A novel approach to model 4 decades of marine chemical data

The awareness of the negative effects of chemical pollution in the sixties has led to an increased concern on the chemical status of the marine environment in the following decades. International regulation in Europe started with the Oslo and Paris convention in the seventies, later on leading to the OSPAR commission. At national level, extended research on chemical pollutants in marine sediments and marine biota was done within the “Project Mer/Projekt Zee” from 1970 to 1976. Since then, a long series of research and monitoring projects was conducted, reporting on the chemical status of the Belgian Part of the North&nbsp;Sea. &nbsp; Within the 4demon project, a major work package focused on the collection, quality control and intercalibration of more than 40 years of data on heavy metals and polychlorinated biphenyls. In this presentation, the modelling approach and results on sediment data will be&nbsp;presented. &nbsp; Within current OSPAR and MSFD monitoring on chemical pollution, variability in location, seasonality, grain size, etc. is reduced thanks to standardized OSPAR guidelines. This facilitates comparability of data within and between regions and assessments based on 5-15 year timetrends are frequently made. Within more than 40 years of pollution data, variability is much larger, and multiple issues should be tackled to intercalibrate the data: changes in sampling locations and analyses methods over time, missing essential metadata, sample analysis on different grain size fractions,… Therefore, existing time trend modelling approaches could not be applied within the 4Demon project. An alternative approach, focused on cluster analysis and different normalisation procedures was proposed. A parametric linear mixed effect model was used to integrate all data into consistent long term time lines which give a view on PCB and heavy metal pollution on a large time&nbsp;frame. &nbsp; Acknowledgement We want to thank the Belgian Science Policy Office (BELSPO) for the financial support of the 4Demon&nbsp;project.</p

Marine phytoplankton community composition data from the Belgian part of the North Sea, 1968-2010

The Belgian Phytoplankton Database (BPD) is a comprehensive data collection comprising quantitative phytoplankton cell counts from multiple research projects conducted since 1968. The collection is focused on the Belgian part of the North Sea, but also includes data from the French and the Dutch part of the North Sea. The database includes almost 300 unique sampling locations and more than 3,000 sampling events resulting in more than 86,000 phytoplankton cell count records. The dataset covers two periods: 1968 to 1978 and 1994 to 2010. The BPD can be accessed online and provides high quality phytoplankton count data. The species taxonomy is updated, and the count values are quality checked and standardized. Important metadata like sampling date, sampling location, sampling depth and methodology is provided and standardized. Additionally, associated abiotic data and biovolume values are available. The dataset allows to conduct analyses of long-term temporal and spatial trends in phytoplankton community structure in the southern part of the North Sea, including changes in phytoplankton phenology and seasonality

4 Decades of Belgian Marine Monitoring: uplifting historical data to today’s needs - Final Report

Context : Long-term quality checked and integrated datasets for the Belgian Part of the North Sea (BPNS) are essential to detect changes in this complex ecosystem and support policy related decisions.Objectives: - Compile and safeguard quality checked, intercalibrated and integrated datasets and make them publicly accessible for further research and policy purposes.- Improve or develop methods and protocols to assess and interpret environmental change in the BPNS and compare trends with neighbouring areas.- Provide support and advice for policy related decisions and legal measures, like MSFD and OSPAR.Conclusions: A scheme with data management tools has been worked out for efficient data flow throughout the project. The scheme, including the mandatory metadata fields and standardization, can be used as a guideline for future projects. Inventories of datasources, projects and data-originators were compiled and the final datasets are available via the central dataportal. Even after compiling and quality checking the long-term datasets, the scientists had to consider some limitations, like changing methodologies and low data resolution, and incorporate these into their trend analyses procedures. Some remarkable environmental changes over time were observed. Model results of the contaminants showed decreasing trends for heavy metals and PCBs. Zn concentrations, however, were found increasing in marine sediments while As concentrations were found increasing in groyne mussels. Nearby the port of Zeebrugge and the mouth of the Scheldt, PCB concentrations were found slightly increasing again over the last decade. The study on eutrophication showed that nutrient (N, P) riverine concentrations and loads have decreased continuously from the end of the 1980‟s to now. However, this did not result in a comparable decrease of marine nutrient concentrations. No clear long-term trend effect was observed on in situ chlorophyll a concentrations following the nutrient decrease. However, a clear change in chlorophyll a phenology followed the increase in sea surface temperature in the period. Furthermore, biomass, seasonality and structure of diatom and dinoflagellate communities were compared between the 1970s and 2000s for the Belgian Part of the North Sea (BPNS), derived from the newly established Belgian Phytoplankton Database. Distinct changes were observed: changes in diatom and dinoflagellate biomass and shift of fulcrum; changes in community structure, with a trend towards seasonal homogenization in the diatom community; increased occurrence of harmful diatom (Pseudo-nitzschia) and dinoflagellate (e.g. Prorocentrum) genera. The observed changes correlate well with overall increases in temperature and changes in nutrient loads and ratios.And finally, for acidification, pH data reveal an increasing trend from the mid-70‟s to the mid-80‟s and a decrease of pH from the mid-80‟s onwards that seems consistent with changes in primary production patterns. The comparison of CH4 concentrations obtained in 1990 and 2016, showed a decreasing trend consistent with alleviation of eutrophication in the area.Based on the outcome of this successful project, the partners defined various recommendations regarding future monitoring strategies for policy makers

Twenty years of Belgian North Sea aerial surveillance: A quantitative analysis of results confirms effectiveness of international oil pollution legislation

Over the years many policy measures have been taken to prevent illegal oil discharges from ships, like the MARPOL 73/78 Convention (1983) and the Bonn Agreement (1969/1983). However, the number of discharges remained high, leading to chronic oiling of seabirds and sensitive coastlines, therefore further measures were taken. The aim of this study is to quantify the effectiveness of two key legislative regulations: the IMO-designation of the North Sea as MARPOL Special Area which took effect in 1999, and the adoption of the EU Directive on Port Reception Facilities in 2000. Under study is the heavily navigated Belgian Surveillance Area, monitored since 1991, characterised by shallow waters with ecologically important sandbanks. The aerial surveillance data from 1991 to 2010 show a stepwise decrease in ship-source oil pollution. Three time periods can be distinguished with two turning points coinciding with the actual implementation of these key legislative measures, confirming their effectiveness