Archives: Bibliographies

Title

The effect of egg versus seston quality on hatching success, naupliar metabolism and survival of Calanus finmarchicus in mesocosms dominated by Phaeocystis and diatoms

Publication Type

Journal Article

Year of Publication

2012

Authors

Koski M, Yebra L, Dutz J, Jonasdottir SH, Vidoudez C, Jakobsen HH, Pohnert G, Nejstgaard JC

Journal

Marine Biology

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Keywords

mesocosm, Phaeocystis, Calanus, Copepod, Skeletonema, 11 m3, Bergen, Espegrend, Norway

Abstract

We studied the effect of a developing Skeletonemamarinoi/Phaeocystis spp. bloom on Calanus finmarchicushatching success, early naupliar survival andmetabolism. Our focus was (1) on the development ofreproductive rates during a bloom initiation, peak anddecline in relation to the production of potentially toxicalgal metabolites and (2) on the proportional importance offemale nutrition versus naupliar food environment for theproduction of viable nauplii. Despite polyunsaturatedaldehyde (PUA) production by both S. marinoi and Phaeocystissp., we did not observe any harmful effects onhatching success or naupliar survival and condition in anystages of the short-term (1 week) algal bloom. Hatchingsuccess appeared to be controlled by egg lipid composition,while the beneficial effect of a high food concentration wasreflected in naupliar RNA:DNA ratio, protein content andtotal production of viable nauplii. The egg lipids reflectedseston lipids, indicating that the egg fatty acid compositionwas not modified by the females. Our results suggest thatunselective feeding and/or retention of specific lipids caninduce qualitative food limitation, although recruitmentduring the S. marinoi/Phaeocystis sp. bloom was high.

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Title

Stronger impact of dispersant plus crude oil on natural plankton assemblages inshort-term marine mesocosms

Publication Type

Journal Article

Year of Publication

2012

Authors

Jung WS, Kwon YO, Joo KC, Kang JH, Kim M, Shim JW, Kim YO

Journal

Journal of Hazardous Materials

Volume

217-218

Pagination

338-349

ISBN Number

Keywords

mesocosm, Crude oil, Dispersant, Planktonic communities, Total petroleum hydrocarbon, Geoje island, Korea, 1 m3

Abstract

To assess the effects of crude oil and dispersant on marine planktonic ecosystems, analyses were performedin 1000-L mesocosm over a period of nine days. Triplicate experiments were conducted for twodifferent treatments, namely, addition of crude oil alone and oil plus dispersant. In the mesocosm with oilplus dispersant, high concentrations of total petroleum hydrocarbon (TPH) were soon found in the bottomlayer. In addition, most planktonic communities responded drastically to the presence of dispersantacting to disperse TPH: total bacterial abundances increased for the first two days and then decreasedrapidly for the remainder of the experiment. The abundance of heterotrophic flagellates increased rapidlyin association with the increase in bacterial cells. The abundance of phytoplankton and zooplanktoncommunities decreased clearly within two days. Time-delayed relationship also revealed that the TPHconcentration had a significant negative relationship with phyto- and zooplankton communities withintwo days. However, most planktonic communities were affected less adversely in the mesocosms treatedwith crude oil alone than in those treated with both crude oil and dispersant. The present results demonstratethat the planktonic ecosystem was damaged more severely by the introduction of dispersant thanby the harmful effects of crude oil itself. Therefore, caution should be taken when considering the directapplication of dispersant in natural environments, even though it has the advantage of rapidly removingcrude oil.

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Title

Initial size structure of natural phytoplankton communities determines the response to Daphnia diel vertical migration

Publication Type

Journal Article

Year of Publication

2012

Authors

Haupt F, Stockenreiter M, Boersma M, Stibor H

Journal

Journal of Limnology

Volume

71

Pagination

125-134

ISBN Number

1129-5767

Keywords

Lake Brunnsee, Germany, freshwater, mesocosm, behavior, algae, trait mediated interactions, Nutrients, refuge effect., 7.8m3

Abstract

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Date of Published

2012

Accession Number

WOS:000303943400013

Type of Article

Alternate Journal

Title

Effects of stratification depth and dissolved organic matter on brackish bacterioplankton communities

Publication Type

Journal Article

Year of Publication

2012

Authors

Grubisic LM, Brutemark A, Weyhenmeyer GA, Wikner J, Bamstedt U, Bertilsson S

Journal

Marine Ecology Progress Series

Volume

453

Pagination

37-48

ISBN Number

Keywords

Bacterial community composition, DOM, Stratification depth, mesocosm, Brackish, phytoplankton, Umea, Sweden, 2.5 m3

Abstract

Bacterioplankton growth is often directly or indirectly controlled by external energysubsidies via organic matter inputs or solar radiation. We carried out a mesocosm experiment toassess how bacterioplankton communities responded to elevated levels of dissolved organicmatter (DOM) and experimentally controlled stratification depth. The month-long experimentconsisted of 2500 l mesocosms subjected to 4 experimental manipulations in triplicate: the stratificationdepth was set to either 1.5 or 3.5 m, with or without experimental addition of ambient levelsof chromophoric DOM. DOM addition had a significant effect on bacterial community compositionas assessed by terminal restriction fragment length polymorphism of amplified 16S rRNA genes.In contrast, there were no effects of the DOM amendment on bacterial biomass or production.Mixing depth and the coupled effective light climate in the photic zone also had a significanteffect on bacterial community composition. Furthermore, shallow mixing depth was associatedwith enhanced primary production, whereas DOM addition had a negative effect on phyto -plankton biomass and productivity. Our results suggest that bacterial community composition iscoupled to primary production under the studied coastal nutrient regime, and point to a key roleof DOM quality in controlling bacterioplankton communities.

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Title

Combining gut fluorescence technique and spatial analysis to determine Littorina littorea grazing dynamics in nutrient-enriched and nutrient-unenriched littoral mesocosms

Publication Type

Journal Article

Year of Publication

2012

Authors

Diaz ER, Krauvelin P, Erlandsson J

Journal

Marine Biology

Volume

159

Pagination

837-852

ISBN Number

Keywords

mesocosm, land based, littorina, 12 m3, Solbergstrand, Oslofjord, Norway

Abstract

Spatiotemporal distribution patterns in relationto feeding behavior of herbivorous gastropods have beenstudied extensively, but still knowledge about small-scalepatterns is limited in relation to eutrophication. Thisexperimental study aimed to describe the small-scale distributionof Littorina littorea in nutrient-enriched andnutrient-unenriched mesocosms in a merely atidal regionand relate the distribution to food abundance and possiblecompeting organisms, while checking simultaneously forfeeding activities. The latter part was accomplishedthrough the ‘‘gut fluorescence technique’’ GFT (which, toour knowledge, has not previously been used for benthicgrazers) to estimate per capita grazing rates and the formerpart through monitoring of spatial heterogeneity of L. littoreaand co-variation with sessile organisms (usingsemivariograms and cross-semivariograms, respectively).After 5 months of nutrient addition, the abundance andbiomass of L. littorea had increased in enriched systems,which also had significantly higher total biomass of greenalgae. Gut pigment content was higher in L. littorea fromenriched mesocosms, and gut depletion rate was higher inL. littorea from unenriched mesocosms. Spatial analysisshowed that L. littorea exhibited generally random patterns(suggesting feeding activities) but sometimes (often in themorning) spatial patchiness (clumped distribution) in bothenriched and unenriched conditions. There was mainlypositive co-variation between L. littorea and biofilm, whiledifferent nutrient conditions exhibited contrasting co-variationbetween L. littorea and barnacles (positive co-variationin enriched and negative co-variation in unenrichedmesocosms). The study offered insights into how feedingbehavior and spatial distribution of a species may interactwith community components differently under differentnutrient regimes. The applied methodology can be usefulfor purposes of faster examination of grazing effectsamong different regions and also to compare grazingintensities and interactions between grazers and the benthiccommunities in disturbed (including pollution and nutrientenrichment) and non-disturbed systems, as well as in upwellingversus non-upwelling areas.

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Title

Harmful algal blooms: How strong is the evidence that nutrient ratios and forms influence their occurrence?

Publication Type

Journal Article

Year of Publication

2012

Authors

Davidson K, Gowen RJ, Tett P, Bresnan E, Harrison PJ, McKinney A, Milligan S, Mills DK, Silke J, Crooks AM

Journal

Estuarine Coastal and Shelf Science

Volume

Pagination

1-15

ISBN Number

Keywords

phytoplankton, Harmful algae, Nutrient ratios, eutrophication, mesocosm, review

Abstract

There is a perception that anthropogenically-driven changes in nutrient supply to coastal waters influencesthe abundance, frequency and toxicity of harmful algal blooms (HABs) through a change in theform or ratio of nutrient that limits phytoplankton growth. If nutrient concentrations are not limiting forgrowth, then ratios do not influence floristic composition. At non-limiting concentrations, evidence thatalteration of nitrogen: phosphorus (N:P) ratios has stimulated HABs is limited, and primarily based onhypothesised relationships in relatively few locations (in particular: Tolo Harbour Hong Kong and DutchCoastal Waters). In all cases, an unequivocal causal link between an increase in HABs (frequency,magnitude or duration) and change in N or P as the limiting nutrient is difficult to establish. The silicon(Si) limitation hypothesis is generally supported by experimental evidence and field data on the nuisanceflagellate Phaeocystis. We found little evidence that high N:Si ratios preferentially promote harmfuldinoflagellates over benign species. Laboratory studies demonstrate that nutrient ratios can influencetoxin production, but genus and species specific differences and environmental control make extrapolationof these data to the field difficult. Studies of the role of dissolved and particulate organic nutrientsin the growth of HAB species, while limited, demonstrate the potential for organic nutrients (especiallyorganic N) to support the growth of a range of HAB species. There is a clear need for better understandingof the role of mixotrophy in the formation of HABs and for studies of HAB and non-HAB species incompetition for environmentally realistic concentrations of organic nutrients

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Title

Effects of light availability on mixotrophy and microzooplankton grazing in an oligotrophic plankton food web: Evidences from a mesocosm study in Eastern Mediterranean waters

Publication Type

Journal Article

Year of Publication

2012

Authors

Calbet A, Martínez RA, Isari S, Zervoudaki S, Nejstgaard JC, Pitta P, Sazhin AF, Sousoni D, Gomes A, Berger SA, Tsagaraki TM, Ptacnik R

Journal

Journal of Experimental Marine Biology and Ecology

Volume

424–425

Pagination

66-77

ISBN Number

0022-0981

Keywords

dilution experiments, Eastern Mediterranean, Light, mesocosm, microzooplankton, Mixotrophy

Abstract

Plankton biomass and composition in the pelagic zone of oceans is exposed to changes in availability of light and nutrients due to large-scale ocean circulation and water column stratification. We hypothesized that displacement of plankton from surface to deeper darker waters would not only favor heterotrophy over time, as previously suggested, but also first rapidly affect the level of mixotrophy and, consequently, overall microbial grazing in plankton food webs. To test this in an oligotrophic marine system we incubated Eastern Mediterranean water (from 10 m depth north of Crete in September 2010) in 2.8 m3 mesocosms simulating two different light intensities at the sampling station, surface waters (ca. 10 m; mesocosms L1) and deeper layers (ca. 50–60 m; mesocosms L4). The biomass and abundance of the main planktonic groups were monitored either daily or every second day, depending on the group. Microzooplankton grazing rates and the contribution of mixotrophic feeding were estimated by a combination of dilution experiments and incubations with live fluorescently labeled algae (LFLA). Although no nutrients were added to the mesocosms the chlorophyll a increased during the first 2 days of the experiment in both treatments. This increase resulted from phytoplankton growth in the light L1-mesocosm (autotrophic biomass was ca. doubled in L1 compared to L4), but was mostly due to photoadaptation of the algae in the L4-mesocosm, as indicated by lower carbon to chlorophyll a ratios. By the end of the experiment, the total biomass of protozoan and metazoan grazers in L1 was ca. twofold higher than in L4. The microzooplankton responded within the first 24 h, showing different grazing activity in L1 than in L4. Microzooplankton grazing rates on total Chl a were similar in both treatments; however, phytoplankton instantaneous growth rates were higher in the more illuminated mesocosm. This resulted in a closer coupling between both rates in L4, where all production was grazed daily, than in L1. Nevertheless, the overall flux of carbon through the microzooplankton was 33–60% higher in L1 compared to L4 throughout the experiment. The fraction of mixotrophy in the ciliate community varied in L1 (20–50%), but decreased over time in L4 from 50% to 30%. Our results do not support studies from freshwater, postulating that reduced light and nutrient limitation may increase herbivore production due to stoichiometric effects. Finally, we discuss how mixotrophy may bias rate estimates in dilution experiments.

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A mesocosm experiment coupled with optical measurements to assess the fate and sinking of atmospheric particles in clear oligotrophic waters

Publication Type

Journal Article

Year of Publication

2012

Authors

Bressac M, Guieu C, Doxaran D, Bourrin F, Obolensky G, Grisoni JM

Journal

Geochemical Marine Letters

Volume

32

Pagination

153-164

ISBN Number

Keywords

mesocosm, oligotrophic, saharn dust, 52 m3, Corsica, Italy, mediterranean

Abstract

It has recently been postulated that lithogenic particlessuch as Saharan dust strongly influence particulateorganic carbon export to the deep ocean by acting as mineralballast. However, our understanding of the processes involvedremains scant. In the present study, optical measurementswere performed to monitor variations in the concentration,composition and size distribution of particles in suspensionwithin the water column after simulating a Saharan dust eventin very clear Mediterranean waters off Corsica in June 2010.A new methodology set up in large mesocosms proved verysuccessful in this regard. Values obtained simultaneously fromthree instruments (WetLabs ECO-BB3, WetLabs ac-9, SequoiaScientific LISST-100) provided evidence that (1) partof the Saharan dust pool has a rapid settling velocity (?24–86 m day?1), (2) particulate export following a dust event is anonlinear multi-step process and (3) export is controlled inpart by the formation of organic-mineral aggregates. Thisexperimental study provides the first insight of the complexexport processes occurring after a dust event involving bothphysical and biogeochemical forcings in clear oligotrophicwaters.

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Title

High predictability of spring phytoplankton biomass in mesocosms at the species, functional group and community level

Publication Type

Journal Article

Year of Publication

2012

Authors

Bauer B, Sommer U, Gaedke U

Journal

Freshwater biology

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divergence, hierarchical level, mesocosms, predictability, replicates, mesocosm, Kiel indoor, Kiel, Germany, 1.4 m3

Abstract

1. Models aim to predict phytoplankton dynamics based on observed initial conditions and a set ofequations and parameters. However, our knowledge about initial conditions in nature is neverperfect. Thus, if phytoplankton dynamics are sensitive to small variations in initial conditions,they are difficult to predict.2. We used time-series data from indoor mesocosm experiments with natural phyto- andzooplankton communities to quantify the extent to which small initial differences in the species,functional group and community biomass in parallel treatments were amplified or buffered overtime. We compared the differences in dynamics between replicates and among all mesocosms of1 year.3. Temperature-sensitive grazing during the exponential growth phase of phytoplankton causeddivergence. In contrast, negative density dependence caused convergence.4. Mean differences in biomass between replicates were similar for all hierarchical levels. Thisindicates that differences in their initial conditions were amplified to the same extent. Even thoughlarge differences in biomass occasionally occurred between replicates for a short time, dynamicsreturned to the same path at all hierarchical levels. This suggests that internal feedbackmechanisms make the spring development of phytoplankton highly predictable

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Title

Decreased marine dimethyl sulfide production under elevated CO2 levels in mesocosm and in vitro studies

Publication Type

Journal Article

Year of Publication

2012

Authors

Avgoustidi V, Nightingale PD, Joint I, Steinke M, Turner SM, Hopkins FE, Liss PS

Journal

Environmental Chemistry

Volume

9

Pagination

399-404

ISBN Number

Keywords

DMS, mesocosm, acidification, review

Abstract

The oceans have absorbed approximately half of theCO2 produced by human activities and it is inevitable thatsurface seawaters will become increasingly acidified. The effect of lower pH on marine organisms and ocean–atmosphereexchanges is largely unknown but organisms with CaCO3 structural components are likely to be particularly affected.Because calcifying phytoplankton are significant producers of dimethyl sulfide (DMS), it is vital to understand how lowerseawater pH may affect DMS production and emission to the atmosphere. Here we show, by mesocosm (Raunefjorden,Norway, April–May 2003) and in vitro studies, that the net production of DMS and its cellular precursor dimethylsulfoniopropionate(DMSP) is approximately halved in microbial communities subjected to doubled CO2 levels. Our findingsprovide evidence that the amount of DMS entering the atmosphere could decrease in the future. Because atmosphericoxidation ofDMScan lead to climate cooling by increasing cloud albedo, a consequence of reducedDMSemissions from alower pH ocean would be an enhancement in global warming.

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