Bacteria in sea ice and underlying water of the eastern Weddell Sea in midwinter

Helmke, Elisabeth; Weyland, H.

doi:10.3354/meps117269

Cited by 126 publications

(124 citation statements)

References 26 publications

Supporting

Mentioning

115

Contrasting

Order By: Relevance

“…Overall BP Leu and TdR in ice were low, but were comparable to those of Kuparinen et al (2011) obtained on predator-free batch cultures from melted 2-weekold sea ice. The bacterial abundance and ice salinities were in the same range to other studies measuring bacterial production in sea ice in the Southern Ocean (Grossmann and Dieckmann, 1994;Helmke and Weyland, 1995), the Arctic Ocean (Kaartokallio et al, 2013;Nguyen and Maranger, 2011) and the Baltic Sea (Kuparinen et al, 2007). Unlike many studies done in natural sea ice, algae and other typical larger sea ice organisms were absent in our experiment, which may have led to lower bacterial production, since ice algae may be a source of autochthonous DOM in ice ).…”

Section: Bacterial Growth Production and Imprints On Nutrient Concenmentioning

confidence: 45%

Physical and bacterial controls on inorganic nutrients and dissolved organic carbon during a sea ice growth and decay experiment

et al. 2014

View full text Add to dashboard Cite

a b s t r a c t a r t i c l e i n f oWe investigated how physical incorporation, brine dynamics and bacterial activity regulate the distribution of inorganic nutrients and dissolved organic carbon (DOC) in artificial sea ice during a 19-day experiment that included periods of both ice growth and decay. The experiment was performed using two series of mesocosms: the first consisted of seawater and the second consisted of seawater enriched with humic-rich river water. We grew ice by freezing the water at an air temperature of −14°C for 14 days after which ice decay was induced by increasing the air temperature to −1°C. Using the ice temperatures and bulk ice salinities, we derived the brine volume fractions, brine salinities and Rayleigh numbers. The temporal evolution of these physical parameters indicates that there was two main stages in the brine dynamics: bottom convection during ice growth, and brine stratification during ice decay. The major findings are: (1) the incorporation of dissolved compounds (nitrate, nitrite, ammonium, phosphate, silicate, and DOC) into the sea ice was not conservative (relative to salinity) during ice growth. Brine convection clearly influenced the incorporation of the dissolved compounds, since the non-conservative behavior of the dissolved compounds was particularly pronounced in the absence of brine convection. (2) Bacterial activity further regulated nutrient availability in the ice: ammonium and nitrite accumulated as a result of remineralization processes, although bacterial production was too low to induce major changes in DOC concentrations. (3) Different forms of DOC have different properties and hence incorporation efficiencies. In particular, the terrestrially-derived DOC from the river water was less efficiently incorporated into sea ice than the DOC in the seawater. Therefore the main factors regulating the distribution of the dissolved compounds within sea ice are clearly a complex interaction of brine dynamics, biological activity and in the case of dissolved organic matter, the physico-chemical properties of the dissolved constituents themselves.

show abstract

Section: Bacterial Growth Production and Imprints On Nutrient Concenmentioning

confidence: 45%

Physical and bacterial controls on inorganic nutrients and dissolved organic carbon during a sea ice growth and decay experiment

et al. 2014

View full text Add to dashboard Cite

show abstract

“…The variety of distinct morphological bacter~al types within the ice, including bacteria with slime sheaths and with appendages, is very common (about 20%) among sea ice isolates from the Antarctic (Helmke & Weyland 1995). Similar morphotypes were also found within the sea ice 01 the Kiel Bight (Fig.…”

Section: Tbn Tbbmentioning

confidence: 52%

Bacteria in sea ice and underlying brackish water at 54°26'5"N (Baltic Sea, Kiel Bight)

Möck

Meiners²,

Giesenhagen³

1997

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Bacterial response to the rare event of solid ice cover in the western Baltic Sea (Kiel Bight) was investigated from February to March 1996. Samples (ice cores, brine and water) were taken at a shallow, near-shore station at irregular time intervals. Bacterial abundance, biomass and production were measured in brine and the underlying water as were the concentrations of NOa, NOa, NH,, PO, and SiO,. Vertical distributions of bacterial abundance, biomass, morphotypes and size classes and chlorophyll a and nutrients were investigated within sea ice. A bacterial growth experiment with brine bacteria was carried out to measure bacterial carbon production via total incorporation of [3H]thymidine (TTI) and [ 3~] l e u c i n e (TLI). During February the abundance, biomass and production of bacteria within brine exceeded values from under-ice water, whereas the opposite was observed in March. High N o 3 and NH4 concentrations in ice and under-ice water of up to 112 pM and 55 pM, respectively, resulted in N:P ratios of 18 to 330. Algae and bacteria were considered to benefit from that nutrient supply. For bacteria this was supported by TT1 and particularly high TLI rates during the ice situation, with TL1:TTI ratios of 25 to 213. The high TLI rates were due to a large degree of unspecific labeling by leucine and characterised the bacleria during winter 1996 as extremely active. Bacterial production (based on TTI) rose in water from 0.021 1-19 C 1-' h-' at the beginning to 0.909 pg C 1-' h-' at the end of the investigation, and in brine from 0.122 to 0.235 pg C 1-' h-'. Abundance of bacteria in brine increased from 1.7 X 106 cells ml-' initially to 2.8 X 10' cells ml-' in March. The average cell volume of these bacteria was 0.2 pm3 whereas the bactena in water reached only 0.08 pm3 The bacterial assemblage in the ice was dominated by large rods and in the water by small rods and cocci. Bacterivorous activity within sea ice was assumed to be reduced due to the speclfic vertlcal distribution of the different bacterial size classes. This was further supported by a good correlation between the development of the bacterial standing stock and the potential blomass, in sea ice as well as in the underlying water, calculated from generation times towards the end of the investigation. Low grazing pressure, high standing stocks of algae and sufficient substrate supply accounted for bacterial biornass within the ice and the underlying water that exceeded that from former winters by far A comparison with Arctic and Antarctic sites demonstrated that the bacterial community withln the sea ice showed many similarities to those found in sea ice of polar regions.

show abstract

“…The effect of seeding on bacteria is poorly documented. Phylogenetic studies showed that sea ice bacterial population is similar to the seawater community (Bowman et al 1997), metabolically active (Brinkmeyer et al 2003) and that psychrophilic species were preferentially present in sea ice (Delille 1992;Helmke and Weyland 1995). Kaartokallio et al (2005) reported that, in Baltic sea ice, ice-derived bacterial communities were able to adapt to salinity changes while under-ice bacterial assemblages seemed to suffer from osmotic stress.…”

Section: Autotrophsmentioning

confidence: 99%

Effect of melting Antarctic sea ice on the fate of microbial communities studied in microcosms

et al. 2013

View full text Add to dashboard Cite

Although algal growth in the iron-deficient Southern Ocean surface waters is generally low, there is considerable evidence that winter sea ice contains high amounts of iron and organic matter leading to ice-edge blooms during austral spring. We used field observations and shipbased microcosm experiments to study the effect of the seeding by sea ice microorganisms, and the fertilization by organic matter and iron on the planktonic community at the onset of spring/summer in the Weddell Sea. Pack ice was a major source of autotrophs resulting in a ninefold to 27-fold increase in the sea ice-fertilized seawater microcosm compared to the ice-free seawater microcosm. However, heterotrophs were released in lower numbers (only a 2-to 6-fold increase). Pack ice was also an important source of dissolved organic matter for the planktonic community. Small algae (\10 lm) and bacteria released from melting sea ice were able to thrive in seawater. Field observations show that the supply of iron from melting sea ice had occurred well before our arrival onsite, and the supply of iron to the microcosms was therefore low. We finally ran a ''sequential melting'' experiment to monitor the release of ice constituents in seawater. Brine drainage occurred first and was associated with the release of dissolved elements (salts, dissolved organic carbon and dissolved iron). Particulate organic carbon and particulate iron were released with low-salinity waters at a later stage.

show abstract

Bacteria in sea ice and underlying water of the eastern Weddell Sea in midwinter

Cited by 126 publications

References 26 publications

Physical and bacterial controls on inorganic nutrients and dissolved organic carbon during a sea ice growth and decay experiment

Physical and bacterial controls on inorganic nutrients and dissolved organic carbon during a sea ice growth and decay experiment

Bacteria in sea ice and underlying brackish water at 54°26'5"N (Baltic Sea, Kiel Bight)

Effect of melting Antarctic sea ice on the fate of microbial communities studied in microcosms

Contact Info

Product

Resources

About