Tropical marine ecosystems provide a wide range of provisioning, regulating, supporting and cultural services to millions of people. They also largely contribute to blue carbon sequestration. Mangroves, seaweeds, and seagrass habitats are important because they store large amounts of organic carbon while fish play a fundamental role in the carbon transport to deep waters. Protecting and restoring tropical marine ecosystems is of great value to society because their decline impairs the vital services they provide, such as coastal protection and seafood supplies. In this marine policy paper, we present options for enhancing blue carbon sequestration in tropical coastal areas. In addition, we outline the economic value of four components of coastal ecosystems (mangroves, seagrass beds, seaweed forests and fish) and discuss the economic levers society can apply to ensure the end of the current gross mismanagement of tropical blue carbon ecosystems. Market-based solutions, such as carbon taxes or fines for violations that use the ‘polluter pays' principle, can be very effective in achieving national or international climate agreements. Private investment can also finance the preservation of blue carbon ecosystems. One widely known financing method for blue carbon conservation, particularly of mangroves, is the use of municipal bonds, which can be issued like traditional bonds to finance the day-to-day obligations of cities, states and counties. Non-philanthropic investments can also be used in order to protect these ecosystems, such as debt-for-nature swaps and the improved application of regulatory frameworks. Overall, the protection of tropical marine ecosystems is an ecological imperative and should also be seen as an opportunity for new revenue streams and debt reduction for countries worldwide.
We contribute to the identification of marine biodiversity status and changes in the coastal area of Southeast Greenland through consultation with holders of local and Indigenous knowledge (LEK/IK). Through in-depth interviews with coastal fishermen and hunters in the Ammassalik area, we explore a range of changes to known and new species in relation to ecosystem dynamics. Key observations include diminishing presence of polar cod (Boreogadus saida), new abundance of known fish species (Gadus morhua, Salvelinus alpinus, Reinhardtius hippoglossoides, Cyclopterus lumpus), inflow of new/rare species of whales, fish, and shellfish (Oncorhynchus gorbuscha, Lamna nasus, Paralithodes camtschaticus, Physeter macrocephalus, Globicephala melas, Megaptera novaeangliae, Phocoena phocoena), and increasing absence in the fjords of some local seal species (Cystophora cristata and Pusa hispida). Observed changes in local abundances are understood with reference to the physical changes in temperature, ocean currents, glacier melt, and snowfall. Changed dynamics in prey-predator relationships are observed to mediate the local presence of target species. Other environmental changes include an influx of new food items in food chains and increased seaweed growth. Our study confirms the relevance and timeliness of systematically incorporating local and Indigenous knowledge to enhance the understanding of coastal marine dynamics in the context of climate change and the geographical 'opening' of the East Greenlandic region.
Continuous inspection and mapping of the seabed allows for monitoring the impact of anthropogenic activities on benthic ecosystems. Compared to traditional manual assessment methods which are impractical at scale, computer vision holds great potential for widespread and long-term monitoring.
We deploy an underwater remotely operated vehicle (ROV) in Jammer Bay, a heavily fished area in the Greater North Sea, and capture videos of the seabed for habitat classification. The collected JAMBO dataset is inherently ambiguous: water in the bay is typically turbid which degrades visibility and makes habitats more difficult to identify. To capture the uncertainties involved in manual visual inspection, we employ multiple annotators to classify the same set of images and analyze time spent per annotation, the extent to which annotators agree, and more.
We then evaluate the potential of vision foundation models (DINO, OpenCLIP, BioCLIP) for automating image-based benthic habitat classification. We find that despite ambiguity in the dataset, a well chosen pre-trained feature extractor with linear probing can match the performance of manual annotators when evaluated in known locations. However, generalization across time and place is an important challenge.
Spatial tools to calculate cumulative impact assessments on the environment (CIA) are important contributors to the implementation of an ecosystem-based approach to maritime spatial planning (MSP). Ecosystem dynamics are increasingly important to understand as the activities and pressures in marine areas increase. Results from the application of a new training set for the CIA tool MYTILUS, developed in capacity-building MSP projects for active learning environments, illustrate important points on how the CIA method can be used in systematic scenario design. The feedback from its use in an online PhD course outlines how the training set successfully enables researchers from different disciplines and different parts of the world to meet the CIA approach with such interest and understanding that it enables them to highlight the strengths as well as the shortcomings of the tool interface, tool capabilities, and CIA method, even when none of these researchers are CIA experts. These promising results are presented in this paper and advocate for the increasing use of MYTILUS and similar CIA tools in MSP stakeholder sessions where no preliminary CIA expertise can be expected. The key strengths and challenges of training CIA with MYTILUS are discussed to point out focus points for how to make its approaches increasingly fit for participatory and decision-making processes in MSP to utilize its promising abilities for supporting ecosystem-based management.
An analytical framework is presented to describe the attenuation of regular and irregular waves propagating over floating seaweed farms. Kelp blades suspended on longlines are modelled, as a first approximation, as rigid bars rotating around their upper ends. Assuming small-amplitude blade motions under low to moderate sea conditions, the frequency-dependent transfer function of the rotations can be obtained, with quadratic drag loads linearized. Subsequently, the hydrodynamic problem with regular waves propagating over suspended seaweed canopies is formulated using the continuity equation and linearized momentum equations with additional source terms in the vegetation region. Analytical solutions are obtained for attenuated regular waves with their heights decaying exponentially as they propagate over the canopy. These solutions are utilized as the basis for predicting wave attenuation of irregular waves while stochastic linearization of the quadratic drag loads is employed. In contrast to energy-conservation-based models, which assume the velocity profile follows linear wave theory, the present solution can predict the reduced velocity inside the canopy. The analytical solutions are validated against experimental data and verified against a numerical flow solver. The model is capable of resolving the wave attenuation, along with velocity profiles and phase lag. Drag and inertial force exhibit cancellation effects on wave decay and both affect phase lag.
In 2020, the Danish Ministry of Environment and Food launched a new state-led ecolabelling scheme for fish originating from small-scale, 'low-environmental-impact' fisheries; "Nature-friendly". The label was introduced to a domestic market where the vast majority of the fish landed by Danish vessels was already certified by the global leader in certification of (wild caught) fish products, the Marine Stewardship Council (MSC). MSC's high market penetration created a situation where especially small-scale fishermen felt that MSC certification had developed into a market norm without providing fishermen the benefits of demonstrating extraordinarily sustainable practices and thereby gaining competitive advantages. Rather, MSC's market penetration was perceived as undermining efforts to brand and market fish originating from small-scale fisheries as particularly sustainable. This article explores the processes that led up to the NaturSkånsom labeling scheme by applying a 'power in planning and policy framework' as an analytical lens. Through the NaturSkånsom process, the article investigates what happens when an ecolabel becomes a market norm, how small-scale fisheries actors who feel disadvantaged by such a development and environmental organizations form alliances, mobilize support and multiple resources to strengthen their positions in the political settings. The examination of this case highlights how stakeholders traditionally thought of as less resourceful can gain political influence. The article offers a glimpse into a possible, emerging future where those who perceive themselves as the most sustainable producers may increasingly view large and dominating ecolabels simultaneously as obstacles and forces for positive change.