2021
Hood, James M.; Collis, Lyndsie M.; Schade, John D.; Stark, Rebecca A.; Finlay, Jacques C.
Longitudinal patterns and linkages in benthic fine particulate organic matter composition, respiration, and nutrient uptake Journal Article
In: Limnology and Oceanography, 2021.
Abstract | Links | BibTeX | Tags: benthic, fine particulate organic matter, microbial biomass, Nutrient Cycling, Stream Ecology
@article{Hood2021,
title = {Longitudinal patterns and linkages in benthic fine particulate organic matter composition, respiration, and nutrient uptake},
author = {James M. Hood and Lyndsie M. Collis and John D. Schade and Rebecca A. Stark and Jacques C. Finlay},
url = {https://aslopubs.onlinelibrary.wiley.com/doi/10.1002/lno.11781},
doi = {10.1002/lno.11781},
year = {2021},
date = {2021-05-01},
journal = {Limnology and Oceanography},
abstract = {Longitudinal changes in the structure and function of river ecosystems have long been recognized, yet our understanding of how such patterns shape elemental cycles remains limited. In particular, while benthic fine particulate organic matter (POM, 0.7–1000 μm) may control many stream nutrient cycles, less is known about longitudinal patterns or controls of benthic POM‐associated nutrient uptake. We conducted a survey of benthic POM‐associated respiration and nutrient uptake as well as microbial biomass (bacteria and algae) and benthic POM composition in four size classes (0.7–53 μm, 53–106 μm, 106–250 μm, and 250–1000 μm) in six streams in the forested South Fork Eel River watershed (California), encompassing a longitudinal gradient in light availability and primary production. Benthic POM at downstream sites was composed of smaller particles with lower organic matter content that were richer in nitrogen and autotrophic material. Areal respiration and nutrient uptake rates increased 11‐ to 67‐fold with stream size. While microbial activity rates did not increase with stream size, benthic POM‐associated microbial biomass increased 20‐fold with stream size, and closely tracked a 15‐fold increase in light availability, and primary production. Thus, microbial biomass, not activity, determined longitudinal patterns in benthic POM‐associated areal nutrient uptake and respiration rates. We attribute longitudinal patterns in microbial biomass to increases in light availability and primary production. Our findings help clarify the role of local (primary production) and upstream processes in shaping ecosystem structure and function.},
keywords = {benthic, fine particulate organic matter, microbial biomass, Nutrient Cycling, Stream Ecology},
pubstate = {published},
tppubtype = {article}
}
Longitudinal changes in the structure and function of river ecosystems have long been recognized, yet our understanding of how such patterns shape elemental cycles remains limited. In particular, while benthic fine particulate organic matter (POM, 0.7–1000 μm) may control many stream nutrient cycles, less is known about longitudinal patterns or controls of benthic POM‐associated nutrient uptake. We conducted a survey of benthic POM‐associated respiration and nutrient uptake as well as microbial biomass (bacteria and algae) and benthic POM composition in four size classes (0.7–53 μm, 53–106 μm, 106–250 μm, and 250–1000 μm) in six streams in the forested South Fork Eel River watershed (California), encompassing a longitudinal gradient in light availability and primary production. Benthic POM at downstream sites was composed of smaller particles with lower organic matter content that were richer in nitrogen and autotrophic material. Areal respiration and nutrient uptake rates increased 11‐ to 67‐fold with stream size. While microbial activity rates did not increase with stream size, benthic POM‐associated microbial biomass increased 20‐fold with stream size, and closely tracked a 15‐fold increase in light availability, and primary production. Thus, microbial biomass, not activity, determined longitudinal patterns in benthic POM‐associated areal nutrient uptake and respiration rates. We attribute longitudinal patterns in microbial biomass to increases in light availability and primary production. Our findings help clarify the role of local (primary production) and upstream processes in shaping ecosystem structure and function.
2006
McNeely, C.; Clinton, S. M.; Erbe, J. M.
Landscape variation in C sources of scraping primary consumers in streams Journal Article
In: Journal of the North American Benthological Society, vol. 25, no. 4, pp. 787-799, 2006.
Abstract | Links | BibTeX | Tags: carbon source, diet, drainage area, Eel River drainage, epilithon, fine particulate organic matter, food web, Glossosoma, Heptageniidae, scrapers, Stable carbon isotopes
@article{McNeely2006,
title = {Landscape variation in C sources of scraping primary consumers in streams},
author = {C. McNeely and S. M. Clinton and J. M. Erbe},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/McNeely_2006_Benth.pdf},
doi = {10.1899/0887-3593(2006)025[0787:LVICSO]2.0.CO;2},
year = {2006},
date = {2006-01-01},
journal = {Journal of the North American Benthological Society},
volume = {25},
number = {4},
pages = {787-799},
abstract = {We studied variation in C and energy flow in stream food webs by examining primary consumer diets and potential food sources at 8 sites of different drainage areas in the South Fork Eel River drainage. Both heptageniid mayfly nymphs and Glossosoma caddisfly larvae are considered scrapers in traditional functional feeding group classification, but past studies suggested that they differed in their relative use of terrestrial and algal C in some streams. In our study, microscopic examination and stable C isotope ratios (δ13C) suggested an increasing contribution of algae to both epilithic biofilms and fine particulate organic matter as stream drainage area and productivity increased. The proportion of algal cells in biofilms of small, unproductive streams was low, and biofilm δ13C values were similar to those of terrestrial detritus, suggesting that biofilms were composed primarily of heterotrophic microorganisms. Glossosoma larvae fed selectively on algae where it was scarce within the biofilms of small forested streams. In contrast, heptageniid mayfly nymphs did not appear to feed selectively on algae, but consumed algae and other materials in proportion to their abundance in the environment. These feeding patterns may have consequences for energy flow through food webs. Heptageniid mayflies feeding on biofilms in unproductive streams may augment the flow of dissolved organic C from terrestrial sources through food webs. In contrast, selective feeding by abundant Glossosoma larvae may reduce the flow of algal C through food webs because they are resistant to aquatic predators.},
keywords = {carbon source, diet, drainage area, Eel River drainage, epilithon, fine particulate organic matter, food web, Glossosoma, Heptageniidae, scrapers, Stable carbon isotopes},
pubstate = {published},
tppubtype = {article}
}
We studied variation in C and energy flow in stream food webs by examining primary consumer diets and potential food sources at 8 sites of different drainage areas in the South Fork Eel River drainage. Both heptageniid mayfly nymphs and Glossosoma caddisfly larvae are considered scrapers in traditional functional feeding group classification, but past studies suggested that they differed in their relative use of terrestrial and algal C in some streams. In our study, microscopic examination and stable C isotope ratios (δ13C) suggested an increasing contribution of algae to both epilithic biofilms and fine particulate organic matter as stream drainage area and productivity increased. The proportion of algal cells in biofilms of small, unproductive streams was low, and biofilm δ13C values were similar to those of terrestrial detritus, suggesting that biofilms were composed primarily of heterotrophic microorganisms. Glossosoma larvae fed selectively on algae where it was scarce within the biofilms of small forested streams. In contrast, heptageniid mayfly nymphs did not appear to feed selectively on algae, but consumed algae and other materials in proportion to their abundance in the environment. These feeding patterns may have consequences for energy flow through food webs. Heptageniid mayflies feeding on biofilms in unproductive streams may augment the flow of dissolved organic C from terrestrial sources through food webs. In contrast, selective feeding by abundant Glossosoma larvae may reduce the flow of algal C through food webs because they are resistant to aquatic predators.