Benthic zone

About: Benthic zone is a research topic. Over the lifetime, 23176 publications have been published within this topic receiving 763926 citations.

A major ecosystem shift in the northern Bering Sea.

Abstract: Until recently, northern Bering Sea ecosystems were characterized by extensive seasonal sea ice cover, high water column and sediment carbon production, and tight pelagic-benthic coupling of organic production. Here, we show that these ecosystems are shifting away from these characteristics. Changes in biological communities are contemporaneous with shifts in regional atmospheric and hydrographic forcing. In the past decade, geographic displacement of marine mammal population distributions has coincided with a reduction of benthic prey populations, an increase in pelagic fish, a reduction in sea ice, and an increase in air and ocean temperatures. These changes now observed on the shallow shelf of the northern Bering Sea should be expected to affect a much broader portion of the Pacific-influenced sector of the Arctic Ocean.

The Role of Benthic Invertebrate Species in Freshwater Ecosystems: Zoobenthic species influence energy flows and nutrient cycling

Abstract: 119 Small invertebrates are functionally important in many terrestrial and aquatic ecosystems (Wilson 1992, Freckman et al. 1997, Palmer et al. 1997, Postel and Carpenter 1997). In freshwater sediments, benthic invertebrates are diverse and abundant, but they are often patchily distributed and relatively difficult to sample, especially when they live in deep subsurface sediments. Thus, the species richness and functional importance of freshwater benthic invertebrates generally go unnoticed until unexpected changes occur in ecosystems. Unanticipated changes in freshwater ecosystems are often due to alterations in the complex connections among sediment-dwelling species and associated food webs (e.g., Goedkoop and Johnson 1996, Lodge et al. 1998b, Stockley et al. 1998) or to disturbances, such as floods or drought (e.g., Covich 1993, Power 1995, Johnson et al. 1998), that alter the species composition of the benthos. In addition, benthic species can themselves constitute a disturbance, such as when they transmit diseases. For example, certain benthic invertebrate species (e.g., Tubifex tubifex) serve as parasite-transmitting vectors; if these invertebrates increase in abundance in stream sediments, they may spread a lethal disease to trout, causing trout populations to decline (Brinkhurst 1997). Fish kills may also occur because of increased accumulation of nutrients, which cause formation of toxic algal blooms, deoxygenation of deeper, density-stratified waters, and high concentrations of ammonia or hydrogen sulfide (Covich 1993). The bottom muds of lakes and streams may at first glance appear to be uniform and, therefore, unlikely habitats for high biodiversity. However, physical, chemical, and biological processes create significant horizontal and vertical heterogeneities in the substrata (Figure 1) that provide a physical template for distinct niches (Hutchinson 1993). These sedimentary processes include changes in direction and rates of flows, differential deposition of sediment grain sizes and dead organisms, growth and death of roots, burrowing and sediment reworking, and fecal production by benthic consumers. Microhabitats are also created by chemical gradients and microzonation in concentrations of dissolved oxygen, hydrogen sulfide, ammonia, phosphorus, and other critical chemicals (Groffman and Bohlen 1999). Colwell (1998) emphasizes that such “biocomplexity” of habitats and biological relationships is an important aspect of biodiversity. Bioturbation and other biotic interactions create extensive biocomplexity in freshwater sediments (Charbonneau and Hare 1998). These biocomplexities must be better understood if clean drinking water and recreational uses of fresh waters are to be maintained. Science-based policies require an ecosystem perspective on the multiple roles of many diverse benthic species. Previous studies have often dealt with the “goods” produced by benthic species, such as the quantity of prey items consumed by fish. These goods are clearly important components of food webs, but how their functional relationships respond to changes in species composition are also important. In this article, we highlight examples of how some species have a disproportionately large impact on food-web dynamics and how particular species provide essential ecosystem services. These ecosystem functions include sediment mixing, nutrient cycling, and energy flow through food webs. The Role of Benthic Invertebrate Species in Freshwater Ecosystems

Microhabitats of benthic foraminifera within deep-sea sediments

Abstract: Benthic foraminifera are protozoans found throughout the deep-sea environment, secreting a test of calcium carbonate or constructing a test of cemented sediment particles (agglutinated or arenaceous foraminifera). In typical deep-sea sediments, the organic cement of agglutinated taxa degrades upon burial in the sediment and, consequently, few specimens survive in the fossil record. In contrast, calcareous species are well preserved in most oceanic sediments, except at abyssal depths where most carbonate sediment is dissolved because of high levels of carbonate under-saturation of the bottom waters. Although benthic foraminifera have been widely used in studies of Cenozoic palaeoceanography, little is known about the ecology of deep-sea species. I present here an analysis of living (stained) benthic foraminifera within the upper 15 cm of deep-sea sediments, which reveals species-specific microhabitat preferences, with distinct morphological features found with epifaunal and infaunal species. The existence of infaunal habitats suggests that the distribution of certain foraminifera is not directly controlled by overlying bottom-water conditions, but by physicochemical conditions within the sediments. The microhabitat preferences may also explain interspecific carbon isotope differences, as existing data show that infaunal foraminifera generally have lower δ13C isotope values than epifaunal species.

Marine community ecology

Abstract: Part I: Processes Influencing Pattern in Benthic Communities Physical Processes that Generate Pattern in Marine Communities Geological History of the Living Shore Biota Genetic Structure in the Sea: From Populations to Communities Natural Disturbance and the Dynamics of Marine Benthic Communities The Ecology and Evolution of Marine Consumer-Prey Interactions The Larval Ecology of Marine Communities Supply Side Ecology: The Nature and Consequences of Variations in Recruitment of Intertidal Organisms Habitat Modification and Facilitation in Benthic Marine Communities Part II: Community Types Soft Sediment Communities Salt Marsh Communities Seagrass Community Ecology Rocky Subtidal Communities Deep-Sea Communities The Ecology of Coral Reefs Mangrove Communities Part III: Marine Community Conservation Issues Human Alterations of Marine Communities Caveat Studium Conservation and Management of Marine Communities The Ecology of Marine Protected Areas