Effects of cage fish farming on phytoplankton community structure, biomass and primary production in an aquaculture area in the middle Adriatic Sea

2010 ◽  
Vol 42 (9) ◽  
pp. 1393-1405 ◽  
Author(s):  
Sanda Skejić ◽  
Ivona Marasović ◽  
Olja Vidjak ◽  
Grozdan Kušpilić ◽  
Živana Ninčević Gladan ◽  
...  
Keyword(s):  
Community Structure ◽  
Primary Production ◽  
Phytoplankton Community ◽  
Adriatic Sea ◽  
Fish Farming ◽  
Phytoplankton Community Structure ◽  
Aquaculture Area ◽  
Cage Fish

Deep chlorophyll-a maximum at one station in the middle Adriatic Sea

2002 ◽  
Vol 82 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Živana Ninčević ◽  
Ivona Marasović ◽  
Grozdan Kušpilić
Keyword(s):  
Community Structure ◽  
Phytoplankton Community ◽  
Adriatic Sea ◽  
Vertical Mixing ◽  
Size Fraction ◽  
Phytoplankton Community Structure ◽  
Phytoplankton Blooms ◽  
Chemical Factors ◽  
Phytoplankton Size ◽  
Physical And Chemical

Deep or subsurface chlorophyll-a maximum (DCM) was studied at one station in the middle Adriatic from December 1996 to June 1998. Chlorophyll-a concentration, abundance, volume carbon concentration, size-fraction of phytoplankton and phytoplankton community structure were determined. In addition, physical and chemical factors as well as nutrients were determined. The DCM occurs during both the vertical mixing and stratification period in the middle Adriatic Sea. It is most frequent between 50 and 75 m. It is located below the pycnocline and it is associated with the nutricline. Phytoplankton size-fraction and community structure vary seasonally. The DCM is most pronounced during spring phytoplankton blooms with diatom dominance. Procaryotic picoplankton Synechococcus sp. was abundant in DCM during summer stratification. The DCM represents both a biomass maximum and a phytoplankton adaptation to low irradiance.

Picophytoplankton contribution to phytoplankton community structure in the Gulf of Venice (NW Adriatic Sea)

2006 ◽  
Vol 91 (1) ◽  
pp. 51-70 ◽  
Author(s):  
Fabrizio Bernardi Aubry ◽  
Francesco Acri ◽  
Mauro Bastianini ◽  
Alessandra Pugnetti ◽  
Giorgio Socal
Keyword(s):  
Community Structure ◽  
Phytoplankton Community ◽  
Adriatic Sea ◽  
Phytoplankton Community Structure

scholarly journals Climate change impacts on net primary production (NPP) and export production (EP) regulated by increasing stratification and phytoplankton community structure in CMIP5 models

2015 ◽  
Vol 12 (15) ◽  
pp. 12851-12897 ◽  
Author(s):  
W. Fu ◽  
J. Randerson ◽  
J. K. Moore
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Primary Production ◽  
Phytoplankton Community ◽  
Net Primary Production ◽  
Climate Change Impacts ◽  
Climate Impacts ◽  
Cmip5 Models ◽  
Phytoplankton Community Structure ◽  
Rcp 8.5

Abstract. We examine climate change impacts on net primary production (NPP) and export production (sinking particulate flux; EP) with simulations from nine Earth System Models (ESMs) performed in the framework of the fifth Coupled Model Inter-comparison Project (CMIP5). Global NPP and EP are reduced considerably by the end of the century for the intense warming scenario of Representative Concentration Pathway (RCP) 8.5. Relative to the 1990s, global NPP in the 2090s is reduced by 2.3–16 % and EP by 7–18 %. The models with the largest increases in stratification (and largest relative reductions in NPP and EP) also show the largest positive biases in stratification for the contemporary period, suggesting some potential overestimation of climate impacts on NPP and EP. All of the CMIP5 models show an increase in stratification in response to surface ocean warming and freshening that is accompanied by decreases in NPP, EP, and surface macronutrient concentrations. There is considerable variability across models in the absolute magnitude of these fluxes, surface nutrient concentrations, and their perturbations by climate change, indicating large model uncertainties. The negative response of NPP and EP to stratification increases reflects a bottom-up control, as nutrient flux to the euphotic zone declines. Models with dynamic phytoplankton community structure show larger declines in EP than in NPP. This is driven by phytoplankton community composition shifts, with a reduced percentage of NPP by large phytoplankton under RCP 8.5, as smaller phytoplankton are favored under the increasing nutrient stress. Thus, projections of the NPP response to climate change in the CMIP5 models are critically dependent on the simulated phytoplankton community structure, the efficiency of the biological pump, and the resulting (highly variable) levels of regenerated production. Community composition is represented relatively simply in the CMIP5 models, and should be expanded to better capture the spatial patterns and the changes in export efficiency that are necessary for predicting climate impacts on NPP.

scholarly journals Climate change impacts on net primary production (NPP) and export production (EP) regulated by increasing stratification and phytoplankton community structure in the CMIP5 models

2016 ◽  
Vol 13 (18) ◽  
pp. 5151-5170 ◽  
Author(s):  
Weiwei Fu ◽  
James T. Randerson ◽  
J. Keith Moore
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Primary Production ◽  
Phytoplankton Community ◽  
Net Primary Production ◽  
Climate Change Impacts ◽  
Cmip5 Models ◽  
Nutrient Concentrations ◽  
Phytoplankton Community Structure ◽  
Export Production

Abstract. We examine climate change impacts on net primary production (NPP) and export production (sinking particulate flux; EP) with simulations from nine Earth system models (ESMs) performed in the framework of the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Global NPP and EP are reduced by the end of the century for the intense warming scenario of Representative Concentration Pathway (RCP) 8.5. Relative to the 1990s, NPP in the 2090s is reduced by 2–16 % and EP by 7–18 %. The models with the largest increases in stratification (and largest relative declines in NPP and EP) also show the largest positive biases in stratification for the contemporary period, suggesting overestimation of climate change impacts on NPP and EP. All of the CMIP5 models show an increase in stratification in response to surface–ocean warming and freshening, which is accompanied by decreases in surface nutrients, NPP and EP. There is considerable variability across the models in the magnitudes of NPP, EP, surface nutrient concentrations and their perturbations by climate change. The negative response of NPP and EP to increasing stratification reflects primarily a bottom-up control, as upward nutrient flux declines at the global scale. Models with dynamic phytoplankton community structure show larger declines in EP than in NPP. This pattern is driven by phytoplankton community composition shifts, with reductions in productivity by large phytoplankton as smaller phytoplankton (which export less efficiently) are favored under the increasing nutrient stress. Thus, the projections of the NPP response to climate change are critically dependent on the simulated phytoplankton community structure, the efficiency of the biological pump and the resulting levels of regenerated production, which vary widely across the models. Community structure is represented simply in the CMIP5 models, and should be expanded to better capture the spatial patterns and climate-driven changes in export efficiency.

Phytoplankton diversity and productivity in a highly turbid, tropical coastal system (Bach Dang Estuary, Vietnam)

2011 ◽  
Vol 8 (1) ◽  
pp. 487-525 ◽  
Author(s):  
E. J. Rochelle-Newall ◽  
V. T. Chu ◽  
O. Pringault ◽  
D. Amouroux ◽  
R. Arfi ◽  
...  
Keyword(s):  
Community Structure ◽  
Primary Production ◽  
Bacterial Production ◽  
Methyl Mercury ◽  
Phytoplankton Community ◽  
Inorganic Mercury ◽  
Phytoplankton Community Structure ◽  
Wet Season ◽  
Phytoplankton Diversity ◽  
Phytoplankton Distribution

Abstract. The factors controlling estuarine phytoplankton diversity and production are relatively well known in temperate systems. Less however is known about the factors affecting phytoplankton community distribution in tropical estuaries. This is surprising given the economic and ecological importance of these large, deltaic ecosystems, such as are found in South East Asia. Here we present the results from an investigation into the factors controlling phytoplankton distribution and phytoplankton-bacterial coupling in the Bach Dang Estuary, a sub-estuary of the Red River system, in Northern Vietnam. Phytoplankton diversity and primary and bacterial production, nutrients and metallic contaminants (mercury and organotin) were measured during two seasons: wet (July 2008) and dry (March 2009). Phytoplankton community composition differed between the two seasons with only a 2% similarity between July and March. The large spatial extent and complexity of defining the freshwater sources meant that simple mixing diagrams could not be used in this system. We therefore employed multivariate analyses to determine the factors influencing phytoplankton community structure. Salinity and suspended particulate matter were important factors in determining phytoplankton distribution, particularly during the wet season. We also show that phytoplankton community structure is probably influenced by the concentrations of mercury species (inorganic mercury and methyl mercury in both the particulate and dissolved phases) and of tri-, di, and mono-butyl tin species found in this system. Freshwater phytoplankton community composition was associated with dissolved methyl mercury and particulate inorganic mercury concentrations during the wet season, whereas, during the dry season, dissolved methyl mercury and particulate butyl tin species were important factors for the discrimination of the phytoplankton community structure. Phytoplankton-bacterioplankton coupling was also investigated during both seasons. In the inshore, riverine stations the ratio between bacterial production and dissolved primary production was high supporting the hypothesis that bacterial carbon demand is supported by allochthonous riverine carbon sources. The inverse was true in the offshore stations, where BP:DPP values were less than 1, potentially reflecting differences in primary production due to shifting phytoplankton community diversity.

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