Outline This chapter reviews coastal benthic communities with the aim of deriving a global estimate for respiration in these ecosystems. Reefs, mangroves, salt marshes, macroalgae, sea grasses, and unvegetated sediments dominate respiration in the coastal ocean. Estimates of coastal benthic respiration are not well constrained but converge on about 620 Tmol C a −1 . In coastal benthic ecosystems autotrophs and multicellular heterotrophs contribute significantly, and in some systems even dominate respiration unlike most other oceanic ecosystems in which bacteria dominate respiration.
The effectiveness, feasibility, duration of effects, co-benefits, disbenefits, cost effectiveness and governability of four ocean-based negative emissions technologies (NETs) are assessed in comparison to eight other ocean-based measures. Their role in revising UNFCCC Parties' future Nationally Determined Contributions is discussed in the broad context of ocean-based actions for both mitigation and ecological adaptation. All measures are clustered in three policy-relevant categories (Decisive, Low Regret, Concept Stage). None of the ocean-based NETs assessed are identified as Decisive at this stage. One is Low Regret ( Restoring and increasing coastal vegetation ), and three are at Concept Stage, one with low to moderate potential disbenefits ( Marine bioenergy with carbon capture and storage ) and two with potentially high disbenefits ( Enhancing open-ocean productivity and Enhancing weathering and alkalinization ). Ocean-based NETs are uncertain but potentially highly effective. They have high priority for research and development.
The association between corals and photosynthetic dinoflagellates (Symbiodinium spp.) is the key to the success of reef ecosystems in highly oligotrophic environments, but it is also their Achilles' heel due to its vulnerability to local stressors and the effects of climate change. Research during the last two decades has shaped a view that coral host-Symbiodinium pairings are diverse, but largely exclusive. Deep sequencing has now revealed the existence of a rare diversity of cryptic Symbiodinium assemblages within the coral holobiont, in addition to one or a few abundant algal members. While the contribution of the most abundant resident Symbiodinium species to coral physiology is widely recognized, the significance of the rare and low abundant background Symbiodinium remains a matter of debate. In this study, we assessed how coral-Symbiodinium communities assemble and how rare and abundant components together constitute the Symbiodinium community by analyzing 892 coral samples comprising >110 000 unique Symbiodinium ITS2 marker gene sequences. Using network modeling, we show that host-Symbiodinium communities assemble in non-random 'clusters' of abundant and rare symbionts. Symbiodinium community structure follows the same principles as bacterial communities, for which the functional significance of rare members (the 'rare bacterial biosphere') has long been recognized. Importantly, the inclusion of rare Symbiodinium taxa in robustness analyses revealed a significant contribution to the stability of the host-symbiont community overall. As such, it highlights the potential functions rare symbionts may provide to environmental resilience of the coral holobiont.
The influence of lake morphometry on the growth of submerged macrophytes in response to sediment fertilization was studied at sites of varying bottom slope (steep to gentle), wave exposure (high to low), and depth (1.0 and 2.5 m) in Lake Memphremagog (Quebec–Vermont). The biomass increases were on average 2.1 times greater for fertilized plants than for the paired controls. The extent of the growth response was greatest at the 1.0-m sites. The smaller response at the 2.5-m sites was further decreased as exposure to waves increased. The smaller response at 2.5 m (depth of maximum biomass) suggests that factors such as light limitation, length of the growing season, and littoral slope, but not sediment nutrient levels, limit submerged biomass there. The importance of the physical factors appears to increase as the biomass increases. "Overwintering" plants showed greater response to fertilization than those growing from seeds. Overall, the extent of the growth response to sediment fertilization depends on the energy environment (i.e. depth, wave exposure, and slope) of the littoral. The influence of these physical factors explains previous difficulties in finding strong correlations between nutrient levels and the growth of submerged macrophytes.
Coloniality and clonality in marine sessile organisms offer several advantages, such as better space occupation and directional growth. In coral colonies, species-specific functional connections are maintained among polyps, allowing for resource translocation and colony architecture coordination. A potential whole-colony integration mechanism is apical dominance, a phenomenon controlling branching patterns through hormonal signaling in plants and seagrass, yet unconfirmed in scleractinian corals. This study aims at investigating the occurrence of apical dominance in corals, hypothesizing that highly integrated species exhibit this mechanism. We experimentally tested this hypothesis in situ by removing the apical tip in three different species ( Stylophora sp., Acropora hemprichii, A. pharaonis ), presenting two contrasting levels of integration and monitoring their branching morphogenesis over time. After 74 days, the null hypothesis that apical dominance does not occur could not be rejected for A. hemprichii and Stylophora sp., likely due to experimental limitations. However, A. pharaonis exhibited accelerated apical regrowth and increased lateral branching after tip removal, suggesting that apical dominance-like mechanisms may operate in this species. These findings highlight the importance of addressing potential Type 1 and Type 2 errors in experimental design to improve reliability while addressing the emergence of apical dominance in highly integrated coral colonies. Further long-term experiments are needed to capture morphometric changes in slow-growing species, such as A. hemprichii . These findings suggest novel endogenous mechanisms coordinating complex three-dimensional morphogenesis in clonal organisms and offer valuable application in the growing field of coral farming and restoration.
In support of World Ocean Day on June 8th 2024, we are pleased to be hosting Prof Carlos M. Duarte, Distinguished Professor of Marine Science. Prof Duarte's presentation "Rebuilding Marine Life" will be followed by a Q A session chaired by Editors Éva Lörinczi and Greta Hedley-Miller, with the opportunity for the audience to ask questions. Abstract: Hunting, overfishing, habitat loss and pollution have led to a loss of about half of the ocean´s natural capital. However, the ocean remains resilient and able to recover within one human generation, by 2050, if we simultaneously activate seven wedges for recovery. For the first time, the world leaders have agreed on a regenerative approach to ocean conservation, but the investments required to rebuild marine life far exceed those available todate. A new regenerative blue economy, which generates wealth while investing in healthy oceans is required to achieve the goal of a healthy ocean, particularly as the time window to achieve this goal is narrow and rapidly closing.
describir la experiencia inicial en Colombia en el manejo del melanoma de extremidad con perfusión aislada y comparar la respuesta de los subtipos histológicos más frecuentes en Colombia con la literatura.estudio descriptivo, retrospectivo de una serie de pacientes con diagnóstico de melanoma con metástasis en tránsito tratados con perfusión aislada de extremidad, seleccionados entre 2007 y 2016. Las variables cualitativas se analizaron con frecuencias absolutas y relativas. Las cuantitativas con medidas de tendencia central y dispersión.11 pacientes fueron tratados con perfusión aislada de extremidad. Hubo respuesta parcial en siete pacientes (63,6%), enfermedad estable en dos pacientes (18,2%) y progresión en dos pacientes (18,2%). Después del tratamiento, cinco pacientes (45,5%) presentaron complicaciones menores.la perfusión aislada sigue siendo importante para el tratamiento del melanoma localmente avanzado con el fin de mejorar la calidad de vida de los pacientes. La respuesta puede cambiar según el tipo clínico de melanoma, siendo menor, según este estudio, en pacientes con melanoma lentiginoso acral y nodular, aunque por el bajo poder, esto no se puede concluir.to describe the initial experience in Colombia of locally advanced melanoma treated by isolated limb perfusion and compare the response rate of our melanoma subtypes with the literature.descriptive, retrospective study of a series of patients selected between 2007 and 2016. Qualitative variables were analyzed with proportions and frequencies, and quantitative variable with central tendency measures and measures of dispersion.11 patients were treated by isolated limb perfusion. After the treatment, seven patients (63.6%) had partial response, two patients (18.2%) had stable disease and two patients (18.2%) had disease progression. Five patients (45.5%) had mild complications.Isolated limb perfusion is still an important treatment strategy for locally advanced melanoma, with the goal of improving the patient quality of life. The response can change according to the type of melanoma, and could be smaller in patients with acral lentiginous and nodular melanoma, although we cannot make this conclusion with this type of study because it has low power and lack of a comparison group.
