Macroinfaunal Distribution. Relationships Among Burrowing Organisms in Mud Flats.
-
Upload
jeff-jaggars -
Category
Documents
-
view
216 -
download
1
Transcript of Macroinfaunal Distribution. Relationships Among Burrowing Organisms in Mud Flats.
CIRCACCIRCAC
Sea Level Change Tidal Currents
Wave Action Turbidity
Fluvial Deposition
Erosion Ice Gouging
Sediment Texture
Quiescent Deposition
Organic Concentrations
Larval Survival
Sediment Stability
Migratory Predators
Recruitment Success
BioturbationSedentary Predation
Success of Adult Macro-Infaunal Populations
Primary Factors
Secondary Factors
Tertiary Factors
Primary Biological Effects
Secondary Biological Effects
Ultimate Consequence
CIRCACCIRCAC
Tectonic Changes in Sea Level
Tidal Currents
Wave Action Turbidity
Fluvial Deposition
Erosion Ice Gouging
Sediment Texture
Quiescent Deposition
Organic Abundance
Larval Survival
Sediment Stability
Migratory Predators
Recruitment Success
BioturbationResident Predation
Success of Adult Macro-Infaunal Populations
Primary Factors
Secondary Factors
Tertiary Factors
Primary Biological Effects
Secondary Biological Effects
Ultimate Consequence
CIRCACCIRCAC
Factors Influencing Distribution & Abundance of Long-lived Infaunal Organisms
• Two primary factors affecting the distribution of intertidal infauna in Cook Inlet appear to be:
– Extreme tidal currents caused by the large tidal flux and shape of the basin
– Massive loads of silt being dumped from the northern river systems
CIRCACCIRCAC
Secondary Factors for Infaunal Organisms
• Erosion
• Sediment texture
• Larval survival
• Food availability (organic abundance)
• Predation by adult infauna and migratory predators
CIRCACCIRCAC
Site Evaluation
WORTHWHILENOT
WORTHWHILE WORTHWHILENOT
WORTHWHILEEAST SIDE OF INLET WEST SIDE OF INLET
Clam Gulch Boulder PointNE Chisik
IslandKalifornsky
Beach Bishop BeachNo. Tuxedni
BayChickaloon Bay Moose Point Polly Creek
No-name CreekBeach
MIDDLE OF INLET Redoubt CreekSE Corner of
Kalgin Is.Shoal South of
Kalgin Is.Harriet Point
NorthOld Cannery
CreekOldmans Bay,
Kalgin Is.Shoal West of
Kalgin Is.West Foreland
SouthNE Kalgin
IslandNW Kalgin
IslandWest Foreland
North
CIRCACCIRCAC
Conclusions for Sediment and Habitat Conditions
• Range and stability of hydrodynamic conditions in middle and upper Cook Inlet is highly variable
• Wide range of habitats strongly reflects the hydrodynamic and suspended particulate regimes in the inlet
CIRCACCIRCAC
CONCLUSIONS
• Upper inlet is oligotrophic• Intertidal sediments generally nutrient-poor • Concentrations of TOC and TKN, ranging
from moderate to very low, are inversely correlated with particle grain size and with hydrodynamic energy levels
• Eroding peat may be an important source of nutrition in middle and upper Cook Inlet
CIRCACCIRCAC
• C:N ratios are inversely correlated with particle grain size and hydrodynamic energy levels
• Based on Carbon:Nitrogen ratios, it is likely that, in locations such as shoals, the major sources of nutrients for infauna may be bacteria living on sediment or detrital particles (or phytoplankton)
Conclusions for Sediment and Habitat Conditions
CIRCACCIRCAC
If it weren’t for the currents, Cook Inlet would become a gigantic mud flat inhabited with large populations of Macoma balthica
If it weren’t for the mud, Cook Inlet would become current-swept sand and gravel beaches populated with razor or surf clams
Instead, it’s both….
Conclusion
CIRCACCIRCAC
CONCLUSIONS
• By any measure, it is clear that the sediments contain only very low concentrations of hydrocarbons
• Bivalve populations sampled in upper Cook Inlet have not been exposed to detectable concentrations of petroleum hydrocarbon contaminants
CIRCACCIRCAC
CONCLUSIONS
• Tissue and surrounding sediment samples consistently produced completely different PAH and AHC profiles
• Mainly naphthalenes represented in tissues
• The limited suite of hydrocarbon analytes in tissue samples indicates that the organisms in upper Cook Inlet accumulate only a subset of all hydrocarbons found in sediments
CIRCACCIRCAC
Major Factors Likely to Influence Distribution & Abundance of Long-lived Infaunal Organisms
• Intensity of currents and wave action
• Turbidity
• Suspended and deposited nutrition (bacteria, detrital matter, phytoplankton)
• Sediment texture and stability
• Larval settlement and recruitment success
• Mobile and resident predators