Seabed landscapes of the Baltic Sea : Geological characterization of the seabed environment with spatial analysis techniques

Marine ecosystems provide a wide range of ecosystem services to human society, including supporting, regulating, cultural, and provisioning services. The concept of Blue Growth even considers marine areas as potential drivers of the economy. However, despite the long tradition of ocean exploration, the realization of Blue Growth and effective marine spatial planning often suffer from incomplete and scattered marine data over large areas. This dissertation presents a GIS-based approach to analyzing and characterizing the geologic seabed environment of the Baltic Sea. It combines scattered geospatial data to produce spatial representations of the Baltic Sea in terms of the seabed geomorphic features, marine landscapes, and geodiversity. The broad scales of the analyses reflect the scale of the available datasets and the needs of transnational ecosystem-based management. Spatial analysis techniques enabled the identification of coherent geomorphic features and quantification of geodiversity patterns over the entire Baltic Sea region, within the limits of the input data resolution. Based on the results, the overall geological landscape of the Baltic Sea is characterized by plains and basins. Other geomorphic features, such as elevations and valleys, are characteristic of certain sub-regions. The seabed geodiversity generally increases from south to north and from the open sea to areas with a high shore density. The crystalline bedrock areas provide more diverse seabed environments than the sedimentary rock areas. Archipelagos, in particular, stand out as seabed areas with high geodiversity. The results underline the significance of the ongoing processes (erosion, sediment transport, and accumulation), the basement rock type, past glaciations, and certain geological events during the last deglaciation in shaping the seabed environment of the Baltic Sea. The dissertation presents new evidence that the geodiversity of the seafloor influences the distribution of the zoobenthic assemblages of the eastern Gulf of Finland. It is suggested that the high geodiversity and archipelago gradient could directly influence benthic assemblages and biodiversity by providing a multitude of habitats and indirectly by channeling water movement. Additionally, the potential key habitats, rocky reefs, were mapped with good accuracy in seabed areas with limited data, and the features were also recognized to have ecological value. These spatial datasets provide valuable background material for more detailed studies on the rocky reefs and the archipelago areas, as well as for monitoring their status. The study provides spatial information on the seabed characteristics of the Baltic Sea for scientists, marine spatial planners, and managers. The results emphasize that geodiversity should be acknowledged in the ecosystem-based management of marine areas, because it has intrinsic value, it provides several abiotic ecosystem services, and it is associated with the biodiversity and long-term conservation of the marine environment.Maapallon pinta-alasta n. 70 prosenttia on merien peitossa. Tietämys mertenpohjista on vielä suhteellisen vähäistä, vaikka tietoa on kerätty vuosikymmeniä. Lisäksi, olemassa olevat tietoaineistot ovat usein hajallaan eri organisaatioissa. Hajanainen ja hankalasti saatavilla oleva tieto haittaa tehokkaan merialuesuunnittelun toteuttamista. Olemassa olevan aineiston sekä paikkatieto- ja tilastomenetelmien avulla on kuitenkin voitu laajentaa tietämystä meriympäristöstä. Tämä väitöskirja koostuu yhteenvedosta ja neljästä artikkelista, joissa tarkastellaan Itämeren meriympäristöä ja sen geologisia piirteitä paikkatietoaineistojen ja -menetelmien avulla. Analyyseissä on koostettu paikkatietoaineistoa merialueilta ja kehitetty alueellisesti kattavia esityksiä merenpohjan geomorfologisista piirteistä, merenpohjan maisemista ja geodiversiteetistä. Geodiversiteetillä tarkoitetaan geologista monimuotoisuutta, joka on määritetty kallioperän, pohjanmuotojen ja maalajien vaihtelun avulla. Tutkimuksessa on tarkasteltu myös yhden avainelinympäristön, kallioriutan, esiintymistä Saaristomerellä. Tulokset lisäävät ymmärrystämme Itämeren geologisista piirteistä ja niiden alueellisesta vaihtelusta. Itämeren pohjan maisemaa luonnehtivat erilaiset tasangot ja altaat. Pohjanmuodot, kuten kohoumat ja merenpohjan laaksot, ovat tyypillisiä tietyillä Itämeren alueilla. Itämeren pohjan geodiversiteetti vaihtelee myös alueittain; geologinen monimuotoisuus on suurempaa pohjoisosissa kuin etelässä ja rannan lähellä kuin avomeren pohjassa. Saaristoalueet ovat geologisesti erityisen monimuotoisia. Merenpohja on yleensä monimuotoisempaa kiteisen kallioperän alueella kuin sedimenttikivialueella. Erot Itämeren eri alueiden geologissa piirteissä johtuvat kallioperästä, glasiaalihistoriasta ja nykyisistä prosesseista. Tulosten mukaan geodiversiteetti ja saaristoisuus voivat vaikuttaa biodiversiteettiin, sillä geologisen monimuotoisuuden ajatellaan heijastavan pohjaeläinten fyysisen elinympäristön kirjoa. Lisäksi ne voivat vaikuttaa epäsuorasti biodiversiteettiin esimerkiksi ohjaamalla veden virtauksia. Geodiversiteetti pitäisikin ottaa huomioon ekosysteemilähtöisessä merialuesuunnittelussa, koska se tarjoaa monia abioottisia ekosysteemipalveluita ja se on liitetty myös biodiversiteettiin. Väitöskirjan tuottama paikkasidonnainen tieto on tärkeää erityisesti merialuesuunnittelijoille ja tutkijoille

Quantifying seabed geodiversity of the Archipelago Sea, Baltic Sea, Finland

This study investigated the geodiversity of the Archipelago Sea in the northern Baltic Sea, focusing on geological features and their spatial distribution. By adapting methods used in previous Baltic Sea studies, we conducted spatial analyses of geological data sets including bedrock type, seabed substrates and seabed structures. Bedrock and substrate data were freely available, while seabed structures were modelled from bathymetry data. Geodiversity was quantified using a geodiversity index, which considers the variety of physical elements, roughness and area of the unit. The analyses revealed a diverse seabed environment in the Archipelago Sea with varying geodiversity throughout the study area. Significant features contributing to geodiversity included bedrock fracture and fault zones and large end-moraine formations. Similar patterns have been observed in terrestrial areas of Finland. The analyses also detected relations between archipelago zonation and geodiversity with areas of open sea more homogeneous than the middle and inner archipelago. This study formally recognises the complexity of the seabed in the Archipelago Sea and highlights the importance of understanding the geological processes shaping the region. The results can inform maritime spatial planning and sustainable resource management

Characterization of sedimentary depositional environments for land use and urban planning in Espoo, Finland

AbstractThe capital region of Finland is growing rapidly and into areas with challenging construction conditions such as deep fine-grained sediments. In the coastal city of Espoo, present land use is mainly focused in the southern and central parts, which were submerged by the Baltic Sea during the early and mid-Holocene. These areas have experienced saline and brackish water phases during the history of the Baltic Sea Basin. The deposition environments of the presently studied onshore areas are an analogue for the present day offshore Baltic Sea sedimentation settings for fine-grained material. The results from Baltic Sea studies have demonstrated that the seabed topography has a significant role in the deposition of sediments and their properties. In this study, paleotopographic models were created for the ancient Baltic Sea Basin in the Espoo area 1) after deglaciation and 2) during the Litorina transgression and classified into bathymetric (terrain) zones and structures. Topographic classification was combined with the water depth of the Litorina stage, the thickness of fine-grained deposits and wind fetch to establish the overall characteristics of sedimentary environments in the coastal area. Fine-grained sediments can be found mainly in depressions that are classified here as broad, narrow or local. The study found the most challenging environments for construction purposes in sheltered narrow depressions that contain thick layers of fine-grained sediments deposited during the Litorina transgression. These are mainly located in the southern and central parts of Espoo. Minor deep canyons were also found in the northern parts of Espoo. This study provides new prior knowledge for urban planning and construction design in Espoo. The methodology could be applied to other Baltic Sea coastal cities and areas with fine-grained sediments.</p

Picking Up the Pieces—Harmonising and Collating Seabed Substrate Data for European Maritime Areas

The poor access to data on the marine environment is a handicap to government decision-making, a barrier to scientific understanding and an obstacle to economic growth. In this light, the European Commission initiated the European Marine Observation and Data Network (EMODnet) in 2009 to assemble and disseminate hitherto dispersed marine data. In the ten years since then, EMODnet has become a key producer of publicly available, harmonised datasets covering broad areas. This paper describes the methodologies applied in EMODnet Geology project to produce fully populated GIS layers of seabed substrate distribution for the European marine areas. We describe steps involved in translating national seabed substrate data, conforming to various standards, into a uniform EMODnet substrate classification scheme (i.e., the Folk sediment classification). Rock and boulders form an additional substrate class. Seabed substrate data products at scales of 1:250,000 and 1:1 million, compiled using descriptions and analyses of seabed samples as well as interpreted acoustic images, cover about 20% and 65% of the European maritime areas, respectively. A simple confidence assessment, based on sample and acoustic coverage, is helpful in identifying data gaps. The harmonised seabed substrate maps are particularly useful in supraregional, transnational and pan-European marine spatial planning

Characterization of sedimentary depositional environments for land use and urban planning in Espoo, Finland

Funding Information: This study was funded by the Geological Survey of Finland and the K.H. Renlund Foundation. The source data used in the analyses were produced by the City of Espoo. Monica Löfman is thanked for valuable comments on the manuscript. Professor Jussi Leveinen and an anonymous reviewer provided valuable comments that improved the content of the manuscript. Publisher Copyright: © 2021, Geological Society of Finland. All rights reserved.The capital region of Finland is growing rapidly and into areas with challenging construction conditions such as deep fine-grained sediments. In the coastal city of Espoo, present land use is mainly focused in the southern and central parts, which were submerged by the Baltic Sea during the early and mid-Holocene. These areas have experienced saline and brackish water phases during the history of the Baltic Sea Basin. The deposition environments of the presently studied onshore areas are an analogue for the present day offshore Baltic Sea sedimentation settings for fine-grained material. The results from Baltic Sea studies have demonstrated that the seabed topography has a significant role in the deposition of sediments and their properties. In this study, paleotopographic models were created for the ancient Baltic Sea Basin in the Espoo area 1) after deglaciation and 2) during the Litorina transgression and classified into bathymetric (terrain) zones and structures. Topographic classification was combined with the water depth of the Litorina stage, the thickness of fine-grained deposits and wind fetch to establish the overall characteristics of sedimentary environments in the coastal area. Fine-grained sediments can be found mainly in depressions that are classified here as broad, narrow or local. The study found the most challenging environments for construction purposes in sheltered narrow depressions that contain thick layers of fine-grained sediments deposited during the Litorina transgression. These are mainly located in the southern and central parts of Espoo. Minor deep canyons were also found in the northern parts of Espoo. This study provides new prior knowledge for urban planning and construction design in Espoo. The methodology could be applied to other Baltic Sea coastal cities and areas with fine-grained sediments.Peer reviewe

Planning the Bothnian Sea

In all parts of the world the sea is a source of life, of energy, of food, of commerce, of fun. Its water, wind, and waves are all in demand – as a playground for pleasure-seekers and nature-lovers, as a highway for international commerce, as a home for unique communities of wildlife and people. All this is also true for the Bothnian Sea, a part of the northern European Baltic Sea between Finland and Sweden. The Bothnian Sea is used by two neighbouring highly developed societies. There are many demands on its resources, and its open spaces are highly coveted areas for developments such as wind power farms. This relatively sparsely habitated corner of the world is also, at least at times, a place of wild seas and ancient heritage. Like planning on land, maritime spatial planning is a process that has to incorporate ideals of the public good and the various politically-anchored ways to define this, taking in to account private development interests as well as the physical realities of limited natural resources and fragile ecosystems. This book provides an introduction to the Bothnian Sea and the ideas around maritime spatial planning for its offshore areas. We have tried to present a balance between the perspectives of competing interests. As this has been a pilot initiative, we have not aimed to give you ready answers, but instead try to provoke further debate. The Bothnian Sea and its future are in your hands. The edito

Picking Up the PiecesHarmonising and Collating Seabed Substrate Data for European Maritime Areas

The poor access to data on the marine environment is a handicap to government decision-making, a barrier to scientific understanding and an obstacle to economic growth. In this light, the European Commission initiated the European Marine Observation and Data Network (EMODnet) in 2009 to assemble and disseminate hitherto dispersed marine data. In the ten years since then, EMODnet has become a key producer of publicly available, harmonised datasets covering broad areas. This paper describes the methodologies applied in EMODnet Geology project to produce fully populated GIS layers of seabed substrate distribution for the European marine areas. We describe steps involved in translating national seabed substrate data, conforming to various standards, into a uniform EMODnet substrate classification scheme (i.e., the Folk sediment classification). Rock and boulders form an additional substrate class. Seabed substrate data products at scales of 1:250,000 and 1:1 million, compiled using descriptions and analyses of seabed samples as well as interpreted acoustic images, cover about 20% and 65% of the European maritime areas, respectively. A simple confidence assessment, based on sample and acoustic coverage, is helpful in identifying data gaps. The harmonised seabed substrate maps are particularly useful in supraregional, transnational and pan-European marine spatial planning