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

Stimulation of Nitrate Uptake and Photosynthesis by Molybdenum in Castle Lake, California

1980 ◽  
Vol 37 (4) ◽  
pp. 707-712 ◽  
Author(s):  
R. P. Axler ◽  
R. M. Gersberg ◽  
C. R. Goldman
Keyword(s):  
Nitrate Uptake ◽  
Phytoplankton Community ◽  
Euphotic Zone ◽  
Growing Season ◽  
Uptake Rates ◽  
Early Portion ◽  
Rate Of Photosynthesis ◽  
Castle Lake ◽  
Stimulation Of

The uptake rates of 15NO3 and 14CO2 by the natural phytoplankton community at Castle Lake, California, were measured in situ as responses to 5 μg∙L−1 additions of molybdenum. Stimulation of both nitrate uptake and photosynthesis occurred in water samples containing only relatively high amounts of nitrate. This response to added molybdenum disappeared as the growing season progressed and nitrate was depleted in the euphotic zone. Although molybdenum stimulated nitrate uptake by 55% in water collected from the lower euphotic zone, it did not increase the rate of CO2 uptake because at that depth the rate of photosynthesis was most limited by light intensity and not by nitrogen. An analysis of molybdenum bioassays from 1959 to 1963 is integrated with these findings and points to the importance of molybdenum for phytoplankton growth during the early portion of the growing season when nitrate concentrations in the euphotic zone are maximal.Key words: molybdenum, nitrate, nitrate uptake, micronutrient bioassays

scholarly journals ESTIMASI PRODUKTIVITAS PRIMER PERAIRAN BERDASARKAN KONSENTRASI KLOROFIL-A YANG DIEKSTRAK DARI CITRA SATELIT LANDSAT-8 DI PERAIRAN KEPULAUAN KARIMUN JAWA

2017 ◽  
Vol 14 (1) ◽  
Author(s):  
Mulkan Nuzapril ◽  
Setyo Budi Susilo ◽  
James Parlindungan Panjaitan
Keyword(s):  
Chlorophyll A ◽  
Attenuation Coefficient ◽  
Primary Productivity ◽  
Chlorophyll Concentration ◽  
Euphotic Zone ◽  
Landsat 8 ◽  
Secchi Disk ◽  
Estimation Model ◽  
Chlorophyll A Concentration ◽  
Average Value

Sea primary productivity is an important factor in monitoring the quality of sea waters due to his role in the carbon cycle and the food chain for heterotrophic organisms. Estimation of sea primary productivity may be suspected through the values of chlorophyll-a concentration, but surface chlorophyll-a concentration was only able to explain 30% of the primary productivity of the sea. This research aims to build primary productivity estimation model based on chlorophyll-a concentration value of a surface layer of depth until depth compensation. Primary productivity model of relationships with chlorophyll concentration were extracted from Landsat-8 imagery then it could be used to calculated of sea primary productivity. The determination of the depth classification were done by measuring the attenuation coefficient values using the luxmeter underwater datalogger 2000 and secchi disk. The attenuation coefficient values by the luxmeter underwater, ranges between of 0.13-0.21 m-1 and secchi disk ranged, of 0.12 – 0.21 m-1. The penetration of light that through into the water column where  primary productivity is still in progress or where the depth of compensation ranged from 28.75 – 30.67 m. The simple linier regression model between average value of chlorophyll- concentration in all euphotic zone with sea primary productivity has high correlation, it greater than of surface chlorophyll-a concentration (R2 = 0.65). Model validation of sea primary productivity has high accuracy with the RMSD value of 0.09 and satellite-derived sea primary productivity were not significantly different. The satellite derived of chlorophyll-a could be calculated into sea primary productivity.Abstrak Produktivitas primer perairan merupakan faktor penting dalam pemantauan kualitas perairan laut karena berperan dalam siklus karbon dan rantai makanan bagi organisme heterotrof. Estimasi produktivitas primer perairan dapat diduga melalui nilai konsentrasi klorofil-a, namun konsentrasi klorofil-a permukaan laut hanya mampu menjelaskan 30% produktivitas primer laut. Penelitian ini bertujuan untuk membangun model estimasi produktivitas primer berdasarkan nilai konsentrasi klorofil-a dari lapisan kedalaman permukaan sampai kedalaman kompensasi. Model hubungan produktivitas primer dengan konsentrasi klorofil-a yang diekstrak dari citra satelit Landsat-8 kemudian dapat digunakan untuk mengestimasi produktivitas primer satelit. Penentuan klasifikasi kedalaman dilakukan dengan mengukur nilai koefisien atenuasi menggunakan luxmeter underwater datalogger 2000  dan secchi disk. Nilai koefisien atenuasi dengan menggunakan luxmeter underwater berkisar antara 0,13 -0,21m-1 dan secchi disk berkisar antara 0,12 – 0,21 m-1. Penetrasi cahaya yang masuk ke kolom perairan dimana produksi primer masih berlangsung atau kedalaman kompensasi berkisar antara 28,75 – 30,67 m. Model regresi linier sederhana antara konsentrasi klorofil-a rata-rata seluruh zona eufotik dengan produktivitas primer perairan memiliki korelasi yang lebih tinggi dibandingkan konsentrasi klorofil-a permukaan dengan R2= 0,65. Validasi model produktivitas primer memiliki keakuratan yang tinggi dengan RMSD sebesar 0,09 dan produktivitas primer satelit secara signifikan tidak berbeda nyata dengan produktivitas primer data insitu. Sehingga  nilai konsentrasi klorofil-a satelit dapat ditransformasi menjadi produktivitas primer satelit.

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.

scholarly journals Primary productivity measurements in the Ross Sea, Antarctica: A regional synthesis

2021 ◽  
Author(s):  
Walker O. Smith Jr.
Keyword(s):  
Primary Productivity ◽  
Ross Sea ◽  
Chlorophyll Concentration ◽  
Euphotic Zone ◽  
Data Set ◽  
Phaeocystis Antarctica ◽  
Ecological Importance ◽  
Global Biogeochemical Cycles ◽  
Critical Components ◽  
Productivity Measurements

Abstract. Polar systems are undersampled due to the difficulty of sampling remote and challenging environments; however, these systems are critical components of global biogeochemical cycles. Measurements on primary productivity in specific areas can quantify the input of organic matter to food webs, and so are of critical ecological importance as well. However, long-term measurements using the same methodology are available only for a few polar systems. Primary productivity measurements using 14C-uptake incubations from the Ross Sea, Antarctica, are synthesized, along with chlorophyll concentrations at the same depths and locations. A total of 19 independent cruises were completed, and 449 stations occupied where measurements of primary productivity (each with 7 depths) were completed. The incubations used the same basic simulated in situ methodology for all. Integrated water column productivity for all stations averaged 1.10 ± 1.20 g C m−2 d−1, and the maximum was 13.1 g C m−2 d−1. Annual productivity calculated from the means throughout the growing season equalled 146 g C m−2 yr−1. Mean chlorophyll concentration in the euphotic zone (the 1 % irradiance level) was 2.85 ± 2.68 mg m−3 (maximum concentration was 19.1 mg m−3). Maximum photosynthetic rates at the surface (normalized to chlorophyll) averaged 0.94 ± 0.71 mg C (mg chl)−1 h−1, similar to the maximum rate found in photosynthesis/irradiance measurements. Productivity measurements are consistent with the temporal patterns of biomass found previously, with biomass and productivity peaking in late December; mixed layers were at a minimum at this time as well. Estimates of plankton composition also suggest that pre-January productivity was largely driven by the haptophyte Phaeocystis antarctica, and summer productivity by diatoms. The data set will be useful for a comparison to other Antarctic regions and provide a basis for refined bio-optical models of regional primary productivity.

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.

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
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