scholarly journals ESTIMACIÓN DE LA PRODUCTIVIDAD PRIMARIA EN DOS BAJOS DE LA PARTE SUR DEL GOLFO DE CALIFORNIA, MÉXICO

2008 ◽  
Vol 23 (1-2) ◽  
pp. 39
Author(s):  
G. Verdugo-Díaz ◽  
R. Cervantes Duarte ◽  
M. O. Albáñez-Lucero

Primary productivity estimation in two seamounts in the southern Gulf of California, México Vertical profiles of temperature and natural fluorescence from 100 m deep were made during February 2005. Water transparency was measured using Secchi’s disc, as well samples of superficial water and at maximum of fluorescence deep were collected to analyze inorganic nutrients. In “El Bajo Espiritu Santo” temperature (20 °C at surface) diminished gradually with depth, without significant stratification.Primary productivity shows superficial values close to 6 mg C m-3 h-1, recahing undetectable values at 20 m of depth. In “El Bajo Gorda” surface temperature reached 22 °C and the water column shows a thermocline between 35 m and 45 m of depth. The profiles of primary productivity presented a subsurface maximum (approximately 2 mg C m-3 h-1) associated with the thermocline.

1983 ◽  
Vol 40 (6) ◽  
pp. 792-798 ◽  
Author(s):  
Allan Konopka

Primary productivity in an Indiana lake, which contained a metalimnetic layer of cyanobacteria, was calculated for the summers of 1979–81 by using a numerical model. Production estimates of 183 and 187 g C∙m−2 were obtained for 1979 and 1980; the estimate for 1981 was 50% higher. These values were two- to four-fold higher than estimates made in 1963 and 1964. Production in the metalimnion accounted for 29, 44, and 34% of the total during the three summers. Changes in the vertical distribution of biomass in the water column appeared to have had a greater effect upon metalimnetic production than differences in water transparency or incident solar radiation. The average values measured for the latter two variables were reasonably similar during the 3 yr, whereas the depth at which the metalimnetic layer of cyanobacteria stratified decreased from 9 m in 1979 to 5 m in 1981.


2017 ◽  
Vol 14 (9) ◽  
pp. 2469-2480 ◽  
Author(s):  
Kedong Yin ◽  
Hao Liu ◽  
Paul J. Harrison

Abstract. We hypothesize that phytoplankton have the sequential nutrient uptake strategy to maintain nutrient stoichiometry and high primary productivity in the water column. According to this hypothesis, phytoplankton take up the most limiting nutrient first until depletion, continue to draw down non-limiting nutrients and then take up the most limiting nutrient rapidly when it is available. These processes would result in the variation of ambient nutrient ratios in the water column around the Redfield ratio. We used high-resolution continuous vertical profiles of nutrients, nutrient ratios and on-board ship incubation experiments to test this hypothesis in the Strait of Georgia. At the surface in summer, ambient NO3− was depleted with excess PO43− and SiO4− remaining, and as a result, both N : P and N : Si ratios were low. The two ratios increased to about 10 : 1 and 0. 45 : 1, respectively, at 20 m. Time series of vertical profiles showed that the leftover PO43− continued to be removed, resulting in additional phosphorus storage by phytoplankton. The N : P ratios at the nutricline in vertical profiles responded differently to mixing events. Field incubation of seawater samples also demonstrated the sequential uptake of NO3− (the most limiting nutrient) and then PO43− and SiO4− (the non-limiting nutrients). This sequential uptake strategy allows phytoplankton to acquire additional cellular phosphorus and silicon when they are available and wait for nitrogen to become available through frequent mixing of NO3− (or pulsed regenerated NH4). Thus, phytoplankton are able to maintain high productivity and balance nutrient stoichiometry by taking advantage of vigorous mixing regimes with the capacity of the stoichiometric plasticity. To our knowledge, this is the first study to show the in situ dynamics of continuous vertical profiles of N : P and N : Si ratios, which can provide insight into the in situ dynamics of nutrient stoichiometry in the water column and the inference of the transient status of phytoplankton nutrient stoichiometry in the coastal ocean.


2016 ◽  
Author(s):  
Kedong Yin ◽  
Paul J. Harrison

Abstract. We hypothesize that phytoplankton have the sequential nutrient uptake strategy in order to maintain nutrient stoichiometry and high primary productivity in the water column. Nutrient limited phytoplankton are capable of taking up the limiting nutrient first and they take up non-limiting nutrients when the limiting nutrient debt has been overcome. We used high resolution continuous vertical profiles of nutrients, nutrient ratios and on-board ship incubation experiments to test this hypothesis in the Strait of Georgia. At the surface in summer, ambient nitrate was depleted with excess phosphate and silicate remaining, and as a result, both N : P and N : Si ratios were low. The two ratios increased to about 10 : 1 and 0.45 : 1, respectively, at 20 m. Time series of vertical profiles showed that the leftover phosphate continued to be removed, resulting in additional phosphorus storage by phytoplankton. There were various shapes of vertical profiles of N : P and at the nutricline it changed quickly in response to mixing events. A field incubation of seawater also demonstrated the sequential uptake of nitrate (the most limiting nutrient) and then phosphate and silicate (the non-limiting nutrients). This sequential uptake strategy allows phytoplankton to acquire additional cellular phosphorus and silicon when they are available and wait for nitrogen to become available through frequent mixing of nitrate (or pulsed regenerated ammonium). Thus, phytoplankton show variability of nutrient stoichiometry and are capable of maintaining high productivity by taking advantage of vigorous mixing regimes. To our knowledge, this is the first study to show the dynamics of continuous vertical profiles of N : P and N : Si ratios and to examine the responses of phytoplankton to nutrients supplied naturally by mixing events. The continuous nutrient profiles provided insight into the in situ dynamics of nutrient stoichiometry in the water column and the transient status of nutrient stoichiometry of phytoplankton in the field.


2021 ◽  
Vol 43 ◽  
pp. 101686
Author(s):  
Juan Carlos Hernández-Padilla ◽  
Manuel J. Zetina-Rejón ◽  
F. Arreguín-Sánchez ◽  
Pablo del Monte-Luna ◽  
José T. Nieto-Navarro ◽  
...  

2012 ◽  
Vol 27 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
Erin L. McClymont ◽  
Raja S. Ganeshram ◽  
Laetitia E. Pichevin ◽  
Helen M. Talbot ◽  
Bart E. van Dongen ◽  
...  

2020 ◽  
Vol 54 (3) ◽  
pp. 343
Author(s):  
Erik Coria-Monter ◽  
María Adela Monreal-Gómez ◽  
David Alberto Salas de León ◽  
Elizabeth Durán-Campos

Information on selected bio-optical properties and primary production values of the waters of the Bay of La Paz, southern Gulf of California, is reported during June 2004, a region characterized to have very rich biodiversity, including endemic and endangered species, with high ecological relevance. In-situ measurements of natural fluorescence and photosynthetically available radiation (PAR) enabled the subsequent calculation of the incident irradiance (E0), the light extinction coefficient (k), compensation depth (Zc) and critical depth (Zcr). The results suggest the presence of light propitious conditions for phytoplankton community growth and net primary production, which are highly significant for the potential development of models of light penetration, ocean color, primary productivity, and analyses of organic carbon energy flow.


2010 ◽  
Vol 25 (2) ◽  
pp. 95
Author(s):  
G. Verdugo-Díaz ◽  
A. Martínez-López ◽  
I. Gárate-Lizárraga

Se presentan los cambios en la distribución espacial de la comunidad fitoplanctónica en Bahía Concepción, B.C.S. de 1991 a 1993. Se estimó la abundancia total, la variación espacio-temporal por fracciones de tamaño (nano y microfitoplancton) y se describe su estructura. Se determinaron 235 taxa, en donde las diatomeas fueron el grupo con mayor riqueza de especies (131). Los géneros más importantes fueron Chaetoceros, Rhizosolenia y Nitzschia. El segundo grupo en importancia fue el de los dinoflagelados (92 especies), representados principalmente por Protoperidinium, Ceratium y Prorocentrum; el tercer grupo fueron los silicoflagelados (9 especies), principalmente del genero Dictyocha. Las diatomeas dominaron en la temporada fría cuando la columna de agua se mantiene homogénea, en tanto que los dinoflagelados prosperaron durante la temporada cálida cuando la columna de agua estuvo estratificada. De este último grupo, 10 especies son tóxicas o potencialmente tóxicas. La abundancia fitoplanctónica total no mostró un comportamiento estacional definido, sin embargo, las variaciones interanuales mostraron un decremento de aproximadamente 25% durante 1992 y 1993, asociado con anomalías positivas de temperatura. A pesar de que las abundancias totales disminuyeron, la contribución porcentual de la fracción nanofitoplanctónica se mantuvo. Ecological indicators of the phytoplankton community structure in Bahía Concepción, Gulf of California, Mexico Seasonal changes in the spatial distribution of the phytoplankton community were determined in Bahía Concepción, B.C.S., from 1991 to 1993. The total abundance and the seasonal variations of phytoplankton size fractions (nanno and microphytoplankton) as well as its structure were determined. A total of 235 taxa were identified. Diatoms were the best represented group due to their high species richness (131). The most important genera were Chaetoceros, Rhizosolenia and Nitzschia. The second important group were dinoflagellates (92 species), represented mainly by Protoperidinium, Ceratium and Prorocentrum. The third numerically important group were the silicoflagellates (9 species). The most representative genus of this group was Dictyocha. A major presence of the diatoms was observed during the cold months with a homogeneous water-column. Major presence of dinoflagellates was recorded during the warm season when the water-column appeared stratified. Ten species of dinoflagellates were considered as toxic or potentially toxic. Total phytoplankton abundance did not show a clear seasonal pattern; nevertheless, the interannual variations exhibited an important decline of about 25 % during 1992 and 1993. These changes were related to positive anomalies of temperature. Altough phytoplankton abundance diminished, the percentage contribution of nannophytoplankton was stable.


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