The global decline in estuarine and coastal ecosystems (ECEs) is affecting a number of critical benefits, or ecosystem services. We review the main ecological services across a variety of ECEs, including marshes, mangroves, nearshore coral reefs, seagrass beds, and sand beaches and dunes. Where possible, we indicate estimates of the key economic values arising from these services, and discuss how the natural variability of ECEs impacts their benefits, the synergistic relationships of ECEs across seascapes, and management implications. Although reliable valuation estimates are beginning to emerge for the key services of some ECEs, such as coral reefs, salt marshes, and mangroves, many of the important benefits of seagrass beds and sand dunes and beaches have not been assessed properly. Even for coral reefs, marshes, and mangroves, important ecological services have yet to be valued reliably, such as cross-ecosystem nutrient transfer (coral reefs), erosion control (marshes), and pollution control (mangroves). An important issue for valuing certain ECE services, such as coastal protection and habitat-fishery linkages, is that the ecological functions underlying these services vary spatially and temporally. Allowing for the connectivity between ECE habitats also may have important implications for assessing the ecological functions underlying key ecosystems services, such coastal protection, control of erosion, and habitat-fishery linkages. Finally, we conclude by suggesting an action plan for protecting and/or enhancing the immediate and longer-term values of ECE services. Because the connectivity of ECEs across land-sea gradients also influences the provision of certain ecosystem services, management of the entire seascape will be necessary to preserve such synergistic effects. Other key elements of an action plan include further ecological and economic collaborative research on valuing ECE services, improving institutional and legal frameworks for management, controlling and regulating destructive economic activities, and developing ecological restoration options.

https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1890/10-1510.1

The value of estuarine and coastal ecosystem services

Marine ecosystems are centrally important to the biology of the planet, yet a comprehensive understanding of how anthropogenic climate change is affecting them has been poorly developed. Recent studies indicate that rapidly rising greenhouse gas concentrations are driving ocean systems toward conditions not seen for millions of years, with an associated risk of fundamental and irreversible ecological transformation. The impacts of anthropogenic climate change so far include decreased ocean productivity, altered food web dynamics, reduced abundance of habitat-forming species, shifting species distributions, and a greater incidence of disease. Although there is considerable uncertainty about the spatial and temporal details, climate change is clearly and fundamentally altering ocean ecosystems. Further change will continue to create enormous challenges and costs for societies worldwide, particularly those in developing countries.

http://science.sciencemag.org/content/sci/328/5985/1523.full.pdf

The impact of climate change on the world's marine ecosystems.

Food’s environmental impacts are created by millions of diverse producers. To identify solutions that are effective under this heterogeneity, we consolidated data covering five environmental indicators; 38,700 farms; and 1600 processors, packaging types, and retailers. Impact can vary 50-fold among producers of the same product, creating substantial mitigation opportunities. However, mitigation is complicated by trade-offs, multiple ways for producers to achieve low impacts, and interactions throughout the supply chain. Producers have limits on how far they can reduce impacts. Most strikingly, impacts of the lowest-impact animal products typically exceed those of vegetable substitutes, providing new evidence for the importance of dietary change. Cumulatively, our findings support an approach where producers monitor their own impacts, flexibly meet environmental targets by choosing from multiple practices, and communicate their impacts to consumers.

/pdf/reducing-food-s-environmental-impacts-through-producers-and-2xmi5ihk3n.pdf

Reducing food’s environmental impacts through producers and consumers

Recent research has highlighted the valuable role that coastal and marine ecosystems play in sequestering carbon dioxide (CO(2)). The carbon (C) sequestered in vegetated coastal ecosystems, specifically mangrove forests, seagrass beds, and salt marshes, has been termed blue carbon. Although their global area is one to two orders of magnitude smaller than that of terrestrial forests, the contribution of vegetated coastal habitats per unit area to long-term C sequestration is much greater, in part because of their efficiency in trapping suspended matter and associated organic C during tidal inundation. Despite the value of mangrove forests, seagrass beds, and salt marshes in sequestering C, and the other goods and services they provide, these systems are being lost at critical rates and action is urgently needed to prevent further degradation and loss. Recognition of the C sequestration value of vegetated coastal ecosystems provides a strong argument for their protection and restoration; however, it is necessary to improve scientific understanding of the underlying mechanisms that control C sequestration in these ecosystems. Here, we identify key areas of uncertainty and specific actions needed to address them.

https://esajournals.onlinelibrary.wiley.com/doi/epdf/10.1890/110004

A blueprint for blue carbon: toward an improved understanding of the role of vegetated coastal habitats in sequestering CO2

Aim Our scientific understanding of the extent and distribution of mangrove forests of the world is inadequate. The available global mangrove databases, compiled using disparate geospatial data sources and national statistics, need to be improved.Here,we mapped the status and distributions of global mangroves using recently available Global Land Survey (GLS) data and the Landsat archive. Methods We interpreted approximately 1000 Landsat scenes using hybrid supervised and unsupervised digital image classification techniques. Each image was normalized for variation in solar angle and earth‐sun distance by converting the digital number values to the top-of-the-atmosphere reflectance. Ground truth data and existing maps and databases were used to select training samples and also for iterative labelling. Results were validated using existing GIS data and the published literature to map ‘true mangroves’. Results The total area of mangroves in the year 2000 was 137,760 km 2 in 118 countries and territories in the tropical and subtropical regions of the world. Approximately 75% of world’s mangroves are found in just 15 countries, and only 6.9% are protected under the existing protected areas network (IUCN I-IV). Our study confirms earlier findings that the biogeographic distribution of mangroves is generallyconfinedtothetropicalandsubtropicalregionsandthelargestpercentage of mangroves is found between 5° N and 5° S latitude. Main conclusions We report that the remaining area of mangrove forest in the world is less than previously thought. Our estimate is 12.3% smaller than the most recent estimate by the Food and Agriculture Organization (FAO) of the United Nations.We present the most comprehensive, globally consistent and highest resolution (30 m) global mangrove database ever created.We developed and used better mapping techniques and data sources and mapped mangroves with better spatial and thematic details than previous studies.

http://faculty.jsd.claremont.edu/dmcfarlane/bio176mcfarlane/pdf%20papers/world%20mangrove%20distribution.pdf

Status and distribution of mangrove forests of the world using earth observation satellite data

Series d'experiences en laboratoire permettant de preciser les effets de perturbations physiques des sediments superficiels sur les interactions trophiques au sein de: Bacteries, protozoaires et meiofaune

Effect of physical disturbance on population dynamics and trophic interactions among microbes and meiofauna

http://www.agroparistech.fr/geeft/Downloads/Training/TropEcol/Bib_exercise/4.1a.pdf

Paradigm shifts in mangrove biology

The interactions of mangrove trees with soil and associated microorganisms are complex. Mangrove trees must cope with a harsh, waterlogged environment, being anchored in soils colonized by highly abundant, productive, and diverse microbial assemblages. The soil horizons are usually dominated by biogenic structures, usually crab burrows and deep tree roots, and are often pockmarked with cracks and fissures. These structures and their activities, coupled with drainage and recharge of interstitial water by tides, foster spatially complex patterns of organic matter decomposition within the forest floor. Except for biogenic structures, oxygen penetrates only a few millimeters into the soil, so anaerobic processes dominate early diagenesis. Sulfate reduction is often the major anoxic process, occurring to a soil depth of at least 1 m and relating to root uptake and exudation of dissolved materials. Recent evidence suggests that iron and manganese reduction may be important in close association with roots and crab activities. Mangrove soils are a source of microbially mediated gases, such as CO2, CH4, N2, and N20. The driving factor of plant-soil relations in mangrove forests is the high nutrient and water requirements needed to fuel high rates of tree photosynthesis. Close and highly efficient tree-microbe-soil interrelationships are a major factor in explaining why mangroves are highly productive forests in oligotrophic environments.

Mangrove-microbe-soil relations

The effect of small-scale logging on stand characteristics and soil biogeochemistry in mangrove forests of Timor Leste

The distribution and composition of bathyal (298–1610 m) microbenthos were examined on the Queensland continental slope, the Coral Sea Plateau and the adjacent Queensland and Townsville troughs in the western Coral Sea. Two conspicuous changes in community composition were recorded: (1) ciliates were undetected below 700 m and (2) yeasts and yeast-like cells were undetected above 1150 m. Densities of flagellates decreased, whereas amoebae densities increased significantly with water depth. Densities of living Foraminifera (x = 56 cm−2) increased significantly from the continental slope to the adjacent troughs. Bacterial numbers ranged from 0.1 to 71.0 × 108 cells g −1 dry wt of sediment and decreased significantly with water depth. Chlorophyll a (0.0–19.0 μg g−1 dry wt) and phaeopigment (0.0–4.9 μg g−1 dry wt) concentrations suggest that phytodetritus is a major source of organic matter in this tropical region. Concentrations of organic carbon (0.22–0.52%) and nitrogen (<0.01–0.02%) were low compared to most other deep-sea sediments, with a shallow sediment depth distribution indicating little burial of organic matter. These findings, coupled with the presence of abundant protozoan populations (∼106 m−2), suggest the potential for rapid microbial activity and dentrital utilization in bathyal surface sediments of the western Coral Sea.

Daniel M. Alongi

Papers

Effect of physical disturbance on population dynamics and trophic interactions among microbes and meiofauna

Paradigm shifts in mangrove biology

Mangrove-microbe-soil relations

The effect of small-scale logging on stand characteristics and soil biogeochemistry in mangrove forests of Timor Leste

The distribution and composition of deep-sea microbenthos in a bathyal region of the western Coral Sea