Consulta: subjectFacets:"Primary productivity"
Registros recuperados: 10
Data/hora: 07/06/2024 03:58:56

Making ecological indicators management ready: Assessing the specificity, sensitivity, and threshold response of ecological indicators
Provedor de dados: 5
Autores: Fu, Caihong; Xu, Yi; Bundy, Alida; Grüss, Arnaud; Coll, Marta; Heymans, Johanna J.; Fulton, Elizabeth A.; Shannon, Lynne; Halouani, Ghassen; Velez, Laure; Akoğlu, Ekin; Lynam, Christopher P.; Shin, Yunne-jai.
Moving toward ecosystem-based fisheries management (EBFM) necessitates a suite of ecological indicators that are responsive to fishing pressure, capable of tracking changes in the state of marine ecosystems, and related to management objectives. In this study, we employed the gradient forest method to assess the performance of 14 key ecological indicators in terms of specificity, sensitivity and the detection of thresholds for EBFM across ten marine ecosystems using four modelling frameworks (Ecopath with Ecosim, OSMOSE, Atlantis, and a multi-species size-spectrum model). Across seven of the ten ecosystems, high specificity to fishing pressure was found for most of the 14 indicators. The indicators biomass to fisheries catch ratio (B/C), mean lifespan and...
Tipo: Text
Palavras-chave: Ecological modelling; Fishing pressure; Gradient forest method; Indictor performance; Marine ecosystem; Primary productivity.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00500/61148/64576.pdf

Phytoplancton en baie de Seine. Influence du panache fluvial sur la production primaire
Provedor de dados: 5
Autores: Videau, Christiane; Ryckaert, Mireille; L' Helguen, Stéphane.
Phytoplankton distribution and primary productivity were investigated in the Bay of Seine (eastern English Channel, France) in spring and early summer of 1992 and 1994. In 1992, the horizontal distribution of phytoplankton species was determined over the whole Bay of Seine. In 1994, species distribution and primary productivity were studied along the salinity gradient of the Seine plume and in the neighbouring marine waters. Phytoplankton distribution was characterised by the permanent diatom dominance from early spring to early summer. The spring bloom did not occur uniformly over the bay, but was initiated in the marine waters, in the middle of the bay and progressed towards the coast where it developed, in June, in the diluted waters of the Seine plume....
Tipo: Text
Palavras-chave: Baie de Seine; Production primaire; Phytoplancton; Bay of Seine; Primary productivity; Phytoplankton.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00333/44398/44057.pdf

Paleoproductivity variations in the southern Okinawa Trough since the middle Holocene: Calcareous nannofossil records
Provedor de dados: 5
Autores: Zhao, Jingtao; Li, Tiegang; Li, Jun; Hu, Bangqi.
Based on 17 AMS(14)C age data, we reconstructed high-resolution records of sea surface primary productivity (PP) in the southern Okinawa Trough (MD05-2908) over the last 6.8 ka BP using the calcareous nannofossil carbon isotope and the relative percentage contents of Florisphaera profunda indexes. The underlying mechanism controlling the sea surface PP was then discussed. The sea surface PP, indicated by the coccolith delta C-13 and %Fp conversional equations, decreased with some fluctuations since 6.8 ka BP. This decrease may be connected to the decreased terrigenous input resulting from the reduced East Asian Summer Monsoon (EASM) precipitation. Both the periods of 4-2 ka BP (PME) and 6.8-4.8 ka BP were characterized by relatively higher PP. The former...
Tipo: Text
Palavras-chave: Middle Holocene; The southern Okinawa Trough; Primary productivity; Calcareous nannofossil.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00265/37615/36518.pdf

A relationship between deep-sea benthic oxygen demand and oceanic primary productivity
Provedor de dados: 5
Autores: Christensen, Jp.
A diagenetic model of porewater O-2 was used to examine the relationship between organic carbon flux to the sediments and benthic oxygen demand (BOD). The model predicted that the organic carbon influx to sediments balances BOD as long as sediments are oxygenated. The critical rate occurs when O-2 at infinite depth disappears. With influxes exceeding the critical rate, the O-2 flux into the sediments via molecular diffusion can not consume all incoming organic matter, and anaerobic conditions result in BOD underestimating the carbon influx. Given that low rates of deep-sea BOD approximate the carbon influx below 9 g.C.m(-2).y(-1), a significant multilinear regression was found between published BOD, primary productivity (P-p, both in g.C.m(-2).y(-1))(,)...
Tipo: Text
Palavras-chave: Fonds marins; Oxygène; Production primaire; Respiration; Sédiments; Deep-sea; Oxygen; Primary productivity; Respiration; Sediments.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/00325/43578/44046.pdf

Phytoplancton en baie de Seine. Influence du panache fluvial sur la production primaire
Provedor de dados: 5
Autores: Videau, Christiane; Ryckaert, Mireille; L' Helguen, Stéphane.
Phytoplankton distribution and primary productivity were investigated in the Bay of Seine (eastern English Channel, France) in spring and early summer of 1992 and 1994. In 1992, the horizontal distribution of phytoplankton species was determined over the whole Bay of Seine. In 1994, species distribution and primary productivity were studied along the salinity gradient of the Seine plume and in the neighbouring marine waters. Phytoplankton distribution was characterised by the permanent diatom dominance from early spring to early summer. The spring bloom did not occur uniformly over the bay, but was initiated in the marine waters, in the middle of the bay and progressed towards the coast where it developed, in June, in the diluted waters of the Seine plume....
Tipo: Text
Palavras-chave: Bay of Seine; Primary productivity; Phytoplankton; Baie de Seine; Production primaire; Phytoplancton.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/1998/publication-843.pdf

Intraseasonal variability of nearshore productivity in the Northern Humboldt Current System: the role of coastal trapped waves
Provedor de dados: 5
Autores: Echevin, Vincent; Albert, Aurelie; Levy, Marina; Graco, Michelle; Aumont, Olivier; Pietri, Alice; Garric, Gilles.
The impact of intraseasonal coastal-trapped waves on the nearshore Peru ecosystem is investigated using observations and a regional eddy-resolving physical-ecosystem coupled model. Model results show that intraseasonal variability over the period 2000–2006 represents about one fourth of the total surface chlorophyll variance and one third of the carbon export variance on the Peruvian shelf. Evidence is presented that subsurface nutrient and chlorophyll intraseasonal variability are mainly forced by the coastally trapped waves triggered by intraseasonal equatorial Kelvin waves reaching the south american coast, and propagate poleward along the Peru shore at a speed close to that of high order coastal trapped waves modes. The currents associated with the...
Tipo: Text
Palavras-chave: Coastally trapped waves; Upwelling dynamics; Humboldt system; Intraseasonal variability; Primary productivity.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00166/27692/25885.pdf

Patterns of litter production in a secondary alluvial Atlantic Rain Forest in southern Brazil
Provedor de dados: 88
Autores: Scheer,Maurício Bergamini; Gatti,Gustavo; Wisniewski,Celina; Mocochinski,Alan Yukio; Cavassani,André Targa; Lorenzetto,Alexandre; Putini,Francisco.
Above-ground litter production is one of the most accessible ways to estimate ecosystem productivity, nutrient fluxes and carbon transfers. Phenological patterns and climatic conditions are still not fully explained well for tropical and subtropical forests under less pronounced dry season and non-seasonal climates, as well as the interaction of these patterns with successional dynamics. Monthly litterfall was estimated for two years in a 9 to 10 year old secondary alluvial Atlantic Rain forest. Total litterfall was higher in the site with more developed vegetation (6.4 ± 1.2 ton ha-1 year-1; 95% confidence interval) as compared to the site with less developed vegetation (3.0 ± 1.0 ton ha-1 year-1). The monthly production of 11 litter fractions (eight...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Litterfall; Meteorological variables; Phenology; Primary productivity; Sucession.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042009000400018

Enzyme activities of phytoplankton in the South Shetland Islands (Antarctica) in relation to nutrients and primary production
Provedor de dados: 97
Autores: IRIARTE,JOSÉ L; GONZÁLEZ,RODRIGO R; QUIÑONES,RENATO A; KANG,SUNG-HO; SHIM,JAE H; VALENZUELA,CYNTHIA P.
Given the potential significance of enzyme activities as a link between internal metabolic pathways and environmental nutrients, we investigated the relationships of nitrate reductase (NR) and alkaline phosphatase (AP) with primary production and inorganic nutrients in South Shetland Islands, Antarctica. Enzymatic activities of the phytoplankton (0.7-210 µm), primary productivity, autotrophic biomass and inorganic nutrients were studied in the upper 100 m depth at nine stations during a cruise in the northwestern area of South Shetland Islands (Antarctica), during late austral spring (December 2000). NR activities fluctuated between 0 and 42.8 nmol L-1 h-1 (mean = 10.08 nmol L-1 h-1, SD = 10.42 nmol L-1 h-1), AP activities between 0.81 and 5.67 nmol L-1...
Tipo: Journal article
Palavras-chave: Nitrate reductase; Alkaline phosphatase; Primary productivity; Chlorophyll; Antarctica.
Ano: 2006
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2006000400009

Effects of UV on photosynthesis of Antarctic phytoplankton: models and their application to coastal and pelagic assemblages
Provedor de dados: 97
Autores: NEALE,PATRICK J.; FRITZ,JENNIFER J.; DAVIS,RICHARD F.
We have characterized the photosynthetic response to ultraviolet radiation (UV) of natural phytoplankton assemblages in Antarctic (Southern Ocean) waters. Biological weighting functions (BWFs) and exposure response curves for inhibition of photosynthesis by UV were measured during spring-time ozone depletion (October-November). Two different models were developed to relate photosynthesis to UV exposure. A model that is a function of the duration of exposure (BWF H) applied to assemblages in the well-mixed open waters of the Weddell-Scotia Confluence (WSC, 60° S, 50° W), since responses were a function of cumulative exposure and recovery rates were slow. These assemblages had a variable but generally high sensitivity to UV. A steady-state model (BWF E)...
Tipo: Journal article
Palavras-chave: Southern Ocean; Primary productivity; Ozone depletion; Photosynthesis-irradiance curves; Biological weighting functions.
Ano: 2001
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2001000200006

A potential nutritional modifier for predicting primary productivity of Pinus radiata in New Zealand using a simplified radiation-use efficiency model
Provedor de dados: 118
Autores: Bown,Horacio E; Mason,Euan G; Watt,Michael S; Clinton,Peter W.
H.E. Bown, E.G. Mason, M.S. Watt, and P.W. Clinton. 2013. A potential nutritional modifier for predicting primary productivity of Pinus radiata in New Zealand using a simplified radiation-use efficiency model. Cien. Inv. Agr. 40(2): 361-374. The 3-PG (Physiological Principles in Predicting Growth) radiation-use efficiency model has been widely used and tested for predicting the primary productivity of forests all over the world. This radiation-use efficiency model accounts for plant nutrition through a user-defined dimensionless fertility parameter (fN) that determines the effects a unit of radiation. Currently, this fertility parameter has to be entered by the user based on intuition or experience. The goal of this study was to propose a fertility...
Tipo: Journal article
Palavras-chave: Nutritional modifier; Pinus radiata; Primary productivity; Radiation-use efficiency; Soil C/N; Soil N.
Ano: 2013
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202013000200011