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Historically, the construction of global maps of ocean productivity has been a difficult task (Berger, 1989). Representative, precise, and accurate measurements of carbon fixation rates have been hampered by the errors associated with methodological problems and sampling limitations (Jahnke, 1990). The frustration of biological oceanographers in de...
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Context 1
... distributions of phytoplankton, or more precisely pigment biomass, are best ~ from shipboard and mooring platforms (Table 1 and Fig. 2). Depth-dependent variations in pigment biomass are poorly resolved from satellites and planes since these measurements represent depth- weighted averages of pigments in near-surface waters, i.e., they are limited by the optical attenuation depth ( Gordon and McCluney, 1975;Smith, 1981). Because ship availability and cruise duration ...
Context 2
... to which primary production rates could be estimated by this approach will ultimately be limited by the cost constraints associated with the deployment of bio-optical moorings. Thus, it is obvious that a multiplatform sampling strategy involving satellites. ships. and moorings will be required to provide realistic estimates of global production (Fig. 12). For example, satel1ite-derived estimates of chlorophyll a concentration (Sea- WiFS) and global solar surface irradiance (Bishop and Rossow, 1991) could be used in conjunction with the absorption-based remote sensing models ( Collins et al.. 1986;Morel. 1991) to extrapolate mooring-derived production profiles to three dimensions (i.e., ...
Citations
... Existing PP models are different in complexity and expression, such as exponential, hyperbolic tangent, and rectangular hyperbolic. However, they are mainly based on the same theoretical background that requires PAR, phytoplankton parameter (such as those indicating biomass, Chla and phytoplankton carbon, or those indicating the ability to absorb energy), and efficiency factor (the conversion of the absorbed photon energy to organic carbon) (Bidigare et al., 1992;Lee et al., 2015;Uitz et al., 2010). We extended the absorption-based PP model to consider phytoplankton size class. ...
... The maximum quantum yield of photosynthesis (Ф max ) is a critical parameter in bio-optical models of PP (Babin et al., 1996;Bidigare et al., 1992;Kiefer & Mitchell, 1983;Morel, 1991;Sosik, 1996). The theoretical upper limit for Ф max is commonly set as 0.125 molC mol photons − 1 since eight electrons are required for the evolution of one molecule of O 2 from water (1/8 = 0.125) (Bidigare et al., 1992). ...
... The maximum quantum yield of photosynthesis (Ф max ) is a critical parameter in bio-optical models of PP (Babin et al., 1996;Bidigare et al., 1992;Kiefer & Mitchell, 1983;Morel, 1991;Sosik, 1996). The theoretical upper limit for Ф max is commonly set as 0.125 molC mol photons − 1 since eight electrons are required for the evolution of one molecule of O 2 from water (1/8 = 0.125) (Bidigare et al., 1992). Recently, Xie et al. (2015) described a significant correlation between a ph (4 3 5)/a ph (6 7 6) and Ф max in the NSCS. ...
Modelling vertical changes of size-fractionated phytoplankton primary production (PP) offers a holistic route to describe marine ecosystems and constitutes an important part of remote sensing to accurately estimate the depth-integrated PP in the global oceans. However, there is no size-fractionated PP model established in the Northern South China Sea (NSCS) yet. In situ measured hyperspectral absorption and irradiance data were used to estimate vertical size-fractionated PP. Results demonstrated that the estimated size-fractionated PP showed good agreement with in-situ measurement. r²s are 0.41, 0.69, and 0.83, and median absolute percentage difference are 23.33%, 25.86%, and 31.05% for pico-, nano-, and micro-PP, respectively. The intercept from the linear relationship between ratio of phytoplankton absorption coefficient (aph(4 3 5)/aph(6 7 6)) and quantum yield of photosynthesis have the biggest impact on estimation of PP based on Monte Carlo approach. The model derived PP profiles showed an exponential attenuation shape curve from the surface to the bottom in coastal water of NSCS. In contrast, a decreasing pattern with increasing depth with a maximum in the subsurface layer or at the chlorophyll maximum depth was observed in the open ocean of NSCS. Such an approach can be utilized to depict the vertical variations of size-fractionated PP, which can serve as supplementary of remote sense to reveal their three-dimensional structure.
... Indeed, Synechococcus was found numerically dominant in coastal waters in the Mozambique Channel, followed by Prochlorococcus and then picoeukaryotes in lower abundance (Zubkov and Quartly, 2003). Bidigare et al. (1992) reported that accessory pigments accounted for 60% of the light absorbed in the surface, and 90% at the base of euphotic zones (low-light depth) in the Sargasso Sea. Zeaxanthin associated with cyanobacteria (Prochlorococcus and Synechococcus; Vidussi et al., 2001) represented the major pigments in both surveys; other specific pigments of green algae (CHL-B, Violaxanthine, Neoxanthine), also detected, confirmed the presence of Chlorophyceae. ...
Ecological baselines for the structure and functioning of ecosystems in the absence of human activity can provide essential information on their health status. The Glorieuses islands are located in the Western Indian Ocean (WIO) and can be considered as “pristine” ecosystems that have not been subjected to anthropogenic pressure. Their nutrient context and the microbial assemblages were assessed by determining the abundance of heterotrophic prokaryotes (archaea and bacteria), picocyanobacteria, picoeukaryotes, microphytoplankton and protozooplankton communities in five stations, during two contrasted periods (November 2015 and May 2016). Chlorophyll-a concentrations were always under 1 μg/L and associated to very low levels in orthophosphates, nitrate and dissolved organic carbon, revealing an ultra-oligotrophic status for the Glorieuses waters. Picocyanobacteria confirmed the ultra-oligotrophic status with a predominance of Synechococcus. Zeaxanthin associated with the presence of picocyanobacteria represented the major pigment in both surveys. Three indices of diversity (species richness, Shannon and Pielou indexes) from microscopy observations highlighted the difference of diversity in microphytoplankton between the surveys. A focus on a 16S metabarcoding approach showed a high dominance of picocyanobacteria, Alpha- and Gammaproteobacteria, regardless of station or period. Multivariate analyses (co-inertia analyses) revealed a strong variability of ecological conditions between the two periods, with (i) high nutrient concentrations and heterotrophic nanoflagellate abundance in November 2015, and (ii) high heterotrophic prokaryote and picoeukaryote abundance in May 2016. The impact of a category 5 tropical cyclone (Fantala) on the regional zone in April 2016 is also advanced to explain these contrasted situations. Relative importance of top-down factors between bacterial and heterotrophic nanoflagellates was observed in November 2015 with an active microbial food web. All the results indicate that three microbial indexes potentially can be considered to assess the ecological change in Glorieuses marine waters.
... The unique pigments in an algae strain are often called marker pigments. Marker pigment composition and concentration can be used for species identifi cation and the ratio determination of each species (Bidigare et al., 1992;Millie et al., 1993). Mackey et al. (1998) analyzed the dominant species of phytoplankton at diff erent water depths based on pigment composition and concentration using high performance liquid chromatography (HPLC). ...
Iron is a vital micronutrient for growth of bloom-forming Microcystis aeruginosa and competition with other algae, and its availability is affected by humic acid. The effect of iron and humic acid on growth and competition between M. aeruginosa and Scenedesmus obliquus was assessed. The results showed the growth of M. aeruginosa and S. obliquus in mono-cultures was inhibited by humic acid at low iron concentrations (0.01 mg/L); the maximum inhibition ratios were 67.84% and 38.31%, respectively. The inhibition of humic acid on the two species was significantly alleviated when iron concentrations were 1.00 mg/L, with the maximum inhibition rate reduced to 5.82% for M. aeruginosa and to 23.06% for S. obliquus. S. obliquus was the dominant species in mixed cultures, and the mutual inhibition between M. aeruginosa and S. obliquus at low iron concentration was greater than that at high iron concentration. The inhibition of S. obliquus on M. aeruginosa was reduced at low iron concentrations; it increased at high iron concentrations, as concentrations of humic acid rose.
... Estimating the annual water column integrated primary production (IPP) (symbols and abbreviations are presented in Table 1) and studying its spatiotemporal variability on regional and global scales are among the main tasks of ocean biogeochemistry. Field studies provide in situ measurements but cannot quantify basin and global IPP dynamics without significant extrapolation (Berger, 1989;Bidigare et al., 1992;Koblentz-Mishke et al., 1970). This problem can be resolved by using bio-optical high resolution satellite-derived data (e.g., surface chl a (Chl 0 )), sea surface temperature (T 0 ) and incident photosynthetically available radiation (PAR) (Carder et al., 2004;McClain et al., 1998McClain et al., , 2004O'Reilly et al., 1998) as input variables in the IPP models. ...
Empirical region-specific (RSM), depth-integrated (DIM) and depth-resolved (DRM) primary production models are developed based on data from the Kara Sea during the autumn (September–October 1993, 2007, 2011). The model is validated by using field and satellite (MODIS-Aqua) observations. Our findings suggest that RSM algorithms perform better than non-region-specific algorithms (NRSM) in terms of regression analysis, root-mean-square difference (RMSD) and model efficiency. In general, the RSM and NRSM underestimate or overestimate the in situ water column integrated primary production (IPP) by a factor of 2 and 2.8, respectively. Additionally, our results suggest that the model skill of the RSM increases when the chlorophyll specific carbon fixation rate, efficiency of photosynthesis and photosynthetically available radiation (PAR) are used as input variables. The parameterization of chlorophyll (chl a) vertical profiles is performed in Kara Sea waters with different trophic statuses. Model validation with field data suggests that the DIM and DRM algorithms perform equally (RMSD of 0.29 and 0.31, respectively). No changes in the performance of the DIM and DRM algorithms are observed (RMSD of 0.30 and 0.31, respectively) when satellite-derived chl a, PAR and the diffuse attenuation coefficient (Kd) are applied as input variables.
... Nevertheless, spectral reconstruction can convey information concerning the role of accessory pigments in light absorption. In the Sargasso Sea, Bidigare et al. (1992) noted that accessory pigments accounted for 60% of the light absorbed at the surface and 90% at the base of the euphotic zone. Barlow et al. (2013) observed that the proportion of irradiance absorbed by photosynthetic carotenoids and chlorophyll c increased as light decreased in mixed diatom-flagellate communities on the east coast of South Africa, while there was a high proportion of photoprotective carotenoid absorption at the surface. ...
A study of phytoplankton in a cyclonic eddy was undertaken in the Mozambique Basin between Madagascar and southern Africa during austral winter. CHEMTAX analysis of pigment data indicated that the community comprised mainly haptophytes and diatoms, with Prochlorococcus, prasinophytes and pelagophytes also being prominent to the east and west of the eddy. There was little difference in community structure, chlorophyll-specific absorption [a⁎ph(440)] and pigment:TChla ratios between the surface and the sub-surface chlorophyll maximum (SCM), reflecting acclimation to fluctuating light conditions in a well mixed upper layer. Values for a⁎ph(440) were low for diatom dominance, high where prokaryote proportion was high, and intermediate for flagellate dominated communities. Chlorophyll c and fucoxanthin:TChla ratios were elevated over most of the eddy, while 19’-hexanoyloxyfucoxanthin ratios increased in the eastern and western sectors. In a community comprising mainly flagellates and Prochlorococcus to the west of the eddy, there was high a⁎ph(440) at the surface and elevated ratios for divinyl chlorophyll a, chlorophyll b and 19’-hexanoyloxyfucoxanthin at the SCM. An increase in diadinoxanthin:TChla ratios and a decline in the quantum efficiency of photochemistry in PSII under high light conditions, indicated some photoprotection and photoinhibition at the surface even in a well mixed environment. Diadinoxanthin was the main photoprotective carotenoid within the eddy, while zeaxanthin was the dominant photoprotective pigment outside the eddy. The results of this study will be useful inputs into appropriate remote sensing models for estimating primary production and the size class distribution of phytoplankton in eddies in the southwest Indian Ocean.
... where a algae (λ) refers to a measured value for each individual sample and E d (λ) is the spectral irradiance of the PI incubator derived from Raateoja et al. (2004), who used the same PI incubator. The photosynthesis rate (P) at depth z across the thickness of ice at a 1-cm depth interval was calculated according to Kirk (1994) by: (9) with ɸ calculated after Eppley (1972) and Bidigare et al. (1992) by: ...
Bio-optics is a powerful approach for estimating photosynthesis rates, but has seldom been applied to sea ice, where measuring photosynthesis is a challenge. We measured absorption coefficients of chromophoric dissolved organic matter (CDOM), algae, and non-algal particles along with solar radiation, albedo and transmittance at four sea-ice stations in the Gulf of Finland, Baltic Sea. This unique compilation of optical and biological data for Baltic Sea ice was used to build a radiative transfer model describing the light field and the light absorption by algae in 1-cm increments. The maximum quantum yields and photoadaptation of photosynthesis were determined from 14 C-incorporation in photosynthetic-irradiance experiments using melted ice. The quantum yields were applied to the radiative transfer model estimating the rate of photosyn-thesis based on incident solar irradiance measured at 1-min intervals. The calculated depth-integrated mean primary production was 5 mg C m –2 d –1 for the surface layer (0–20 cm ice depth) at Station 3 (fast ice) and 0.5 mg C m –2 d –1 for the bottom layer (20–57 cm ice depth). Additional calculations were performed for typical sea ice in the area in March using all ice types and a typical light spectrum, resulting in depth-integrated mean primary production rates of 34 and 5.6 mg C m –2 d –1 in surface ice and bottom ice, respectively. These calculated rates were compared to rates determined from 14 C incorporation experiments with melted ice incubated in situ. The rate of the calculated photosynthesis and the rates measured in situ at Station 3 were lower than those calculated by the bio-optical algorithm for typical conditions in March in the Gulf of Finland by the bio-optical algorithm. Nevertheless, our study shows the applicability of bio-optics for estimating the photosynthesis of sea-ice algae.
... Одна из основных проблем изучения и оценки первичной продукции в океане заключается в том, что экспедиционные исследования обеспечивают получение величин ПП (расшифровка символов и аббревиатура названий представлены в табл. 1) для данного места и времени, но не позволяют изучить пространственно-временнýю изменчивость, выявить широкомасштабные и продолжительные тренды этого параметра, а также оценить с достаточной точностью ее годовые величины [20]. Для решения этих задач при помощи экспериментальных судовых данных требуется значительная экстраполяция [19,46], которая делает невозможным произвести с достаточной точностью количественное определение изменчивости ПП в больших пространственно-временных масштабах. ...
Primary production (PP) models of the Kara Sea are developed based on data collected on fall
expeditions (September–October 1993, 2007, and 2011) and their precision assessment utilizes the dataset
collected in September 2013. The algorithms for different model types (depth-integrated and depth-resolved)
are compared. The depth-resolved model performs slightly better than the depth-integrated one (the rootmean-
square-difference (RMSD) are 0.29 and 0.31, respectively). These algorithms utilize the daily assimilation
number (DAN) and photosynthetic efficiency (ψ) as the model coefficients, and surface chlorophyll a
(chl a) and photosynthetically active radiation (PAR) as input variables. These algorithms perform better than
the models that use chl a alone. Our results suggest that an increase in the performance of the Kara Sea PP
models depends on the input of the photophysiological characteristics of phytoplankton (DAN and ψ) and
PAR. To a lesser extent, this concerns the advantages of the depth-resolved model over the depth-integrated
one. The constructed region-specific Kara Sea PP models combined with satellite-derived chl a and PAR can
be used to estimate annual values and long-term variation of PP in hydrologically and hydrochemically similar
waters of the Arctic Ocean.
... Discrete estimates can be extrapolated on the basis of bio-optical characterizations of biomass, light absorption, and photosynthesis-irradiance relationships. Such bio-optical approaches have been applied in a variety of studies (e.g., Bidigare et al., 1987Bidigare et al., , 1992Morel, 1991;Uitz et al., 2008). Bio-optical approaches can benefit from the use of technology such as optical profilers, autonomous underwater vehicles, and profiling optical floats. ...
Relative to their surface area, continental margins represent some of the largest carbon
fluxes in the global ocean, but sparse and sporadic sampling in space and time makes
these systems difficult to characterize and quantify. Recognizing the importance of
continental margins to the overall North American carbon budget, terrestrial and marine
carbon cycle scientists have been collaborating on a series of synthesis, carbon budgeting,
and modeling exercises for coastal regions of North America, which include the Gulf of
Mexico, the Laurentian Great Lakes (LGL), and the coastal waters of the Atlantic,
Pacific, and Arctic Oceans. The Coastal CARbon Synthesis (CCARS) workshops and
research activities have been conducted over the past several years as a partner activity
between the Ocean Carbon and Biogeochemistry (OCB) Program and the North
American Carbon Program (NACP) to synthesize existing data and improve quantitative
assessments of the North American carbon budget.
CCARS activities in all five regions resulted in data compilations that improved estimates
of key carbon fluxes, particularly air-sea fluxes and primary productivity, for which the
most observations exist. Updated carbon budgets have been published for the Gulf of
Mexico (Coble et al., 2010; Benway and Coble, 2014), Atlantic coast (Najjar et al.,
2012), Pacific coast (Alin et al., 2012), Arctic coast (Cross et al., 2014a, b; Evans et al.,
2015), and the LGL (McKinley et al., 2011). Air-sea CO2 flux syntheses have been
published for coastal systems of the Arctic (Cross et al., 2014a; Evans et al., 2015),
Atlantic (Signorini et al., 2013), and the northern Gulf of Mexico (Huang et al., 2015),
and more are underway. For the California Current System (CCS), a convergence of
model- and observation-based air-sea fluxes reflects both the increasing sophistication of
the models and the increase in surface seawater and atmospheric pCO2 observations. A
summary of published carbon flux estimates suggests that Lakes Superior, Michigan, and
Huron are slight CO2 sources and Lakes Erie and Ontario are slight CO2 sinks (McKinley
et al., 2011). CCARS activities fostered collaborative synthesis and intercomparison
across 3-4 different models that provide published estimates of carbon delivery to coastal
regions, which yielded updated estimates of riverine carbon fluxes for most regions.
Despite sparse data sets, CCARS participants also produced some of the first regional
estimates of carbon fluxes from respiration, burial, and submarine groundwater
discharge. Cross-shelf carbon fluxes, which are extremely difficult to constrain with the
limited number of data sets, were calculated using a combination of models and data
from tracer studies. Finally, using a statistical modeling approach, the first estuarine
organic carbon budget for the Atlantic coast was developed based on studies in 12
representative estuarine systems (Herrmann et al., 2015).
Key recommendations of the CCARS data synthesis activities include:
• A comparable synthesis of data from Mexican (Gulf of Mexico and Pacific
coasts) and Canadian (Atlantic coast) waters
• A sustained observing program in all five Laurentian Great Lakes, minimally
including carbon and biogeochemical rate measurements across all seasons
• Improved observational coverage (in space and time) of the Gulf of Alaska
and other sea ice-bearing portions of the Arctic
• Further development of event-scale observing capacity (e.g., novel
autonomous platforms) in all continental margin systems to better quantify
impacts of episodic events on coastal carbon budgets
• Increased use of satellite products and development of algorithms for key
carbon flux estimates (e.g., primary productivity and surface-water pCO2) are
needed, especially observations from high spatial and high temporal resolution
satellite sensors
• Coordination of an all-inclusive carbon flux measurement campaign with
universally established protocols across a small set of representative
estuarine and tidal wetland systems (using a typology approach) across all
regions, including carbon flux measurements in degraded or drowned coastal
ecosystems to better understand policy implications of coastal ecosystem change
• Further development of three-dimensional biogeochemical models with
interactions among tidal wetlands, estuaries, sediments, and shelf waters to
scale up limited observations and integrate across the land-ocean continuum
• Improved process understanding of how energy and land use by humans modify
carbon stocks and fluxes in coastal waters to facilitate anthropogenic attribution
• Integration of social scientists and policy specialists into the planning process
for developing integrated observational and modeling efforts as well as data
harmonization strategies across the land-ocean continuum.
... scaled to the PAR values provided in the exercise, and applies a wavelength dependent absorption as a function of chlorophyll as spectral irradiance is propagated through the water column. Quantum yield varies with depth and is parameterized as a maximum value times both a light dependent term [Bidigare et al., 1992; Waters et al., 1994] and a temperature dependent term. Temperature dependence was assumed to be sigmoidal, and was based on a vertical profile of temperature derived from SST and MLD. ...
We investigated 32 net primary productivity (NPP) models by assessing skills to reproduce integrated NPP in the Arctic Ocean. The models were provided with two sources each of surface chlorophyll-a concentration (chlorophyll), photosynthetically available radiation (PAR), sea surface temperature (SST), and mixed-layer depth (MLD). The models were most sensitive to uncertainties in surface chlorophyll, generally performing better with in situ chlorophyll than with satellite-derived values. They were much less sensitive to uncertainties in PAR, SST, and MLD, possibly due to relatively narrow ranges of input data and/or relatively little difference between input data sources. Regardless of type or complexity, most of the models were not able to fully reproduce the variability of in situ NPP, whereas some of them exhibited almost no bias (i.e., reproduced the mean of in situ NPP). The models performed relatively well in low-productivity seasons as well as in sea ice-covered/deep-water regions. Depth-resolved models correlated more with in situ NPP than other model types, but had a greater tendency to overestimate mean NPP whereas absorption-based models exhibited the lowest bias associated with weaker correlation. The models performed better when a subsurface chlorophyll-a maximum (SCM) was absent. As a group, the models overestimated mean NPP, however this was partly offset by some models underestimating NPP when a SCM was present. Our study suggests that NPP models need to be carefully tuned for the Arctic Ocean because most of the models performing relatively well were those that used Arctic-relevant parameters. This article is protected by copyright. All rights reserved.
... The spatial and temporal scales of marine phenomena and processes are characterized by specific ranges of time and space [1]. Figure 1 shows a scheme which summarizes the main processes from micro-to macro-scale. ...
... The spatial and temporal scales of marine phenomena and processes are characterized by specific ranges of time and space [1]. Figure 1 shows a scheme which summarizes the main processes from micro-to macro-scale. Environmental processes: from macro-to micro-scale Source: [1] The micro-scale has a spatial limit of 1 m and temporal domain of 1-2 days. Micro-scale processes are dominated by turbulence, including biological and mixed layer as well as vertical structure of coastal water and tidal mixing. ...
Results of activities under project Marine Renewables Infrastructure Network for Emerging Energy Technologies (MaRINET) are reported, which led to DEMTE, a database, created on the basis of standardized monitoring of the marine environment during installation, operation and decommissioning of Marine Energy Conversion Systems. Obtained with the consortium partners' available techniques and equipment, the database shows that such instruments cover all identified marine environmental compartments, despite the lack of underwater vehicles and the reduced skills in using satellite technologies. These weaknesses could be overcome by an accurate planning of equipment, techniques and knowledge sharing. The approach here presented also leads to an effective analysis even in non-marine contexts.
