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- Fritzsch, Guido, et al.
(author)
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PCR Survey of Xenoturbella bocki Hox Genes
- 2008
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In: JOURNAL OF EXPERIMENTAL ZOOLOGY (MOL DEV EVOL). - : Wiley. ; 310B:3, s. 278-284
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Journal article (peer-reviewed)abstract
- Xenoturbella bocki has recently been identified as one of the most basal deuterostomes, although an even more basal phylogenetic position cannot be ruled out. Here we report on a polymerase chain reaction survey of partial Hox homeobox sequences of X. bocki. Surprisingly, we did not find evidence for more than five Hox genes, one clear labial/PG1 ortholog, one posterior gene most similar to the PG9/10 genes of Ambulacraria, and three central group genes whose precise assignment to a specific paralog group remains open. We furthermore report on a re-evaluation of the available published evidence of Hox genes in other basal deuterostomes.
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| 2. |
- Andersson, Pia, et al.
(author)
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Marine Acidification : On effects and monitoring of marine acidification in the seas surrounding Sweden
- 2008. - 2008:92
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Reports (other academic/artistic)abstract
- Surface waters in the world oceans have already experienced a pH reduction of about 0.1 units (OSPAR, 2006.) The trend indicates further decrease of pH and is most probably due to increased uptake of atmospheric CO2 and less buffering capacity of ocean waters. The trend is similar in the waters surrounding Sweden. RESEARCH NEEDS Since there is an alarming absence of information regarding the effects of near-future levels of ocean acidification on Swedish marine taxa, there is a clear research need on: • investigations of the effects of ocean acidification on the early life-history stages of key ecosystem-structuring species, and commercially important species of fish and shellfish • ecosystem-level mesocosm studies of the impacts of ocean acidification on Swedish marine systems • improved regional-scale modelling of acidification mechanisms in Swedish coastal waters • testable ecosystem-scale food-web models to articulate with regional acidification models • improved definition of chemical equilibrium constants between pH, AT and CO2 in low saline waters. ACTIONS TO IMPROVE MONITORING At present, pH and AT are monitored monthly at standard depths at 7 stations in Skagerrak, Kattegat and Baltic Proper within the national monitoring programme. Of these are 2 located in coastal waters (Halland and Småland; Type 5 and 9). We recommend that Sweden work to improve the status of pH and AT to be Core variables instead of Main variables in HELCOM COMBINE “High frequency Sampling” program taking into account the last 15 years negative trends in pH in waters surrounding Sweden as well as in the global oceans. We recommend that besides the standard para-meters monitored in the national monitoring program, pH, AT and DIC should be monitored. For completeness, primary production should also be monitored. Below are three monitoring recommendations, where the first is divided into a lowest level and a recommended level. 1. Lowest level: Within the national monitoring program, at least one station per open sea area and all costal stations measure acidification parameters on a monthly basis in the entire water column at standardized depths. The national and regional monitoring programmes should be upgraded in the Gulf of Bothnia so that pH and AT is monitored at standard depths at least monthly at one station each in the Bothnian Bay and Bothnian Sea. Also 2 coastal stations in the Gulf of Bothnia should be established. In addition, one coastal station should be established within Type 14 in the Baltic Proper. 1. Recommended level: the national monitoring program should have at least one station per open sea area and if the area is characterized by strong gradients or other features, there should be more than one station. Some of the stations in the regional monitoring programmes should be upgraded with acidification parameters, for a better geographical coverage. The acidification parameters should be measured on a monthly basis in the entire water column at standardized depths. 2. We recommend that an investigative monitoring is established by extending the parameters that are needed to firmly improve the chemical stability constants between pH, AT, DIC and pCO2 in low saline waters. This can be done by just extending the sampling program at selected monitoring stations. Sampling should cover a period of 2 to 3 years. 3. We recommend that direct water measurement of pCO2 for monitoring purposes should be assessed after the recommendation above is evaluated and that ongoing research projects on pCO2 measurements using ferryboxes are finalised. RECOGNISED PROBLEM AREAS • There are only few long time series of acidification parameters. The time period of measurements is rather short. • The geographical coverage of measurements is rather limited in the waters surrounding Sweden. • The chemical stability constants between pH, AT, DIC and pCO2 are not optimized in low saline waters. • pH budgets are difficult to calculate. • Models need to be improved in order to display present and future small and large scale scenarios. • Little is known of the biological, ecological and economical effects of the current and near future marine acidification. Further research is required.
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