Pub Date : 2007-01-01DOI: 10.1201/9781420050943.ch5
B. Brown
The Andaman Sea lies on the eastern edge of the Indian Ocean, bordered to the west by an arc of islands stretching from northern Sumatra to the Irrawaddy delta. Fringing reefs are abundant in the Andaman and Nicobar Islands (India), Mergui Archipelago (Myanmar), west coasts of Thailand and Malaysia and northwest Sumatra (Indonesia). Most have never been visited by scientists because of political constraints; consequently the region is one of the least studied coral reef areas in the world. Many inshore reefs are intertidal and occur in turbid settings, while offshore reefs exist in clearer waters. Regardless of physical rigours, reefs generally display high cover and high coral diversity. The Andaman Sea has a complex geological history, a varied seafloor topography, a highly dynamic oceanography and a large tidal range (2-5 m) coupled with periodic sea-level depressions. It is also a major sink for sediments from the Irrawaddy, the world's fifth largest river in terms of suspended sediment load. Human-made influences are limited; sedimentation from land reclamation and dredging are a principal negative factor though rising sea temperatures present a major threat. Natural damage results from aerial exposure on low tides, negative sea-level anomalies, earthquakes and tsunamis. The dynamic nature of the Andaman Sea and the in-built stress resistance of many shallow water corals could result in the region being an important 'refuge' during an era of global warming.
{"title":"Coral reefs of the Andaman Sea - An integrated perspective","authors":"B. Brown","doi":"10.1201/9781420050943.ch5","DOIUrl":"https://doi.org/10.1201/9781420050943.ch5","url":null,"abstract":"The Andaman Sea lies on the eastern edge of the Indian Ocean, bordered to the west by an arc of islands stretching from northern Sumatra to the Irrawaddy delta. Fringing reefs are abundant in the Andaman and Nicobar Islands (India), Mergui Archipelago (Myanmar), west coasts of Thailand and Malaysia and northwest Sumatra (Indonesia). Most have never been visited by scientists because of political constraints; consequently the region is one of the least studied coral reef areas in the world. Many inshore reefs are intertidal and occur in turbid settings, while offshore reefs exist in clearer waters. Regardless of physical rigours, reefs generally display high cover and high coral diversity. The Andaman Sea has a complex geological history, a varied seafloor topography, a highly dynamic oceanography and a large tidal range (2-5 m) coupled with periodic sea-level depressions. It is also a major sink for sediments from the Irrawaddy, the world's fifth largest river in terms of suspended sediment load. Human-made influences are limited; sedimentation from land reclamation and dredging are a principal negative factor though rising sea temperatures present a major threat. Natural damage results from aerial exposure on low tides, negative sea-level anomalies, earthquakes and tsunamis. The dynamic nature of the Andaman Sea and the in-built stress resistance of many shallow water corals could result in the region being an important 'refuge' during an era of global warming.","PeriodicalId":54693,"journal":{"name":"Oceanography and Marine Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80720186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-01-01DOI: 10.1201/9781420050943.ch1
W. Clavano, E. Boss, L. Karp‐Boss
In situ measurements of inherent optical properties (IOPs) of aquatic particles show great promise in studies of particle dynamics. Successful application of such methods requires an understanding of the optical properties of particles. Most models of IOPs of marine particles assume that particles are spheres, yet most of the particles that contribute significantly to the IOPs are non- spherical. Only a few studies have examined optical properties of non-spherical aquatic particles. The state-of-the-art knowledge regarding IOPs of non-spherical particles is reviewed here and exact and approximate solutions are applied to model IOPs of marine-like particles. A comparison of model results for monodispersions of randomly oriented spheroids to results obtained for equal- volume spheres shows a strong dependence of the biases in the IOPs on particle size and shape, with the greater deviation occurring for particles much larger than the wavelength. Similarly, biases in the IOPs of polydispersions of spheroids are greater, and can be higher than a factor of two, when populations of particles are enriched with large particles. These results suggest that shape plays a significant role in determining the IOPs of marine particles, encouraging further laboratory and modelling studies on the effects of particle shape on their optical properties.
{"title":"INHERENT OPTICAL PROPERTIES OF NON-SPHERICAL MARINE-LIKE PARTICLES — FROM THEORY TO OBSERVATION","authors":"W. Clavano, E. Boss, L. Karp‐Boss","doi":"10.1201/9781420050943.ch1","DOIUrl":"https://doi.org/10.1201/9781420050943.ch1","url":null,"abstract":"In situ measurements of inherent optical properties (IOPs) of aquatic particles show great promise in studies of particle dynamics. Successful application of such methods requires an understanding of the optical properties of particles. Most models of IOPs of marine particles assume that particles are spheres, yet most of the particles that contribute significantly to the IOPs are non- spherical. Only a few studies have examined optical properties of non-spherical aquatic particles. The state-of-the-art knowledge regarding IOPs of non-spherical particles is reviewed here and exact and approximate solutions are applied to model IOPs of marine-like particles. A comparison of model results for monodispersions of randomly oriented spheroids to results obtained for equal- volume spheres shows a strong dependence of the biases in the IOPs on particle size and shape, with the greater deviation occurring for particles much larger than the wavelength. Similarly, biases in the IOPs of polydispersions of spheroids are greater, and can be higher than a factor of two, when populations of particles are enriched with large particles. These results suggest that shape plays a significant role in determining the IOPs of marine particles, encouraging further laboratory and modelling studies on the effects of particle shape on their optical properties.","PeriodicalId":54693,"journal":{"name":"Oceanography and Marine Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82550721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-01-01DOI: 10.1201/9781420050943.ch7
L. Airoldi, M. Beck
Over the centuries, land reclamation, coastal development, overfishing and pollution have nearly eliminated European wetlands, seagrass meadows, shellfish beds, biogenic reefs and other productive and diverse coastal habitats. It is estimated that every day between 1960 and 1995, a kilometre of European coastline was developed. Most countries have estimated losses of coastal wetlands and seagrasses exceeding 50% of the original area with peaks above 80% for many regions. Conspicuous declines, sometimes to virtual local disappearance of kelps and other complex macroalgae, have been observed in several countries. A few dominant threats have led to these losses over time. The greatest impacts to wetlands have consistently been land claim and coastal development. The greatest impacts to seagrasses and macroalgae are presently associated with degraded water quality while in the past there have been more effects from destructive fishing and diseases. Coastal development remains an important threat to seagrasses. For biogenic habitats, such as oyster reefs and maerls, some of the greatest impacts have been from destructive fishing and overexploitation with additional impacts of disease, particularly to native oysters. Coastal development and defence have had the greatest known impacts on soft-sediment habitats with a high likelihood that trawling has affected vast areas. The concept of 'shifting baselines', which has been applied mostly to the inadequate historical perspective of fishery losses, is extremely relevant for habitat loss more generally. Most habitat loss estimates refer to a relatively short time span primarily within the last century. However, in some regions, most estuarine and near-shore coastal habitats were already severely degraded or driven to virtual extinction well before 1900. Native oyster reefs were ecologically extinct by the 1950s along most European coastlines and in many bays well before that. These shellfish reefs are among the most endangered coastal habitats, but they receive some of the least protection. Nowadays less than 15% of the European coastline is considered in 'good' condition. Those fragments of native habitats that remain are under continued threat, and their management is not generally informed by adequate knowledge of their distribution and status. There are many policies and directives aimed at reducing and reversing these losses but their overall positive benefits have been low. Further neglecting this long history of habitat loss and transformation may ultimately compromise the successful management and future sustainability of those few fragments of native and semi-native coastal habitats that remain in Europe.
{"title":"Loss, status and trends for coastal marine habitats of Europe","authors":"L. Airoldi, M. Beck","doi":"10.1201/9781420050943.ch7","DOIUrl":"https://doi.org/10.1201/9781420050943.ch7","url":null,"abstract":"Over the centuries, land reclamation, coastal development, overfishing and pollution have nearly eliminated European wetlands, seagrass meadows, shellfish beds, biogenic reefs and other productive and diverse coastal habitats. It is estimated that every day between 1960 and 1995, a kilometre of European coastline was developed. Most countries have estimated losses of coastal wetlands and seagrasses exceeding 50% of the original area with peaks above 80% for many regions. Conspicuous declines, sometimes to virtual local disappearance of kelps and other complex macroalgae, have been observed in several countries. A few dominant threats have led to these losses over time. The greatest impacts to wetlands have consistently been land claim and coastal development. The greatest impacts to seagrasses and macroalgae are presently associated with degraded water quality while in the past there have been more effects from destructive fishing and diseases. Coastal development remains an important threat to seagrasses. For biogenic habitats, such as oyster reefs and maerls, some of the greatest impacts have been from destructive fishing and overexploitation with additional impacts of disease, particularly to native oysters. Coastal development and defence have had the greatest known impacts on soft-sediment habitats with a high likelihood that trawling has affected vast areas. The concept of 'shifting baselines', which has been applied mostly to the inadequate historical perspective of fishery losses, is extremely relevant for habitat loss more generally. Most habitat loss estimates refer to a relatively short time span primarily within the last century. However, in some regions, most estuarine and near-shore coastal habitats were already severely degraded or driven to virtual extinction well before 1900. Native oyster reefs were ecologically extinct by the 1950s along most European coastlines and in many bays well before that. These shellfish reefs are among the most endangered coastal habitats, but they receive some of the least protection. Nowadays less than 15% of the European coastline is considered in 'good' condition. Those fragments of native habitats that remain are under continued threat, and their management is not generally informed by adequate knowledge of their distribution and status. There are many policies and directives aimed at reducing and reversing these losses but their overall positive benefits have been low. Further neglecting this long history of habitat loss and transformation may ultimately compromise the successful management and future sustainability of those few fragments of native and semi-native coastal habitats that remain in Europe.","PeriodicalId":54693,"journal":{"name":"Oceanography and Marine Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87511840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-01-01DOI: 10.1201/9781420050943.ch8
E. Poloczanska, R. Babcock, A. Butler, A. Hobday, O. Hoegh‐Guldberg, T. Kunz, R. Matear, D. Milton, T. Okey, A. Richardson
Australia's marine life is highly diverse and endemic. Here we describe projections of climate change in Australian waters and examine from the literature likely impacts of these changes on Australian marine biodiversity. For the Australian region, climate model simulations project oceanic warming, an increase in ocean stratification and decrease in mixing depth, a strengthening of the East Australian Current, increased ocean acidification, a rise in sea level, alterations in cloud cover and ozone levels altering the levels of solar radiation reaching the ocean surface, and altered storm and rainfall regimes. Evidence of climate change impacts on biological systems are generally scarce in Australia compared to the Northern Hemisphere. The poor observational records in Australia are attributed to a lack of studies of climate impacts on natural systems and species at regional or national scales. However, there are notable exceptions such as widespread bleaching of corals on the Great Barrier Reef and poleward shifts in temperate fish populations. Biological changes are likely to be considerable and to have economic and broad ecological consequences, especially in climate-change 'hot spots' such as the Tasman Sea and the Great Barrier Reef.
{"title":"Climate change and Australian marine life","authors":"E. Poloczanska, R. Babcock, A. Butler, A. Hobday, O. Hoegh‐Guldberg, T. Kunz, R. Matear, D. Milton, T. Okey, A. Richardson","doi":"10.1201/9781420050943.ch8","DOIUrl":"https://doi.org/10.1201/9781420050943.ch8","url":null,"abstract":"Australia's marine life is highly diverse and endemic. Here we describe projections of climate change in Australian waters and examine from the literature likely impacts of these changes on Australian marine biodiversity. For the Australian region, climate model simulations project oceanic warming, an increase in ocean stratification and decrease in mixing depth, a strengthening of the East Australian Current, increased ocean acidification, a rise in sea level, alterations in cloud cover and ozone levels altering the levels of solar radiation reaching the ocean surface, and altered storm and rainfall regimes. Evidence of climate change impacts on biological systems are generally scarce in Australia compared to the Northern Hemisphere. The poor observational records in Australia are attributed to a lack of studies of climate impacts on natural systems and species at regional or national scales. However, there are notable exceptions such as widespread bleaching of corals on the Great Barrier Reef and poleward shifts in temperate fish populations. Biological changes are likely to be considerable and to have economic and broad ecological consequences, especially in climate-change 'hot spots' such as the Tasman Sea and the Great Barrier Reef.","PeriodicalId":54693,"journal":{"name":"Oceanography and Marine Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85750120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coralligenous concretions, the unique calcareous formations of biogenic origin in Mediterranean benthic environments, are produced by the accumulation of encrusting algae growing in dim light conditions. This review provides an overview of the results obtained by the main studies dealing with these formations, including the environmental factors which influence the development of coralligenous communities, their distribution, types, assemblages, builders and eroders, the biotic relationships and processes that create and destroy coralligenous assemblages, their dynamics and seasonality, and the functioning of several outstanding and key species. Special attention is devoted to the biodiversity of coralligenous communities and a first estimation of the number of species reported for this habitat is provided. Major disturbances affecting coralligenous communities are discussed, ranging from large-scale events that are probably related to global environmental changes to degradation by waste water or invasive species. Degradation by fishing activities and by divers is also considered. Finally, the main gaps in current scientific knowledge of coralligenous communities are listed and some recommendations are made regarding their protection.
{"title":"Mediterranean coralligenous assemblages: A synthesis of present knowledge","authors":"E. Ballesteros","doi":"10.1201/9781420006391-7","DOIUrl":"https://doi.org/10.1201/9781420006391-7","url":null,"abstract":"Coralligenous concretions, the unique calcareous formations of biogenic origin in Mediterranean benthic environments, are produced by the accumulation of encrusting algae growing in dim light conditions. This review provides an overview of the results obtained by the main studies dealing with these formations, including the environmental factors which influence the development of coralligenous communities, their distribution, types, assemblages, builders and eroders, the biotic relationships and processes that create and destroy coralligenous assemblages, their dynamics and seasonality, and the functioning of several outstanding and key species. Special attention is devoted to the biodiversity of coralligenous communities and a first estimation of the number of species reported for this habitat is provided. Major disturbances affecting coralligenous communities are discussed, ranging from large-scale events that are probably related to global environmental changes to degradation by waste water or invasive species. Degradation by fishing activities and by divers is also considered. Finally, the main gaps in current scientific knowledge of coralligenous communities are listed and some recommendations are made regarding their protection.","PeriodicalId":54693,"journal":{"name":"Oceanography and Marine Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86316322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-01-01DOI: 10.1201/9781420006391.ch2
S. Baden, Susanne P. Eriksson
This review provides an overview of the role, routes and effects of manganese in aquatic crustaceans. Manganese is a naturally abundant metal in marine and freshwater sediments where it is involved in a large number of chemical processes. Although sediments contain high natural concentrations of manganese, the potential danger to benthic organisms has been neglected in studies to date. Manganese bioavailability increases as the result of human impact and it accumulates in biota. Manganese may occur in toxic concentrations (10-20 mg l -1 ) in the bottom water of marine coastal areas after hypoxia, or more locally (e.g., close to industries) as well as in acidic lakes and aquaculture shrimp ponds. Though manganese is an essential metal, it is also an unforeseen toxic metal in the aquatic environment. Although the uptake and elimination of manganese is rapid, manganese affects processes that decrease the fitness of organisms. As manganese bioavailability increases, its uptake is predominately through the water. The midgut gland, nerve tissue, blood proteins and parts of the reproductive organs have the highest accumulation factors and are the main target tissues. The functional effects of manganese in aquatic environments are still sparsely investigated. Recent results show that the immune system, the perception of food via chemosensory organs and a normal muscle extension are affected at manganese concentrations observed in the field.
本文综述了锰在水生甲壳类动物中的作用、途径和影响。锰是一种天然丰富的金属，存在于海洋和淡水沉积物中，参与了大量的化学过程。虽然沉积物中含有高浓度的天然锰，但迄今为止的研究忽视了对底栖生物的潜在危险。锰的生物利用度因人类影响而增加，并在生物群中积累。在海洋沿海地区缺氧后的底水中，锰可能以有毒浓度(10-20 mg l -1)出现，或在局部(例如靠近工业)以及酸性湖泊和水产养殖对虾池中出现更多锰。虽然锰是一种必需的金属，但它也是水生环境中不可预见的有毒金属。虽然锰的吸收和消除是迅速的，但锰影响了降低生物体适应性的过程。随着锰生物利用度的增加，它的吸收主要是通过水。中肠腺、神经组织、血液蛋白和部分生殖器官的蓄积因子最高，是主要靶组织。锰在水生环境中的功能效应研究仍然很少。最近的研究结果表明，免疫系统、通过化学感觉器官对食物的感知和正常的肌肉伸展受到锰浓度的影响。
{"title":"Role, routes and effects of manganese in crustaceans","authors":"S. Baden, Susanne P. Eriksson","doi":"10.1201/9781420006391.ch2","DOIUrl":"https://doi.org/10.1201/9781420006391.ch2","url":null,"abstract":"This review provides an overview of the role, routes and effects of manganese in aquatic crustaceans. Manganese is a naturally abundant metal in marine and freshwater sediments where it is involved in a large number of chemical processes. Although sediments contain high natural concentrations of manganese, the potential danger to benthic organisms has been neglected in studies to date. Manganese bioavailability increases as the result of human impact and it accumulates in biota. Manganese may occur in toxic concentrations (10-20 mg l -1 ) in the bottom water of marine coastal areas after hypoxia, or more locally (e.g., close to industries) as well as in acidic lakes and aquaculture shrimp ponds. Though manganese is an essential metal, it is also an unforeseen toxic metal in the aquatic environment. Although the uptake and elimination of manganese is rapid, manganese affects processes that decrease the fitness of organisms. As manganese bioavailability increases, its uptake is predominately through the water. The midgut gland, nerve tissue, blood proteins and parts of the reproductive organs have the highest accumulation factors and are the main target tissues. The functional effects of manganese in aquatic environments are still sparsely investigated. Recent results show that the immune system, the perception of food via chemosensory organs and a normal muscle extension are affected at manganese concentrations observed in the field.","PeriodicalId":54693,"journal":{"name":"Oceanography and Marine Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74722415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-01-01DOI: 10.1201/9781420006391.ch7
M. Thiel, P. Haye
Rafting of marine and terrestrial organisms has important ecological, biogeographical and evolutionary implications. Herein the general principles of rafting are described and how they contribute to population connectivity. Rafting dispersal has particular characteristics, which may differ substantially from those of species with planktonic larval dispersal. Dispersal distances achieved via rafting can vary considerably: journeys may be very short or in some cases extremely long, depending on currents and wind. Accumulation of rafts in convergence zones facilitates cohesion of travelling groups, possibly reducing the risk of founder populations being very small. This becomes particularly important over long distances where singular founder events could provoke strong reduction of the genetic variability in the founded population. The frequency of transport affects the degree of connectivity between local populations. Three important rafting routes are distinguished: frequent, intermittent and episodic. Frequent rafting routes are found in bays, lagoons and estuaries, and they are typically facilitated by substrata of biotic origin (seagrass, saltmarsh vegetation, intermediate-sized algae and mangroves). Intermittent rafting routes are found along temperate continental shores where they are facilitated primarily by giant kelps. In the subtropics and the Arctic intermittent rafting routes facilitated by wood are particularly important. Episodic rafting routes, which often cross vast areas of open ocean (biogeographic barriers), are facilitated by volcanic pumice, floating trees and occasionally by giant kelps when these are pushed beyond intermittent routes by strong winds or currents. Dispersal events occur in a highly sporadic manner in this latter category of rafting route, but when they happen, large amounts of floating substrata and rafters may be dispersed simultaneously. Intervals between events can be decades, centuries or even millennia, and consequently populations resulting from these events may be isolated from each other for long time periods. Population connectivity on frequent, intermittent and episodic rafting routes is high, intermediate and low, respectively. Genetic studies support these predictions, and furthermore underline that rafting may contribute to population connectivity over a wide range of geographic scales, from 5000 km. Rafting also has a strong effect on evolutionary processes of the organisms dispersed by this means. It is suggested that local recruitment (consequence of direct development) contributes to enhanced rates of population divergence among local populations of common rafters, but occasionally high genetic diversity may result from secondary admixture. Isolation of colonisers after singular episodic rafting events facilitates allopatric speciation. Through these processes rafting dispersal may support local species richness and thus have an influence on local biogeography and biodiversity. Human activitie
{"title":"The ecology of rafting in the marine environment. III. Biogeographical and evolutionary consequences","authors":"M. Thiel, P. Haye","doi":"10.1201/9781420006391.ch7","DOIUrl":"https://doi.org/10.1201/9781420006391.ch7","url":null,"abstract":"Rafting of marine and terrestrial organisms has important ecological, biogeographical and evolutionary implications. Herein the general principles of rafting are described and how they contribute to population connectivity. Rafting dispersal has particular characteristics, which may differ substantially from those of species with planktonic larval dispersal. Dispersal distances achieved via rafting can vary considerably: journeys may be very short or in some cases extremely long, depending on currents and wind. Accumulation of rafts in convergence zones facilitates cohesion of travelling groups, possibly reducing the risk of founder populations being very small. This becomes particularly important over long distances where singular founder events could provoke strong reduction of the genetic variability in the founded population. The frequency of transport affects the degree of connectivity between local populations. Three important rafting routes are distinguished: frequent, intermittent and episodic. Frequent rafting routes are found in bays, lagoons and estuaries, and they are typically facilitated by substrata of biotic origin (seagrass, saltmarsh vegetation, intermediate-sized algae and mangroves). Intermittent rafting routes are found along temperate continental shores where they are facilitated primarily by giant kelps. In the subtropics and the Arctic intermittent rafting routes facilitated by wood are particularly important. Episodic rafting routes, which often cross vast areas of open ocean (biogeographic barriers), are facilitated by volcanic pumice, floating trees and occasionally by giant kelps when these are pushed beyond intermittent routes by strong winds or currents. Dispersal events occur in a highly sporadic manner in this latter category of rafting route, but when they happen, large amounts of floating substrata and rafters may be dispersed simultaneously. Intervals between events can be decades, centuries or even millennia, and consequently populations resulting from these events may be isolated from each other for long time periods. Population connectivity on frequent, intermittent and episodic rafting routes is high, intermediate and low, respectively. Genetic studies support these predictions, and furthermore underline that rafting may contribute to population connectivity over a wide range of geographic scales, from 5000 km. Rafting also has a strong effect on evolutionary processes of the organisms dispersed by this means. It is suggested that local recruitment (consequence of direct development) contributes to enhanced rates of population divergence among local populations of common rafters, but occasionally high genetic diversity may result from secondary admixture. Isolation of colonisers after singular episodic rafting events facilitates allopatric speciation. Through these processes rafting dispersal may support local species richness and thus have an influence on local biogeography and biodiversity. Human activitie","PeriodicalId":54693,"journal":{"name":"Oceanography and Marine Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78368603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-01-01DOI: 10.1201/9781420006391.CH6
M. Collins, R. Villanueva
The cirrate octopods are deep-sea, cold-adapted cephalopod molluscs that are found throughout the world's oceans, usually at depths in excess of 300 m, but shallower in cold water at high latitudes. The gelatinous bodies of the cirrates, which deform when preserved, coupled with low capture rates have caused considerable confusion in the systematics of the group. The taxonomically relevant morphological features are briefly reviewed and the taxonomy revised. On the basis of morphological and molecular information the cirrates are divided into four families, the Cirroteuthidae (including the genera Cirroteuthis, Cirrothauma and Stauroteuthis), Cirroctopodidae (Cirroctopus), Grimpoteuthidae (Cryptoteuthis, Grimpoteuthis and Luteuthis) and Opisthoteuthidae (Opisthoteuthis). A total of 45 species are recognised. The opisthoteuthids are primarily benthic animals, the grimpoteuthids and cirroctopodids benthopelagic and the cirroteuthids essentially pelagic, but generally close to the sea floor. With the exception of two common, shallow, Opisthoteuthis species, the biology of the cirrates is poorly studied. The data on reproductive biology indicate that spawning is extended, with growth continuing during a reproductive period that probably occupies much of the life cycle, an unusual strategy in cephalopods. Diet studies suggest that benthic cirrates feed on small-sized organisms with low swimming speeds and the main prey are amphipods and polychaetes. Cirrate predators include sharks, teleost fishes, fur seals and sperm whales. Behavioural observations, based on underwater photographs, submersible observations and aquarium studies, show a range of postures, modes of locomotion and responses to disturbance that differ between the families. Behavioural observations also help interpret the unusual morphology and physiology of the cirrates, such as the use of cirri, fins, secondary web and bioluminescent emissions
{"title":"TAXONOMY, ECOLOGY AND BEHAVIOUR OF THE CIRRATE OCTOPODS","authors":"M. Collins, R. Villanueva","doi":"10.1201/9781420006391.CH6","DOIUrl":"https://doi.org/10.1201/9781420006391.CH6","url":null,"abstract":"The cirrate octopods are deep-sea, cold-adapted cephalopod molluscs that are found throughout the world's oceans, usually at depths in excess of 300 m, but shallower in cold water at high latitudes. The gelatinous bodies of the cirrates, which deform when preserved, coupled with low capture rates have caused considerable confusion in the systematics of the group. The taxonomically relevant morphological features are briefly reviewed and the taxonomy revised. On the basis of morphological and molecular information the cirrates are divided into four families, the Cirroteuthidae (including the genera Cirroteuthis, Cirrothauma and Stauroteuthis), Cirroctopodidae (Cirroctopus), Grimpoteuthidae (Cryptoteuthis, Grimpoteuthis and Luteuthis) and Opisthoteuthidae (Opisthoteuthis). A total of 45 species are recognised. The opisthoteuthids are primarily benthic animals, the grimpoteuthids and cirroctopodids benthopelagic and the cirroteuthids essentially pelagic, but generally close to the sea floor. With the exception of two common, shallow, Opisthoteuthis species, the biology of the cirrates is poorly studied. The data on reproductive biology indicate that spawning is extended, with growth continuing during a reproductive period that probably occupies much of the life cycle, an unusual strategy in cephalopods. Diet studies suggest that benthic cirrates feed on small-sized organisms with low swimming speeds and the main prey are amphipods and polychaetes. Cirrate predators include sharks, teleost fishes, fur seals and sperm whales. Behavioural observations, based on underwater photographs, submersible observations and aquarium studies, show a range of postures, modes of locomotion and responses to disturbance that differ between the families. Behavioural observations also help interpret the unusual morphology and physiology of the cirrates, such as the use of cirri, fins, secondary web and bioluminescent emissions","PeriodicalId":54693,"journal":{"name":"Oceanography and Marine Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86913138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-01-01DOI: 10.1201/9781420006391.ch5
H. Wägele, M. Ballesteros, C. Ávila
Opisthobranch molluscs are an extremely interesting group of animals, displaying a wide diversity in shape, colour and life strategies. Chemical ecology of this group is particularly appealing since most species have a reduced or absent shell and have developed chemical defences to avoid predation. New results on defensive glandular structures as well as a compilation of literature data in sea slugs (Opisthobranchia, Gastropoda, Mollusca) are presented in this review. Investigation of these structures is based on detailed analyses of the histology of many representative species of all major taxa of the Opisthobranchia. The results are correlated with previous and new findings of secondary metabolites in these animals and are set in a phylogenetic context. Additionally, information on food sources is given. Also, an hypothetical scenario relating chemical ecology to histology is proposed. This information will help future analyses to investigate defensive devices on a much more accurate basis and allow a better understanding of evolutionary processes, which are observed independently in many opisthobranch clades.
{"title":"Defensive glandular structures in opisthobranch molluscs : From histology to ecology","authors":"H. Wägele, M. Ballesteros, C. Ávila","doi":"10.1201/9781420006391.ch5","DOIUrl":"https://doi.org/10.1201/9781420006391.ch5","url":null,"abstract":"Opisthobranch molluscs are an extremely interesting group of animals, displaying a wide diversity in shape, colour and life strategies. Chemical ecology of this group is particularly appealing since most species have a reduced or absent shell and have developed chemical defences to avoid predation. New results on defensive glandular structures as well as a compilation of literature data in sea slugs (Opisthobranchia, Gastropoda, Mollusca) are presented in this review. Investigation of these structures is based on detailed analyses of the histology of many representative species of all major taxa of the Opisthobranchia. The results are correlated with previous and new findings of secondary metabolites in these animals and are set in a phylogenetic context. Additionally, information on food sources is given. Also, an hypothetical scenario relating chemical ecology to histology is proposed. This information will help future analyses to investigate defensive devices on a much more accurate basis and allow a better understanding of evolutionary processes, which are observed independently in many opisthobranch clades.","PeriodicalId":54693,"journal":{"name":"Oceanography and Marine Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87549487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-24DOI: 10.1201/9781420037449-12
F. Manson, N. Loneragan, G. Skilleter, S. Phinn
There is a widely held paradigm that mangroves are critical for sustaining production in coastal fisheries through their role as important nursery areas for fisheries species. This paradigm frequently forms the basis for important management decisions on habitat conservation and restoration of mangroves and other coastal wetlands. This paper reviews the current status of the paradigm and synthesises the information on the processes underlying these potential links. In the past, the paradigm has been supported by studies identifying correlations between the areal and linear extent of mangroves and fisheries catch. This paper goes beyond the correlative approach to develop a new framework on which future evaluations can be based. First, the review identifies what type of marine animals are using mangroves and at what life stages. These species can be categorised as estuarine residents, marine-estuarine species and marine stragglers. The marine-estuarine category includes many commercial species that use mangrove habitats as nurseries. The second stage is to determine why these species are using mangroves as nurseries. The three main proposals are that mangroves provide a refuge from predators, high levels of nutrients and shelter from physical disturbances. The recognition of the important attributes of mangrove nurseries then allows an evaluation of how changes in mangroves will affect the associated fauna. Surprisingly few studies have addressed this question. Consequently, it is difficult to predict how changes in any of these mangrove attributes would affect the faunal communities within them and, ultimately, influence the fisheries associated with them. From the information available, it seems likely that reductions in mangrove habitat complexity would reduce the biodiversity and abundance of the associated fauna, and these changes have the potential to cause cascading effects at higher trophic levels with possible consequences for fisheries. Finally, there is a discussion of the data that are currently available on mangrove distribution and fisheries catch, the limitations of these data and how best to use the data to understand mangrove-fisheries links and, ultimately, to optimise habitat and fisheries management. Examples are drawn from two relatively data-rich regions, Moreton Bay (Australia) and Western Peninsular Malaysia, to illustrate the data needs and research requirements for investigating the mangrove-fisheries paradigm. Having reliable and accurate data at appropriate spatial and temporal scales is crucial for mangrove-fisheries investigations. Recommendations are made for improvements to data collection methods that would meet these important criteria. This review provides a framework on which to base future investigations of mangrove-fisheries links, based on an understanding of the underlying processes and the need for rigorous data collection. Without this information, the understanding of the relationship between mangroves an
{"title":"AN EVALUATION OF THE EVIDENCE FOR LINKAGES BETWEEN MANGROVES AND FISHERIES: A SYNTHESIS OF THE LITERATURE AND IDENTIFICATION OF RESEARCH DIRECTIONS","authors":"F. Manson, N. Loneragan, G. Skilleter, S. Phinn","doi":"10.1201/9781420037449-12","DOIUrl":"https://doi.org/10.1201/9781420037449-12","url":null,"abstract":"There is a widely held paradigm that mangroves are critical for sustaining production in coastal fisheries through their role as important nursery areas for fisheries species. This paradigm frequently forms the basis for important management decisions on habitat conservation and restoration of mangroves and other coastal wetlands. This paper reviews the current status of the paradigm and synthesises the information on the processes underlying these potential links. In the past, the paradigm has been supported by studies identifying correlations between the areal and linear extent of mangroves and fisheries catch. This paper goes beyond the correlative approach to develop a new framework on which future evaluations can be based. First, the review identifies what type of marine animals are using mangroves and at what life stages. These species can be categorised as estuarine residents, marine-estuarine species and marine stragglers. The marine-estuarine category includes many commercial species that use mangrove habitats as nurseries. The second stage is to determine why these species are using mangroves as nurseries. The three main proposals are that mangroves provide a refuge from predators, high levels of nutrients and shelter from physical disturbances. The recognition of the important attributes of mangrove nurseries then allows an evaluation of how changes in mangroves will affect the associated fauna. Surprisingly few studies have addressed this question. Consequently, it is difficult to predict how changes in any of these mangrove attributes would affect the faunal communities within them and, ultimately, influence the fisheries associated with them. From the information available, it seems likely that reductions in mangrove habitat complexity would reduce the biodiversity and abundance of the associated fauna, and these changes have the potential to cause cascading effects at higher trophic levels with possible consequences for fisheries. Finally, there is a discussion of the data that are currently available on mangrove distribution and fisheries catch, the limitations of these data and how best to use the data to understand mangrove-fisheries links and, ultimately, to optimise habitat and fisheries management. Examples are drawn from two relatively data-rich regions, Moreton Bay (Australia) and Western Peninsular Malaysia, to illustrate the data needs and research requirements for investigating the mangrove-fisheries paradigm. Having reliable and accurate data at appropriate spatial and temporal scales is crucial for mangrove-fisheries investigations. Recommendations are made for improvements to data collection methods that would meet these important criteria. This review provides a framework on which to base future investigations of mangrove-fisheries links, based on an understanding of the underlying processes and the need for rigorous data collection. Without this information, the understanding of the relationship between mangroves an","PeriodicalId":54693,"journal":{"name":"Oceanography and Marine Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2005-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75079394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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