Open Marine Archive

Huysman, S.

Van Meulebroek, L.

Vanryckeghem, F.

Van Langenhove, H.

Demeestere, K.

Vanhaecke, L.

 15 
Have plasticizers already reached our marine environment? 
Huysman Steve
1
, Van Meulebroek Lieven
1
, Vanryckeghem Francis
2
, Van Langenhove Herman
2
, 
Demeestere Kristof
2
 and Vanhaecke Lynn
2
 
1 
Department of Veterinary Public Health and Food Safety, Laboratory of Chemical Analysis (LCA), 
Salisburylaan 133, Merelbeke, Belgium 
 E-mail: steve.huysman@ugent.be 
2
 Department of Green Chemistry and Technology, Research Group Environmental Organic 
Chemistry and Technology (EnVOC), Coupure links 653, Ghent, Belgium 
 
Yearly, 4.8 to 12.7 million tons of plastic waste enter our oceans and this amount is expected to 
increase by an order of magnitude by 2025 [1,2]. As a result of this widespread global contamination, 
plasticizers can extensively enter our aquatic ecosystem [3]. Furthermore, the abundance of 
plasticizers has recently prompted significant public and mass media interest due to severe known 
and unknown adverse ecological effects [4,5]. 
 
Therefore, this study engaged in the analysis of plasticizers in seawater samples dispersed in the 
Belgian Part of the North Sea (4 locations) during different seasons (2016-2017). The seawater 
samples were analyzed using an in-house developed and validated ultra-high-performance liquid 
chromatographic high-resolution mass spectrometric (UHPLC-HRMS) platform (Huysman et. Al, 2018, 
submitted in journal of Analytical Chemistry). This platform covered 3 different approaches, i.e. 
targeted, suspected and untargeted analysis. The targeted analysis aims at the quantification of a 
predefined list of 27 common plasticizers. Following this targeted analysis, 16 plasticizers were 
ubiquitously detected with concentrations ranging from 20 to 8000 ng L
-1
. Different conjugates (i.e. 
transformation and degradation products) of the target plasticizers were screened during suspected 
analysis based on an in-house database (n=289), thereby using information about the accurate mass, 
isotopic profile and fragmentation spectrum. As a result, 6 additional suspected plasticizers were 
identified. Subsequently, untargeted analysis revealed 420 different unknown compounds including 
9 with a backbone structure related to the target plasticizers as being verified based on characteristic 
product ions and neutral loss fragments. 
 
In conclusion, our work suggests that different known, suspected and unknown plasticizers have 
reached our aquatic ecosystem and may contribute to adverse ecological effects threatening the 
aquatic ecosystem. Moreover, plasticizers are recently recognized as sensitive biomarkers for 
obtaining epidemiological information [6], which can now be evaluated by our newly developed 
platform. Finally, this work also stresses the urgency of investigating the unknown potential effects 
of plasticizers in the marine environment. 
 
References 
 
[1] J.R. Jambeck, Plastic waste inputs from land into the ocean, Clim. Chang. 2014 Impacts, Adapt. 
Vulnerability. 347 (2015) 1655–1732. doi:10.1017/CBO9781107415386.010. 
[2] Erik, Sebille, Environmental Research Letters A global inventory of small floating plastic debris, 
Environ. Res. Lett. 10 (2015). http://iopscience.iop.org/article/10.1088/1748-
9326/10/12/124006/pdf (accessed November 23, 2017). 
[3] Lind, Circulating Levels of Phthalate Metabolites Are Associated With Prevalent Diabetes in the 
Elderly, 35 (2012) 1519–1524. doi:10.2337/dc11-2396. 
[4] L. Canesi, E. Fabbri, Environmental effects of BPA: Focus on aquatic species, Dose-Response. 13 
(2015) 155932581559830. doi:10.1177/1559325815598304. 
[5] C. Guerranti, E. Grazioli, S. Focardi, M. Renzi, G. Perra, Levels of chemicals in two fish species 
from four Italian fishing areas, Mar. Pollut. Bull. 111 (2016) 449–452. 
doi:10.1016/j.marpolbul.2016.07.002. 
[6] E. Gracia-Lor, S. Castiglioni, R. Bade, F. Been, E. Castrignanò, A. Covaci, et al., Measuring 
biomarkers in wastewater as a new source of epidemiological information: Current state and 
future perspectives, Environ. Int. 99 (2017) 131–150. doi:10.1016/j.envint.2016.12.016. 
 
Keywords: plasticizers; Belgian Part of the North Sea; screening; UHPLC-HRMS  


Have plasticizers already reached our marine environment?

Streicher, M.

Kortenhaus, A.

Troch, P.

 25 
Wave impacts on storm walls: Large scale experiments in the Delta 
flume 
Streicher Maximilian, Kortenhaus Andreas and Troch Peter 
Department of Civil Engineering, Ghent University, Technologiepark 904, 9052 Gent, Belgium 
E-mail: maximilian.streicher@ugent.be  
 
1. Introduction 
 
Coasts of low lying countries, such as The Netherlands, Belgium, UK and Germany are often comprised 
of a gentle foreshore and shallow waters, followed by a dike and a promenade. At the end of the 
promenade buildings or storm walls are constructed. In this setting waves can overtop the dike and 
impact on the storm wall or building. Commonly design guidance for overtopping and overtopped 
bore impacts for this set-up are developed in relatively deep water conditions, neglecting the 
dissipation of wave energy due to depth-limited wave breaking on the foreshore. Recently, the 
reduction in overtopping, the increase in wave periods at the toe have been experimentally studied 
for shallow water and gentle foreshore conditions. Furthermore, numerical simulation have been 
performed in the past. Small scale experiments of overtopped wave impacts on walls are conducted 
and design guidance for overtopped wave impacts on walls for shallow water and gentle foreshore 
conditions were derived. However, a validation based on large scale experimental data of overtopped 
wave impacts for this set-up is still missing. 
 
2. WaLoWa objectives  
 
Within the European project ‘Wave Loads on Walls’ (WaLoWa) model tests in the Delta flume (The 
Netherlands) have been conducted in March 2017. The project is a cooperation of Ghent University 
(Belgium), TU Delft (The Netherlands), RWTH Aachen (Germany), University of Bari, University of 
Florence (Italy) and Flanders Hydraulics Research (Belgium). The project is financed by a grant 
by Hydralab+ in the framework of the EC Horizon 2020 program. The program provides researchers 
access to large scale coastal engineering test facilities in Europe. The main objectives are: (a) to study 
the impact behavior of overtopped waves on vertical structures (b) to study scale effects by comparing 
the obtained results to small-scale experiments conducted using a similar geometry, (c) to analyze 
bed profile changes and suspended sediment concentration of the sandy foreshore, (d) to validate 
numerical models in terms of wave evolution over the foreshore and wave impacts on the wall, (e) to 
study the overtopped flow formation on the promenade and (f) to apply new measurement techniques 
for this set-up. 
 
3. Experimental set-up  
 
The scale model geometry is divided into four parts: (1) A sandy foreshore with a slope of 1/35 over 
a flume length of 80m, made from ~1000m³ of sand, (2) Both a concrete dike with a 1/2 slope and 
(3) a 2.3m wide promenade are attached to the foreshore, (4) A vertical, 1.6m high wall at the end of 
the promenade. All values are given in model scale using Froude similarity 1/4.3 and are given more 
detailed in Streicher et al. (2017). Irregular and Bichromatic waves were tested during the 
experiments. Waves representing a storm with a 1000 year return period and an additional water level 
to account for sea level rise result in the tested superstorm conditions. In (part 1) the incoming wave 
parameters and morphological evolution of the sand bed are measured, in (part 2) the run-up and 
overtopping are surveyed. In (part 3) the overtopping flow parameters layer thickness and velocity 
are monitored and in (part 4) the impact forces and pressures on the wall and the flow aeration are 
measured. 
 
4. Discussion  
 
During the VLIZ talk the large-scale WALOWA model tests, conducted in the largest wave flume facility 
of the world, will be presented. An outline of the objectives, model construction, test program and 
measured parameters will be given. With the obtained large-scale data set a detailed study of wave 
impact processes along the coasts of shallow waters and gentle foreshores is enabled and numerical 
model validation facilitated. The importance of large-scale physical model testing in coastal 
engineering will be addressed by highlighting preliminary results. More detailed the pressure 
distribution induced by a wave impacting the wall will be discussed. 
 
 26 
Acknowledgement  
  
The work described in this publication was supported by the European Community’s Horizon 2020 
Research and Innovation Programme through the grant to HYDRALAB-PLUS, Contract no. 654110. 
 
Reference 
 
Streicher, M., Kortenhaus, A., Altomare, C., Gruwez, V., Hofland, B., Chen, X., Marinov, K., Scheres, 
B., Schüttrumpf H., Hirt, M., Cappietti, L., Esposito, A., Saponieri, A., Valentini, N., Tripepi, G., 
Pasquali, D., Di Risio, M., Aristodemo, F., Damiani, L., Willems., M., Vanneste D., Suzuki, T., Klein 
Breteler, M., Kaste, D. (2017). “WALOWA (Wave Loads on Walls) – Large-scale experiments in the Delte 
Flume”.  Proceedings of the 8th SCACR conference 3rd – 6th October, Santander (Spain). 
 
Keywords: coastal engineering; storm walls; overtopping; wave impacts; large-scale experiments  


Wave impacts on storm walls: Large scale experiments in the Delta flume

Strypsteen, G

Rauwoens, P.

 27 
Dynamic sand: Towards a resilient Belgian coast 
Strypsteen Glenn and Rauwoens Pieter 
KU Leuven, Department of Civil Engineering, Technology Cluster Construction, Spoorwegstraat 12, 
8200 Brugge, Belgium 
E-mail: glenn.strypsteen@kuleuven.be  
 
At some parts of the Belgian coast, dunes are replaced by dikes which form a fixed boundary in the 
coastal zone. In order to maintain a sustainable and climate-resilient coast, combining coastal safety 
objectives with natural development like wind-blown sand transport gets more important. Opposed 
to storm-wave processes, leading to beach erosion, quantitative understanding of wind-blown 
(Aeolian) processes, leading to accretion, is necessary.  Wind-blown sand from the beach allows dunes 
to grow vertically with sea-level rise, thereby ensuring long-term coastal safety. Moreover, it is crucial 
for the biodiversity within the coastal region. For the past two years, the dynamic morphological 
behavior of the coast as a result of sand transport by wind is studied with innovative monitoring 
techniques at Mariakerke-Bad and Koksijde. It is noticed that sand transport dynamics are dependent 
on local conditions such as beach dimensions, beach topography and also meteorological and surface 
characteristics. Results show that the typical beach topography at Mariakerke-Bad (artificial cliff and 
high beach) changes rapidly during onshore moderate wind conditions (9 m/s). The artificial cliff and 
high beach, introduced and managed by the coastal town, changes towards a beach with a more 
natural slope. Based on our results, we are able to understand the dynamics of wind-blown sand 
transportt at a managed beach and to quantitfy the time scales at which sand transport events take 
place. 
 
Keywords: wind-blown transport; monitoring techniques; coastal resilience; managed beach; 
topographical changes  


Dynamic sand: towards a resilient Belgian coast

Bodur, Y.

Felden, J.

Wenzhöfer, F.

Braeckman, U.

 72 
Disturbance effects from the 79N Glacier (Northeast Greenland) on 
local benthos ecosystem functions: correlating data from then and 
now 
Bodur Yasemin
1
, Felden Janine
2
, Frank Wenzhöfer
3
 and Braeckman Ulrike
4 
1 University of Bremen, Bibliothekstraße 1, 28359 Bremen, Germany 
E-mail: ybodur@uni-bremen.de  
2 MARUM Center for Marine Environmental Sciences, Leobener Straße 8, 28359 Bremen, Germany 
3 Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359 Bremen, Germany 
4 Marine Biology Research Group, Department of Biology, Ghent University, Krijgslaan 281/S8, 
9000 Ghent, Belgium 
 
Glacier mass loss is seen as the main player for global sea level rise, but little is known about how 
increasing glacier disturbance, coming along with the accelerated retreat, will influence local marine 
ecosystems and their functions in a changing climate. 
 
We investigated the effects of recent glacier retreat from the 79N Glacier, Northeast Greenland, on 
local benthic communities and their functions. Samples were collected in September/October 2017 
during PS109 onboard RV Polarstern at 13 stations either with a benthic Lander or a Multicorer. 
Oxygen consumption was measured ex situ over time. For benthic community characterization 
(bacterial abundances and soft bottom macrofauna), subsamples were taken for every station. In 
parallel, sediment granulometry and porosity, pigment and TOC concentrations and porewater 
chemistry (DIC, nutrients, sulfate, chloride) were assessed to characterize the habitat. 
 
Bacterial abundances in 0-1 cm sediment depth varied between 3.306*10
8 
and 2.607*10
9
 cells ml
-1
 
and did not follow a specific geographical pattern; highest abundances were observed at the Norske 
Trough and the Djimphna Sund. Abundances in 4-5 cm depth ranged from 1.163*10
8
 to 2.711*10
9
 
cells ml
-1
. Total oxygen uptake varied between -1.199 and 1.670 mmol m
-2
 d
-1
 with lowest values near 
the glacier and highest values at the inner Norske Trough. 
 
The results, together with the obtained macrofauna community data, will be compared to data 
published in the early nineties that were taken in the same region (Piepenburg et al. 1997; Rowe et 
al. 1997; Ambrose and Renaud 1995), which would be a first attempt to evaluate changes in the 
benthos attributed to the effect of glacial melt water and allow an evaluation of how ecosystems and 
their services will alter in the future. 
 
References 
 
- Ambrose, William G., and Paul E. Renaud. 1995. “Benthic Response to Water Column Productivity 
Patterns: Evidence for Benthic-Pelagic Coupling in the Northeast Water Polynya.” Journal of 
Geophysical Research: Oceans 100 (C3):4411–21. https://doi.org/10.1029/94JC01982. 
- Piepenburg, Dieter, William G. Ambrose, Angelika Brandt, Paul E. Renaud, Michael J. Ahrens, and 
Preben Jensen. 1997. “Benthic Community Patterns Reflect Water Column Processes in the 
Northeast Water Polynya (Greenland).” Journal of Marine Systems 10 (1–4):467–82. 
https://doi.org/10.1016/S0924-7963(96)00050-4. 
- Rowe, Gilbert T., Gregory S. Boland, Elva G. Escobar Briones, Marta Elizabeth Cruz-Kaegi, Adrian 
Newton, Dieter Piepenburg, Ian Walsh, and Jody Deming. 1997. “Sediment Community Biomass 
and Respiration in the Northeast Water Polynya, Greenland: A Numerical Simulation of Benthic 
Lander and Spade Core Data.” Journal of Marine Systems 10 (1–4):497–515. 
https://doi.org/10.1016/S0924-7963(96)00065-6. 
 
Keywords: arctic; climate change; glacier disturbance; benthic functions; infauna  


Disturbance effects from the 79N Glacier (Northeast Greenland) on local benthos ecosystem functions: correlating data from then and now

Camargo, C.

Hernandez, F.

Soetaert, K.

 75 
Importance of quality control for sea level observations  
Camargo Carolina
1
, Hernandez Francisco
2
 and Soetaert Karline
3 
1 
Oceans & Lakes, VUB, Pleinlaan 2,1050 Brussels, Belgium 
 E-mail: carmacha@vub.ac.be 
2
 Flanders Marine Institute (VLIZ), InnovOcean site, Wandelaarkaai 7, 8400 Ostend, Belgium 
3
  NIOZ, Korringaweg 7, Yerseke, The Netherlands 
 
Sea level is a widely used oceanographic parameter. Sea level observations are important for several 
practical and scientific reasons, from basic knowledge for coastal erosion and defense projects to the 
understanding of tides, oceans dynamics and short-term climate change (Pugh, 1987; Rickards & 
Kilonsky, 1997). Furthermore, real and near real-time applications of sea level include tsunami and 
storm surge warnings (NOAA, 2103). 
 
Under the scope of the Intergovernmental Oceanographic Commission of UNESCO (IOC), the Global 
Sea Level Observing System (GLOSS) was established in 1985 as the coordinator of global and regional 
sea level networks (Merrifield et al, 2009). The main component of the global network is the GLOSS 
Core Network (GCN), composed of 300 tide gauge stations distributed around the world (GLOSS, 
2012). In addition to the 264 active GLOSS stations, the IOC Sea Level Station Monitoring Facility, 
hosted by the Flanders Marine Institute (VLIZ), receives real-time sea level data from another 613 
stations worldwide. While the real-time data processing and storing is carried out by VLIZ, the long-
term quality controlled sea level records is handled by the Permanent Service for Mean Sea Level 
(PSMSL) 
 
Quality Control (QC) is necessary to maintain common standards and allow consistency and reliability 
of archived data (BODC, 2007). In relation to real-time data, QC ensures credibility and value of the 
data (IOOS, 2016). Sea Level QC can be divided in three levels: Near Real-time; Level 1 (after 1 hour 
to 1 month); and Level 2 (months to years). Level 1 and 2 of the IOC Sea Level Stations is performed 
by the University of Hawaii Sea Level Centre (UHSLC) and the British Oceanographic Data Centre 
(BODC), respectively. 
 
The aim of the present thesis is to perform QC of Level 1 on a chosen number of stations of the IOC 
Monitoring Network, followed by a Level 2 QC including tidal predictions and residual analysis. 
Measured sea level values that deviate from the predicted may indicate errors but also tidal events 
like tsunamis and storm surges, thus having some quality control for the real and near real-time data. 
Sea level data is acquired from the IOC Monitoring Network in R Studio Server®.  Initially, this work is 
focusing on 5 active stations. After having the QC treatment for the working stations, the procedure 
will be applied for the rest of the IOC Network Stations. Data treatment is performed with the open 
source software R (R core team, 2017). Quality Control procedures are gathered from the available 
literature, focusing mainly on tests described in the GLOSS [1] & BODC [2] Manuals. 
 
QC of the stations is still an on-going work, and the results will be presented in the poster. The poster 
will show a case study of an IOC Station before and after the Quality Control treatment. 
 
References 
 
[1] Global Sea-Level Observing System (GLOSS), 2011. Manual on Quality Control of Sea Level 
Observations, Version 1.0, 38pp. Draft. 
[2] British Oceanographic Data Centre (BODC), 2007. Data Quality Control Procedures, Version 3.0. 
(September 2007), 75pp. 
  
- Global Sea-Level Observing System (GLOSS), 2012. The Global Sea Level Observing System – 
Implementation Plan 2012. UNESCO/IOC, 41pp. IOC Technical Series No.100. 
- Integrated Ocean Observing System (IOOS), 2016. Manual for Real-Time Quality Control of Water 
Level Data – A guide to Quality Control and Quality Assurance for Water Level Observations. 
Version 2.0. 
- Merrifield, M. et al, 2009. The Global Sea Level Observing System (GLOSS). In: Hall, J.; Harrison, 
D.E., and Stammer, D. (eds.) Proceedings of OceanObs’09: Sustained Ocean Observations and 
Information for Society, Vol. 2. (Venice, Italy). 
- National Oceanographic and Atmospheric Agency (NOAA), 2013. Why Measure Water Levels? In: 
Tides and Currents. https://tidesandcurrents.noaa.gov/levelwhy.html 
 76 
- Pugh, D. T., 1987. Tides, Surges and mean sea-level. Book. John Wiley & Sons, 472. 
- Rickards, L., & Kilonsky, B.,1997. Developments in sea level data management and exchange. 
Ocean Data Symposium. (Dublin, Ireland). 
- R Core Team (2017). R: A language and environment for statistical computing. R Foundation for 
- Statistical Computing, Vienna, Austria. URL https://www.R-project.org/ 
 
Keywords: sea level; quality control; GLOSS 
  


Importance of quality control for sea level observations

Guden, R.M.

Vafeiadou, A.-M.

De Meester, N.

Derycke, S.

Moens, T.

 90 
Living apart-together: Microhabitat differentiation of cryptic 
nematode species in a saltmarsh habitat 
Guden Rodgee Mae
1
, Vafeiadou Anna-maria
1
, De Meester Nele
1
, Derycke Sofie
2
 and Moens Tom
2 
1
  Marine Biology Lab, Department of Biology, Ghent University, Krijgslaan 281, S8, 9000 Ghent, 
Belgium 
 E-mail: rodgeemae.guden@ugent.be 
2
  Institute for Agricultural and Fisheries Research, Aquatic Environment and Qualit, Ankerstraat 1, 
8400 Oostende, Belgium 
 
Coexistence of highly similar species is at odds with ecological theory of competition; coexistence, 
then, requires stabilizing mechanisms such as differences in ecological niche. In the bacterivore 
nematode Litoditis marina complex associated with macro-algae, four cryptic lineages (Pm I-IV) have 
been found to co-occur in the field along the south-western coast and estuaries of The Netherlands. 
Here we investigate the temporal and/or spatial niche differentiation in their natural environment 
using a qPCR-based detection and relative quantification method. We collected different algal species 
(i.e. two Fucus species and Ulva sp.) and separate algal structures (i.e. receptacula, thalli, non-fertile 
tips and bladders) at different sampling times and different months, to examine differences in 
microhabitat use between coexisting L. marina species. Results demonstrate that the cryptic species 
composition varied among different algal species and algal structures, which was also subject to 
temporal shifts. Pm I dominated on Fucus spp., Pm II showed dominance on Ulva sp. while Pm III 
overall had the lowest frequencies. Microhabitat partitioning was most pronounced between the two 
cryptic species which had similar microbiomes (Pm I and Pm II), and less so between the two species 
which had significantly different microbiomes (PmI and PmIII), suggesting that species which share 
the same microhabitats may avoid competition through resource partitioning. The interplay of 
microhabitat differentiation and temporal dynamics among the cryptic species of L. marina implies 
that there is a complex interaction between biotic components and abiotic factors which contributes 
to their coexistence in the field. 
 
Keywords: cryptic diversity; microhabitat use; temporal; spatial; qPCR  


Living apart-together: microhabitat differentiation of cryptic nematode species in a saltmarsh habitat

Kerckhof, F.

De Mesel, I.

Degraer, S.

 97 
Invading European shores: First European record of the acorn 
barnacle Balanus glandula Darwin, 1854 
Kerckhof Francis, Ilse De Mesel and Steven Degraer 
Marine Ecology and Management, Operational Directorate Natural Environment, Royal Belgian 
Institute of Natural Sciences, 3De en 23ste Linieregimentsplein, 8400 Oostende, Belgium 
E-mail: francis.kerckhof@naturalsciences.be  
 
Balanus glandula Darwin, 1854 is a sessile (acorn) barnacle native to the Pacific coast of North 
America ranging from the Aleutian Islands to Bahia de San Quintín (Baja California). During the past 
half century this barnacle successfully invaded subsequently the coasts of Argentina, Japan and South 
Africa. Recently, we discovered specimens during surveys of hard substrata biofouling communities 
in Belgian marine waters. This invasive species is new to the European marine fauna. We encountered 
specimens first in July 2015. In October 2016, the species proved to be common on navigational 
buoys from Belgian coastal waters and we discovered large numbers of B. glandula on many groynes 
all along the Belgian coast and in the harbour of Zeebrugge. We identified the species both 
morphologically and genetically. We found two generations, indicating that B. glandula had settled in 
2015 (probably the first year of its presence) and also in 2016 and 2017. Given its invasion history 
elsewhere, we forecast that B. glandula is at the brink of invading other European shores. 
 
In its native and also introduced ranges B. glandula is a common rocky intertidal barnacle, found in 
the middle to high intertidal zone. Along the Belgian coast, B. glandula lives in the high and mid 
intertidal zone, where it co-occurs with the introduced New Zealand barnacle Elminius (Austrominius) 
modestus and the indigenous barnacle Semibalanus balanoides. Balanus glandula is well adapted to 
survive in the highest intertidal zone as it is able to withstand desiccation over a long period of time. 
Since B. glandula grows to a larger size and is physically more robust than native and already 
introduced European species such as S. balanoides, E. modestus and Chthamalus spp., we expect this 
new invader to successfully compete with the other intertidal barnacle species and hence impact rocky 
intertidal biodiversity. Competition with Balanus crenatus and the indigenous blue mussel Mytilus 
edulis seems less likely since both species live lower in the intertidal zone. Balanus glandula 
contributes to a growing number of introduced species that colonize the artificial hard substrata 
along the southern North Sea coasts. Since the species might be difficult to distinguish from other, 
similar looking Western European intertidal barnacles, we provide identification characters. 
 
Keywords: Belgium; invasive species; Cirripedia; introduced species  


Invading European shores: first European record of the acorn barnacle Balanus glandula Darwin, 1854

Mohamed, A.H.

 102 
Mapping of seagrass beds and cover change analysis using Landsat 
imageries, Gazi bay Kenya 
Mohamed Ahmed Hussein 
Vrije Universiteit Brussel, Box 394, Henri Schoofslaan 12, 1160 Audeghem, Belgium 
E-mail: ahmedhusseinmzee@gmail.com  
 
Global climate change as a consequence of increasing anthropogenic emissions is one of the most 
contested yet more pervasive threats to marine ecosystems. However, the ocean’s ability to sequester 
and store significant amounts of carbon due to coastal ecosystems such as mangroves, tidal marshes 
and seagrasses collectively labeled “coastal blue carbon ecosystems” makes it possible for us to tackle 
this problem. Of particular interest are seagrass meadows which are now starting to be recognized 
as important carbon sinks that not only trap and store organic carbon generated within the seagrass 
beds but also trap and bury allochthonous carbon. Seagrass beds are widely distributed and provide 
nursery ground and habitat for marine organisms including epiphytic algae. They trap nutrients and 
accumulate sediments therefore improving the water quality and stabilize the bottom. Furthermore, 
they are a direct food source for fish and other endangered species such as turtles, dugongs and 
waterfowl. Nonetheless, seagrass beds are the least well-studied blue carbon ecosystems that are 
currently threatened to disappear due to anthropogenic activities such as eutrophication, turbidity, 
sedimentation and human infrastructural development in form of aquaculture and construction. In 
Kenya and with specific emphasis to Gazi bay, extensive research work has been done on adjacent 
seagrass ecosystems such as mangroves but with relatively little coverage on seagrass beds. In fact, 
the only official records of detailed seagrass mapping and monitoring that exist for this Bay date back 
to a study by Coppejan et al., 1992 and Dahdouh-Guebas et al., 1999; thus the conclusion that there 
are insufficient data for even a best guess of total seagrass coverage in Kenya. This study takes 
advantage of the free and open access satellite data to investigate the present cover and temporal 
change in seagrass bed in Gazi bay Kenya using archived Landsat data from 1997 to 2017. Processing 
of data involved: converting Landsat data to top of atmosphere reflectance, water column correction 
for light attenuation with depth, sunglint correction for easy classification, image classification using 
supervised methods, accuracy assessment and detection of change in cover. Maximum Likelihood 
classification results indicate a current total cover of approximately 647 hectares with a producer 
accuracy and user accuracy of over 80%. Overall the seagrass beds in the bay have decline by 574 
hectares in a period of 20 years giving a rate of 47% loss. This loss can be attributed to destructive 
fishing practices, erosion and sedimentation. 
 
Keywords: seagrasses; mapping  


Mapping of seagrass beds and cover change analysis using Landsat imageries, Gazi Bay Kenya

Peignot, Q.

Frédérich, B.

Lepoint, G.

Michel, L.

 105 
δ13C and δ15N measurements in Antarctic Notothenioid fishes: 
variation of their trophic ecology.  
Peignot Quentin
1
, Frédérich Bruno
1
, Lepoint Gilles
1
 and Michel Loïc
2
 
1
 Laboratory of Oceanology, MARE Centre, University of Liège, B6c, 4000 Liège, Belgium 
 E-mail: qpeignot@gmail.com 
2
  Deep-Sea Environments Laboratory (LEP), Ifremer Brittany, 29280 Plouzané, France  
 
The Southern Ocean currently undergoes major environmental modifications related to climate 
change such as changes in the sea ice cover, temperature and acidification.  When faced with 
environmental changes, all organisms are expected to have some intrinsic capacity to adapt their 
ecological habits to their new life conditions. Currently, biological traits of many Antarctic species are 
still unknown and we need such information to assess their capacity to adapt to natural and 
anthropogenic perturbations. Notothenioidei (Perciformes), or icefishes, are endemic to the Southern 
Ocean and they are an important trophic component of these marine ecosystems. 
 
To better understand their resources partitioning and the influence of environmental changes on their 
trophic ecology, we used muscle stable isotopes ratios of carbon (δ13C) and nitrogen (δ15N) of two 
widespread genera of icefishes (Trematomus and Lepidonotothen) sampled in 2002/2004 and/or in 
2015/2016. Isotopic niches (which are a proxy of the realized ecological niches) were modeled using 
the SIBER (Stable Isotope Bayesian Ellipses in R) R-package. 
 
For the two sampling periods, our results revealed a great variation in isotopic compositions among 
Notothenioid fishes, suggesting that they exploit a wide array of resources. The overlap between the 
isotopic niches of Trematomus and Lepidonotothen genera in 2002/2004 highlights a possible past 
competition for resources. Moreover, temporal evolution of niches suggests taxon-specific ecological 
plasticity in response to variation in environmental parameters and/or in prey availability. An increase 
in resources partitioning between the two genera was observed over the studied period. In the future, 
it would be interesting to complete our results with a stomach content analysis and to use mixing 
models including isotopic composition of potential preys to identify possible changes in their trophic 
ecology.  
 
Keywords: Southern Ocean; environmental modifications; trophic ecology; icefish; stable isotopes  


δ13C and δ15N measurements in Antarctic Notothenioid fishes: variation of their trophic ecology

UHPLC-HRMS based targeted and untargeted screening of plasticizers in the 
marine environment 
 
Huysman Steve1, Van Meulebroek Lieven1,Vanryckeghem Francis2, Van Langenhove 
Herman2, Demeestere Kristof2 , and Vanhaecke Lynn1 
1Ghent University, Department of Veterinary Public Health and Food Safety, Laboratory of 
Chemical Analysis (LCA), Merelbeke, Belgium 
2Ghent University, Department of Sustainable Organic Chemistry and Technology, Research 
Group Environmental Organic Chemistry and Technology (EnVOC), Ghent, Belgium 
 
Corresponding authors: Steve.Huysman@Ugent.be and Lynn.Vanhaecke@Ugent.be  
 
The cumulative amount of plastics entering our aquatic environment is predicted to increase 
by an order of magnitude by 2025, resulting in the extensive entree of plasticizers. Plasticizers, 
i.e. phthalate acid esters and alkylphenols, are easily released into the aquatic environment 
as a result of their weak physical bonding to plastic polymers. As it has been shown that 
continuous exposure to plasticizers results in a plethora of adverse ecological effects, 
monitoring phthalate acid esters and alkylphenols in the marine environment is of great 
importance to provide insight in the widespread occurence of these compounds in our 
aquatic ecosystems. 
 
Therefore, this study engaged on the analysis of the abovementioned compound groups in 
seawater samples obtained from different locations in the Belgian Part of the North Sea 
during different seasons (2016-2017). The seawater samples were analyzed using an in-house 
developed and validated ultra-high-performance liquid chromatographic high-resolution 
mass spectrometric (UHPLC-HRMS) method. This novel analytical method was specifically 
designed to minimize false-positive detections resulting from laboratory contamination of 
plasticizers. Performing the targeted analysis of 27 plasticizers revealed the prevalence of 16 
unique plasticizers in the seawater samples. Alkylphenols and phthalates were respectively 
detected at concentrations ranging from 24 to 8000 ng L-1 and 20 to 2580 ng L-1. Moreover, 
multivariate statistics displayed the highest concentrations of ethylphenol and dibutyl 
phthalate in the harbor of Ostend. Next to the native plasticizers, also primary plasticizer 
metabolites (mono-phthalates) were ubiquitously detected with concentrations ranging 
between 25 and 2550 ng L-1. Subsequent to the targeted screening, untargeted analysis of the 
same seawater samples revealed 3688 different unknown compounds. Further data analysis 
for identification purposes occurred through online environmental database search, including 
MarineLit, Marine Drugs, EPA, drugsbank, ACTor and EAWAG biodegradation. In conclusion, 
the ubiquitous prevalence of plasticizers in our marine waters suggests that plasticizers will 
have reached different trophic levels throughout our aquatic ecosystem and may thus 
contribute to adverse ecological effects threatening the quality of our marine environment.  
 
Acknowledgments 
The authors acknowledge the Belgian Science Policy (BELSPO) for funding the NewSTHEPS 
project (BR/143/A2/NEWSTHEPS; www.newstheps.be) in which this work fits. 


UHPLC-HRMS based targeted and untargeted screening of plasticizers in the marine environment

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δ<sup>13</sup>C and δ<sup>15</sup>N measurements in Antarctic Notothenioid fishes: variation of their trophic ecology

UHPLC-HRMS based targeted and untargeted screening of plasticizers in the marine environment

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