Insights into seascape ecology: landscape patterns as drivers in coastal marine ecosystems = Perspectives en l'ecologia del paisatge marí: els patrons del paisatge com a factors de control en els ecosistemes marins costaners

[eng] Habitats commonly occur as more or less interconnected patches constituting spatial heterogeneous mosaics. Connectivity and interactions among habitats can determine their functioning. Therefore, ecological patterns and processes within these habitats, and among them, are modulated by the spatial structure of the entire mosaic. Landscape ecology is aimed at understanding how the composition (patch types and sizes) and configuration (how those patches are arranged spatially) of habitats in a mosaic influence the functioning of the overall system and its individual components (the patches and the species moving across), at a panoply of spatial scales. Interactions at landscape level are usually associated either to the movement of organisms (active mobile entities) or to the transfer of materials (passive mobile entities) from one habitat to another. Applying landscape ecology, the interactions among and within ecosystems can be identified and evaluated to optimize conservation efforts across broad spatial scales. This approach, although has been successfully used in terrestrial ecosystems, remains poorly explored in the marine realm. This thesis is an attempt to assess the influence of landscape patterns in the ecological function of marine habitats. The thesis focus on the study of coastal landscapes (or seascapes) due to its resemblance to terrestrial ones, and because they are among the most vulnerable to human action and climate change. With this objective we focus on the study of three main processes of special importance in the coastal systems. First, we focus on the study of landscape patterns influence on fluxes of material among habitats of the coastal seascape and resource-driven processes, such as trophic webs and recycling of nutrients. Secondly, we study how landscape patterns can influence on sediment carbon storage in coastal habitats, particularly in seagrass ecosystems. And in third place we study the influence of landscape patterns in shaping communities. In particular we study the role of landscape patterns in shaping littoral fish assemblages, as due to its mobility they can be strongly affected by the landscape structure and their biology could also play an important role.). Doing this, we attempt not only to improve general knowledge on seascape ecology, but also to provide new insights useful for management. Therefore, this thesis provide new evidence emphasizing the importance of landscape-level interactions and processes in driving coastal ecosystems, and underlining how the relative abundance of habitats and their spatial arrangement influence ecological functions across the coastal ecosystem mosaic.[cat] Al medi natural els hàbitats es troben normalment en forma de taques més o menys connectades, formant mosaics heterogenis. La connectivitat entre hàbitats i les interaccions que tenen lloc entre ells poden ser determinants en el seu funcionament. Per tant, els patrons de distribució d’espècies i els processos ecològics que hi tenen lloc vénen influïts tant per la composició d'aquest mosaic (és a dir, la mida i el tipus de les taques d'hàbitats que s’hi troben), com per la seva configuració (com les taques es disposen espacialment). L’ecologia del paisatge busca esbrinar com s’exerceix aquesta influència. Les interaccions entre els hàbitats s'associen normalment al moviment d'organismes (elements de moviment actiu) o a la transferència de materials (elements de moviment passiu). Entendre aquestes interaccions pot ajudar a millorar el coneixement de la dinàmica ecològica dels ecosistemes implicats, i a la vegada optimitzar els esforços de conservació que s’hi esmercen. Les aproximacions basades en aquests conceptes i, en general, en l’ecologia del paisatge, tot i que s'ha desenvolupat molt als sistemes terrestres, encara resten per explorar al medi marí. Aquesta tesi pretén contribuir a atenuar aquest biaix, tot avaluant la influència dels patrons del paisatge en la funció ecològica del hàbitats marins. La tesi es centra en l'estudi dels paisatges marins costaners, per la seva semblança amb els paisatges terrestres i per la seva vulnerabilitat a l'acció humana i al canvi climàtic. Amb aquest objectiu, ens centrem en l'estudi de tres grans processos d'especial importància en els sistemes costaners. En primer lloc, estudiem com els patrons del paisatge marí costaner poden influir sobre els fluxos de materials entre hàbitats i les conseqüències que se’n deriven per processos ecològics clau, com el funcionament de les xarxes tròfiques i el reciclatge de nutrients. En segon lloc estudiem com els patrons del paisatge poden influir en l’emmagatzemament de carboni orgànic en sediments marins, concretament el carboni que queda retingut al sediment de praderes d’angiospermes marines. En tercer lloc analitzem com, o fins a quin punt, els patrons del paisatge expliquen l’estructuració de les comunitats d'organismes, tot aplicant una aproximació multiescala. Concretament, estudiem la comunitat de peixos litorals, espècies mòbils que es poden veure afectades per aquests patrons de maneres diverses i on la biologia de cada espècie pot jugar un paper molt important. Aquesta tesi pretén no només aprofundir en el coneixement que es té de l’ecologia del paisatge marí, sinó també proveir de noves aproximacions i eines que millorin la gestió i conservació dels hàbitats marins costaners. Així doncs, la tesi aporta noves evidències que emfatitzen la importància de processos i interaccions a escala de paisatge (quan més d'un hàbitat entra en joc), destacant que, l’abundància dels diferents hàbitats i la seva disposició espacial tenen un fort paper en el funcionament i l’ecologia dels hàbitats marins

Sinking seaweed in the deep ocean for carbon neutrality is ahead of science and beyond the ethics

Sinking vast amounts of seaweed in the deep ocean is currently being proposed as a promising ocean carbon dioxide removal strategy as well as a natural-based solution to mitigate climate change. Still, marketable carbon offsets through large-scale seaweed sinking in the deep ocean lack documentation and could involve unintended environmental and social consequences. Managing the risks requires a number of urgent actions

Sinking seaweed in the deep ocean for carbon neutrality is ahead of science and beyond the ethics

Unidad de excelencia María de Maeztu CEX2019-000940-MSinking vast amounts of seaweed in the deep ocean is currently being proposed as a promising ocean carbon dioxide removal strategy as well as a natural-based solution to mitigate climate change. Still, marketable carbon offsets through large-scale seaweed sinking in the deep ocean lack documentation and could involve unintended environmental and social consequences. Managing the risks requires a number of urgent actions

High variability of Blue Carbon storage in seagrass meadows at the estuary scale

Seagrass meadows are considered important natural carbon sinks due to their capacity to store organic carbon (Corg) in sediments. However, the spatial heterogeneity of carbon storage in seagrass sediments needs to be better understood to improve accuracy of blue carbon assessments, particularly when strong gradients are present. We performed an intensive coring study within a sub-tropical estuary to assess the spatial variability in sedimentary Corg associated with seagrasses, and to identify the key factors promoting this variability. We found a strong spatial pattern within the estuary, from 52.16 mg Corg cm-3 in seagrass meadows in the upper parts, declining to 1.06 mg Corg cm-3 in seagrass meadows at the estuary mouth, despite a general gradient of increasing seagrass cover and seagrass habitat extent in the opposite direction. The sedimentary Corg underneath seagrass meadows came principally from allochthonous (non-seagrass) sources (~70-90%), while the contribution of seagrasses was low (~10-30%) throughout the entire estuary. Our results showed that Corg stored in sediments of seagrass meadows can be highly variable within an estuary, attributed largely to accumulation of fine sediments and inputs of allochthonous sources. Local features and the existence of spatial gradients must be considered in blue carbon estimates in coastal ecosystems

The zooxanthellate scleractinian coral Oulastrea crispata (Lamarck, 1816), an overlooked newcomer in the Mediterranean Sea?

The zooxanthellate scleractinian coral Oulastrea crispata, a widely distributed species across central Indo-Pacific nearshore marine habitats, has been first reported from the Mediterranean Sea (Corsica) in 2014. Here we report on two new sites for this species in the NW Mediterranean Sea and provide a general description of external morphological characters of the colonies and a detailed account of the cnidom to help future identifications. Living specimens may appear virtually identical to small colonies (~5 cm) of the Mediterranean zooxanthellate scleractinian Cladocora caespitosa. While this species shows long, ramified, independent corallites, with cylindrical calices, O. crispata has enlarged, cup-like calices, which can be joined by the coenosteum. It also shows clear differences among several groups of nematocysts, principally the presence in the filaments of large penicilli (p-mastigophore) of one type, which are absent in C. caespitosa. Identifications based on underwater observations or even the analysis of photographs may easily lead to misleading identifications. We hypothesize that O. crispata may have gone unnoticed because of misidentifications as C. caespitosa. More detailed research is needed to get reliable maps of the actual distribution of this apparently non-indigenous species in the Mediterranean Sea

Comunidades de peces del atolón de Clipperton (Pacífico oriental tropical) y su relación con la cobertura de corales

Clipperton Atoll, one of the most isolated coral reefs worldwide, is of great scientific interest due to its geomorphology and high levels of endemism. This study explored the reef fish assemblage structure of Clipperton Atoll and its relationship with live coral cover. Nine stations were sampled at three sites and three depths (6, 12 and 20 m) around the reef, measuring fish species richness and biomass and hermatypic coral cover (at genus level). We evaluated variation in species richness, biomass and diversity of fish assemblages among sites and depths, as well as the relationship between the entire fish assemblage composition and live coral cover. The results showed that species richness and biomass were similar among sites, but differed across depths, increasing with depth. In contrast, diversity differed among sites but not among depths. Multivariate analyses indicated that fish assemblage composition differed among sites and depths in relation to changes in cover of coral of the genera Pocillopora, Porites, Pavona and Leptoseris, which dominate at different depths. The results showed that fish species richness and diversity were low at Clipperton Atoll and that, in isolated coral reefs with a low habitat heterogeneity and low human disturbance, live coral cover has a significant influence on the spatial variation of the reef fish assemblages. This study highlights the importance of coral habitat structure in shaping coral reef fish assemblages.El atolón de Clipperton, uno de los arrecifes de coral más aislados del mundo, presenta un gran interés científico por su geomorfología y endemismo. Este estudio analizó la estructura de las comunidades de peces de arrecife de este atolón y su relación con la cobertura de coral vivo. Para ello se muestrearon nueve estaciones alrededor del arrecife en tres sitios a tres profundidades (6, 12, 20 m), registrando, la riqueza y biomasa de peces, así como la cobertura de coral hermatípico a nivel de género. Se evaluó la variación de la riqueza, biomasa y diversidad de peces entre sitios y profundidades, así como la relación de la composición y biomasa de peces con la cobertura de coral vivo. Los resultados mostraron que la riqueza y biomasa fueron similares entre los sitios, pero diferentes entre profundidades, ya que incrementan con la profundidad. En contraste, la diversidad difirió entre sitios pero no entre profundidades. Los análisis multidimensionales indicaron que la comunidad de peces fue diferente entre sitios y profundidades, relacionándolo con la cobertura de coral de los géneros Pocillopora, Porites, Pavona y Leptoseris, que dominan a distinta profundidad. Los resultados evidenciaron una baja riqueza y diversidad de peces arrecifales en el atolón de Clipperton. En arrecifes de coral aislados, con baja heterogeneidad de hábitats y poca perturbación humana, la cobertura de coral vivo influye en la variación espacial de las comunidades de peces arrecifales. Este estudio resalta la importancia de la estructura del hábitat de coral en la conformación de las comunidades de peces arrecifales

Desenvolupament de nou material docent basat en eines TIC per a la realització de pràctiques relacionades amb l’òptica fisiològica

L’òptica fisiològica és la matèria que estudia el procés visual des d’un punt de vista fonamentalment òptic. S’encarrega de l’estudi de l’ull com a sistema òptic i receptor d’energia radiant, així com de les característiques de la visió binocular. És de fonamental importància en el Grau en Òptica i Optometria, on l’estudiant assoleix i integra les competències bàsiques necessàries per a desenvolupar la seva futura professió, i te un paper significatiu en el Màster d’Optometria i Ciències de la Visió, on l’òptic-optometrista amplia i reforça els seus coneixements. També s’estudia des d’un punt de vista més tècnic i aplicat en el Master in Photonics. Les assignatures relacionades amb l’òptica fisiològica incorporen pràctiques en les que s’avalua la resposta d’un observador a diversos estímuls, mitjançant tècniques psicofísiques de mesura. Gràcies a les recents innovacions tecnològiques, en els laboratoris de recerca més avançats i en algunes universitats espanyoles (com la de València i d’Alacant, les quals han visitat els professors implicats en aquest projecte), la presentació d’estímuls es realitza en monitors d’ordinador calibrats i d’elevada resolució, la qual cosa permet prescindir en gran mesura de muntatges experimentals generalment complexes que s’han utilitzat fins l’actualitat. És per aquest motiu que el principal objectiu del present projecte consisteix en elaborar nou programari específic adaptat a les noves tecnologies que permeti la realització de pràctiques relacionades amb l’òptica fisiològica mitjançant la utilització d’eines TIC, podent així millorar alguns dels muntatges experimentals que s’utilitzaven fins al moment a la Facultat d’Òptica i Optometria de Terrassa (FOOT). El desenvolupament d’aquest material ha permès millorar l’aprenentatge de continguts i habilitats, i per tant de competències específiques i transversals dels estudiants, proporcionant més qualitat docent final de les assignatures vinculades a la matèria d’òptica fisiològica.Peer Reviewe

Assessing the risk of carbon dioxide emissions from blue carbon ecosystems

“Blue carbon” ecosystems, which include tidal marshes, mangrove forests, and seagrass meadows, have large stocks of organic carbon (Corg) in their soils. These carbon stocks are vulnerable to decomposition and – if degraded – can be released to the atmosphere in the form of CO2. We present a framework to help assess the relative risk of CO2 emissions from degraded soils, thereby supporting inclusion of soil Corg into blue carbon projects and establishing a means to prioritize management for their carbon values. Assessing the risk of CO2 emissions after various kinds of disturbances can be accomplished through knowledge of both the size of the soil Corg stock at a site and the likelihood that the soil Corg will decompose to CO2

Hot spots and hot moments in seagrass 'blue carbon' science

When seagrass meadows are destroyed, what happens to the 'blue carbon' stored within their sediments; does it stay in the ground, or is it released into the atmosphere? Is it possible to manage seagrass ecosystems so that they sequester more blue carbon? With seagrasses now recognised as globally-significant carbon sinks, the answers to these questions have important consequences for nature-based climate change mitigation and adaptation (i.e. 'biosequestration'). We make the case that microbes fundamentally control the fate of sequestered blue carbon within seagrass, and, therefore, management efforts aimed at bolstering blue carbon opportunities within seagrass ecosystems need to target processes that influence (directly or indirectly) microbial remineralisation of blue carbon. New data will be presented showing that blue carbon occurs in hotspots and changes in the geochemistry of seagrass sediments - such as those caused by disturbance - can create hot moments, whereby organic carbon within sediments undergoes rapid and substantial microbial remineralisation. In order to better manage seagrass ecosystems for blue carbon benefits, we outline three recommendations: reducing anthropogenic nutrient inputs, reinstating top-down control of bioturbator populations, and restoring hydrology. These processes are amenable to management control, they promote microbial dormancy and limit microbial priming, and offer ecosystem benefits beyond carbon sequestration

Key biogeochemical factors affecting soil carbon storage in Posidonia meadows

Unidad de excelencia María de Maeztu MdM-2015-0552Biotic and abiotic factors influence the accumulation of organic carbon (Corg) in seagrass ecosystems. We surveyed Posidonia sinuosa meadows growing in different water depths to assess the variability in the sources, stocks and accumulation rates of Corg. We show that over the last 500 years, P. sinuosa meadows closer to the upper limit of distribution (at 2-4m depth) accumulated 3- to 4-fold higher Corg stocks (averaging 6.3 kg Corg m¯²/ at 3- to 4-fold higher rates (12.8 gCorg m¯² yr¯¹/ compared to meadows closer to the deep limits of distribution (at 6-8m depth; 1.8 kg Corg m¯² and 3.6 g Corg m¯² yr¯¹/. In shallower meadows, Corg stocks were mostly derived from seagrass detritus (88% in average) compared to meadows closer to the deep limit of distribution (45% on average). In addition, soil accumulation rates and fine-grained sediment content (< 0.125 mm) in shallower meadows (2.0mm yr¯¹ and 9 %, respectively) were approximately 2-fold higher than in deeper meadows (1.2mm yr¯¹ and 5 %, respectively). The Corg stocks and accumulation rates accumulated over the last 500 years in bare sediments (0.6 kg Corg m¯² and 1.2 g Corg m¯² yr¯¹/ were 3- to 11-fold lower than in P. sinuosa meadows, while fine-grained sediment content (1 %) and seagrass detritus contribution to the Corg pool (20 %) were 8- and 3-fold lower than in Posidonia meadows, respectively. The patterns found support the hypothesis that Corg storage in seagrass soils is influenced by interactions of biological (e.g., meadow productivity, cover and density), chemical (e.g., recalcitrance of Corg stocks) and physical (e.g., hydrodynamic energy and soil accumulation rates) factors within the meadow. We conclude that there is a need to improve global estimates of seagrass carbon storage accounting for biogeochemical factors driving variability within habitats