The Formation of Subtropical Phytoplankton Blooms Is Dictated by Water Column Stability During Winter and Spring in the Oligotrophic Northwestern North Pacific

While winter storms are generally common in western Europe, the rarer summer storms may result in more pronounced impacts on lake physics. Using long-term, high frequency datasets of weather and lake thermal structure from the west of Ireland (2005 to 2017), we quantified the effects of storms on the physical conditions in a monomictic, deep lake close to the Atlantic Ocean. We analysed a total of 227 storms during the stratified (May to September, n = 51) and non-stratified (November to March, n = 176) periods. In winter, as might be expected, changes were distributed over the entire water column, whereas in summer, when the lake was stratified, storms only impacted the smaller volume above the thermocline. During an average summer (May–September) storm, the lake number dropped by an order of magnitude, the thermocline deepened by an average of 2.8 m, water column stability decreased by an average of 60.4 j m−2 and the epilimnion temperature decreased by a factor of five compared to the average change in winter (0.5 °C vs. 0.1 °C). Projected increases in summer storm frequency will have important implications for lake physics and biological pathways.

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Differing Growth Responses of Major Phylogenetic Groups of Marine Bacteria to Natural Phytoplankton Blooms in the Western North Pacific Ocean

Applied and Environmental Microbiology ◽

10.1128/aem.02952-10 ◽

2011 ◽

Vol 77 (12) ◽

pp. 4055-4065 ◽

Cited By ~ 76

Author(s):

Yuya Tada ◽

Akito Taniguchi ◽

Ippei Nagao ◽

Takeshi Miki ◽

Mitsuo Uematsu ◽

...

Keyword(s):

Organic Matter ◽

Bacterial Community ◽

North Pacific ◽

Bacterial Production ◽

Western North Pacific ◽

Bacterial Abundance ◽

North Pacific Ocean ◽

Growth Potential ◽

Phytoplankton Blooms ◽

Content Type

ABSTRACTGrowth and productivity of phytoplankton substantially change organic matter characteristics, which affect bacterial abundance, productivity, and community structure in aquatic ecosystems. We analyzed bacterial community structures and measured activities inside and outside phytoplankton blooms in the western North Pacific Ocean by using bromodeoxyuridine immunocytochemistry and fluorescencein situhybridization (BIC-FISH).Roseobacter/Rhodobacter, SAR11,Betaproteobacteria,Alteromonas, SAR86, andBacteroidetesresponded differently to changes in organic matter supply.Roseobacter/Rhodobacterbacteria remained widespread, active, and proliferating despite large fluctuations in organic matter and chlorophylla(Chl-a) concentrations. The relative contribution ofBacteroidetesto total bacterial production was consistently high. Furthermore, we documented the unexpectedly large contribution ofAlteromonasto total bacterial production in the bloom. Bacterial abundance, productivity, and growth potential (the proportion of growing cells in a population) were significantly correlated with Chl-aand particulate organic carbon concentrations. Canonical correspondence analysis showed that organic matter supply was critical for determining bacterial community structures. The growth potential of each bacterial group as a function of Chl-aconcentration showed a bell-shaped distribution, indicating an optimal organic matter concentration to promote growth. The growth ofAlteromonasandBetaproteobacteriawas especially strongly correlated with organic matter supply. These data elucidate the distinctive ecological role of major bacterial taxa in organic matter cycling during open ocean phytoplankton blooms.

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Relationship of water column stability to the growth, condition, and survival of pink salmon (Oncorhynchus gorbuscha) in the northern coastal Gulf of Alaska and Prince William Sound

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f2012-031 ◽

2012 ◽

Vol 69 (5) ◽

pp. 955-969 ◽

Cited By ~ 3

Author(s):

Sara E. Miller ◽

Milo Adkison ◽

Lewis Haldorson

Keyword(s):

Water Column ◽

Growth Condition ◽

Pink Salmon ◽

Gulf Of Alaska ◽

Oncorhynchus Gorbuscha ◽

Biological Parameters ◽

Prince William Sound ◽

Pink Salmon Oncorhynchus Gorbuscha ◽

Fish Condition ◽

Water Column Stability

Water column stability has been hypothesized to affect growth and ultimately survival of juvenile fish. We estimated the relationships between stability and the growth, condition, and marine survival of several stocks of pink salmon ( Oncorhynchus gorbuscha ) within Prince William Sound (PWS), Alaska, USA, and the northern coastal Gulf of Alaska (GOA) shelf. There was a stronger correlation among the biological parameters of the fish than between the biological parameters and physical conditions. While stability and fish condition during early marine residence in PWS were important to year-class survival, stability of the water column that juveniles experienced as they migrated to the open waters of the GOA did not play a key role in determining survival to adulthood. Below-average stability just prior to capture within PWS combined with positive fish condition was related to increased year-class survival. Our results are similar to previous studies that concluded that slower and weaker development of stratification with a deeper mixed layer depth may be important for juvenile pink salmon survival in PWS.

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CARACTERISTICAS FISICO-QUIMICAS DE LA BAHIA DE SANTA MARTA (AGOSTO 1980 - JULIO 1981)

Bulletin of Marine and Coastal Research ◽

10.25268/bimc.invemar.1983.13.0.485 ◽

2016 ◽

Vol 13 ◽

Cited By ~ 3

Author(s):

Gustavo Ramírez T.

Keyword(s):

Surface Water ◽

Water Column ◽

Annual Cycle ◽

Water Column Stability ◽

Physical Chemical ◽

Chemical Conditions

Physical-chemical conditions have been studied in the Bay of Santa Marta, Colombian Caribbean, from August 1980 to July 1981. The results obtained at nine stations indicate that the surface water is rather homogeneous and of mainly oceanic character. In the period from december to april water temperatures were lowest (<25®C), salinity highest (>36°/oo) and undersaturation with oxigen occured (<91%) these factors together with pH, alcalinity and the variation of water column stability are indicating an upwelling phenomenon in this period and allow the stablishment of an approximated model for the annual cycle the bay.

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Mechanisms of dissolved and labile particulate iron supply to shelf waters and phytoplankton blooms off South Georgia, Southern Ocean

Biogeosciences ◽

10.5194/bg-15-4973-2018 ◽

2018 ◽

Vol 15 (16) ◽

pp. 4973-4993 ◽

Cited By ~ 10

Author(s):

Christian Schlosser ◽

Katrin Schmidt ◽

Alfred Aquilina ◽

William B. Homoky ◽

Maxi Castrillejo ◽

...

Keyword(s):

Southern Ocean ◽

Water Column ◽

Mixed Layer ◽

Surface Mixed Layer ◽

Pore Waters ◽

Phytoplankton Blooms ◽

Faecal Pellets ◽

South Georgia ◽

Shelf Sediments ◽

Bottom Waters

Abstract. The island of South Georgia is situated in the iron (Fe)-depleted Antarctic Circumpolar Current of the Southern Ocean. Iron emanating from its shelf system fuels large phytoplankton blooms downstream of the island, but the actual supply mechanisms are unclear. To address this, we present an inventory of Fe, manganese (Mn), and aluminium (Al) in shelf sediments, pore waters, and the water column in the vicinity of South Georgia, alongside data on zooplankton-mediated Fe cycling processes, and provide estimates of the relative dissolved Fe (DFe) fluxes from these sources. Seafloor sediments, modified by authigenic Fe precipitation, were the main particulate Fe source to shelf bottom waters as indicated by the similar Fe ∕ Mn and Fe ∕ Al ratios for shelf sediments and suspended particles in the water column. Less than 1 % of the total particulate Fe pool was leachable surface-adsorbed (labile) Fe and therefore potentially available to organisms. Pore waters formed the primary DFe source to shelf bottom waters, supplying 0.1–44 µmol DFe m−2 d−1. However, we estimate that only 0.41±0.26 µmol DFe m−2 d−1 was transferred to the surface mixed layer by vertical diffusive and advective mixing. Other trace metal sources to surface waters included glacial flour released by melting glaciers and via zooplankton egestion and excretion processes. On average 6.5±8.2 µmol m−2 d−1 of labile particulate Fe was supplied to the surface mixed layer via faecal pellets formed by Antarctic krill (Euphausia superba), with a further 1.1±2.2 µmol DFe m−2 d−1 released directly by the krill. The faecal pellets released by krill included seafloor-derived lithogenic and authigenic material and settled algal debris, in addition to freshly ingested suspended phytoplankton cells. The Fe requirement of the phytoplankton blooms ∼ 1250 km downstream of South Georgia was estimated as 0.33±0.11 µmol m−2 d−1, with the DFe supply by horizontal/vertical mixing, deep winter mixing, and aeolian dust estimated as ∼0.12 µmol m−2 d−1. We hypothesize that a substantial contribution of DFe was provided through recycling of biogenically stored Fe following luxury Fe uptake by phytoplankton on the Fe-rich shelf. This process would allow Fe to be retained in the surface mixed layer of waters downstream of South Georgia through continuous recycling and biological uptake, supplying the large downstream phytoplankton blooms.

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