skip to main content

Search for: All records

Award ID contains: 1637630

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Abstract

    River networks regulate carbon and nutrient exchange between continents, atmosphere, and oceans. However, contributions of riverine processing are poorly constrained at continental scales. Scaling relationships of cumulative biogeochemical function with watershed size (allometric scaling) provide an approach for quantifying the contributions of fluvial networks in the Earth system. Here we show that allometric scaling of cumulative riverine function with watershed area ranges from linear to superlinear, with scaling exponents constrained by network shape, hydrological conditions, and biogeochemical process rates. Allometric scaling is superlinear for processes that are largely independent of substrate concentration (e.g., gross primary production) due to superlinear scaling of river network surface area with watershed area. Allometric scaling for typically substrate-limited processes (e.g., denitrification) is linear in river networks with high biogeochemical activity or low river discharge but becomes increasingly superlinear under lower biogeochemical activity or high discharge, conditions that are widely prevalent in river networks. The frequent occurrence of superlinear scaling indicates that biogeochemical activity in large rivers contributes disproportionately to the function of river networks in the Earth system.

  2. Free, publicly-accessible full text available October 18, 2023
  3. abstract Coastal ecosystems play a disproportionately large role in society, and climate change is altering their ecological structure and function, as well as their highly valued goods and services. In the present article, we review the results from decade-scale research on coastal ecosystems shaped by foundation species (e.g., coral reefs, kelp forests, coastal marshes, seagrass meadows, mangrove forests, barrier islands) to show how climate change is altering their ecological attributes and services. We demonstrate the value of site-based, long-term studies for quantifying the resilience of coastal systems to climate forcing, identifying thresholds that cause shifts in ecological state, and investigating the capacity of coastal ecosystems to adapt to climate change and the biological mechanisms that underlie it. We draw extensively from research conducted at coastal ecosystems studied by the US Long Term Ecological Research Network, where long-term, spatially extensive observational data are coupled with shorter-term mechanistic studies to understand the ecological consequences of climate change.
    Free, publicly-accessible full text available August 16, 2023
  4. Ghinassi, Massimiliano (Ed.)
    Free, publicly-accessible full text available June 1, 2023
  5. Abstract A parasite can change its host’s behavior in spectacular ways. When the saltmarsh amphipod Orchestia grillus (Bosc, 1802) is infected with the trematode Levinseniella byrdi (Heard, 1968) it is bright orange and is found in the open unlike uninfected individuals. I tested the hypothesis that infected amphipods are found in the open because L. byrdi reverses their innate photophobia. During daytime treatments and when placed in a dark chamber, 0% of the uninfected and 20% of the infected amphipods, on average, moved to the light chamber after 30 minutes. When placed in a light chamber, 91% of the uninfected and 53% of the infected amphipods, on average, went to the dark side after 30 minutes. These results clearly indicate that O. grillus is normally photophobic, but not drawn to light when infected with L. byrdi. Instead, L. byrdi appears to neutralize the amphipod’s photophobia. Uninfected O. grillus are typically found under vegetation. I hypothesize that O. grillus with L. byrdi infections wander into open, unvegetated habitats randomly. In addition, 94% of infected amphipods could be touched by a finger in the field suggesting they can be easily caught by predators. Levinseniella byrdi infects at least three other amphipod hosts,more »Chelorchestia forceps (Smith & Heard, 2001), Uhlorchestia spartinophila (Bousfield & Heard, 1986), and U. uhleri (Shoemaker, 1930). The parasite-manipulation hypothesis suggests that the parasite-induced changes (conspicuous body color and neutralized light response) are adaptive for L. byrdi to make amphipod hosts more susceptible to bird predators, the definitive hosts. This hypothesis remains to be tested.« less
    Free, publicly-accessible full text available June 1, 2023
  6. Free, publicly-accessible full text available May 1, 2023
  7. Free, publicly-accessible full text available April 1, 2023
  8. Free, publicly-accessible full text available March 28, 2023