Transport Of Particulate Organic Matter Research Articles

Eiefsis Bay Anoxia: Nutrient Conditions and Benthic Community Structure

Abstract. The changes in the concentrations of silicate, phosphate, and inorganic nitrogen in Eiefsis Bay. an intermittently anoxic basin, arc described and related to the changes in the physical properties of the water. Winter convection resulted in a very small vertical gradient of temperature, salinity, oxygen, and nutrients. Stratification started to develop in May and persisted for about 6 months. High values of silicate, phosphate, and ammonia occurred during the anoxic conditions prevailing in summer. The vertical transport of particulate organic matter and decomposition of abundant pelagic and benthic organic matter during the summer produced a low oxygen level in the bottom layer below the pycnoclinc. A high sea water temperature and vertical stability contributed to the development of anoxic conditions during the summer in the near bottom layer and to mass mortality of benthic macrofauna. Also the Eiefsis Bay anoxia appears to have had significant ecological effects on many other marine species, including several of economic importance.

Bottom layer anoxia in the central part of the Gulf of Trieste in the late summer of 1983

Anoxic conditions in the near-bottom layer below the pycnocline were observed in September 1983 causing mass mortality of benthic macrofauna in the central part of the Gulf of Trieste. The vertical transport of particulate organic matter and decomposition of abundant pelagic and benthic organic matter during the summer produced a low oxygen level in the near-bottom layer below the pycnocline when this layer was sufficiently close to the bottom. A high sea water temperature and vertical stability contributed to the development of anoxic conditions in September 1983 in the near-bottom layer.

The Role of Benthic Macroinvertebrates in Detritus Dynamics of Streams: A Computer Simulation

Detritus dynamics in Big Hurricane Branch, a second—order stream at Coweeta Hydrologic Laboratory in the southern Appalachian Mountains, were simulated with a computer model, using data from a variety of Coweeta stream studies. The model was used to evaluate the role of macroinvertebrates in the stream. Macroinvertebrates accounted for only a small portion of the respiration of detritus; their major role was conversion of benthic detritus into transported detritus. Macroinvertebrates were responsible for 27% of annual particulate organic matter (POM) transport, though when they were removed there was only a 10% reduction in POM transport because of a compensatory increase in storm transport. The contribution of macroinvertebrates to POM transport during nonstorm periods was much more significant, as high as 83% in late summer. Based on an annual budget, macroinvertebrates decrease the efficiency of detritus processing in low—order streams, because they increase transport loss. On a longer time scale, however, macroinvertebrates prevent accumulation of large amounts of detritus in the stream and major losses during infrequent large storms. By stabilizing long—term detritus export dynamics, they provide an important link between low—order and higher—order streams.

Benthic response to sedimentation of a spring phytoplankton bloom: Process and budget

The response of benthos to sedimentation of the spring phytoplankton bloom in the Kiel Bight (Western Baltic Sea) is described in terms of biomass (ATP) and activity (heat production and ETS-activity). Input of the bloom (11.5 g C m-2) over a period from March 25 to April 19, 1980 to the sediment surface was in the form of cells and fresh phytodetritus as indicated by low C/N ratios (≦7) and high energy charge values (0.78). Benthic microbial activity was immediately stimulated by this input as heat production doubled and the activity of ETS tripled over winter values within 12 d in the absence of a significant increase in ambient temperature. A comparison of the two activity parameters suggests that anaerobic metabolism is more important during the winter (February and March) than after input of the bloom. Meiofauna was not able to take part in the first activity outburst. Benthic ATP-biomass (excluding macrofauna) doubled in late April due to microbial production, and doubled again in early May when meiofauna started reproductive activity. For macrofauna a general statement was not possible, although the sediment surface feeder Macoma baltica commenced a build up of glycogen and lipid resources immediately following bloom input whereas Nephtys ciliata, feeding on sediment and small macrofauna, showed a less pronounced and delayed effect from this input. An energy budget based on heat production measurements was calculated. A daily heat loss of the benthic community of 21.7 KJ m-2 d-1 (35.5 KJ m-2 d-1) was found, when a depth of 3 cm sediment (5 cm) was assumed. Heat production of macrofauna contributed less than 5% of this activity. The input of the bloom was “burned” within 21 (13) d. Preliminary estimations for an annual budget suggest that the vertical transport of particulate organic matter via sedimentation can only explain 25% (15%) of the benthic activity in the shallow water ecosystem of the Kiel Bight. This indicates the presence of other sources of organic carbon such as benthic primary production or other transport processes providing carbon to the sediments.

Stream detritus dynamics: Regulation by invertebrate consumers

Insecticide treatment of a small, Appalachian forest stream caused massive downstream insect drift and reduced aquatic insect densities to <10% of an adjacent untreated reference stream. Reduction in breakdown rates of leaf detritus was accompanied by differences in quantity and composition of benthic organic matter between the two streams. Following treatment, transport of particulate organic matter was significantly lower in the treated stream than in the reference stream whereas no significant differences existed prior to treatment. Our results indicate that macroinvertebrate consumers, primarily insects, are important in regulating rates of detritus processing and availability to downstream communities.

Vertical transport of particulate organic matter in the deep Bering Sea and gulf of Alaska

Sediment trap arrays were deployed at two deep ocean stations, one in the Bering Sea and the other in the Gulf of Alaska, in the summer of 1975. The sediment trap was constructed of a pair of polyethylene cylinders (0.185 m2 opening) with funnel-shaped bases. The trap is equipped with a lid which is closed before recovery by a tripping messenger system triggered by an electric time release. 37–68% of the total organic carbon fluxes (37–38% in the Bering Sea; 48–68% in the Gulf of Alaska) were represented by large particles (67µm<) such as fecal matter and fecal pellets which contributed minor fractions to the total particulate organic matter concentration in sea water. The total fluxes were 11.1 and 14.2 mg C m−2d−1 at 1,510 and 2,610 m respectively at the station (3,800 m) in the Bering Sea, and were 7.60, 4.66 and 3.27 mg C m−2d−1 at 900, 1,500 and 1,875 m respectively at the station (4,150 m) in the Gulf of Alaska. The former values are several times greater than the latter, suggesting that there is a regional variation in the vertical carbon flux in deep layers. The fluxes were approximately equivalent to 1 to 3% of primary productivity in the overlying surface layers. These observations suggest that deep-water ecosystems may be influenced by relatively rapid sinking of large particles such as fecal matter and fecal pellets from near surface production.

Particulate Organic Matter Transport to the Deep Sea by Salp Fecal Pellets

Free-floating sediment traps were suspended at 200 and 900 m in the northern North Pacific Ocean during 20-21 May, 1974. A considerable amount of large, dark-green particles, larger than 1 mm in diameter, was collected at both depths. These large particles corresponded morphologically with fecal pellets of salps. Vertical carbon flux was estimated to be 10.5 and 6.7 mg C m 2 d ' at 200 and 900 m, respectively. This suggests that vertical transport of salp fecal pellets could play a n important role in meeting the energy requirements of bathypelagic organisms in the open ocean.

Particulate organic matter transport to the deep sea by salp fecal pellets : Iseki, K., 1981. Mar. Ecol.-Prog. Ser., 5(1):55–60

Particulate organic matter transport to the deep sea by salp fecal pellets : Iseki, K., 1981. Mar. Ecol.-Prog. Ser., 5(1):55–60

Transport of particulate organic material between salt marsh and estuary

The macrophyte production and the transport of particulate organic matter between march and adjacent estuary have been investigated for a 30 ha salt marsh along the Oosterschelde estuary, The Netherlands. The primary production of macrophytes, measured with Smalley's method, was 837–1030 g dry organic matter.m−2.year−1. Measurements of amounts of particulate organic matter transported through one of the main tidal creeks in the salt march resulted in a net import. On average 31% of the material brought in by the flood settled in the marsh. The majority of this material is smaller than 63 μm. On the other hand large floating material is exported during storm tides, although the quantity seems to be smaller than that of the suspended material imported. The differences between various marshes with regard to export and import of organic matter are explained in terms of marsh level, primary production, turbulent diffusion, sinking and resuspension of particulate matter and biotic transformations.

Diel vertical migration bySalpa aspera and its potential for large-scale particulate organic matter transport to the deep-sea

In mid-summer 1975 throughout the Western Slope Water of the North Atlantic Ocean, massive numbers ofSalpa aspera performed a diel vertical migration of at least 800 m. This resulted in a movement of 85 to 90% of the total zooplankton biomass out of the upper 500 m during the day. Fecal pellet production and losses from this salp population were estimated to contribute approximately 12 mg C m-2 day-1 to the deep planktonic and benthic populations. If all this organic matter reached the deep-sea floor, it would represent over 100% of the daily deep-sea benthic infauna energy requirements.

Transport of particulate organic matter by bubbles in marine waters 1

Flotation experiments with surface marine waters collected from estuarine, continental shelf, slope, and open ocean waters showed that about half of the originally present particulate organic carbon and nitrogen was adsorbed and transported by bubbles to the surface froth. Recovery values were a function of primary production and other environmental parameters. In only one instance was there evidence of selective removal of particles with C:N ratios differing from those left behind.The estimated open ocean transport of POC by bubbles was five times higher than an earlier estimate due to the unexpected efficiency of the flotation column at low concentrations of open ocean POC. Budget calculations indicated little or no conversion of dissolved to particulate organic carbon. Large macroscopic particles quickly formed in the froth produced by bubbling, an aggregation phenomenon which may be of importance in the transport of large particle POC to deep waters.