Heili Lowman

Duke University | DU · Department of Biology

Streams and river ecosystems contribute to global carbon cycle via collecting, storing, transforming and producing organic matter. The general paradigm is that most stream ecosystems are heterotrophic, respiring more carbon than they produce, nonetheless, many streams are autotrophic for some time, and a few may autotrophic on an annual scale. Peri...

Modeling and sensor innovations in the last decade have enabled routine and continuous estimation of daily gross primary productivity (GPP) for rivers. Here, we generate and evaluate within and across year variability for 59 US rivers for which we have compiled a 14‐yr time series of daily GPP estimates. River productivity varied widely across (med...

Increased occurrence, size, and intensity of fire result in significant but variable changes to hydrology and material retention in watersheds with concomitant effects on stream biogeochemistry. In arid regions, seasonal and episodic precipitation results in intermittency in flows connecting watersheds to recipient streams that can delay the effect...

River ecosystem function depends on flow regimes that are increasingly modified by changes in climate, land use, water extraction, and flow regulation. Given the wide range of variation in flow regime modifications and autotrophic communities in rivers, it has been challenging to predict which rivers will be more resilient to flow disturbances. To...

Synthesis research in ecology and environmental science improves understanding, advances theory, identifies research priorities, and supports management strategies by linking data, ideas, and tools. Accelerating environmental challenges increases the need to focus synthesis science on the most pressing questions. To leverage input from the broader...

We examined the distribution and processing of terrestrial organic material, derived from the disposal of material from a massive debris flow event following a major wildfire in a coastal California (USA) catchment in intertidal and nearshore subtidal marine sediments. Organic matter biomarkers, pyrogenic carbon and lignin phenols, were used to tra...

Throughout the past decade, many studies have reported adverse effects in biota following microplastic exposure. Yet, the field is still emerging as the current understanding of microplastic toxicity is limited. At the same time, recent legislative mandates have required environmental regulators to devise strategies to mitigate microplastic polluti...

Watersheds are often degraded by human activities, reducing their ability to provide ecosystem functions and services. While governmental agencies have put forward plans for improving watershed health, resources are limited, and choices must be made as to which watersheds to prioritize and what actions to take. Prioritization tools with sufficient...

Giant kelp Macrocystis pyrifera forms extensive forests on temperate reefs, providing habitat and food for a diversity of marine life. Kelp biomass varies in response to changing ocean temperatures, but physiological responses as reflected in the nutritional quality of kelp tissue are poorly understood. Over a 19-year period in southern California,...

Terrestrial organic matter (TOM) exported to nearshore marine regions may be altered by drought or large amounts of precipitation. We examined how significant precipitation in southern California during the winter seasons of 2015 and 2016, following a prolonged drought from 2011 to 2015, impacted the quantity and quality of TOM transported to nears...

Sandy beaches are widespread ecosystems that often sustain food webs with allochthonous subsidies of organic matter. We examined the contribution of intertidal talitrid amphipods, a dominant consumer of macroalgal wrack subsidies on sandy beaches in temperate zones, to the remineralization of wrack and resulting nutrient concentrations in intertida...

The Introduction to Sustainability course at the University of Iowa seeks to educate the aware, informed and action-oriented sustainable citizen. A phenomenographic analysis and retrospective pretest were utilized to determine how students formed conceptions of sustainability as a result of completing the course. The study indicated that student co...

The molecular structures of six small molecule organic compounds have been studied by X-ray diffraction in collaboration with undergraduate students enrolled in an advanced integrated laboratory course. The structures of 3-chloro-2-fluorobenzonitrile (1) [orthorhombic, P212121, a = 3.7679(13) Å, b = 12.546(4) Å, c = 13.780(5) Å], 5-chloro-2-fluorob...