Limnology and Oceanography Letters最新文献

Light affects the cellular iron (Fe) requirement of phytoplankton because of its presence in major photosynthetic proteins. Thus, interactions between variable Fe concentrations and light intensities could restrict photosynthetic carbon fixation in the ocean. Here we show a narrowing of the optimal light range for growth of a marine cyanobacterium, Prochlorococcus strain NATL1A, a member of LLI ecotype, under Fe limitation. The response of the cells to variations in Fe and light involved differential changes in the cellular content of low-Fe photosystem II (PSII) and Fe-rich photosystem I (PSI), and associated up to 23-fold changes in PSII : PSI ratios, showing an unprecedented extreme plasticity of the photosynthetic apparatus. Our study demonstrated the physiological effects of Fe and light interactions on this low-light-adapted Prochlorococcus strain, and increases our understanding of the reasons for the wide distribution of this and possibly other Prochlorococcus strains in the ocean.

Studies investigating gene flow in sessile or sedentary marine species typically draw conclusions about larval dispersal by investigating genetic structure of adults. Here, we generated microsatellite data from adults, recruits, settlers and planktonic larvae of the brown mussel, Perna perna, from the southeast coast of South Africa, and identified a consistent mismatch in genetic structure between the adults and all earlier life stages. While adults could be assigned to two major geographical groups (western and eastern), most of the early-stage mussels were strongly affiliated with the eastern group. This suggests that few of the early-stage individuals present in the western portion of the sampling range will eventually establish themselves in the adult population, highlighting the importance of post-recruitment processes as drivers of population structure. Our findings caution against the exclusive use of genetic data generated from adults to assess population connectivity facilitated by the dispersal of planktonic propagules.

Wilson, S. J., and others. 2024. Global subterranean estuaries modify groundwater nutrient loading to the ocean. Limnol. Oceanogr.: Lett. 9: 411–422. doi:10.1002/lol2.10390.

In the author affiliation section, the first and third affiliation for the co-author “Michael Ernst Böttcher” have been revised to “Geochemistry & Isotope Biogeochemistry, Leibniz Institute for Baltic Sea Research, Warnemünde, Germany” and “Interdisciplinary Faculty, University of Rostock, Rostock, Germany.” The second affiliation has no changes and it has been left as it was stated originally in this article when it was first published online.

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The impacts of climate change on Arctic marine systems are noticeable within the scientific “lifetime” of most researchers and the iconic image of a polar bear struggling to stay on top of a melting ice floe captures many of the dominant themes of Arctic marine ecosystem change. But has our focus on open-ocean systems and parameters that are more easily modeled and sensed remotely neglected an element that is responding more dramatically and with broader implications for Arctic ecosystems? We argue that a complementary set of changes to the open ocean is occurring along Arctic coasts, amplified by the interaction with changes on land and in the sea. We observe an increased number of ecosystem drivers with larger implications for the ecological and human communities they touch than are quantifiable in the open Arctic Ocean. Substantial knowledge gaps exist that must be filled to support adaptation and sustainability of socioecological systems along Arctic coasts.

Biomass estimates are crucial for modeling and understanding energy flow through ecosystems. Many modeling frameworks rely on published body weights of organisms to convert density estimates to biomass. However, published body weight data are limited to few taxa in a limited number of systems. Here we present mean individual weights for common benthic macroinvertebrates of the Laurentian Great Lakes from over 2000 benthic samples and 8 yr of data collection. We also compiled wet to dry weight conversions to facilitate data reuse for researchers interested in dry weight. We compared our benthic invertebrate weights to other lakes, demonstrating when weight measurements may be applied outside the Great Lakes. Sensitivity analyses supported the robustness of our calculations. Our dataset is applicable to food web energy flow models, calculation of secondary production, interpretation of trophic markers, and for understanding how biomass distribution varies by benthic invertebrate species in the Great Lakes.

Coastal lagoons are important nutrient filters and carbon sinks but may release large amounts of methane (CH₄) to the atmosphere. Here, we hypothesize that eutrophication and population density will turn coastal lagoons into stronger methane emitters. We report benthic fluxes from 187 sediment cores incubated from three of the largest European lagoons suffering persistent eutrophication. Methane fluxes were mainly driven by sediment porosity, organic matter, and dissolved inorganic carbon (DIC) fluxes. Methane was always supersaturated (250–49,000%) in lagoon waters leading to large, variable emissions of 0.04–26 mg CH₄ m⁻² d⁻¹. Combining our new dataset with earlier estimates revealed a global coastal lagoon emission of 7.9 (1.4–34.7) Tg CH₄ yr⁻¹ with median values of 5.4 mg CH₄ m⁻² d⁻¹. Lagoons with very highly populated catchments released much more methane (223 mg CH₄ m⁻² d⁻¹). Overall, projected increases in eutrophication, organic loading and population densities will enhance methane fluxes from lagoons worldwide.

Marine microbes are strongly interrelated to trace metals in the ocean. How the availability of trace metals selects for prokaryotic taxa and the potential feedback of microbial processes on the trace metal distribution in the ocean remain poorly understood. We investigate here the potential reciprocal links between diverse prokaryotic taxa and iron (Fe), manganese (Mn), copper (Cu), and nickel (Ni) as well as apparent oxygen utilization (AOU) across 12 well-defined water masses in the Southern Indian Ocean (SWINGS—South West Indian Ocean GEOTRACES GS02 Section cruise). Applying partial least square regression (PLSR) analysis, we show that the water masses are associated with particular latent vectors that are a combination of the spatial distribution of prokaryotic taxa, trace elements, and AOU. This approach provides novel insights on the potential interactions between prokaryotic taxa and trace metals in relation to organic matter remineralization in distinct water masses of the ocean.