scholarly journals Protist communities along freshwater–marine transition zones in Hudson Bay (Canada)

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Loïc Jacquemot ◽  
Dimitri Kalenitchenko ◽  
Lisa C. Matthes ◽  
Adrien Vigneron ◽  
Christopher J. Mundy ◽  
...  
Keyword(s):  
River System ◽  
Amplicon Sequencing ◽  
Estuarine Circulation ◽  
Nutrient Concentrations ◽  
Hudson Bay ◽  
Transition Zones ◽  
Microbial Eukaryote ◽  
Microbial Eukaryotes ◽  
Species Overlap ◽  
Three Rivers

One of the most striking ecological divides on Earth is between marine and nearby freshwater environments, as relatively few taxa can move between the two. Microbial eukaryotes contribute to biogeochemical and energy cycling in both fresh and marine waters, with little species overlap between the two ecosystems. Arctic and sub-Arctic marine systems are relatively fresh compared to tropical and temperate systems, but details of microbial eukaryote communities along river-to-sea transitions are poorly known. To bridge this knowledge gap, we investigated three river-to-sea transitions (Nelson, Churchill, and Great Whale Rivers) in sub-Arctic Hudson Bay through 18S rRNA amplicon sequencing to identify microbial eukaryotes along the salinity and biogeochemical gradients. Salinity acted as the principal dispersal barrier preventing freshwater microorganisms from colonizing marine coastal waters, with microbial eukaryote communities of the three rivers clustering together. Just offshore, communities clustered by coastal regions associated with nutrient concentrations. Analysis of indicator species revealed that communities in the nitrate-depleted coastal water off the Churchill and Great Whale Rivers were dominated by heterotrophic taxa and small photosynthetic protists. In contrast, the Nelson offshore community was characterized by a high proportion of the diatom Rhizosolenia. A distinct community of heterotrophic protists was identified in the three estuarine transition zones, suggesting specialized estuarine communities. Such specialization was most marked in the Nelson River system that was sampled more intensely and showed estuarine circulation. The autochthonous community was composed of the bacterial grazers Katablepharis, Mataza, and Cryothecomonas, as well as brackish species of the diatoms Skeletonema and Thalassiosira. These findings suggest that flow regulation on the Nelson River that modifies estuarine circulation would affect estuarine community composition and distribution in the transition zone.

Temporal variation of larval fish assemblages of the Murray Mouth in prolonged drought conditions

2013 ◽  
Vol 64 (10) ◽  
pp. 932 ◽  
Author(s):  
L. B. Bucater ◽  
J. P. Livore ◽  
C. J. Noell ◽  
Q. Ye
Keyword(s):  
Fish Assemblages ◽  
Larval Fish ◽  
River System ◽  
Sampling Period ◽  
Marine Species ◽  
Flow Regulation ◽  
Nursery Areas ◽  
Transition Zones ◽  
Murray Darling Basin ◽  
Drought Conditions

Estuaries are transition zones that link freshwater and marine ecosystems and are often used as nursery areas by fish. The Murray–Darling Basin, which is heavily affected by flow regulation and water extraction, is the largest river system in Australia and terminates at the Murray Mouth estuary. Protracted drought conditions resulted in extremely low flows to the Murray Mouth that affected water condition, fish abundance, community structure and fish use of the estuary (e.g. nursery areas). The aims of the present study were to examine temporal changes in larval fish assemblages in this estuary. The assemblages were dominated by two gobiid species, Arenigobius bifrenatus and Tasmanogobius lasti. There was a noticeable absence or low abundance of freshwater, diadramous and large-bodied marine species that use this estuary for reproductive functions. Monthly differences in larval fish assemblages, between August–September and October–November, were attributed to increases in the abundances of A. bifrenatus in October and November and oscillation in T. lasti during the entire sampling period. The outcomes of the present study suggested that larval fish assemblages in drought conditions are limited to small-bodied species tolerant of high salinities and that freshwater flows are needed for the estuary to function as a nursery for other species.

New Complexities in Zoogeography and Taxonomy of the Pygmy Whitefish (Prosopium coulteri)

1972 ◽  
Vol 29 (12) ◽  
pp. 1772-1775 ◽  
Author(s):  
C. C. Lindsey ◽  
W. G. Franzin
Keyword(s):  
River System ◽  
Yukon Territory ◽  
Hudson Bay ◽  
The South ◽  
Bristol Bay ◽  
River Drainage ◽  
Bay Area ◽  
First Time ◽  
Mackenzie River

Pygmy whitefish (Prosopium coulteri) are recorded for the first time from the Peel–Mackenzie river drainage (Elliott Lake, Yukon Territory) and from the Hudson Bay drainage (Waterton Lakes, Alberta, in the South Saskatchewan–Nelson river system). The morphology of specimens from both localities contradicts the previously known pattern of a southeastern "low-rakered" and a northwestern "high-rakered" form (with the two forms occurring sympatrically in some lakes of the Bristol Bay area). Specimens from Elliott Lake, the most northerly known locality, resemble the southeastern form and those from Waterton Lakes the northwestern form. Both Waterton and Elliott lakes lie close to unglaciated refugia, suggesting that the species may have survived Wisconsin glaciation and diverged in several different watersheds.

New crayfish species records from the Sipsey Fork drainage, including Lewis Smith Reservoir (Alabama, USA): native or introduced species?

2015 ◽  
Vol 21 (1) ◽  
pp. 17-32
Author(s):  
Susan B. Adams ◽  
Craig Roghair ◽  
Colin Krause ◽  
Melvin L. Warren ◽  
J. Allison Cochran ◽  
...  
Keyword(s):  
Introduced Species ◽  
Native Species ◽  
River System ◽  
Orconectes Virilis ◽  
Transition Zones ◽  
Intestinal Contents ◽  
Black Bass ◽  
Community Changes ◽  
Black Warrior River ◽  
Crayfish Species

Abstract As part of a study of aquatic faunal community changes along riverine-lacustrine transition zones upstream of Lewis Smith Reservoir in northwest Alabama, USA, we collected crayfish from 60 sites in the Sipsey Fork, Brushy Creek, and selected tributaries (Black Warrior River system). After finding two unexpected and possibly-introduced crayfish species, we expanded our investigation of crayfish distributions to include crayfish obtained from stomachs of black bass (Micropterus spp.) caught at seven sites in the reservoir. To explore what crayfish species were in the drainage historically, we examined museum databases as well as stomach and intestinal contents of a variety of preserved fishes that were caught in the Sipsey Fork and Brushy Creek drainages upstream of the reservoir in the early 1990’s. Of the seven crayfish species collected, one, Orconectes (Procericambarus) sp. nr ronaldi, was not previously reported from Alabama, and another, O. lancifer, was not reported from the Black Warrior River system prior to the study. Three are known or possibly introduced species. Upstream of the reservoir, the native species Cambarus obstipus, C. striatus, and O. validus were common. The same three species were found in fish collected in the 1990’s. Orconectes perfectus was found only in the reservoir but may be native to the drainage. Orconectes lancifer was in the reservoir and in stream reaches influenced by the reservoir. Evidence points to O. lancifer being introduced in the drainage, but this is uncertain. Orconectes sp. nr ronaldi was found in a relatively small portion of Brushy Creek and its tributaries, in both flowing and impounded habitats, and may be introduced. Orconectes virilis is introduced in Alabama and was found only in stomachs of fish collected in the reservoir.

scholarly journals Forecasting the discharge into Hoa Binh reservoir by applying the connecting model marine - imech1D

2008 ◽  
Vol 30 (3) ◽  
Author(s):  
Nguyen Tien Cuong ◽  
Trinh Thu Phuong
Keyword(s):  
Hydrological Model ◽  
River System ◽  
The Other ◽  
Hydrological Models ◽  
Flood Season ◽  
The Difference ◽  
Three Rivers ◽  
Hoa Binh

Da river is the biggest one of three rivers: Da, Thao and Lo which flow into Hong river, so calculating and forecasting correctly the discharge to Hoa Binh reservoir take an important role in managing the task of flood preventing in the Hong - Thai Binh river system. In this paper, a connected hydraulic-hydrological model is developed. The model was applied to forecast the discharge into Hoa Binh reservoir in the flood season 2006. The difference of this connected hydraulic-hydrological model in comparison with the other hydrological models is using the complete Saint-Venant 1D to simulate flow in rivers. Results of verification of the model show that it is good enough for practice.

scholarly journals Historical distribution records and new records confirm and extend the distribution of the Silver Lamprey, Ichthyomyzon unicuspis, in the Hayes River, Hudson Bay watershed, Manitoba

2013 ◽  
Vol 127 (3) ◽  
pp. 262
Author(s):  
J. David Tyson ◽  
Douglas A. Watkinson
Keyword(s):  
New Records ◽  
River System ◽  
Hudson Bay ◽  
Historical Records ◽  
James Bay ◽  
Historical Distribution

We reviewed historical records and observations of the Silver Lamprey (Ichthyomyzon unicuspis) in the Hayes River in the Hudson Bay watershed. New records are presented from the Seeber River in the upper Hayes River system that extend the distribution of the Silver Lamprey in northern Manitoba. A new designatable unit for the Silver Lamprey, the Southern Hudson Bay–James Bay, is proposed.

Reach- and mat-scale differences in Microcoleus autumnalis (cyanobacterium) accrual along velocity and nitrate gradients in three New Zealand rivers

2020 ◽  
Vol 77 (2) ◽  
pp. 401-412
Author(s):  
Tara G. McAllister ◽  
Susanna A. Wood ◽  
Emma M. MacKenzie ◽  
Ian Hawes
Keyword(s):  
Shear Stress ◽  
New Zealand ◽  
High Velocity ◽  
Grazing Pressure ◽  
Nutrient Concentrations ◽  
Intermediate Water ◽  
Scale Cover ◽  
Three Rivers ◽  
Nutrient Conditions

Proliferations of the toxic, mat-forming cyanobacterium Microcoleus autumnalis are an increasingly recognized problem in cobble-bed rivers worldwide. This study explored how flow and nutrient concentrations influence mat expansion. Microcoleus autumnalis was inoculated into cobbles placed in runs, riffles, and pools in three rivers with different nutrient conditions, and mat size was monitored over 21 days. The following hypotheses were tested: (i) mat expansion will reflect cover increases at the reach scale; (ii) biomass and cover will be highest in high-velocity habitats; and (iii) under similar velocities, nutrient concentrations will be more important than other abiotic and biotic variables in determining expansion rates. Mat expansion accurately reflected the increase in reach-scale cover, and expansion was most rapid at intermediate water velocities (0.25–0.45 m·s–1). Mats persisted the longest in riffles. Accrual cycles were terminated earlier in runs than in riffles, as high expansion rates resulted in patches reaching maximum mat size rapidly. Although M. autumnalis accrual differed among rivers, this was attributed to differences in shear stress and grazing pressure rather than nutrient concentrations.

Late-summer distribution of phytoplankton in relation to water mass characteristics in Hudson Bay and Hudson Strait (Canada)

1997 ◽  
Vol 54 (8) ◽  
pp. 1937-1952 ◽  
Author(s):  
M Harvey ◽  
J -C Therriault ◽  
N Simard
Keyword(s):  
Phytoplankton Biomass ◽  
Water Mass ◽  
Environmental Gradients ◽  
Late Summer ◽  
Tidal Mixing ◽  
Nutrient Concentrations ◽  
Hudson Bay ◽  
Phytoplankton Assemblage ◽  
Near Surface ◽  
Chl A

Descriptive and multivariate analytical methods were used to analyze the early September (1993) abundance and species composition of phytoplankton in relation to water mass characteristics in Hudson Bay and Hudson Strait. Four groups of stations distributed along well-defined environmental gradients characterizing the distribution of physical and chemical variables were identified. The first group, located in the most southern region of Hudson Bay, was strongly influenced by freshwater runoffs from James Bay and from the other major rivers around the bay and was characterized by a relatively high phytoplankton biomass (chlorophyll a (Chl a) > 1.0 µg ·L-1) in the near-surface waters and by a phytoplankton assemblage equally dominated by small flagellates and dinoflagellates. The second group, located in an area northwest of the Belcher and Sleeper islands, was characterized by relatively well-mixed conditions where small diatoms composed about 50% of the phytoplankton assemblage. The third group occupied the upper part of the bay and the entrance of the strait and was characterized by the lowest surface nutrient concentrations encountered. A clear subsurface chlorophyll maximum dominated by small flagellates (>55% of the assemblage) was observed in this region. The fourth group was located in the central part of the strait where the highest surface nutrient concentrations and phytoplankton biomass values (Chl a > 2.0 µg ·L-1) were observed. The phytoplankton assemblage there was clearly dominated by small diatoms (>80%). These conditions are related to the presence of more intense tidal mixing in this region. The phytoplankton standing crop within this area was comparable with that observed during an autumn bloom situation in most temperate regions of the world's ocean.

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