Iron bioavailability in the Southern Ocean

Hassler, Christel; Schoemann, Véronique; Boyé, Marie; Tagliabue, Alessandro; Rozmarynowycz, Mark J.; McKay, R. Michael L.

doi:10.1201/b12157-3

Cited by 38 publications

(32 citation statements)

References 301 publications

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“…Nogueira et al (2010) observed the effects of the dams constructed in Paranapanema River on the structure of phytoplankton and pointed out that they had a negative effect on the richness of these organisms. Discharge of nutrients into water bodies have been reported to increase phytoplankton density, especially cyanobacteria (PIZZOLON et al, 1999;NOGUEIRA et al, 2010;GOWEN et al, 2012). Furthermore, Chellappa and Costa (2003) found that the intensive fish-farming in a northeastern Brazil reservoir provided favorable conditions for the dominance of cyanobacteria.…”

Section: Introductionmentioning

confidence: 99%

Impact of filamentous cyanobacteria on the water quality of two tropical reservoirs

Barros

Lopes

Carvalho³

et al. 2017

RBRH

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Artificial lakes play an important role in water availability in tropical semi-arid Northeastern Brazil. However, in addition to the negative effects that dams have on the water quality of rivers, other practices such as discharge of untreated wastewater, intensive crop fertilization and fish farming have been contributing to water quality deterioration. Climate change may be another driver of water quality decrease. Increases in precipitation and drought intensities as well as temperature increase may redefine the dynamics of planktonic communities and favour species more adapted to the new environment. Water samples were collected in two reservoirs selected based on the recurrence of positive results for saxitoxins, Acarape do Meio (AM) and Sitios Novos (SN). In general, diversity in SN (1.08) was higher than in the AM (0.60). Phytoplankton dynamics in these reservoirs differ from other reservoirs in the same region of Brazil, in the sense that filamentous cyanobacteria are dominant. Furthermore, lower diversity, concentration and richness of chlorophyceae and bacillariophyceae were found in both reservoirs. Increase in diversity was observed during the intense rainy season of 2011, suggesting a slight improvement of water quality. A close inverse correlation between Cylindrospermopsis sp and other cyanobacteria was found in SN (R 2 = -0.862) and in AM (R 2 = -0.997) and the data collected demonstrates that a season with intensive rainfall may lead to lower cyanobacteria concentrations probably due to water dilution and higher flushing rates.Keywords: Artificial reservoirs; Freshwater cyanobacteria; Semi-arid regions; Temporal phytoplankton dynamics; Eutrophication. RESUMOOs lagos artificiais tem um papel primordial na disponibilidade hídrica no semi-árido Brasileiro. Entretanto, além dos efeitos negativos que os barramentos dos rios causam sobre a qualidade da água, a descarga de esgotos, a irrigação e a piscicultura intensivas vêm acentuando a deterioração da qualidade da água em um ritmo sem precedentes nesta região. A mudança climática é outro fator de impacto negativo na qualidade da água. O aumento da intensidade das precipitações pode redefinir a dinâmica das comunidades de plâncton e espécies mais adaptadas a ambientes extremamente variáveis. Os reservatórios estudados, Acarape do Meio (AM) e Sítios Novos (SN), foram selecionados com base na recorrência de resultados positivos para saxitoxinas. A dinâmicas do fitoplâncton encontrada, difere de outras áreas da mesma região, no sentido em que as cianobactérias filamentosas são dominantes. Baixas diversidade, concentração média e riqueza de Chlorophyceae e Bacillariophyceae foram encontrados em ambos os reservatórios, embora tenha sido observado um aumento durante o intenso período chuvoso de 2011, sugerindo uma ligeira melhoria da qualidade da água. Em geral, a diversidade no reservatório SN (1,08) foi maior que no AM (0,60). Uma correlação inversa entre a concentração de Cylindrospermopsis sp e outras cianobactérias foi encontrada nos reservatór...

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Section: Introductionmentioning

confidence: 99%

Impact of filamentous cyanobacteria on the water quality of two tropical reservoirs

Barros

Lopes

Carvalho³

et al. 2017

RBRH

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“…One of the many risks to coastal aquaculture are HABs as they can cause mortalities for the farmed species, predominantly fish, and infections through biotoxins via shellfish consumption, such as Diarrhetic Shellfish Poisoning (DSP), Paralytic Shellfish Poisoning (PSP); Neurotoxic Shellfish Poisoning (NSP), and Amnesic Shellfish Poisoning (ASP). In some areas, HABs can be linked to anthropogenic influences through e.g., urban sewage and agriculture-induced nutrient-rich river-run offs (Gowen et al, 2012), however, other blooms originate naturally, e.g., due to El Niño events. After a severe algal bloom in 2016, Chilean aquaculture experienced extreme mortalities of ∼40 million farmed salmons, which caused a financial loss of US $800 million (Apablaza et al, 2017).…”

Section: Environmental Benefits and Limitationsmentioning

confidence: 99%

State of the Art and Challenges for Offshore Integrated Multi-Trophic Aquaculture (IMTA)

et al. 2018

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By moving away from coastal waters and hence reducing pressure on nearshore ecosystems, offshore aquaculture can be seen as a possible step towards the large-scale expansion of marine food production. Integrated multi-trophic aquaculture (IMTA) in nearshore water bodies has received increasing attention and could therefore play a role in the transfer of aquaculture operations to offshore areas. IMTA holds scope for multi-use of offshore areas and can bring environmental benefits from making use of waste products and transforming these into valuable co-products. Furthermore, they may act as alternative marine production systems and provide scope for alternative income options for coastal communities, e.g., by acting as nodes for farm operation and maintenance requirements. This paper summarizes the current state of knowledge on the implications of the exposed nature of offshore and open ocean sites on the biological, technological and socio-economic performance of IMTA. Of particular interest is improving knowledge about resource flows between integrated species in hydrodynamic challenging conditions that characterize offshore waters.

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“…Methods described in (Gowen et al, 1995) Phytoplankton composition As found in White et al, 1988;Hill et al, 1994Hill et al, , 1996Dickey-Collas et al, 1996a;Gowen et al, 1998a;Trimmer et al, 1999Trimmer et al, , 2003Lynam et al, 2011) McKinney et al, 1997;Gowen et al, 1999Gowen et al, , 2012Scherer, 2012 Diatoms (large) Si-requiring; cells >20 µm total length; Rhizosolenia, Guinardia, Thalassiosira, Coscinodiscus McKinney et al, 1997;Gowen et al, 1999Gowen et al, , 2012Scherer, 2012 Silico (6), where the numbers are the "functional groups" of Benedetti et al (2015) who classify them all as "nonpredators," i.e., as feeders (in various ways) on protoctistan microplankton of detritus; seasonal succession Pseudocalanus to Acartia in WIS Scrope-Howe and Gowen et al, 1998aGowen et al, , 1999 Copepods (large) >2.5 mm as adults; including copepodites; Calanus (4), also "nonpredators"; overwinter in deep water, so their seasonal cycle as well as size distinguishes them from the other copepods…”

Section: Ecohydrodynamicsmentioning

confidence: 99%

“…We see this as highly dynamic at the species level (Gowen et al, 2012), naturally varying both inter-annually and seasonally, but always with a requirement for a dynamic balance of functional groups or "lifeforms." Assessment can thus be based on the relative seasonal patterns of microplankton lifeforms, such as the succession from diatoms to dinoflagellates expected in seasonally-stratifying temperate seas.…”

Section: Assessment Scheme For Ges In the Pelagic Habitatmentioning

confidence: 99%

Assessing the State of the Pelagic Habitat: A Case Study of Plankton and Its Environment in the Western Irish Sea

2016

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Much work had been undertaken on tracking change in the condition of marine pelagic ecosystems and on identifying regime shifts. However, it is also necessary to relate change to states of good ecosystem health or what the European Marine Strategy Framework Directive (MSFD) calls "Good Environmental Status" (GES). Drawing on existing scientific and legislative principles, including those of OSPAR's "Strategy to Combat Eutrophication," we propose a framework for assessing the status of what the MSFD calls the "pelagic habitat" in temperate coastal seas. The framework uses knowledge of local ecohydrodynamic conditions, especially those relating to the stratification and optical environment, to guide expectations of what would be recognized as healthy in terms of ecosystem "organization" and "vigor." We apply this framework to the seasonally stratified regime of the Western Irish Sea, drawing on published and new work on stratification, nutrient, and phytoplankton seasonal cycles, zooplankton, and the implications of plankton community structure and production for higher trophic levels. We conclude that, despite human pressures including nutrient enrichment, and the food-web effects of fisheries, the pelagic ecosystem here is in GES, and hence may be used as a reference for the "Plankton Index" method of tracking change in state space in seasonally stratified waters.

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Iron bioavailability in the Southern Ocean

Cited by 38 publications

References 301 publications

Impact of filamentous cyanobacteria on the water quality of two tropical reservoirs

Impact of filamentous cyanobacteria on the water quality of two tropical reservoirs

State of the Art and Challenges for Offshore Integrated Multi-Trophic Aquaculture (IMTA)

Assessing the State of the Pelagic Habitat: A Case Study of Plankton and Its Environment in the Western Irish Sea

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