Effect of Nutrient Additions on Lower Trophic Levels of an Oligotrophic Lake with a Seasonal Deep Chlorophyll Maximum

1990 ◽  
Vol 47 (2) ◽  
pp. 262-273 ◽  
Author(s):  
Ken S. Shortreed ◽  
John G. Stockner
Keyword(s):  
Inorganic Nitrogen ◽  
Euphotic Zone ◽  
Fold Increase ◽  
Trophic Levels ◽  
Deep Chlorophyll Maximum ◽  
Nitrogen And Phosphorus ◽  
Chlorophyll Maximum ◽  
Nutrient Additions ◽  
Prominent Component ◽  
Dominant Member

Inorganic nitrogen and phosphorus were added to the surface of selected areas of Sproat Lake, Vancouver Island, British Columbia for varying periods in 1985 and 1986. The lake is monomictic, oligotrophic, and for much of each year has a deep chlorophyll maximum (DCM) located near the bottom of the euphotic zone (20–25 m). Epilimnetic chlorophyll concentrations are low (ca. 0.5 μg∙L−1) in summer, and DCM concentrations are from three to 10 times higher. The diatom Rhizosolenia eriensis was a dominant species in the epilimnion in spring and at the DCM for much of the year, but was rare in the epilimnion during summer, and consequently was not affected by the nutrient additions. Cyclotella spp. were also abundant in spring, were a prominent component of the DCM, and increased in abundance during nutrient additions. The cyanobacterium Synechococcus was the dominant member of the autotrophic picoplankton community and during the nutrient additions densities reached 300 000∙mL−1 (a 10-fold increase). Bacterioplankton numbers also increased during nutrient additions, at times exceeding 3.0 × 106∙mL−1. The DCM was formed and maintained by sinking cells, by occasional active photosynthesis at the DCM, and by an increase in chlorophyll/cell.

scholarly journals Independent iron and light limitation in a low-light-adapted Prochlorococcus from the deep chlorophyll maximum

2020 ◽  
Vol 15 (1) ◽  
pp. 359-362
Author(s):  
Nicholas J. Hawco ◽  
Feixue Fu ◽  
Nina Yang ◽  
David A. Hutchins ◽  
Seth G. John
Keyword(s):  
Light Intensity ◽  
High Efficiency ◽  
Iron Concentration ◽  
Euphotic Zone ◽  
Theoretical Models ◽  
Light Limitation ◽  
Deep Chlorophyll Maximum ◽  
North Pacific Subtropical Gyre ◽  
Low Light ◽  
Chlorophyll Maximum

AbstractThroughout the open ocean, a minimum in dissolved iron concentration (dFe) overlaps with the deep chlorophyll maximum (DCM), which marks the lower limit of the euphotic zone. Maximizing light capture in these dim waters is expected to require upregulation of Fe-bearing photosystems, further depleting dFe and possibly leading to co-limitation by both iron and light. However, this effect has not been quantified for important phytoplankton groups like Prochlorococcus, which contributes most of the productivity in the oligotrophic DCM. Here, we present culture experiments with Prochlorococcus strain MIT1214, a member of the Low Light 1 ecotype isolated from the DCM in the North Pacific subtropical gyre. Under a matrix of iron and irradiance matching those found at the DCM, the ratio of Fe to carbon in Prochlorococcus MIT1214 cells ranged from 10–40 × 10−6 mol Fe:mol C and increased with light intensity and growth rate. These results challenge theoretical models predicting highest Fe:C at lowest light intensity, and are best explained by a large photosynthetic Fe demand that is not downregulated at higher light. To sustain primary production in the DCM with the rigid Fe requirements of low-light-adapted Prochlorococcus, dFe must be recycled rapidly and at high efficiency.

Contribution of Rhizosolenia eriensis and Cyclotella spp. to the Deep Chlorophyll Maximum of Sproat Lake, British Columbia, Canada

1990 ◽  
Vol 47 (1) ◽  
pp. 128-135 ◽  
Author(s):  
Leland J. Jackson ◽  
John G. Stockner ◽  
Paul J. Harrison
Keyword(s):  
Spatial Separation ◽  
Deep Chlorophyll Maximum ◽  
Nitrogen And Phosphorus ◽  
Low Light ◽  
Temporal And Spatial Distribution ◽  
Neutral Buoyancy ◽  
Chlorophyll Maximum ◽  
Centric Diatoms ◽  
Temporal And Spatial ◽  
Lake Fertilization

Experimental fertilization of Sproat Lake with nitrogen and phosphorus greatly increased the abundance of two centric diatoms: Cyclotella spp. and Rhizosolenia eriensis. A decrease in sinking rates to neutral buoyancy at 17.5–22.5 m, an area of high nutrients and low light, coupled with sedimentation estimates of 106–107 celis∙m−2∙d−1, provide strong evidence that diatoms contribute to the formation of a seasonal deep chlorophyll maximum (DCM). The position of the Sproat Lake DCM, occurring at or just above the 1% light depth, appears to be largely determined by the light regime. R. eriensis bloomed and sank out of the mixed layer early in the spring before lake fertilization began. Immediately after fertilization, concentrations of nitrate and phosphate were elevated for 1 h only in the top 1 m of the water column. Most R. eriensis cells were well below 1 m and benefited little from the nutrient addition because of temporal and spatial separation. Cyclotella spp. occurred in the upper epilimnion and bloomed later in the year and consequently benefited (by large density increases) from fertilization. It is important to consider the temporal and spatial distribution of phytoplankton in determining which species will increase in abundance as a result of areal fertilization.

Influence of added nutrient on the seasonal variation of algal growth potential of Mt Bold reservoir, South Australia

1982 ◽  
Vol 33 (3) ◽  
pp. 475 ◽  
Author(s):  
GG Ganf
Keyword(s):  
Algal Growth ◽  
South Australia ◽  
Euphotic Zone ◽  
Growth Potential ◽  
Nutrient Depletion ◽  
Nitrogen And Phosphorus ◽  
Nutrient Additions ◽  
Two Temperatures ◽  
Enrichment Experiments ◽  
Nutrient Analyses

Bioassay experiments with the natural phytoplankton assemblage showed that the major nutrient input to Mt Bold reservoir, South Australia, occurred with the onset of winter rains. Growth potential within the euphotic zone generally increased from June to November but was undetectable from December to March when the autumn overturn circulated nutrient-rich water from the hypolimnion to cause an increase in growth. Subsequently, the growth potential fell and did not rise until the onset of winter rains. Routine enrichment experiments with phosphorus, nitrogen and Na-EDTA substantially increased the growth potential above the control during periods of suspected nutrient depletion. During periods of nutrient depletion, the influence of 10 single and 45 dual nutrient additions showed that only the combined addition of nitrogen and phosphorus caused a significant increase in growth potential. To investigate further the influence of nitrogen and phosphorus on algal growth, factorial nutrient-enrichment experiments using five levels of both nitrogen and phosphorus and three of Na-EDTA at two temperatures (11 and 20�C) were conducted. The work is discussed in relation to the routine nutrient analyses done by the Engineering and Water Supply Department of South Australia.

Seasonal Dynamics of the Deep-Chlorophyll Maximum in Castle Lake, California

1983 ◽  
Vol 40 (2) ◽  
pp. 208-214 ◽  
Author(s):  
John C. Priscu ◽  
Charles R. Goldman
Keyword(s):  
Primary Productivity ◽  
Chlorophyll Concentration ◽  
Euphotic Zone ◽  
Deep Chlorophyll Maximum ◽  
Deep Basin ◽  
Photoautotrophic Growth ◽  
Chlorophyll Maximum ◽  
Early Portion ◽  
Castle Lake ◽  
Do So

Vertical profiles of chlorophyll concentration measured during 1980 in Castle Lake showed that a deep maximum developed immediately after ice thaw and persisted in the deep basin of the lake until autumn overturn. In the early portion of the ice-free season, low epilimnetic turbidity allows enough light to reach this deep-chlorophyll layer to produce a deep-primary productivity maximum. Photoautotrophic growth appears to maintain the deep-chlorophyll maximum early in the season whereas the accumulation of sinking organisms appears to do so later in the season. Although the deep-water phytoplankton have reduced rates of photosynthesis late in the season, they maintain their ability to photosynthesize immediately upon exposure to light. Consequently, the redistribution of deepwater chlorophyll at fall overturn can increase the chlorophyll concentration of the euphotic zone (0–15 m) by 58% which can potentially increase primary productivity in this zone by 81%.Key words: deep-chlorophyll maximum, primary productivity, aphotic viability

scholarly journals LED Lighting and High-Density Planting Enhance the Cost-Efficiency of Halimione portulacoides Extraction Units for Integrated Aquaculture

2021 ◽  
Vol 11 (11) ◽  
pp. 4995
Author(s):  
Marco Custódio ◽  
Paulo Cartaxana ◽  
Sebastián Villasante ◽  
Ricardo Calado ◽  
Ana Isabel Lillebø
Keyword(s):  
Plant Density ◽  
Inorganic Nitrogen ◽  
High Density ◽  
Planting Density ◽  
Nitrogen And Phosphorus ◽  
Integrated Aquaculture ◽  
Halimione Portulacoides ◽  
White Leds ◽  
Artificial Lighting ◽  
Aquaculture Effluents

Halophytes are salt-tolerant plants that can be used to extract dissolved inorganic nutrients from saline aquaculture effluents under a production framework commonly known as Integrated Multi-Trophic Aquaculture (IMTA). Halimione portulacoides (L.) Aellen (common name: sea purslane) is an edible saltmarsh halophyte traditionally consumed by humans living near coastal wetlands and is considered a promising extractive species for IMTA. To better understand its potential for IMTA applications, the present study investigates how artificial lighting and plant density affect its productivity and capacity to extract nitrogen and phosphorous in hydroponic conditions that mimic aquaculture effluents. Plant growth was unaffected by the type of artificial lighting employed—white fluorescent lights vs. blue-white LEDs—but LED systems were more energy-efficient, with a 17% reduction in light energy costs. Considering planting density, high-density units of 220 plants m−2 produced more biomass per unit of area (54.0–56.6 g m−2 day−1) than did low-density units (110 plants m−2; 34.4–37.1 g m−2 day−1) and extracted more dissolved inorganic nitrogen and phosphorus. Overall, H. portulacoides can be easily cultivated hydroponically using nutrient-rich saline effluents, where LEDs can be employed as an alternative to fluorescent lighting and high-density planting can promote higher yields and extraction efficiencies.

Deep chlorophyll maximum (DCM) in the Red Sea

2021 ◽  
Vol 14 (3) ◽  
Author(s):  
Mohideen Wafar ◽  
Mohammad Ali Qurban ◽  
Zahid Nazeer ◽  
Karuppusamy Manikandan
Keyword(s):  
Red Sea ◽  
Deep Chlorophyll Maximum ◽  
Chlorophyll Maximum

scholarly journals Feedback Regulation between Aquatic Microorganisms and the Bloom-Forming Cyanobacterium Microcystis aeruginosa

2019 ◽  
Vol 85 (21) ◽  
Author(s):  
Meng Zhang ◽  
Tao Lu ◽  
Hans W. Paerl ◽  
Yiling Chen ◽  
Zhenyan Zhang ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Microcystis Aeruginosa ◽  
Lake Taihu ◽  
Inorganic Nitrogen ◽  
Microbial Community Composition ◽  
Nitrogen And Phosphorus ◽  
Content Type ◽  
Coculture System ◽  
Eukaryotic Microorganisms ◽  
Aquatic Microorganisms

ABSTRACT The frequency and intensity of cyanobacterial blooms are increasing worldwide. Interactions between toxic cyanobacteria and aquatic microorganisms need to be critically evaluated to understand microbial drivers and modulators of the blooms. In this study, we applied 16S/18S rRNA gene sequencing and metabolomics analyses to measure the microbial community composition and metabolic responses of the cyanobacterium Microcystis aeruginosa in a coculture system receiving dissolved inorganic nitrogen and phosphorus (DIP) close to representative concentrations in Lake Taihu, China. M. aeruginosa secreted alkaline phosphatase using a DIP source produced by moribund and decaying microorganisms when the P source was insufficient. During this process, M. aeruginosa accumulated several intermediates in energy metabolism pathways to provide energy for sustained high growth rates and increased intracellular sugars to enhance its competitive capacity and ability to defend itself against microbial attack. It also produced a variety of toxic substances, including microcystins, to inhibit metabolite formation via energy metabolism pathways of aquatic microorganisms, leading to a negative effect on bacterial and eukaryotic microbial richness and diversity. Overall, compared with the monoculture system, the growth of M. aeruginosa was accelerated in coculture, while the growth of some cooccurring microorganisms was inhibited, with the diversity and richness of eukaryotic microorganisms being more negatively impacted than those of prokaryotic microorganisms. These findings provide valuable information for clarifying how M. aeruginosa can potentially modulate its associations with other microorganisms, with ramifications for its dominance in aquatic ecosystems. IMPORTANCE We measured the microbial community composition and metabolic responses of Microcystis aeruginosa in a microcosm coculture system receiving dissolved inorganic nitrogen and phosphorus (DIP) close to the average concentrations in Lake Taihu. In the coculture system, DIP is depleted and the growth and production of aquatic microorganisms can be stressed by a lack of DIP availability. M. aeruginosa could accelerate its growth via interactions with specific cooccurring microorganisms and the accumulation of several intermediates in energy metabolism-related pathways. Furthermore, M. aeruginosa can decrease the carbohydrate metabolism of cooccurring aquatic microorganisms and thus disrupt microbial activities in the coculture. This also had a negative effect on bacterial and eukaryotic microbial richness and diversity. Microcystin was capable of decreasing the biomass of total phytoplankton in aquatic microcosms. Overall, compared to the monoculture, the growth of total aquatic microorganisms is inhibited, with the diversity and richness of eukaryotic microorganisms being more negatively impacted than those of prokaryotic microorganisms. The only exception is M. aeruginosa in the coculture system, whose growth was accelerated.

Bacterioplankton, Phytoplankton, and Zooplankton Communities in a British Columbia Coastal Lake Before and After Nutrient Reduction

1986 ◽  
Vol 43 (8) ◽  
pp. 1504-1514 ◽  
Author(s):  
F. Joan Hardy ◽  
Ken S. Shortreed ◽  
John G. Stockner
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Inorganic Nitrogen ◽  
Size Fraction ◽  
Growing Season ◽  
Nutrient Reduction ◽  
Nitrogen And Phosphorus ◽  
Coastal Lake ◽  
Before And After ◽  
High Concentrations

Inorganic nitrogen and phosphorus were applied weekly during the growing season from 1980 to 1982 and twice weekly in 1983 to Hobiton Lake, a warm monomictic coastal lake in British Columbia. The lake was not fertilized in 1984. Average numbers of bacteria during the growing season decreased from a high of 1.53 × 106∙mL−1 in the fertilized condition to 0.84 × 106∙mL−1 in the unfertilized condition. Chlorophyll a concentrations decreased from a maximum seasonal average of 2.69 μg∙L−1 (1981) to 1.30 μg∙L−1 (1984), and algal numbers decreased from 5.83 × 104∙mL−1 (1983) to 2.29 × 104∙mL−1 (1984). Although the numbers of phytoplankton in each size fraction (picoplankton, nanoplankton, or microplankton) decreased in the unfertilized condition, the greatest change was an almost fourfold decrease in picoplankton, which consisted of 90% cyanobacteria (primarily Synechococcus spp.). Abundance of the large diatoms Rhizosolenia spp. and Melosira spp. increased in 1984, resulting in an increase in average seasonal algal volume. Average densities of medium (0.15–0.84 mm) and large (0.85–1.5 mm) zooplankton were greatest in 1982, while rotifers and small zooplankton (0.10–0.14 mm) were most dense in 1984 following nutrient reduction. The lake had relatively high concentrations of planktivorous juvenile sockeye salmon (Oncorhynchus nerka) that appeared to minimize any direct effect of nutrient additions on zooplankton densities.

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