David C. Burrell

Fjords: Processes and Products

1 Introduction.- 1 Fjords and Their Study.- 1.1 Definition, Distribution, and History.- 1.2 Environmental Setting and Study.- 1.3 The Past, Present, and Future of Fjord Research.- 2 Environmental Setting.- 2.1 Geomorphology.- 2.2 Climate.- 2.3 Oceanographic Characteristics.- 2.4 Sediment Sources and Transport Mechanisms.- 2.5 Fjord History.- 2.6 Characteristic Features of Fjord Coastlines.- 2.7 Summary.- 2 Processes and Products.- 3 The Fluvial-Deltaic Environment.- 3.1 Runoff.- 3.2 Sediment Transport.- 3.3 Paraglacial Sedimentation.- 3.4 Fjord-Head Deltas.- 3.5 Summary.- 4 Circulation and Sediment Dynamics.- 4.1 Fjord Estuarine Circulation.- 4.2 Hypopycnal Sedimentation.- 4.3 Hyperpycnal Flow.- 4.4 Flushing and Deep Water Renewal.- 4.5 Ice Influences.- 4.6 Mixing Processes and the Seafloor Environment.- 4.7 Summary.- 5 Subaqueous Slope Failures.- 5.1 Mass Sediment Properties and Subaqueous Slope Stability.- 5.2 Release Mechanisms.- 5.3 Mass Transport Processes.- 5.4 The Products of Subaqueous Slope Failure.- 5.5 Summary.- 6 Biotic Processes.- 6.1 Pelagic and Littoral Processes.- 6.2 The Fjord Benthic Environment.- 6.3 Summary.- 7 Biogeochemistry.- 7.1 Particulate Sediment.- 7.2 Aerobic Diagenetic Reactions.- 7.3 Anoxic Environments.- 7.4 Summary.- 3 Implications/Applications.- 8 Environmental Problems: Case Histories.- 8.1 Introduction.- 8.2 Agfardlikavsa Fjord, Greenland.- 8.3 Resurrection Bay, Alaska.- 8.4 Port Valdez, Alaska.- 8.5 Howe Sound, British Columbia.- 8.6 Rupert Inlet, British Columbia.- 8.7 Saguenay Fjord, Quebec.- 8.8 Iddefjord, Norway/Sweden.- 8.9 Saudafjord, Southwest Norway.- 8.10 Sorfjord, West Norway.- 8.11 Ranafjord, Northern Norway.- 8.12 Loch Eil, Scotland.- 8.13 By fjord, Sweden.- 8.14 Summary of Impacts in Other Fjords.- 9 Future Fjord Research.- 9.1 Oceanographic Problems and Projects.- 9.2 Biogeochemical Problems and Projects.- 9.3 Biological Problems and Projects.- 9.4 Geological-Related Problems and Projects.- 9.5 Approaches.- References.- Fjord Index.

Sediment Transport and Accumulation in a Fjord Basin, Glacier Bay, Alaska

Sediment transport and accumulation were studied over several years to define the sedimentary environment in a fan-terminated, active valley glacier and adjacent fjord at Queen Inlet, Glacier Bay National Monument, Alaska. Recently exposed ice-contact sediment at the glacier snout is entrained during summer and early fall by meltwater streams crossing a subaerial-intertidal outwash fan. Suspended sediment in the meltwater (sediment loads exceed 1 g/liter at the inlet head) subsequently yields a cold, surface sediment plume overlying warmer saline water in the fjord basin. Mixing of these layers produces flocculation and settling occurs in discrete layers; each layer is considered to represent one tidal cycle. No gravel is present in fjord floor sediment, although both colluvium and outwash fan sediments contain gravel. This gravel distribution eliminates sliding, slumping of the outwash fan, and ice rafting as major contributors to fjord basin sediment in Queen Inlet. Piston cores of muddy fjord basin sediment show cyclical, thin, black horizons, thought to be annually produced. Spacing of these marker horizons indicates that sediment accumulation may exceed 1 m/year at the inlet head. The fjord floor is cut by sinuous valleys with natural levees, terraces, and sandy silt axial sediment. These valleys are believed to be the result of sediment-transporting bottom currents.

Trace elements in marine waters by atomic absorption spectrophotometry

Abstract Trace elements of interest in sea water fall into two well-defined categories. Strontium, lithium, and rubidium are ideally suited to determination by atomic absorption spectrophotometry since minimal sample preparation is required and standard equipment may be utilized; standardization of techniques by which large batches of samples may be rapidly and accurately processed, is important. The transition elements are present in significantly lower concentrations and in complex, and largely unknown, chemical forms; pre-concentration is vital, Solvent extraction can also provide a crude differentiation between total and extractable fractions.

Suspended sediment dynamics in Blue Fjord, western Prince William Sound, Alaska☆

Abstract Glacier meltwater and suspended sediment discharge in Blue Fjord occurs over a brief 5-month period in summer. Suspended sediment concentrations in the meltwater stream reach 300 mg l −1 , and this sediment forms a surface turbid plume at the fjord head. Suspended sediment concentrations in the surface plume range from 200 mg l −1 at the head to a few mg l −1 5 km away at the mouth. Turbidity does not seem to be related to density structure of the water column. Suspended sediment sinks through the water column with most sediment settling at slack low water. Sediment trap measurements show an April sediment flux of 1.5 mg dry sediment cm −2 day −1 at the head and 0.75 mg cm −2 day −1 at the mouth (mostly diatom frustules). September trap measurements yield a sediment flux of 53 mg cm −2 day −1 at the head and 2 mg cm −2 day −1 at the mouth (mostly detrital inorganic silicates in the mud size range). Bottom sediment in the fjord basin is mostly mud, with an admixture of sand at the fjord head. Grainsize modes decrease from an average of 46 μm at the head to 8 μm 2 km away; no trend is discernable for sediments in the outermost 4 km of the fjord basin. Mud accumulates in the fjord at the rate of about 100 mm/meltwater year at the head, 10 mm year −1 in mid-fjord, and 4 mm year −1 in the 190 m basin inside the sill at the fjord mouth.

Soluble aluminum in marine and fresh water by gas-liquid chromatography.

Abstract The feasibility of determining the extractable aluminum contents of natural waters, with particular emphasis on sea water, by gas-liquid partition chromatography has been demonstrated. The metal is chelated with trifluoroacetylacetone, extracted into toluene and injected into the Chromatograph using direct on-column injection. Under optimized instrumental conditions, better than picogram quantities of aluminum as the trifluoroacetylacetone complex may be detected.

Direct determination of zinc in seawater by atomic absorption spectrophotometry

Abstract A direct atomic absorption spectrophotometric technique for the determination of total zinc in marine waters is described. The detection limit in a seawater matrix by this method is 2·10 -4 μg zinc, and 0.25-ml samples may be analysed without any pre-analysis preparation. Contamination problems are shown to be severe for zinc and initial attempts to evaluate the various chemical and physical forms present in natural water samples have had limited success.

Subaqueous Slope Failure

Fjords are ideal environments for the study of nearly every form of submarine slide and type of sediment gravity flow. Fjords are characterized by some very steep slopes and may have rates of sedimentation that far outpace the rates of consolidation. These underconsolidated sediments may fail under their own weight or because of stimulus from earthquakes, giant waves, and man. As a consequence, there are many examples in fjords of both loss of life and extensive damage to port facilities and settlements. Thus the study of subaqueous slope failures is environmentally important, particularly in predicting their occurrence and frequency.

Extraction of cobalt, iron, indium and zinc from sea water by means of the trifluoroacetylacetone-toluene system

Abstract Iron, indium, cobalt and zinc may be completely and rapidly extracted in a single extraction with an equal volume of toluene-trifluoroacetylacetone (0.1 M) for Fe and In, and toluene-trifluoroacetylacetone (0.1 M)-isobutylamine (0.4 M) for Co and Zn. A 90% extraction or indium is obtained with an aqueous/organic volume ratio of 20, and a 88.5% extraction for iron with a volume ratio of 40. There is a deviation of the iron and indium extraction curves from seawater compared with the theoretical trivalent metal curves; this is attributed to the high concentration of halogen ions in seawater, which makes seawater a superior medium for solvent extraction.

Mineralogy and distribution of clay size sediment in Glacier bay, Alaska

ABSTRACT The mineralogy of clay size bottom sediment was studied in the main channel and adjacent fiords in Glacier Bay, Alaska to determine if a lateral change in clay composition occurs as sediment is carried from, a fresh water to marine environment. X-ray analysis, indicates a dominance of chlorite and trioctahedral mica which does not change in composition or abundance laterally. The lack of diagenetic formation of new minerals probably is due to the rapid rate of clay sedimentation and also due to the minor amount of chemical degraduation at the source in this sub-arctic environment.

Patterns of carbon supply and distribution and oxygen renewal in two Alaskan fjords

The deep basin water of Resurrection Bay (a single-silled fjord at 60°N on the south-central Alaskan coast) is renewed each summer with water having a dissolved oxygen concentration > 4 ml l−1. Prior to 1976 > 90% of the allochthonous organic carbon supply to the basin was from fish-processing waste. Oxygen concentrations at the bottom were reduced to around 1 ml l1 during the winter, and Heggie and Burrell (1981) have computed that a quantity of carbon > 50% of the annual phytoplankton production (19 moles C m−2 yr−1) was oxidized within the basin and near-surface sediments. Very little carbon (0.6 moles m−2 yr−1) is removed via sediment burial in this estuary. Boca de Quadra Fjord is located at approximately 55°N adjacent to the Alaska—British Columbia border. The annual summer flushing sequence of the deep (365 m) central basin is basically the same as in Resurrection Bay. Estimated benthic respiration (around 8 moles C m−2 yr−1) may be supported by the in-fjord annual primary production (> 12 molesCm−2 in 1980). The mean annual input of terrigenous particulate carbon is estimated to be of the same order of magnitude as the loss rate within the basin by sediment burial (9.0 moles C m−2 yr−1). The relatively high flux of allochthonous carbon into Boca de Quadra thus appears to consist predominantly of refractory material which does not create a significant oxygen demand within the basin.