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Aquatic macrophytes are one of the biological quality elements in the Water Framework Directive (WFD) for which status assessments must be defined. We tested two methods to classify macrophyte species and their response to eutrophication pressure: one based on percentiles of occurrence along a phosphorous gradient and another based on trophic ranking of species using Canonical Correspondence Analyses in the ranking procedure. The methods were tested at Europe-wide, regional and national scale as well as by alkalinity category, using 1,147 lakes from 12 European states. The grouping of species as sensitive, tolerant or indifferent to eutrophication was evaluated for some taxa, such as the sensitive Chara spp. and the large isoetids, by analysing the (nonlinear) response curve along a phosphorous gradient. These thresholds revealed in these response curves can be used to set boundaries among different ecological status classes. In total 48 taxa out of 114 taxa were classified identically regardless of dataset or classification method. These taxa can be considered the most consistent and reliable indicators of sensitivity or tolerance to eutrophication at European scale. Although the general response of well known indicator species seems to hold, there are many species that were evaluated differently according to the database A. Kolada selection and classification methods. This hampers a Europe-wide comparison of classified species lists as used for the status assessment within the WFD implementation process.

Six years of simultaneous moored observations near the western and eastern boundaries of the South Atlantic are combined with satellite winds to produce a daily time series of the basin-wide meridional overturning circulation (MOC) volume transport at 34.5°S. The results demonstrate that barotropic and baroclinic signals at both boundaries cause significant transport variations, and as such must be concurrently observed. The data, spanning~20 months during 2009-2010 and~4 years during 2013-2017, reveal a highly energetic MOC record with a temporal standard deviation of 8.3 Sv, and strong variations at time scales ranging from a few days to years (peak-to-peak range = 54.6 Sv). Seasonal transport variations are found to have both semiannual (baroclinic) and annual (Ekman and barotropic) timescales. Interannual MOC variations result from both barotropic and baroclinic changes, with density profile changes at the eastern boundary having the largest impact on the year-to-year variations.Plain Language Summary Changes in the meridional overturning circulation, characterized by north-south flows throughout the Atlantic Ocean basin and vertical exchange between the surface and the deep ocean, are related to changes in important ocean-atmosphere-climate signals like precipitation patterns, sea level, and extreme weather (e.g., drought, heat waves, and hurricane intensification). This study presents, for the first time, a multiyear daily record of the meridional overturning circulation flow based on direct measurements in the South Atlantic Ocean at 34.5°S. The roughly six years of observations presented in this study provided the ability to study seasonal and interannual changes in these important flows with continuous daily data, and they demonstrated a complexity of the ocean circulation as compared to other latitudes where this flow has been studied in the past.

Defining the overall ecological status of lakes according to the Water Framework Directive (WFD) is to be partially based on the species composition of the aquatic macrophyte community. We tested three assessment methods to define the ecological status of the macrophyte community in response to a eutrophication pressure as reflected by total phosphorus concentrations in lake water. An absolute species richness, a trophic index (TI) and a lake trophic ranking (LTR) method were tested at Europe-wide, regional and national scales as well as by alkalinity category, using data from 1,147 lakes from 12 European states. Total phosphorus data were used to represent the trophic status of individual samples and were plotted against the calculated TI and LTR values. Additionally, the LTR method was tested in some individual lakes with a relatively long time series of monitoring data. The TI correlated well with total P in the Northern European lake types, whereas the relationship in the Central European lake types was less clear. The relationship between total P and light extinction is often very good in the Northern European lake types compared to the Central European lake types. This can be one of the reasons for a better agreement between the indices and eutrophication pressure in the Northern European lake types. The response of individual lakes to changes in the abiotic environment was sometimes represented incorrectly by the indices used, which is a cause of concern for the use of single indices in status assessments in practice

The Meridional Overturning Circulation (MOC) is a primary mechanism driving oceanic heat redistribution on Earth, thereby affecting Earth’s climate and weather. However, the full-depth structure and variability of the MOC are still poorly understood, particularly in the South Atlantic. This study presents unique multiyear records of the oceanic volume transport of both the upper (<~3100 meters) and abyssal (>~3100 meters) overturning cells based on daily moored measurements in the South Atlantic at 34.5°S. The vertical structure of the time-mean flows is consistent with the limited historical observations. Both the upper and abyssal cells exhibit a high degree of variability relative to the temporal means at time scales, ranging from a few days to a few weeks. Observed variations in the abyssal flow appear to be largely independent of the flow in the overlying upper cell. No meaningful trends are detected in either cell.

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In 1991, eggs of the common tern (Sterna hirundo) were collected at eight different locations and incubated artificially. The residual yolk sacs of the hatchlings from the highly polluted colonies, located in the main sedimentation area of the Rhine and Meuse rivers, contained on average 16 ng TEQ (toxicity equivalency) per gram lipid, which was fivefold higher than the concentrations in the reference colony. The hepatic EROD activity was induced fourfold compared to the reference colony (p < 0.005). At the individual level, a significant relationship was found between log TEQ and both log EROD and log PROD (r = 0.568, p < 0.05 and r = 0.661, p < 0.02, respectively). Average TEQ concentration in chicks that hatched after 23 d of incubation were twice the concentration of those that hatched after 21 d (p < 0.05). No concentration‐related effects on morphology and physiology were found. The non‐ortho‐ and mono‐ortho‐PCBs were predominant regarding the total TEQ, while the PCDDs and PCDFs contributed less than 10%. The PCB patterns were highly similar among the individual birds and among different locations. In contrast, PCDD and PCDF patterns were not similar at all locations, and two distinct patterns could be recognized and related to sediments that were deposited during different time periods.

The existence and strength of the annual KwaZulu-Natal (KZN) sardine run has long been a conundrum to fishers and scientists alike particularly that the sardine Sardinops sagax migrate along the narrow Transkei shelf against the powerful, warm Agulhas Current. However, examination of ship-borne acoustic Doppler current profiler (S-ADCP) data collected during two research surveys in 2005 indicated that northward-flowing coastal countercurrents exist at times between the Agulhas Bank and the KZN Bight, near Port Alfred, East London, Port St Johns and Durban. The countercurrent near Port Alfred extended as far east as the Keiskamma River, within an upwelling zone known to exist there. An ADCP mooring at a depth of 32 m off Port Alfred indicated that the countercurrent typically lasted a few days, but at times remained in the same direction for as long as 10 days. Velocities ranged between 20 and 60 cm s -1 with maximum values of ~80 cm s -1 . The S-ADCP data also highlighted the existence of cyclonic flow in the Port St Johns-Waterfall Bluff coastal inset, with a northward coastal current similarly ranging in velocity between 20 and 60 cm s -1 . CTD data indicated that this was associated with shelf-edge upwelling, with surface temperatures 2-4°C cooler than the adjacent core temperature (24-26°C) of the Agulhas Current. Vertical profiles of the S-ADCP data showed that the countercurrent, about 7 km wide, extends down the slope to at least 600 m, where it appeared to link with the deep Agulhas Undercurrent at 800 m. S-ADCP and sea surface temperature (SST) satellite data confirmed the existence of the semi-permanent, lee-trapped, cyclonic eddy off Durban, associated with a well-defined northward coastal current between Park Rynie and Balito Bay. Analysis of three months (May-July 2005) of satellite SST and ocean colour data showed the shoreward core-boundary of the Agulhas Current (24°C isotherm) to commonly be close to the coast along the KZN south coast, as well as between the Kei and Mbhashe rivers on the Transkei shelf. The Port St Johns-Waterfall Bluff cyclonic eddy was also frequently visible in these satellite data. Transient cyclonic eddies, which spanned 150-200 km of shelf, appeared to move downstream in the shoreward boundary of the Agulhas Current at a frequency of about once a month. These seemed to be break-away Durban eddies. Data collected by ADCP moorings deployed off Port Edward in 2005 showed that these break-away eddies and the well-known Natal Pulse are associated with temporary northward countercurrents on the shelf, which can last up to six days. It is proposed that these countercurrents off Port Alfred, East London and Port St Johns assist sardine to swim northwards along the Transkei shelf against the Agulhas Current, but that their progress north of Waterfall Bluff is dependent on the arrival of a transient, southward-moving, break-away Durban cyclonic eddy, which apparently sheds every 4-6 weeks, or on the generation of a Natal Pulse. This passage control mechanism has been coined the 'Wat...