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To address how phytoplankton in the Great Lakes respond to macro- and micronutrients, we conducted a bottle incubation enrichment experiment using water collected from blooming (Maumee Bay and Fox River) and non-blooming sites (Detroit River and Ford River) in Lakes Erie and Michigan, respectively, during late summer. Surface water from these locations was collected and taken to Kent State University either via overnight shipping (Lake Michigan sites) or driven directly after collection (Lake Erie sites). Chlorophyll a (an index of overall biomass), community composition and toxicity were all measured as responses to treatments of labile inorganic nitrogen (N), phosphorus (P) and a mixture of micronutrients (chemical symbols: Fe, Mn, Mo, Ni, Zn). 

Metals are used in primary producer metabolic pathways, such as photosynthesis and the acquisition of macronutrients nitrogen (N) and phosphorus (P), yet we often do not know their potential as limiting nutrients in freshwaters. In the Great Lakes, metals have sometimes been identified as limiting the acquisition of macronutrients, mostly in off-shore waters that are relatively isolated from tributary inputs and sediment interactions. We hypothesized that another area where metals might be important was within harmful algal blooms (HABs). Harmful algal blooms are more likely to occur where N and P loads are elevated due to human activities, but short-term growth assays still often find summer bloom communities are N or P limited due to high biotic demand. This high biotic is associated with rapid nutrient recycling which may increase demand for trace metals beyond the available supply. A relatively common cyanotoxin (microcystin) has also been hypothesized to have a role in trace metal management, so trace metal demand may also influence the toxicity of bloom communities. Here, we used nutrient diffusing substrates to measure the magnitude of macronutrient and trace metal effects on growth and toxicity of biofilms suspended in 10 nearshore sites in Lake Michigan and Lake Erie (5 with and 5 without perennial HABs). We measured microcystin, chlorophyll a, ash free dry mass and community composition on the experimental biofilms. 

Abstract The paper examines relationships between stormwater control measure (SCM) priorities and environmental value orientations among stormwater managers in Cleveland, Ohio and Denver, Colorado, metro regions with contrasting environmental conditions and policy contexts. While studies show that governance explains differences in broad SCM priorities, less is known about what motivates individual “street level bureaucrats” who influence decisions at the project level. Drawing from cognitive social science perspectives, this study surveyed stormwater professionals (n = 185) about primary and co‐benefit SCM priorities and environmental value orientation. Results revealed different primary SCM priorities by region: Cleveland and Denver respondents prioritized quantity and quality goals, respectively, reflecting regional context. Co‐benefit priorities correlated to two environmental value orientation clusters — “Traditional Technocrats” with relatively anthropocentric orientations and “Champions” with relatively ecocentric orientations — who were equally abundant in both regions. Findings suggest that environmental value orientation influences co‐benefit priorities, which may have implications for project level articulation of policy. 

River ecosystems receive and process vast quantities of terrestrial organic carbon, the fate of which depends strongly on microbial activity. Variation in and controls of processing rates, however, are poorly characterized at the global scale. In response, we used a peer-sourced research network and a highly standardized carbon processing assay to conduct a global-scale field experiment in greater than 1000 river and riparian sites. We found that Earth’s biomes have distinct carbon processing signatures. Slow processing is evident across latitudes, whereas rapid rates are restricted to lower latitudes. Both the mean rate and variability decline with latitude, suggesting temperature constraints toward the poles and greater roles for other environmental drivers (e.g., nutrient loading) toward the equator. These results and data set the stage for unprecedented “next-generation biomonitoring” by establishing baselines to help quantify environmental impacts to the functioning of ecosystems at a global scale.