scholarly journals Influence of atmospheric nutrients on primary productivity in a coastal upwelling region

2010 ◽  
Vol 24 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Katherine R. M. Mackey ◽  
Gert L. van Dijken ◽  
Simran Mazloom ◽  
Andrea M. Erhardt ◽  
John Ryan ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Coastal Upwelling ◽  
Atmospheric Nutrients

scholarly journals Population parameters and the relationships between environmental factors and abundance of the Acetes americanus shrimp (Dendrobranchiata: Sergestidae) near a coastal upwelling region of Brazil

2015 ◽  
Vol 63 (3) ◽  
pp. 229-238
Author(s):  
Ana Paula Freitas dos Santos ◽  
Sabrina Morilhas Simões ◽  
Gabriel Lucas Bochini ◽  
Cinthia Helena Costa ◽  
Rogerio Caetano da Costa
Keyword(s):  
Population Dynamics ◽  
Sexual Dimorphism ◽  
Environmental Factors ◽  
Primary Productivity ◽  
Low Temperatures ◽  
Coastal Upwelling ◽  
Statistical Correlation ◽  
Individual Growth ◽  
Otter Trawl ◽  
Population Parameters

AbstractThe population dynamics of Acetes americanus was investigated, focusing on the sex ratio, individual growth, longevity, recruitment and relationship between abundance and environmental factors in the region of Macaé, strongly influenced by coastal upwelling. Otter trawl net samplings were performed from July 2010 to June 2011 at two points (5 m and 15 m). Nearly 19,500 specimens, predominantly females (77.15%), were captured. Their sizes, larger than that of males, indicated sexual dimorphism. Shrimps at lower latitudes present larger sizes and longer longevity than those from higher latitudes. This difference is probably due to low temperatures and high primary productivity. Though no statistical correlation was found between abundance and environmental factors, the species was more abundant in temperatures closer to 20.0º C and in months with high chlorophyll-a levels. Due to the peculiar characteristics of this region, A. americanusshowed greater differences in size and longevity than individuals sampled in other studies undertaken in the continental shelf of Southeast Brazil.

scholarly journals Investigation of the abundance, distribution and composition of microplastics at coastal upwelling sites in the Atlantic Ocean

2016 ◽  
Author(s):  
La Daana K Kanhai ◽  
Rick Officer ◽  
Ian O'Connor ◽  
Richard C Thompson
Keyword(s):  
Atlantic Ocean ◽  
Surface Waters ◽  
Primary Productivity ◽  
Null Hypothesis ◽  
Latitudinal Gradient ◽  
Coastal Upwelling ◽  
Abundance Distribution ◽  
Significant Difference ◽  
Benguela Upwelling ◽  
Canary Upwelling

Microplastics are an issue of international concern due to the fact that these substances may potentially threaten biota by (i) causing physical harm, (ii) transporting persistent, bioaccumulating and toxic (PBT) substances and, (iii) leaching plastic additives. Within the world’s oceans, areas which experience coastal upwelling are biota rich due to their high levels of primary productivity. The assessment of microplastic presence in areas which experience coastal upwelling is vital as it will indicate whether microplastics are an issue of concern in areas which support key biological resources. The null hypothesis of the present study is that microplastic abundance will be lower in areas where there is upwelling. As such, the present study aims to investigate whether microplastic abundance in upwelled areas in the Atlantic Ocean is significantly different from non-upwelled areas. Based on an opportunistic voyage aboard the RV Polarstern, microplastics will be sampled in sub-surface waters along a diverse latitudinal gradient in the Atlantic Ocean i.e. from Bremerhaven (Germany) to Cape Town (South Africa). Based on the proposed route, it will be possible to determine microplastic levels at two areas of coastal upwelling in the Atlantic Ocean (i) Canary Upwelling Ecosystem (CUE) and (ii) Benguela Upwelling Ecosystem (BUE). The results will then be analysed to determine whether there was a statistically significant difference between ‘upwelled areas’ and ‘non-upwelled areas’.

scholarly journals Investigation of the abundance, distribution and composition of microplastics at coastal upwelling sites in the Atlantic Ocean

2016 ◽  
Author(s):  
La Daana K Kanhai ◽  
Rick Officer ◽  
Ian O'Connor ◽  
Richard C Thompson
Keyword(s):  
Atlantic Ocean ◽  
Surface Waters ◽  
Primary Productivity ◽  
Null Hypothesis ◽  
Latitudinal Gradient ◽  
Coastal Upwelling ◽  
Abundance Distribution ◽  
Significant Difference ◽  
Benguela Upwelling ◽  
Canary Upwelling

Microplastics are an issue of international concern due to the fact that these substances may potentially threaten biota by (i) causing physical harm, (ii) transporting persistent, bioaccumulating and toxic (PBT) substances and, (iii) leaching plastic additives. Within the world’s oceans, areas which experience coastal upwelling are biota rich due to their high levels of primary productivity. The assessment of microplastic presence in areas which experience coastal upwelling is vital as it will indicate whether microplastics are an issue of concern in areas which support key biological resources. The null hypothesis of the present study is that microplastic abundance will be lower in areas where there is upwelling. As such, the present study aims to investigate whether microplastic abundance in upwelled areas in the Atlantic Ocean is significantly different from non-upwelled areas. Based on an opportunistic voyage aboard the RV Polarstern, microplastics will be sampled in sub-surface waters along a diverse latitudinal gradient in the Atlantic Ocean i.e. from Bremerhaven (Germany) to Cape Town (South Africa). Based on the proposed route, it will be possible to determine microplastic levels at two areas of coastal upwelling in the Atlantic Ocean (i) Canary Upwelling Ecosystem (CUE) and (ii) Benguela Upwelling Ecosystem (BUE). The results will then be analysed to determine whether there was a statistically significant difference between ‘upwelled areas’ and ‘non-upwelled areas’.

Revised Ages for Laminated Sediment and a Holocene-Marker Diatom from the Northern California Continental Slope

1994 ◽  
Vol 41 (1) ◽  
pp. 131-135 ◽  
Author(s):  
Eileen Hemphill-Haley ◽  
James V. Gardner
Keyword(s):  
Mass Spectrometry ◽  
Continental Slope ◽  
Primary Productivity ◽  
Coastal Upwelling ◽  
California Current ◽  
Northern California ◽  
Laminated Sediment ◽  
Climatic Regime ◽  
Reliable Marker ◽  
Upper Slope

AbstractConventional and accelerator mass spectrometry 14C ages indicate that laminated sediment in three cores from the northern California continental slope near 38°N and 39°N were deposited between 42,000 and 25,000 yr B.P. This revises and refines our previous estimates that laminated sediment accumulated during the late Pleistocene to early Holocene (J. V. Gardner and E. Hemphill-Haley, 1986, Geology 14, 691-694). Preservation of laminated sediment on the upper slope in this area suggests a period of intense coastal upwelling, high primary productivity, and resultant depletion of oxygen in bottomwaters preceding the onset of global glacial conditions. The transition from Pleistocene to Holocene conditions, and the establishment of a modern climatic regime driven by the California Current, included the incursion of the subtropical diatom, Pseudoeunotia doliola. P. doliola is common in sediment younger than about 10,000 yr and thus is a reliable marker species for identifying Holocene deposits off northern California.

scholarly journals Carbon regeneration in the Cariaco Basin, Venezuela

2017 ◽  
Vol 65 (1) ◽  
pp. 19-28
Author(s):  
Arístides Marquez ◽  
Andrew Dale ◽  
Luis Troccoli Ghinaglia ◽  
Fabiola López Monroy ◽  
William Senior ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Primary Productivity ◽  
Organic Material ◽  
Inorganic Carbon ◽  
Coastal Upwelling ◽  
Anaerobic Respiration ◽  
Total Alkalinity ◽  
Cariaco Basin ◽  
Oxic Zone ◽  
Carbon Regeneration

Abstract The carbon regeneration in the water column of the Cariaco Basin (Venezuela) was investigated using a regression model of total alkalinity (TA) and the concentration of total inorganic carbon (TCO2). Primary productivity (PP) was determined from the inorganic carbon fraction assimilated by phytoplankton and the variation of the 22 and 23ºC isotherm was used as an indicator of coastal upwelling. The results indicate that CO2 levels were lowest (1962 µmol/kg) at the surface and increased to 2451 µmol/kg below the oxic-anoxic redox interface. The vertical regeneration distribution of carbon was dominated (82%) by organic carbon originating from the soft tissue of photosynthetic organisms, whereas 18% originated from the dissolution of biogenic calcite. The regeneration of organic carbon was highest in the surface layer in agreement with the primary productivity values. However, at the oxic-anoxic interface a second more intense maximum was detected (70-80%), generated by chemotrophic respiration of organic material by microorganisms. The percentages in the anoxic layers were lower than in the oxic zone because aerobic decomposition occurs more rapidly than anaerobic respiration of organic material because more labile fractions of organic carbon have already been mineralized in the upper layers.

scholarly journals Seasonal Distribution of Nutrients and Primary Productivity on the Eastern Continental Shelf of Venezuela as Influenced by the Orinoco River

2016 ◽  
Author(s):  
JAIME BONILLA ◽  
William James Senior
Keyword(s):  
Continental Shelf ◽  
Primary Productivity ◽  
Coastal Upwelling ◽  
Nutrient Status ◽  
Dry Season ◽  
Wet Season ◽  
Orinoco River ◽  
Carbon 14 ◽  
Low Salinity ◽  
The Caribbean

Nitrogenous nutrients, dissolved silicate, and salinity were measured in surface waters and shallowhydrocasts along similar cruise tracks during the spring (dry season) and fall (wet season) of 1988. Bothcruises transected the eastern Caribbean, transited the Gulf of Paria, ran parallel to the Orinoco Deltaand into the main channel of the Orinoco River. Trends in primary productivity were also measuredby daily carbon 14 incubations. In both seasons, samples covered the range from highly oligotrophicand transparent to highly productive and rich in biogenic and abiogenic particulate matter. Most of theOrinoco outflow appears to turn N to NW and remains in shallow waters off Venezuela andsurrounding Trinidad, permitting benthic regeneration of river-borne nutrients. However, the role ofthe Orinoco and associated low-salinity coastal waters in fertilizing large areas of the easternCaribbean basin, as suggested by satellite imagery, can be approximated crudely from the nutrientcomposition at Boca de Dragon, which is representative of the nutrient status of these waters as theyflow into deeper Caribbean waters. Additional nutrients may be supplied to the area primarily fromAmazon-derived water entering the Caribbean Basin further north, with some coastal upwelling alongthe continental shelf in the dry season.

Southeast tropical Atlantic changing from subtropical to tropical conditions

2021 ◽  
Author(s):  
Marisa Roch ◽  
Peter Brandt ◽  
Sunke Schmidtko
Keyword(s):  
Wind Stress ◽  
Surface Waters ◽  
Primary Productivity ◽  
Coastal Upwelling ◽  
Ocean Dynamics ◽  
Upper Ocean ◽  
Tropical Atlantic ◽  
Ocean Stratification ◽  
Tropical Conditions ◽  
Stress Changes

<div> <p><span>A warming and freshening trend of the mixed layer in the upper southeast tropical Atlantic Ocean (SETA) is observed by the Argo observation array during the time period of 2006 to 2019. Thus, the ocean surface density is reducing. This has an impact on the upper-ocean stratification which intensified by more than 30 % in the SETA region since 2006. The initial typical subtropical stratification with a salinity maximum at the surface is shifted to more tropical conditions characterized by warmer and fresher surface waters and a subsurface salinity maximum. </span></p> </div><div> <p><span>A more detailed analysis of isopycnals shows a continuous upward displacement of isopycnal surfaces suggesting that wind stress curl-driven upwelling has to play an essential role. Therefore, ASCAT wind stress changes are examined, revealing that increased open ocean wind curl-driven upwelling but also partly counteracting reduced coastal upwelling due to weakened alongshore southerly winds are present. Changing alongshore winds might be a reason why tropical surface waters spread further southward reaching more into the SETA region. Besides, atmospheric fluxes could further impact upper ocean characteristics. </span></p> </div><div> <p><span>Changes in the upper-ocean stratification matter as they affect not only physical ocean dynamics such as ocean ventilation processes but also biogeochemical and ecological activities such as nutrient fluxes and fisheries. Nevertheless, the consequences of increased stratification for upwelling regions are not yet fully understood. The SETA upwelling system is a key region for enhanced nutrient supply to the euphotic zone and hence, a core nutrient source for high coastal primary productivity. </span></p> </div><p>We aim to assess the recent change of upper-ocean stratification towards tropical conditions at the sea surface in the SETA region and explore its driving mechanisms as well as possible consequences for the primary productivity and fisheries off Angola and Namibia, in order to improve our understanding of what is happening as a result of intensified upper-ocean stratification in upwelling regions.</p>

The impact of global warming on the upwellings and primary productivity at the southern limb of the California Current, Baja California, Mexico

2020 ◽  
Author(s):  
Jose Carriquiry ◽  
Christina Treinen-Crespo ◽  
Julio Villaescusa ◽  
Ann Pearson ◽  
Loic Barbara
Keyword(s):  
Primary Productivity ◽  
Large Scale ◽  
Baja California ◽  
Coastal Upwelling ◽  
Current System ◽  
California Current ◽  
Phytoplankton Productivity ◽  
California Current System ◽  
Instrumental Records ◽  
The Impact

<p>Although most simulation models published have concluded that coastal upwelling will intensify in three of the most productive marine ecosystems of the world, the results seem contradictory for the California Current System (CCS). These contradictory results may be due to the fact that instrumental records are too short to yield reliable predictions. Because of this, we opted to test this hypothesis by studying the sedimentary record of Soledad basin, in Baja California, Mexico, using geochemical proxies to reconstruct at ultra-high resolution the history of productivity and sea surface temperature during the last two millennia, with particular emphasis on the Anthropocene. Our results indicate that SST (alkenones and TEX-86) do not show a cooling trend during the Anthropocene, but rather multidecadal cycles related to PDO. Likewise, primary productivity organic biomarkers [i.e., alkenone concentration (C37 Total) as a proxy for phytoplankton productivity, etc] show an increasing trend that started 2000 years ago with prominent multidecadal cycles, but without any observable trend taking place during the Anthropocene. An interesting feature of the organic matter record is the increasing amplitude of the cycles towards the present, starting 2000 years ago. Primary productivity is probably controlled by large scale mesoscale eddies developing at the southern Baja California margin.</p>

scholarly journals Net primary productivity, upwelling and coastal currents in the Gulf of Ulloa, Baja California, Mexico

2011 ◽  
Vol 8 (5) ◽  
pp. 1979-1999 ◽  
Author(s):  
E. González-Rodríguez ◽  
A. Trasviña-Castro ◽  
G. Gaxiola-Castro ◽  
L. Zamudio ◽  
R. Cervantes-Duarte
Keyword(s):  
Satellite Data ◽  
Primary Productivity ◽  
Baja California ◽  
Net Primary Productivity ◽  
Coastal Upwelling ◽  
Production Model ◽  
Coastal Current ◽  
Western Coast ◽  
Productive Area ◽  
Seasonal Signal

Abstract. The Gulf of Ulloa, a highly productive area off the western coast of Baja California Peninsula, is examined for five successive years (2003–2007) by using satellite data and seasonal net primary productivity estimates obtained by a vertical generalized production model. The results clearly identify a seasonal signal of coastal upwelling in productivity estimates. Highest values occur from May to June and sometimes July. We also find influence of an equatorward coastal current able of transporting water from neighboring north upwelling areas to the Gulf of Ulloa in winter–spring. This flow contributes to increase the seasonal net primary productivity. The opposite occurs in summer, when a warm poleward current of tropical characteristics arrives to the region. Our findings reveal that such warm coastal current suppressed the productivity in the whole.

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