skip to main content

Explore Research Products in the NSF-PAR

Title: Natural and synthetic microfibers alter growth and behavior in early life stages of estuarine organisms
Increasing shares of microfibers are being detected in environmental samples and a closer look to identify the risk associated with them using ecologically relevant endpoints, especially at sensitive early life stages, is needed. To assess exposure hazards, we used rope samples representative of fiber types ubiquitous in coastal systems, where microfibers are often the most common debris type found in the water column. To compare responses to natural vs. synthetic microfibers, we used rinsed “natural” cotton, polyester, and polypropylene microfibers (80-150 µm length, 8-20 µm width) created from the rope. Larval and juvenile estuarine indicator species Inland Silverside (Menidia beryllina) and mysid shrimp (Americamysis bahia) , respectively, were exposed to these three microfiber types at three concentrations (3, 10, 30 particles/ml) along a 5-25 PSU salinity gradient to mimic estuarine conditions. Behavioral responses, growth, and ingestion were measured. The cotton microfibers were not detected in the digestive tracts of Silversides, however, both the polyester and polypropylene microfibers were detected in the Silversides’ stomach and gut lining. None of the fiber types were detected in mysid shrimps. Mysids exposed to cotton microfibers had fewer behavioral effects compared to Silversides, who responded more to cotton. Cotton exerted no effect on growth in Silversides but did cause reduced growth in the mysids at the two lower salinities. In contrast, polyester and polypropylene were identified to have a significant dose dependent effect on mysid and Silverside behavior as well as growth was affected in at least one of the three salinities at concentrations as low as 3 particles/ml. Cotton impacted both the organism’s behavior more at higher salinities, whereas polyester and polypropylene had more impacts at lower salinities. This raises concerns for microfiber impacts on estuarine ecosystems and the need for policies to limit microfiber production and outfall into the aquatic environment.  more » « less
Award ID(s):
1935028
NSF-PAR ID:
10459063
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
Frontiers in Marine Science
Volume:
9
ISSN:
2296-7745
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ( , Limnology and Oceanography Letters)
    Abstract

    Microplastics are ubiquitous in marine systems; however, knowledge of the effects of these particles on marine fauna is limited. Ocean‐borne plastic debris accumulates in littoral ecosystems worldwide, and invertebrate infauna inhabiting these systems can ingest small plastic particles and fibers, mistaking them for food. We examined the effect of microplastic fibers on physiological and reproductive outcomes in a nearshore organism by exposing Pacific mole crabs (Emerita analoga) to environmentally relevant concentrations of microsized polypropylene rope fibers. We compared adult gravid female crab mortality, reproductive success, and embryonic developmental rates between microfiber‐exposed and control crabs. Pacific mole crabs exposed to polypropylene rope had increased adult crab mortality, and decreased retention of egg clutches, causing variability in embryonic development rates. These effects of microplastic ingestion on a nearshore prey species have implications for predators such as surf perf and shore birds, as plastic use, and resultant microplastic presence in nearshore environments increases. Microplastics are ubiquitous in marine and sandy beach environments, posing a significant threat to the marine organisms that reside therein. The most predominant classification of microplastics found have been microfibers. Although a number of biological effects of microplastics have been measured, with documented effects on growth, little research has examined how microplastic fibers affect reproductive output and subsequent development of offspring. We examined the effects of exposure to microfibers on adult mortality, reproductive output, and embryonic development of the filter feeding Pacific mole crab (E. analoga), a dominant infaunal organism on sandy beaches. We demonstrate the effects of microplastic ingestion on mole crab mortality and embryonic development, filling a gap in the current knowledge on the impact of microplastics.

     
    more » « less
  2. ; ; ; ( , Advanced Materials)
    Abstract

    Scaffold‐guided formation of neuronal‐like networks, especially under electrical stimulation, can be an appealing avenue toward functional restoration of injured nervous systems. Here, 3D conductive scaffolds are fabricated based on printed microfiber constructs using near‐field electrostatic printing (NFEP) and graphene oxide (GO) coating. Various microfiber patterns are obtained from poly(l‐lactic acid‐co‐caprolactone) (PLCL) using NFEP and complexity is achieved via modulating the fiber overlay angles (45°, 60°, 75°, 90°), fiber diameters (15 to 148 µm), and fiber spatial organization (spider web and tubular structure). Upon coating GO onto PLCL microfibers via a layer‐by‐layer (L‐b‐L) assembly technique and in situ reduction into reduced GO (rGO), the obtained conductive scaffolds, with 25–50 layers of rGO, demonstrate superior conductivity (≈0.95 S cm−1) and capability of inducing neuronal‐like network formation along the conductive microfibers under electrical stimulation (100–150 mV cm−1). Both electric field (0–150 mV cm−1) and microfiber diameter (17–150 µm) affect neurite outgrowth (PC‐12 cells and primary mouse hippocampal neurons) and the formation of orientated neuronal‐like networks. With further demonstration of such guidance to neuronal cells, these conductive scaffolds may see versatile applications in nerve regeneration and neural engineering.

     
    more » « less
  3. ; ; ; ; ; ; ; ; ( , Science Robotics)

    Fibers capable of generating axial contraction are commonly seen in nature and engineering applications. Despite the broad applications of fiber actuators, it is still very challenging to fabricate fiber actuators with combined large actuation strain, fast response speed, and high power density. Here, we report the fabrication of a liquid crystal elastomer (LCE) microfiber actuators using a facile electrospinning technique. Owing to the extremely small size of the LCE microfibers, they can generate large actuation strain (~60 percent) with a fast response speed (<0.2 second) and a high power density (400 watts per kilogram), resulting from the nematic-isotropic phase transition of liquid crystal mesogens. Moreover, no performance degradation is detected in the LCE microfibers after 106cycles of loading and unloading with the maximum strain of 20 percent at high temperature (90 degree Celsius). The small diameter of the LCE microfiber also results in a self-oscillatory behavior in a steady temperature field. In addition, with a polydopamine coating layer, the actuation of the electrospun LCE microfiber can be precisely and remotely controlled by a near-infrared laser through photothermal effect. Using the electrospun LCE microfiber actuator, we have successfully constructed a microtweezer, a microrobot, and a light-powered microfluidic pump.

     
    more » « less
  4. ; ; ; ; ; ; ; ( , Toxics)
    Changing salinity in estuaries due to sea level rise and altered rainfall patterns, as a result of climate change, has the potential to influence the interactions of aquatic pollutants as well as to alter their toxicity. From a chemical property point of view, ionic concentration can increase the octanol–water partition coefficient and thus decrease the water solubility of a compound. Biologically, organism physiology and enzyme metabolism are also altered at different salinities with implications for drug metabolism and toxic effects. This highlights the need to understand the influence of salinity on pesticide toxicity when assessing risk to estuarine and marine fishes, particularly considering that climate change is predicted to alter salinity regimes globally and many risk assessments and regulatory decisions are made using freshwater studies. Therefore, we exposed the Inland Silverside (Menidia beryllina) at an early life stage to seven commonly used pesticides at two salinities relevant to estuarine waters (5 PSU and 15 PSU). Triadimefon was the only compound to show a statistically significant increase in toxicity at the 15 PSU LC50. However, all compounds showed a decrease in LC50 values at the higher salinity, and all but one showed a decrease in the LC10 value. Many organisms rely on estuaries as nurseries and increased toxicity at higher salinities may mean that organisms in critical life stages of development are at risk of experiencing adverse, toxic effects. The differences in toxicity demonstrated here have important implications for organisms living within estuarine and marine ecosystems in the Anthropocene as climate change alters estuarine salinity regimes globally. 
    more » « less
  5. ; ; ; ( , Advanced Optical Materials)
    Abstract

    Partial laser treatment is introduced to carbon‐based microfibers to generate excellent photon sensing capability without bias. This treatment brings about a Seebeck coefficient distribution along the sample's length, out of which a photovoltage with no external bias is generated and sensed. Using a line‐shaped laser spot, carbon microfiber (CMF), graphene microfiber (GMF), and graphene aerogel fiber (GAF) are investigated for their response to µm‐scale photon irradiation. A higher sensitivity for the incident photon is found for the GAF with no position sensitivity. More Seebeck coefficient variation is also observed for the GAF considering the amount of laser power used for the laser treatment. A weaker Seebeck coefficient spatial variation is observed for the GMF compared with the GAF. However, its photovoltage shows an abrupt magnitude change from the laser‐treated region to the non‐treated one. Despite the low spatial variation of the Seebeck coefficient for the CMF, it features an excellent and accurate position‐sensitive photoresponse with polarization change over a distance of ≈100 µm. Such unique capability prompts novel applications in using partially annealed CMF for sensing the position of optical beams at the microscale.

     
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email