scholarly journals Unique habitat and macroinvertebrate assemblage structures in spring-fed streams: a comparison among lowland tributaries and mainstreams in northern Japan

2020 ◽  
Author(s):  
Masaru Sakai ◽  
Katsuya Iwabuchi
Keyword(s):  
Primary Productivity ◽  
Standing Stock ◽  
Fine Sediment ◽  
River Networks ◽  
Canopy Openness ◽  
Macroinvertebrate Assemblage ◽  
Temperature Regimes ◽  
Periphyton Biomass ◽  
Stable Flow ◽  
Northern Japan

AbstractThe stable flow and temperature regimes of spring-fed streams are distinct from the dynamic regimes of other streams. We investigated differences in habitat and macroinvertebrate assemblages among a spring-fed tributary, an adjacent non-spring-fed tributary, and mainstream reaches. Current velocity was slowest in the spring-fed reach and percent fine sediment deposition was 3.8–13.9 times higher than in non-spring streams. Mean periphyton biomass was greatest in the mainstream reach where canopy openness was greatest, whereas the standing stock of detritus was greatest in the spring-fed reach. These results suggest that the stable flow regime in the spring-fed stream leads to the accumulation of fine sediment and detritus on the streambed. Oligochaeta and chironomids, which are burrower-gatherers, were remarkably abundant in the spring-fed reach and total macroinvertebrate abundance was 3.4–12.2 times greater than in the other reaches. Sprawler-grazer ephemeropterans were abundant in the mainstream reaches, likely due to higher primary productivity. Allomyia sp, which depend on cool spring-fed habitats, were found only in the spring-fed reach. The macroinvertebrate assemblage in the spring-fed reach was characterized by numerous burrowers, collector-gatherers, and crenobiont taxa, highlighting the contribution of these habitats to beta diversity in river networks.

Studies on a Calanus Patch II. The estimation of algal productive rates

1963 ◽  
Vol 43 (2) ◽  
pp. 339-347 ◽  
Author(s):  
D. H. Cushing
Keyword(s):  
Primary Productivity ◽  
Unit Volume ◽  
Standing Stock ◽  
Single Species ◽  
Algal Community ◽  
Division Rate ◽  
Common Experience ◽  
Unit Surface ◽  
The Common ◽  
Algal Material

Algal productive rates have rarely been estimated at sea, although many estimates have been made of primary productivity as g carbon/m2/day. A distinction may be drawn between productive rate and productivity, and it is in the use of the term ‘standing stock’. The latter is the quantity of living algal material per unit volume or beneath unit surface. The productive rate is the rate at which the standing stock reproduces itself; for a given species it is of course a division rate. It is expedient to use the term ‘division rate’ for a single species, but the term ‘productive rate’ may be used for the whole algal community. The productivity is the product of standing stock and productive rate and so contains in it the very great variations of standing stock that are the common experience of all planktologists.

Complex life under the McMurdo Ice Shelf, and some speculations on food webs

2019 ◽  
Vol 31 (2) ◽  
pp. 80-88 ◽  
Author(s):  
Stacy Kim
Keyword(s):  
Food Webs ◽  
Primary Productivity ◽  
Benthic Community ◽  
Open Water ◽  
Fine Sediment ◽  
Soft Corals ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Technological Limitations ◽  
Hard Substrates

AbstractHabitats under ice shelves are minimally explored, primarily because of technological limitations. These areas are separated from photosynthetic primary productivity by thick ice and distance to open water. Nevertheless, a diverse macrofaunal benthic community was discovered at 188 m depth, 80 km back from the edge of the McMurdo Ice Shelf. The general habitat was fine sediment with occasional dropstones, and dominant taxa were polychaetes and brittle stars, with alcyonacean soft corals and anemones on hard substrates. Gelatinous animals were abundant near the seafloor, and possibly part of a food web that supports the benthic community.

Open-Source, Low-Cost, In-Situ Turbidity Sensor for River Network Monitoring

2021 ◽  
Author(s):  
Jessica Droujko ◽  
Peter Molnar
Keyword(s):  
Suspended Sediment ◽  
Control Volume ◽  
Low Cost ◽  
Scattered Light ◽  
Fine Sediment ◽  
River Networks ◽  
Smart Water ◽  
Sediment Types ◽  
Wide Range ◽  
Global Biogeochemical Cycles

Abstract Fine sediment transport in rivers is important for catchment nutrient fluxes, global biogeochemical cycles, water quality and pollution in riverine, coastal and marine ecosystems. Monitoring of suspended sediment in rivers with current sensors is challenging and expensive and most monitoring setups are restricted to few single site measurements. To better understand the spatial heterogeneity of fine sediment sources and transport in river networks there is a need for new smart water turbidity sensing that is multi-site, accurate and affordable. In this work, we have created such a sensor, which detects scattered light from an LED source using two detectors in a control volume, and can be placed in a river. We compare several replicates of our sensor to different commercial turbidity probes in a mixing tank experiment using two sediment types over a wide range of typical concentrations observed in rivers. Our results show that we can achieve precise and reproducible turbidity measurements in the 0-4000 NTU or 0-16g/L range. Our sensor can also be used directly as a suspended sediment sensor and bypass an unnecessary calibration to Formazin. The developed turbidity sensor is much cheaper than existing options of comparable quality and is especially intended for distributed sensing across river networks.

Life history and environmental inference through retrospective morphometric analysis of bryozoans: a preliminary study

2000 ◽  
Vol 80 (6) ◽  
pp. 1127-1128 ◽  
Author(s):  
Aaron O'Dea ◽  
Beth Okamura
Keyword(s):  
Primary Productivity ◽  
Life Histories ◽  
Colony Growth ◽  
Bay Of Fundy ◽  
Seasonal Fluctuations ◽  
Temperature Regimes ◽  
Morphometric Analyses ◽  
Thermal Regimes ◽  
Preliminary Study ◽  
Flustra Foliacea

A preliminary comparative analysis of colony growth and zooid size in the perennial bryozoan Flustra foliacea (Bryozoa: Cheilostomatida) reveals reduced colony growth in the Bay of Fundy relative to growth in the Menai Straits and the Skagerrak, while seasonal fluctuations in zooid size are in synchrony with temperature regimes. Such retrospective morphometric analyses may allow inferences of primary productivity and thermal regimes and provide insights into the life histories of both Recent and fossil bryozoans.

scholarly journals Impacts of sediment derived from erosion of partially-constructed road on aquatic organisms in a tropical river: The Río San Juan, Nicaragua and Costa Rica

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242356
Author(s):  
Blanca Ríos Touma ◽  
G. Mathias Kondolf ◽  
Scott Walls
Keyword(s):  
Developing Countries ◽  
Aquatic Ecosystems ◽  
Aquatic Organisms ◽  
Economic Benefits ◽  
Fine Sediment ◽  
San Juan ◽  
The South ◽  
North Bank ◽  
Periphyton Biomass ◽  
Temperate Climates

Throughout the humid tropics, increased land disturbance and concomitant road construction increases erosion and sediment delivery to rivers. Building road networks in developing countries is commonly a priority for international development funding based on anticipated socio-economic benefits. Yet the resulting erosion from roads, which recent studies have shown result in at least ten-fold increases in erosion rates, is not fully accounted for. While effects of road-derived sediment on aquatic ecosystems have been documented in temperate climates, little has been published on the effects of road-induced sediment on aquatic ecosystems in developing countries of the tropics. We studied periphyton biomass and macroinvertebrate communities on the deltas of Río San Juan tributaries, comparing north-bank tributaries draining undisturbed rain forest with south-bank tributaries receiving runoff from a partially-built road experiencing rapid erosion. Periphyton biomass, richness and abundance of macroinvertebrates overall, and richness and abundance of Ephemeroptera, Plecoptera and Trichoptera were higher on the north-bank tributary deltas than the south-bank tributary deltas. These findings were consistent with prior studies in temperate climates showing detrimental effects of road-derived fine sediment on aquatic organisms. A Non-Metric Multidimensional Scaling (NMDS) analysis showed the impacted community on the south-bank deltas was influenced by poorly-sorted substrate with greater proportions of fine sediment and higher water temperatures.

scholarly journals Primary productivity below the seafloor at deep-sea hot springs

2018 ◽  
Vol 115 (26) ◽  
pp. 6756-6761 ◽  
Author(s):  
Jesse McNichol ◽  
Hryhoriy Stryhanyuk ◽  
Sean P. Sylva ◽  
François Thomas ◽  
Niculina Musat ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Deep Sea ◽  
Carbon Fixation ◽  
Hot Springs ◽  
Standing Stock ◽  
Deep Ocean ◽  
Rrna Gene ◽  
Geothermal Fluids ◽  
In Situ Conditions ◽  
Activity Measurements

Below the seafloor at deep-sea hot springs, mixing of geothermal fluids with seawater supports a potentially vast microbial ecosystem. Although the identity of subseafloor microorganisms is largely known, their effect on deep-ocean biogeochemical cycles cannot be predicted without quantitative measurements of their metabolic rates and growth efficiency. Here, we report on incubations of subseafloor fluids under in situ conditions that quantitatively constrain subseafloor primary productivity, biomass standing stock, and turnover time. Single-cell-based activity measurements and 16S rRNA-gene analysis showed thatCampylobacteriadominated carbon fixation and that oxygen concentration and temperature drove niche partitioning of closely related phylotypes. Our data reveal a very active subseafloor biosphere that fixes carbon at a rate of up to 321 μg C⋅L−1⋅d−1, turns over rapidly within tens of hours, rivals the productivity of chemosynthetic symbioses above the seafloor, and significantly influences deep-ocean biogeochemical cycling.

Impact of Effective Light Climate on Periphyton in the Nutrient Impacted River Ganges

2016 ◽  
Vol 2 (1 and 2) ◽  
pp. 59-68
Author(s):  
Usha Pandey ◽  
Jitendra Pandey
Keyword(s):  
Large Fraction ◽  
Light Attenuation ◽  
Standing Stock ◽  
Secchi Depth ◽  
Organic Load ◽  
Light Climate ◽  
Regulated Rivers ◽  
Periphyton Biomass ◽  
Assimilation Capacity ◽  
The Impact

Anthropogenic releases in large regulated rivers are overriding their organic load assimilation capacity and ability to rejuvenate. Effective light penetration in such water bodies are constrained by trade-off between organic load and benthic oxygen supply.We investigated the impact of light climate, as influenced by dissolved organic carbon (DOC) and phytoplankton shading effect, on periphyton biomass accrual in Ganges during summer low flows. Periphyton chlorophyll a decreased with increasing growth of phytoplankton and DOC. Periphyton biomass showed significant negative correlation with DOC (R2=0.9483; p less than 0.0001) and phytoplankton biomass (R2=0.9251; p less than 0.0001) and positive correlation with Secchi depth (R2=0.9506; p less than 0.0001). Among taxonomic divisions, Chlorophyta, with 24-60% of total standing stock, showed higher biomass at sites characterized by moderate nutrients and DOC levels. Cyanophyta (39-74%) contributed large fraction at eutrophic sites and Bacillariophyta (2-5%) at moderately eutrophic sites. Cyanophycean alga Phormidium appeared dominant at sites enriched in nutrients. The study indicated that light attenuation driven by DOC and phytoplankton is leading to erode benthic primary producers and redistribution of taxonomic divisions in Ganges, which may, by implication, entail a similar shift in the trophic cascades.

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