Early Career Ocean Professionals for the protection and sustainable use of tropical coastal ecosystems
Chairs: Carolin Müller & Tim Dudeck
Tropical coastal ecosystems are critical to biodiversity, local livelihoods, and global ecological processes, yet they face mounting pressures from anthropogenic activities, climate change, and unsustainable resource use. This session showcases the work of early career researchers advancing our understanding of these vital systems through innovative approaches and interdisciplinary perspectives. Presentations will explore cutting-edge methodologies in habitat mapping, hydrological interactions, governance frameworks, and nutrient dynamics, offering insights into the complexities of tropical coastal ecosystems. Together, these studies highlight the challenges and opportunities for protecting and sustainably managing tropical coasts in a rapidly changing world.
11:15
Deep dive into coral reef community mapping: Detection and morphological description of coral colonies using AI
by Khishma Modoosoodun Nicolas
ZMT & University of Bremen
Accurate and scalable mapping of coral reefs is important for effective conservation and ecological monitoring. This study investigates the application of deep learning-based instance segmentation for predicting individual Scleractinian coral colonies on the Pelorus Reef in the Great Barrier Reef, leveraging high-resolution orthomosaic maps. Traditional methods of coral colony detection involve manual annotation and visual inspection, which are labour-intensive and time-consuming, particularly for large-scale reefs. In this study, supervised instance segmentation offers a promising alternative by automating the detection process and scaling up the predictions of coral colonies. A state-of-the-art convolutional neural network (CNN) method is utilized to develop an instance segmentation model to train on a dataset of annotated orthomosaic tiles, each labelled with bounding boxes and segmentation masks at different coral morphology levels. The objective is to scale the prediction process from a manually annotated subset to the entire reef site, thereby enhancing mapping efficiency and coverage. Experiments such as data augmentation are performed to boost the model performance to improve prediction accuracy. The ultimate goal is to establish a scalable and efficient workflow that can be applied to new reef sites, thus providing a standardised and consistent approach to coral community mapping.
11:30
Investigation of submarine groundwater discharge on a tidally influenced coast in India
by Cátia Milene Ehlert von Ahn | Soumya Kanta Nayak | Naveen Gupta | Murugan Ramasamy | Nandimandalam Janardhana Raju | Nils Moosdorf
ZMT | School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India |School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India | ZMT | School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India | ZMT; Institute of Geosciences, Kiel University, Kiel, Germany
Submarine groundwater discharge (SGD) is an important transport pathway between land and ocean. The term SGD covers a wide range of processes, compositions and origins, including not only the direct discharge of fresh groundwater, but also diffuse and brackish porewater fluxes through permeable surface sediments. The mixing zone between fresh groundwater and seawater in the coastal sediments forms a subterranean estuary (STE) where nutrients undergo biogeochemical transformations before reaching the ocean. The aim of the presented study is to understand the biogeochemical processes at the STE of a section of the Odisha coast (east coast of India). The climate is tropical with an annual rainfall of about 1550 mm. Sampling took place in the pre-monsoon (May 2024) and postmonsoon (October 2024) seasons. Sediment porewater (down to 125 cm) and seawater were sampled in transects along the coastline in the intertidal zone. Samples were collected for the measurement of several parameters including nutrients. The surface and pore waters showed a large difference in salinity values between the two campaigns: during premonsoon, salinities were up to 36 PSU, while after the monsoon the salinities decreased and the maximum value was 30 PSU. During the post-monsoon season, more low salinity spots were detected along the coastline and the values were positively correlated with the beach elevation. A seepage line with the presence of diffuse SGD was found at about 2m above the sea level. This indicates the formation of an STE, suggesting that SGD is an important phenomenon in the region. The concentration of dissolved phosphate and silicate from the pre-monsoon campaign suggests that STE plays a role in the transport of nutrients towards the sea. Further studies will continue to evaluate the role of STE in the final fluxes to the coastal waters.
11:45
Using a three-dimensional justice framework to analyse mangrove management and (re)establishment efforts in Colombia and Malaysia – Preliminary results
by Mondane Fouqueray
ZMT
Using a three-dimensional justice framework to analyse mangrove management and (re)establishment efforts in Colombia and Malaysia – Preliminary results
Mangrove forests are inherently social-ecological, with deeply interconnected and interdependent social and ecological aspects. Coastal zones, often densely populated, face intense land-use competition, including urban development, agricultural expansion, and pond-building for the aquaculture industry. Additionally, factors such as coastal erosion, sea-level rise, and extreme events are contributing to global mangrove loss. Due to the rapid development of payment for ecosystem services mechanisms, such as carbon credits, and the increased demand for “nature-based solutions”, mangrove (re)establishment projects are gaining momentum, receiving increased funding and attention. However, such projects typically have had high rates of failure. Results of a systematic literature review conducted in 2024 showed that uneven power relations were a major barrier to mangrove (re)establishment success. Power and justice are intricately linked in issues of natural resource management. This subsequent research therefore uses a three dimensional (procedural, distributive and recognition) justice framework, to analyse mangrove management and (re)establishment efforts through a Colombian and a Malaysian case study. The following research questions will be addressed:
Justice in mangrove management: How do relations between different stakeholder groups generate or perpetuate (un)just mangrove use and management?
Justice in mangrove (re)establishment: How did (re)establishment efforts materialise in the two case study areas, and what are the resulting effects on justice? What parallels can be drawn between the case studies and the literature review results?
Preliminary results will be presented, any and all feedback or suggestions are very welcome.
12:00
Nutrients in Kenya’s Coastal waters: Analyzing sources, pathways, and ecological implications
by Nancy A. Oduor | Nils Moosdorf
ZMT; The University of Kiel, Christian-Albrecht University (CAU), Faculty of Mathematics and Natural Sciences | ZMT; The University of Kiel, Christian-Albrecht University (CAU), Faculty of Mathematics and Natural Sciences
This study investigated the nutrient dynamics in Kenya’s coastal waters, focusing on anthropogenic nutrient inputs, their ecological implications, and the risks posed by harmful microalgae. It addresses spatial and temporal patterns of nutrient enrichment, sources and pathways of nutrient influx, and their influence on phytoplankton assemblages and potentially harmful microalgae. Field surveys, laboratory analyses, and literature reviews were conducted over a one-year period (August 2021–July 2022).
The findings reveal significant spatiotemporal variability in nutrient concentrations, with estuaries and tidal creeks near urban areas, such as Tudor Creek, exhibiting elevated levels of dissolved inorganic nitrogen (DIN), salinity, turbidity, and temperature. Seasonal variations showed nutrient-rich freshwater inflows during wet periods. A notable shift from nitrogen-limited conditions to DIN enrichment was observed, with phosphorus and silica becoming limiting factors. This shift altered phytoplankton community dynamics, increasing the prevalence of harmful microalgae species. Anthropogenic sources such as agricultural runoff, sewage discharge, industrial effluents, ballast water, submarine groundwater discharge, and atmospheric deposition were identified as key contributors to nutrient enrichment. These inputs substantially affected ecological quality by fostering harmful algal blooms and altering phytoplankton diversity. The study identified 59 taxa of potentially harmful microalgae, with low abundances below bloom thresholds, and 47% of these taxa are potential toxin producers. However, no phycotoxins were detected during the study period. These findings contribute to the broader understanding of nutrient and phytoplankton dynamics in data deficient tropical coastal ecosystems in Africa and provide a basis for sustainable management practices in Kenya’s coastal waters.
Keywords: Nutrient pollution, phytoplankton assemblages, harmful microalgae, SGD, Kenya.