and protein content, is essential. Here, we present a—to the best of our knowledge—first adapted protocol to quantify lipid, carbohydrate and protein content in Eurythoe spp., as well as a comparison of female and male individuals of two species of the genus, referred to as spec. 1 (Eurythoe cf. complanata) and spec. 2 (Eurythoe sp.). Overall, the values of the lipid content ranged between 7 and 13% of the dry weight (DW) with the male polychaetes of spec. 1 showing lower lipid concentrations compared to the other species. Additionally, the male polychaetes showed higher carbohydrate levels than females or individuals of the other species. Carbohydrate concentrations between 3 and 10% DW were measured. The protein content of all specimens was between 27 and 37% DW. A 90-day feeding experiment revealed highest specific growth rates (SGR) of the group fed with a control of pellets, compared to algae commercially available as fish feed and spinach. Spontaneous fragmentation, known as a form of asexual reproduction among annelids, occurred over the experimental run. Despite the revealed high potential as a feed source for aquaculture purposes, more detailed investigations are necessary, especially regarding the targeted feeding and potential complications due to their venom.},
note = {Online available at: \url{https://doi.org/10.1007/s10499-025-02407-9} (DOI). Heydtmann, A.; von Waldthausen, C.; Keuter, S.; Kunzmann, A.; Stuthmann, L.: Polychaetes as aquaculture feed: feeding experiments and nutritional value analysis of Eurythoe spp.. Aquaculture International. 2026. vol. 34, no. 1, 15. DOI: 10.1007/s10499-025-02407-9}}
@misc{russnak_the_elbe_2025, 
author={Russnak, Vanessa,Sanders, Tina,Keuter, Sabine,Koll, Raphael,Dähnke, Kirstin},
title={The Elbe Estuary microbiome shifts with salinity and discharge and depends on fresh organic matter and nutrient availability},
year={2025},
howpublished = {journal article},
doi = {https://doi.org/10.1111/1758-2229.70349},
abstract = {The Elbe Estuary (Germany) stretches 142 km from the weir in Geesthacht to the North Sea. It is classified as mesotidal, partially mixed and heavily impacted by anthropogenic activities and modifications. Despite well-documented changes in ecosystem status, little is known about the microbial community in its surface water. In this study, we used 16S rDNA sequencing to characterize bacterial communities in surface water of the Elbe Estuary. Samples were collected across three seasons (winter, spring, and summer) in 2021 and 2022, to assess the relationship between environmental factors and bacterial community structure. Our analyses revealed that bacterial community diversity and composition varied seasonally and along the estuary stretch and were closely linked to physicochemical properties. Alpha diversity was highest in winter and in oligohaline samples. Distance based redundancy analysis showed that salinity, discharge, temperature, inorganic nitrogen (NO2), and silicate are key factors in shaping the bacterial community compositions. Although spatial differences were observed, seasonal variation was the main determinant of bacterial diversity and community structure. Overall, our results show that anthropogenic pressures and seasonal changes are reflected in a dynamic microbial community with metabolic functions strongly shaped by human activity.},
note = {Online available at: \url{https://doi.org/10.1111/1758-2229.70349} (DOI). Russnak, V.; Sanders, T.; Keuter, S.; Koll, R.; Dähnke, K.: The Elbe Estuary microbiome shifts with salinity and discharge and depends on fresh organic matter and nutrient availability. Environmental Microbiology Reports. 2025. vol. 18, no. 3, e70349. DOI: 10.1111/1758-2229.70349}}