GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Salinity tolerance of diapausing eggs of freshwater zooplankton (2004)
    Oxford, UK : Blackwell Science Ltd
    Freshwater biology 49 (2004), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. Many freshwater zooplankton produce diapausing eggs capable of withstanding periods of adverse environmental conditions, such as anoxia, drought and extreme temperature. These eggs may also allow oligostenohaline species to survive increased salinity during periods of tidal flux or evaporation, and here we test the ability of diapause eggs to withstand such conditions.2. Salinity tolerance may also enable organisms to invade new environments. The increased rate of introduction of non-indigenous species to the Laurentian Great Lakes since 1989, when ballast water exchange regulations (to replace fresh/brackish water at sea with full seawater) were first implemented for transoceanic vessels, has stimulated studies that explore mechanisms of introduction, other than of active animals, in ballast water. One hypothesis proposes that freshwater organisms transported in ballast tanks as diapausing eggs may be partially responsible for the increased rate of species introduction, as these eggs may tolerate a wide array of adverse environmental conditions, including exposure to saline water.3. We collected ballast sediments from transoceanic vessels entering the Great Lakes, isolated diapausing eggs of three species (Bosmina liederi, Daphnia longiremis and Brachionus calyciflorus), and measured the effect of salinity on hatching rate. In general, exposure to salinity significantly reduced the hatching rate of diapausing eggs. However, as non-indigenous species can establish from a small founding population, it is unclear whether salinity exposure will be effective as a management tool.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.2004.01185.x
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    facet.materialart.
    Unknown
    A Lab-On-Chip Phosphate Analyzer for Long-term In Situ Monitoring at Fixed Observatories: Optimization and Performance Evaluation in Estuarine and Oligotrophic Coastal Waters (2017)
    Frontiers
    In:  Frontiers in Marine Science, 4 .
    Details
    Publication Date: 2021-04-23
    Description: The development of phosphate sensors suitable for long-term in situ deployments in natural waters, is essential to improve our understanding of the distribution, fluxes, and biogeochemical role of this key nutrient in a changing ocean. Here, we describe the optimization of the molybdenum blue method for in situ work using a lab-on-chip (LOC) analyzer and evaluate its performance in the laboratory and at two contrasting field sites. The in situ performance of the LOC sensor is evaluated using hourly time-series data from a 56-day trial in Southampton Water (UK), as well as a month-long deployment in the subtropical oligotrophic waters of Kaneohe Bay (Hawaii, USA). In Kaneohe Bay, where phosphate concentrations were characteristic of the dry season (0.13 ± 0.03 μM, n = 704), the in situ sensor accuracy was 16 ± 12% and a potential diurnal cycle in phosphate concentrations was observed. In Southampton Water, the sensor data (1.02 ± 0.40 μM, n = 1,267) were accurate to ±0.10 μM relative to discrete reference samples. Hourly in situ monitoring revealed striking tidal and storm derived fluctuations in phosphate concentrations in Southampton Water that would not have been captured via discrete sampling. We show the impact of storms on phosphate concentrations in Southampton Water is modulated by the spring-neap tidal cycle and that the 10-fold decline in phosphate concentrations observed during the later stages of the deployment was consistent with the timing of a spring phytoplankton bloom in the English Channel. Under controlled laboratory conditions in a 250 L tank, the sensor demonstrated an accuracy and precision better than 10% irrespective of the salinity (0–30), turbidity (0–100 NTU), colored dissolved organic matter (CDOM) concentration (0–10 mg/L), and temperature (5–20°C) of the water (0.3–13 μM phosphate) being analyzed. This work demonstrates that the LOC technology is mature enough to quantify the influence of stochastic events on nutrient budgets and to elucidate the role of phosphate in regulating phytoplankton productivity and community composition in estuarine and coastal regimes.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    DOI: 10.3389/fmars.2017.00255
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 3
    facet.materialart.
    Unknown
    Efficacy of open-ocean ballast water exchange as a means of preventing invertebrate invasions between freshwater ports (2007)
    American Society of Limnology and Oceanography
    In:  Limnology and Oceanography, 52 (6). pp. 2386-2397.
    Details
    Publication Date: 2020-07-09
    Description: Ballast water is a major vector of nonindigenous species invasion globally. Mandatory ballast water exchange (BWE) was implemented for vessels carrying ballast water into the Great Lakes in 1993. Despite the implementation of this policy, few data are available on its effectiveness, and invasions have continued to be reported in the Great Lakes. In this study, we conducted experiments to assess the efficacy of BWE on six operational transoceanic vessels traveling from the Great Lakes to European ports. Each vessel had paired ballast tanks, one of which was designated as a control that remained filled with Great Lakes water, while the other was exchanged with mid‐ocean water. Community composition was assessed immediately after tanks were filled and again prior to water discharge in European ports. BWE was verified by ship records and, in two cases, by in situ water quality sensors. BWE was highly effective (〉99% loss) for reducing concentrations of freshwater zooplankton. Live sentinel amphipods and oligochaetes deployed in incubator chambers sustained nearly universal mortality in tanks that experienced BWE, but not in unexchanged tanks. Finally, BWE reduced in situ recruitment of zooplankton from diapausing eggs present in ballast sediments in additional incubator chambers deployed in these tanks. Collectively, these studies support the contention that BWE by transoceanic vessels traveling between freshwater ports results in ballast water that would exceed proposed International Maritime Organization (2004) ballast water performance standards if these standards were applied to freshwater species only. Thus, BWE provides strong protection to freshwater ecosystems against invasions by both pelagic and benthic freshwater species.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.4319/lo.2007.52.6.2386
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
    facet.materialart.
    Unknown
    Quagga mussel (Dreissena rostriformis bugensis) selective feeding of phytoplankton in Saginaw Bay (2014)
    Elsevier
    In:  Journal of Great Lakes Research, 40 . pp. 83-94.
    Details
    Publication Date: 2019-05-24
    Description: Experiments from May to December measuring selective grazing and egestion of different phytoplankton taxa in natural Saginaw Bay (Lake Huron) seston by shallow-water morph quagga mussels (Dreissena bugensis rostriformis) showed that the mussels were highly selective filter feeders and that their net clearance rates on different species ranged widely, resulting in food consumption that was strongly driven by seasonal phytoplankton dynamics. Overall, net clearance rates by quagga mussels on the entire phytoplankton assemblage were similar to those observed for zebra mussels (Dreissena polymorpha) during the 1990s. Phytoplankton taxon, rather than size, was more important to food selection since quagga mussels cleared similar sized but different species of algae at very different rates. In contrast to many studies with zebra mussels, larger-sized algae such as Dinobryon divergens, Aulacoseira italica, Fragilaria crotonensis, and Anabaena were cleared at high rates and rejected at lower rates than many smaller species within the same broad taxonomic group. We suspect that these differences between dreissenid species do not stem from species differences but methodological factors and phytoplankton composition of systems studied. Small-sized diatoms, green algae with thick cell walls (Scenedesmus and Oocystis), and colonial cyanobacteria with gelatinous sheaths (Aphanocapsa, Chroococcus, and Microcystis) were cleared at low rates and rejected in high proportion in pseudofeces or feces during all seasons. We describe the likely mechanisms of pre- and post-ingestive behavior that explain these differences, which relate to phytoplankton size, morphology, cell wall characteristics, and chemical composition. Changes in the Great Lakes phytoplankton communities are consistent with mussel grazing preferences.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.jglr.2013.11.011
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...