Seagrass meadows, or submerged aquatic vegetation, constitute an ecosystem with great importance to the coastal zone, and may be characterized as the most productive ecosystem on Earth. In addition to the provision of habitat for a wide variety of species, protection of the coastal zone and production of organic matter base for the marine trophic web, these environments have been recognized for their great capacity to store organic carbon in their soils and are, therefore, a priority area for the mitigation of increased carbon in the atmosphere. In spite of the great importance of these areas, there is little information about the soils of these ecosystems, mainly using an approach based on the genesis of its soils. Thus, this thesis covers 4 chapters aiming to: (i) evaluate changes in the characteristics of seagrass meadows publications in the last 50 years, identify knowledge gaps and priorities for future studies; (ii) to discuss the paradoxical lack of information on Brazilian seagrass meadows soils, stimulate studies to understand their characteristics and contribute to the correct inclusion of seagrass meadows soils in the Brazilian System for Soil Classification; (iii) characterize and investigate soils of seagrass meadows along the Brazilian coast, in order to understand the pedogenetic processes within these soils; and (iv) identify variations in the biogeochemical processes related to the dynamics of Fe, Mn and S along the Brazilian coast, aiming to provide an improved basis for the understanding of this ecosystem and subsidies for the use and protection policies of these coastal areas. / As pradarias marinhas (seagrasses), ou vegetação aquática submersa, constituem um ecossistema de grande importância para a zona costeira, caracterizando-se como o ecossistema mais produtivo da Terra. Além de fornecer habitat para uma grande variedade de espécies, favorecer a estabilidade costeira e produzir matéria orgânica base para a teia trófica marinha, estes ambientes têm sido reconhecidos pela grande capacidade de armazenar carbono orgânico em seus solos e são, portanto, prioritários para as medidas de mitigação do aumento de carbono na atmosfera. Apesar da grande importância desse ecossitema, há pouca informação a respeito dos solos onde estes ecossistemas estão inseridos, principalmente utilizando uma abordagem baseada na gênese dos solos. Esta tese contempla 4 capítulos cujos objetivos visam avaliar as mudanças nas características das publicações sobre pradarias marinhas nos últimos 50 anos, identificando lacunas de conhecimentos e prioridades para estudos futuros; discutir a paradoxal ausência de informação sobre os solos das pradarias marinhas do Brasil, estimulando estudos para o entendimento de suas características e contribuindo para a correta inclusão de solos de pradarias marinhas no Sistema Brasileiro de Classificação de solos; caracterizar e investigar os solos das pradarias marinhas ao longo da costa brasileira, com vistas a entender os processos pedogenéticos atuantes nestes solos; e Identificar variações nos processos biogeoquímicos relacionados à dinâmica de Fe, Mn e S ao longo da costa brasileira, com a finalidade de fornecer base para o entendimento deste ecossistema e subsídios para as políticas de proteção e de uso destas áreas costeiras.

Seagrass meadows, or submerged aquatic vegetation, constitute an ecosystem with great importance to the coastal zone, and may be characterized as the most productive ecosystem on Earth. In addition to the provision of habitat for a wide variety of species, protection of the coastal zone and production of organic matter base for the marine trophic web, these environments have been recognized for their great capacity to store organic carbon in their soils and are, therefore, a priority area for the mitigation of increased carbon in the atmosphere. In spite of the great importance of these areas, there is little information about the soils of these ecosystems, mainly using an approach based on the genesis of its soils. Thus, this thesis covers 4 chapters aiming to: (i) evaluate changes in the characteristics of seagrass meadows publications in the last 50 years, identify knowledge gaps and priorities for future studies; (ii) to discuss the paradoxical lack of information on Brazilian seagrass meadows soils, stimulate studies to understand their characteristics and contribute to the correct inclusion of seagrass meadows soils in the Brazilian System for Soil Classification; (iii) characterize and investigate soils of seagrass meadows along the Brazilian coast, in order to understand the pedogenetic processes within these soils; and (iv) identify variations in the biogeochemical processes related to the dynamics of Fe, Mn and S along the Brazilian coast, aiming to provide an improved basis for the understanding of this ecosystem and subsidies for the use and protection policies of these coastal areas. / As pradarias marinhas (seagrasses), ou vegetação aquática submersa, constituem um ecossistema de grande importância para a zona costeira, caracterizando-se como o ecossistema mais produtivo da Terra. Além de fornecer habitat para uma grande variedade de espécies, favorecer a estabilidade costeira e produzir matéria orgânica base para a teia trófica marinha, estes ambientes têm sido reconhecidos pela grande capacidade de armazenar carbono orgânico em seus solos e são, portanto, prioritários para as medidas de mitigação do aumento de carbono na atmosfera. Apesar da grande importância desse ecossitema, há pouca informação a respeito dos solos onde estes ecossistemas estão inseridos, principalmente utilizando uma abordagem baseada na gênese dos solos. Esta tese contempla 4 capítulos cujos objetivos visam avaliar as mudanças nas características das publicações sobre pradarias marinhas nos últimos 50 anos, identificando lacunas de conhecimentos e prioridades para estudos futuros; discutir a paradoxal ausência de informação sobre os solos das pradarias marinhas do Brasil, estimulando estudos para o entendimento de suas características e contribuindo para a correta inclusão de solos de pradarias marinhas no Sistema Brasileiro de Classificação de solos; caracterizar e investigar os solos das pradarias marinhas ao longo da costa brasileira, com vistas a entender os processos pedogenéticos atuantes nestes solos; e Identificar variações nos processos biogeoquímicos relacionados à dinâmica de Fe, Mn e S ao longo da costa brasileira, com a finalidade de fornecer base para o entendimento deste ecossistema e subsídios para as políticas de proteção e de uso destas áreas costeiras.

Urban runoff continues to impair water quality and there is an increasing need for stormwater management within the limited confines of urban spaces. We propose a system of structural soil and trees that can be incorporated beneath pavement. Structural soil has a high load-bearing capacity yet is engineered to support tree root growth. Stormwater is directed into a structural soil reservoir below the pavement where tree roots can also thrive. Two container experiments evaluated tree function in this system. We examined whether tree roots can grow into compacted subsoils and if root penetration increases soil infiltration rate. Quercus velutina, Acer rubrum, and a no-tree variant were planted in 26.5 L (7 gal) containers and the rootballs surrounded by compacted clay loam. Roots grew into all layers of the compacted soil. Infiltration rate increased by 63% (+/-2%) compared to no-tree containers. A second experiment evaluated water uptake and tree development in fluctuating water tables. Quercus bicolor and Fraxinus pennsylvanica were planted in 94.6 L (25 gal) containers with structural soils (either Stalite or CU® Structural Soil). Trees were subjected to fluctuating water tables simulating infiltration rates of 2, 1, and 0.1 cm/hr for two growing seasons. Trees thrived in all infiltration regimes but roots were shallower in slowly drained treatments. Trees grew best and transpired the highest water volume with moderate infiltration. Even if trees uptake only small volumes of water, increased canopy size compared to conventional plantings (because of greater penetrable soil volume) allows greater rainfall interception thus decreasing runoff. / Master of Science