Effects of Environmental Disturbance on the Distribution and Primary Production of Benthic Algae on a British Columbia Estuary

1976 ◽  
Vol 33 (5) ◽  
pp. 1175-1187 ◽  
Author(s):  
W. M. Pomeroy ◽  
J. G. Stockner
Keyword(s):  
Primary Production ◽  
Dominant Species ◽  
Benthic Algae ◽  
Salinity Range ◽  
Low Light ◽  
Benthic Environment ◽  
River Training ◽  
Salinity Water ◽  
Species Being ◽  
Vaucheria Dichotoma

Construction of a river training dyke at Squamish, B.C., has resulted in strong salinity, water transparency, and sedimentation gradients across the estuary face which have significantly affected the distribution and primary production of benthic algae. The estuary west of the dyke is now a very unstable habitat for algal colonization and growth. During river freshet, heavy sedimentation and salinities less than 3‰ make algal survival difficult. At other times of the year, a salinity range of up to 25‰ is common over a tidal cycle. Algae in this area are generally strongly euryhaline, the dominant species being Enteromorpha minima, Rhizoclonium riparium, and Vaucheria dichotoma; mean production is 0.6 g Cm−2 day−1. The eastern portion of the estuary has a more stable benthic environment; lower sedimentation and higher salinity result in greater species diversity, biomass, and primary production. Dominant species are E. minima, Ulva lactuca, Pylaiella littoralis, and a variety of diatom communities. These algae tend to be weakly euryhaline, with optimum salinities between 15 and 30‰. Mean production is 2.2 g C m−2 day−1. Recent intrusion of Fucus vesiculosus strongly indicates that the eastern estuary is developing into a more marine habitat.Primary production of benthic algae is maintained by the wax and wane of low light and high light favoring species. Annual production estimates of 215 g C m−2 approximate those for estuaries at similar latitudes.

Net Primary Production and Carbon Stocks for Subarctic Mesic–Dry Tundras with Contrasting Microtopography, Altitude, and Dominant Species

Ecosystems ◽  
2009 ◽  
Vol 12 (5) ◽  
pp. 760-776 ◽  
Author(s):  
Matteo Campioli ◽  
Anders Michelsen ◽  
Andreas Demey ◽  
Annemie Vermeulen ◽  
Roeland Samson ◽  
...  
Keyword(s):  
Primary Production ◽  
Dominant Species ◽  
Net Primary Production ◽  
Carbon Stocks

Shark longline fishery of Papua New Guinea: size and species composition and spatial variation of the catches

2020 ◽  
Vol 71 (6) ◽  
pp. 627
Author(s):  
William T. White ◽  
Leontine Baje ◽  
Sharon A. Appleyard ◽  
Andrew Chin ◽  
Jonathan J. Smart ◽  
...  
Keyword(s):  
Papua New Guinea ◽  
Dominant Species ◽  
New Guinea ◽  
Species Level ◽  
Longline Fishery ◽  
Specific Identification ◽  
Level Information ◽  
Sea Area ◽  
Number Of Individuals ◽  
Species Being

This study provides the first detailed investigation of the catches of the shark longline fishery in Papua New Guinea. Fisheries observers collected data on shark catches from a total of 318 longline sets between May and June 2014, before its closure in July 2014. In all, 14694 sharks were recorded with a total estimated biomass of 439 tonnes (Mg). Eighteen species of sharks were recorded in the observer data, with the most dominant species being Carcharhinus falciformis, which constituted more than 90% of the total catches by both weight and number of individuals. The level of observer misidentification was low (<10%), which reflected the use of region-specific identification guides by well-trained fisheries observers. The most diverse catches were in the Solomon Sea area, whereas catches in most other areas, particularly the Bismarck Sea areas, were less diverse and more strongly dominated by C. falciformis. Size and sex ratios varied by species, highlighting the importance of obtaining species-level information from the fishery being investigated. Any consideration by fisheries managers to reopen this fishery needs to consider the effect this will have on the species targeted and the livelihoods of coastal fishers who also rely on the same resources.

scholarly journals Interannual and Seasonal Changes in the Benthic Algae Flora of Coral Reef in Xiaodong Hai (Hainan Island, China)

2019 ◽  
Vol 7 (8) ◽  
pp. 243
Author(s):  
Eduard A. Titlyanov ◽  
Tamara V. Titlyanova ◽  
Anna V. Scriptsova ◽  
Yuxiao Ren ◽  
Xiubao Li ◽  
...  
Keyword(s):  
Species Diversity ◽  
Seasonal Changes ◽  
Dominant Species ◽  
Benthic Algae ◽  
Hainan Island ◽  
Algal Turf ◽  
Macroalgal Species ◽  
Antarctic Waters ◽  
Maximum Similarity ◽  
The Tropics

Intensive algal sampling conducted in 2016–2019 in the Xiaodong Hai locality (Hainan Island, South China Sea), yielded a total of 198 benthic macroalgal species and their taxonomic forms (54% reds, 20% browns and 26% greens) and 20 species of Cyanobacteria. The largest number of species belonged to the families Rhodomelaceae, Ceramiaceae and Corallinaceae (Rhodophyta); Sargassaceae and Dictyotaceae (Phaeophyceae); Cladophoraceae and Caulerpaceae (Chlorophyta). The majority (79%) of species inhabiting only the tropics or subtropics were previously recorded and 21% of the species were also inhabiting temperate latitudes. Cosmopolitan algae inhabiting from the tropics to Arctic or Antarctic waters amounted to 14%. The level of maximum similarity of macroalgal species diversity in different years was on average more than 70%, interannual species specificity was observed only in the group of dominating species in algal turf communities. The seasonal variability of floras was manifested in a significant decrease in species diversity from the dry season to the rainy and in the change of dominant species in algal turf communities.

scholarly journals Interactive effects of temperature and light during deep convection: a case study on growth and condition of the diatom Thalassiosira weissflogii

2014 ◽  
Vol 72 (6) ◽  
pp. 2061-2071 ◽  
Author(s):  
B. Walter ◽  
J. Peters ◽  
J. E. E. van Beusekom ◽  
M. A. St. John
Keyword(s):  
Primary Production ◽  
Deep Convection ◽  
Growth Conditions ◽  
Interactive Effects ◽  
Light Conditions ◽  
Thalassiosira Weissflogii ◽  
Pulsed Light ◽  
Low Light ◽  
Chl A ◽  
The North

Abstract Aim of this study was to expose phytoplankton to growth conditions simulating deep winter convection in the North Atlantic and thereby to assess changes in physiology enabling their survival. Growth rate, biochemical composition, and photosynthetic activity of the diatom Thalassiosira weissflogii were determined under two different light scenarios over a temperature range of 5–15°C to simulate conditions experienced by cells during winter deep convection. These metrics were examined under a low light scenario (20 µmol m−2 s−1, 12/12 h light/dark), and compared with a scenario of short light pulses of a higher light intensity (120 µmol m−2 s−1, 2/22 h light/dark). Both experimental light conditions offered the same daily light dose. No growth was observed at temperatures below 8°C. Above 8°C, growth rates were significantly higher under low light conditions compared with those of short pulsed light exposures, indicating a higher efficiency of light utilization. This could be related to (i) a higher content of Chl a per cell in the low light trial and/or (ii) a more efficient transfer of light energy into growth as indicated by constantly low carbohydrate levels. In contrast, pulsed intense light led to an accumulation of carbohydrates, which were catabolized during the longer dark period for maintaining metabolism. Light curves measured via Chl a fluorescence indicated low light assimilation for the algae exposed to short pulsed light. We postulate that our trial with short light pluses did not provide sufficient light to reach full light saturation. In general, photosynthesis was more strongly affected by temperature under pulsed light than under low light conditions. Our results indicate that model estimates of primary production in relation to deep convection, which are based on average low light conditions, not considering vertical transportation of algae will lead to an overestimation of in situ primary production.

scholarly journals INVENTARISASI JENIS BURUNG PANTAI DI KAWASAN PULAU MARSEGU KABUPATEN SERAM BAGIAN BARAT PROVINSI MALUKU

2020 ◽  
Vol 8 (1) ◽  
pp. 16
Author(s):  
Billy Seipalla
Keyword(s):  
Food Availability ◽  
Human Activity ◽  
Dominant Species ◽  
Common Species ◽  
Island Region ◽  
Nature Tourism ◽  
Marine Tourism ◽  
The Government ◽  
Gathering Place ◽  
Species Being

This research was conducted on the island of Marsegu because this area is included in the area of the natural marine tourism park which should be the concern of the government and the community around the island. The study aimed to determine the species of shorebirds found in the Marsegu island region in the western part Seram. The study was conducted in the morning and evening for 2 days at the location which is a gathering place for shorebirds. In the study location, 8 species of shorebirds were found and then inventoried and identified. The number of shorebirds species found in the Marsegu island area was 8 species, among others; Coral egrets (Egratta sacra), Big Egrets (Egretta alba), Trinil Beach (Actitis hypoleucos), Little sea worms (Sterna albifrons), Black wing sea worms (Sterna fuscata), Big (Fregata minor), Sea-eagle belly white (Haliaetus leucogaster), Bondol Hawk (Indus Haliastur), with the dominant species being the Big Cingkalang (Fregata minor). The most common species are large Cikalang (minor Fregata), small sea virgin (Sterna albifrons), and large egret (Egretta alba). Factors that cause the survival of shorebirds on the Marsegu island region because they store a lot of food supplies. In addition, food availability is affected by a lack of human activity in this region and the establishment of this area as a Marine Nature Tourism Park.

Extended Fractional-Flow Model of Low-Salinity Waterflooding Accounting for Dispersion and Effective Salinity Range

SPE Journal ◽  
2019 ◽  
Vol 24 (06) ◽  
pp. 2874-2888 ◽  
Author(s):  
Hasan Al–Ibadi ◽  
Karl D. Stephen ◽  
Eric J. Mackay
Keyword(s):  
Relative Permeability ◽  
Flow Behavior ◽  
Flow Analysis ◽  
Salinity Range ◽  
Fractional Flow ◽  
Low Salinity ◽  
Low Salinity Water ◽  
Low Salinity Waterflooding ◽  
Salinity Water ◽  
The Impact

Summary Low–salinity waterflooding (LSWF) is an emergent technology developed to increase oil recovery. Laboratory–scale testing of this process is common, but modeling at the production scale is less well–reported. Various descriptions of the functional relationship between salinity and relative permeability have been presented in the literature, with respect to the differences in the effective salinity range over which the mechanisms occur. In this paper, we focus on these properties and their impact on fractional flow of LSWF at the reservoir scale. We present numerical observations that characterize flow behavior accounting for dispersion. We analyzed linear and nonlinear functions relating salinity to relative permeability and various effective salinity ranges using a numerical simulator. We analyzed the effect of numerical and physical dispersion of salinity on the velocity of the waterflood fronts as an expansion of fractional–flow theory, which normally assumes shock–like behavior of water and concentration fronts. We observed that dispersion of the salinity profile affects the fractional–flow behavior depending on the effective salinity range. The simulator solution is equal to analytical predictions from fractional–flow analysis when the midpoint of the effective salinity range lies between the formation and injected salinities. However, retardation behavior similar to the effect of adsorption occurs when these midpoint concentrations are not coincidental. This alters the velocities of high– and low–salinity water fronts. We derived an extended form of the fractional–flow analysis to include the impact of salinity dispersion. A new factor quantifies a physical or numerical retardation that occurs. We can now modify the effects that dispersion has on the breakthrough times of high– and low–salinity water fronts during LSWF. This improves predictive ability and also reduces the requirement for full simulation.

Primary Production

2001 ◽  
Author(s):  
William D. Bowman ◽  
Melany C. Fisk
Keyword(s):  
Primary Production ◽  
Temporal Variation ◽  
Dominant Species ◽  
Biological Diversity ◽  
Alpine Tundra ◽  
Spatial And Temporal Variation ◽  
Niwot Ridge ◽  
Continuous Plant ◽  
Environmental Causes ◽  
Underlying Mechanisms

The production of biomass by plants is of central importance to energy, carbon, and nutrient fluxes in ecosystems. Knowledge of the spatial and temporal variation of production and the underlying biotic and physical controls on this variation are central themes in ecosystem science. The goals of this chapter are to present the estimates of spatial patterns in above- and belowground production associated with the major community types found on Niwot Ridge and other alpine areas of the southern Rocky Mountains and to examine the likely environmental causes and underlying mechanisms responsible for spatial and temporal variation in production as elucidated by experimental and observational studies. Rates of primary production and standing crops of plant biomass are low in alpine tundra relative to other ecosystem types (Lieth and Whittaker 1975; Zak et al. 1994). However, within communities (i.e., at the plot level), there is large variation in rates of production, the degree of biotic control over response to environmental change, and the principal environmental constraints of primary production. As a result, the alpine is one of the most dynamic ecosystems for research. For example, there is a tenfold difference in annual aboveground production between the most and least productive sites with continuous plant cover on Niwot Ridge. In addition, the high plant diversity is a source of potential variation in physiological and developmental control of plant response to the environment. Dominant species include sedges, grasses, shrubs, and forbs, among which are N2-fixing Trifolium species. Nearly all of the dominant species may be mycorrhizal. Soil moisture, a driving force for many biotic processes, may vary by an order of magnitude between wet and dry sites following prolonged periods of drought. Thus the alpine tundra of Niwot Ridge, which might appear superficially homogeneous, in fact has complex physical and biotic gradients. This spatial variation prevents simple generalizations about single limiting resources or climatic driving forces determining spatial and temporal variation in productivity. Billings (1973) defined the mesotopographic gradient as a working unit for describing the alpine landscape, as it encompasses the full range of snow accumulation and associated microclimates and thus biological diversity.

scholarly journals Fertilization of an oligotrophic lake with a deep chlorophyll maximum: predicting the effect on primary productivity

1997 ◽  
Vol 54 (5) ◽  
pp. 1177-1189 ◽  
Author(s):  
H P Gross ◽  
W A Wurtsbaugh ◽  
C Luecke ◽  
P Budy
Keyword(s):  
Primary Production ◽  
Chlorophyll A ◽  
Primary Productivity ◽  
Sockeye Salmon ◽  
Deep Chlorophyll Maximum ◽  
Light Penetration ◽  
Low Light ◽  
Nutrient Additions ◽  
Light Levels ◽  
The Mean

We investigated how epilimnetic fertilization would affect chlorophyll levels and light penetration of oligotrophic sockeye salmon (Oncorhynchus nerka) lakes and how the resulting self-shading would affect primary production of the prominent deep chlorophyll maxima (DCM) of the lakes. Epilimnetic nutrient additions to large mesocosms (330 m3) in Redfish Lake, Idaho, increased levels of primary productivity and chlorophyll a but decreased Secchi depths and light available in the metalimnion and hypolimnion. Redfish Lake and other Sawtooth Valley (Idaho) lakes had DCM in which the mean chlorophyll a peaks were 240-1000% of mean epilimnetic chlorophyll a concentrations. The DCM existed at low light levels and accounted for 36-72% of the lakes' primary production. Simulations using photosynthesis-irradiance (P-I) curves demonstrated that fertilization would increase predicted water column primary production by 75-101%. Most of this increase occurred in the epilimnion, with only a slight decrease occurring in the DCM as the result of increased shading.

Benthic algae in littoral and profundal areas of a deep subarctic lake

1981 ◽  
Vol 59 (6) ◽  
pp. 1026-1033 ◽  
Author(s):  
James W. Moore
Keyword(s):  
Species Composition ◽  
Relative Abundance ◽  
Deep Water ◽  
Benthic Algae ◽  
Common Species ◽  
Low Light ◽  
Nitzschia Palea ◽  
Light Levels ◽  
Subarctic Lake ◽  
Achnanthes Minutissima

Collections of benthic algae were made in an isolated subarctic lake during July and August 1975. Samples were taken from 30 stations situated at depths of 0.1 to 35 m. The number of species associated with sediments declined with depth from 66 to 22 m. Achnanthes minutissima, Navicula pupula, Cymbella spp., and Nostoc pruniforme reached greatest relative abundance in shallow water whereas Nitzschia palea and Nitzschia dissipata were relatively common below 20 m. Amphora ovalis, Gyrosigma spenceri, and Tabellaria flocculosa did not exhibit a consistent distribution pattern. Standing crops of the epipelon ranged from3 × 106 cells cm−2 (8.5 × 10 μm3 cm−2) at a depth of 0.1–5 m to8 × 103 cells cm−2 (7 × 106 μm3 cm−2) below 20 m. Low light levels, and to a lesser degree, temperature were the most important factors influencing the diversity, species composition, and density of the epipelon in deep water.The epipsammic community consisted of 10 species at all depths. Although Achnanthes pinnata was rare in deep water, the relative abundance of other common species (Amphora ovalis var. pediculus, Fragilaria construens var. venter, and Achnanthes minutissima) was constant at all stations. Standing crops varied from 3.5 × 104 cells cm−2 (39 × 106 μm3 cm−2) at 0.1–5 m to0.3 × 104 cells cm−2 (0.3 × 106 μm3 cm−2) below 20 m. Although low light levels probably controlled densities in deep water, physical characteristics of the substrate determined the diversity and species composition of the community.

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