Responses of the South Florida Coastal and Estuarine Ecosystems to Climate Variability, Extreme Weather Events & Sea Level Rise Over the Last ~4,800 Years
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Responses of the South Florida Coastal and Estuarine Ecosystems to Climate Variability, Extreme Weather Events & Sea Level Rise over the last ~4,800 years Anna Wachnicka & Lynn Wingard SERC, Florida International University, Miami, FL USGS, Reston, VA Climate Change, and the Estuarine & Coastal Systems Greenhouse Gases Air Ocean CO2 Temperature Levels Water • water quality Atmospheric Temperature •loss of benthic habitats Circulation Oceanic pH • increased algae blooms Sea Level Precipitation Rise Patterns • impact on coral reefs & other pH sensitive organisms • inundation Freshwater • flood & storm damage Flows • coastal erosion • saltwater intrusion Estuarine Salinity Nutrient • salinity patterns Turbidity • rising water tables Circulation Patterns Pollution • wetland loss • distribution of organisms • increased algae blooms • species distribution • hypoxia • habitat loss • loss of benthic habitats Pacific and Atlantic Ocean Influence on Precipitation & Salinity Patterns in South Florida Shifts in the mean SST (1881‐2011) Probability = 0.05, cutoff length = 10, Huber parameter = 1 AR(1) = 0.41 (OLS), subsample size = 10 0.6 0.4 (°C) 0.2 t (cm) 0 y Wes ) anomalies ‐0.2 1881 1886 1891 1896 1901 1906 1911 1916 1921 1926 1931 1936 1941 1946 1951 1956 1961 1966 1971 1976 1981 1986 1991 1996 2001 2006 2011 SST p (C . Miami (cm) ip. Ke ex x c d x ‐0.4 Prec mi Tem O inde ‐0.6 DO inde Ann. Pre Ann. Mia ENSO in AM P 2000 1995 1990 1985 1980 1975 1970 Source: McCabe (2004) Age (Cal. Years) 1965 1960 1955 1950 0 50 100150200 0 50 10015020023.0 24.0 25.0 26.0 -1.5 0.0 1.5 -0.5 0.0 0.5-2.0 -1.0 0.0 1.0 2.0 How Estuaries Respond to Warmer Temperatures & Sea Level Rise? δ18O δ13C The Past is the Key to the Future… Sampling Locations Everglades National Park Miami Biscayne Bay Shark River Slough Taylor River Slough Gulf of Atlantic Mexico Ocean Florida Bay N 148 Modern sites 11 Sediment cores (analyzed) 10 Sediment cores (not analyzed) Sampling Locations Gulf of Mexico Dry Tortugas Marquesas Keys Surface sediment samples Sediment cores (analyzed) SedimentSAMPLE cores COLLECTION Modern samples Epipelon Epiphyton • XRF core scanner for elemental analysis CAT‐scan Plankton • Radiometric Methods: 210Pb,14C Peat and Marl Deposits in Florida Bay cores Peat mixed with marl ~4840 B.P. ~3040 B.P. Bob Allen & Ninemile Bank Cores Modeling the Structure of Diatom Assemblages using Artificial Neural Networking Algorithms (ANN) 1. Self Organizing Maps (SOM) used to reduce dimensionality & to classify samples according to similarities in sp. composition 2. Samples with distinct diatom communities represented by coordinates (X,Y) according to their env. features 3. Backpropagation Learning Algorithm (BPN) uses env. features of the samples as input var. & coordinates as output var. 4. The predicted values (Ẋ,Ẏ) ploted on a 12 celled SOM map to test predictability of BNP Self Organizing Map with Each Cell Corresponding to a Specific Assemblage Jacknife leave‐one‐out validation procedure of BPN used to compare observed and predicted sample allocations Samples allocated to a given cell have similar Next step (not done yet) will be to correlate the taxa diatom assemblages with different env. gradients Major Shifts in Diatom Communities in South Florida cores Everglades National Park 1956 1956 1974 ~1980s Gulf of Mexico 1956 1957 1958 1980s 1954 Atlantic 1980s Ocean Major Restructuring of Diatom Assemblages, Florida Bay and Biscayne Bay, Post-1940s 12 10 8 6 4 2 sum of regime shift indices shift regime of sum 0 2000 1995 1990 1985 1980 1975 1970 1965 1960 1955 1950 1945 1940 1935 1930 1925 1920 1915 1910 1905 1900 1895 1890 1885 1880 1875 1870 1865 1860 1855 1850 NNA FBA CBA TC RB NB BA Biscayne Bay Florida Bay • Regime Shift Index (RSI) = cumulative sum of normalized anomalies relative to a critical value • Method used: Sequential t-test Analyzes of Regime Shifts (STAR) Wachnicka et al. (In Prep.) Sum of Regime Shifts Microbenthic CommunityResponse to Environmental 0 1 2 3 4 5 6 1998 1995 1991 Change, Featherbed Bank(BiscayneBay) 1988 1985 1981 1980 1978 1975 1971 1968 1965 diatoms 1962 1961 1958 1956 ostracodes 1954 1951 1950 1948 1944 foraminifera 1941 1938 1937 1934 1931 1930 1928 1924 1921 Wachnicka al.(In et Prep.) 1918 1916 1914 1913 1911 1908 1904 1901 1900 Shark deeper River water/G. ~AD 1989 (Entrance 0 Paralia sulcata 5 of 10 M. 15 Triceratium reticulum 20 taxa 25 30 Actinoptychus senarius 35 ~ to AD Depth 40 (cm) Cyclotella litoralis 1900 45 50 Ponce 55 Grammatophora complex 60 65 Thalassiosira complex 70 Cymatosira belgica de 0.00.20.40.6 Hyalodiscus scoticus Leon 0.00 0.05 0.10 Biddulphia complex 0.00 0.05 0.10 Gyrosigma balticum Bay) 0.00 0.05 0.10 Tryblionella granulata 0.0 0.1 0.2 Cocconeis complex 0.00 0.05 0.10 Diploneis complex 0.00 0.05 0.10 0.00 0.05 0.10 Z1 FU 0.00 0.05 0.10 Z2A CONISS 0.00 0.05 0.10 Z2B 0.00 0.05 0.10 Z2C 0.00 0.05 0.10 Z2D 0.00 0.05 0.10 Z3A Z3B 2468101 Total sum of squares 2 Changes in Salinity in Florida Bay Florida Bay & Biscayne Bay Biscayne Ninemile Bank No Name Bank Bay 1995 1995 Aver. 42 ppt. 1990 1985 1985 1980 1975 1975 1970 Severe 1965 1965 1960 droughts of 1955 the 1970s 1955 1950 1945 1945 1940 Aver. 44 ppt. 1935 1935 1930 1925 Age (Cal. Years) Age (Cal. Age Years) (Cal. 1925 1920 1915 1910 1915 1905 1900 1895 1905 1890 1885 1880 1895 1875 1870 1885 35 40 45 50 55 30 34 38 42 46 Salinity (ppt.) Wachnicka et al. (2013b, 2013c) Are Algal Blooms More Frequent Now then in the Past? ? 1995 1990 1985 1980 1975 1970 1965 1960 1955 1950 1945 1940 1935 1930 1925 Age (Cal. Years) Age (Cal. 1920 1915 1910 1905 1900 1895 1890 COURTESY OF NOAA / NOAA 1885 1880 1875 Lindsey Visser (NOAA) shows a 1870 sampling net slimed by algae during a survey of Biscayne Bay Taxon Abundance (July 2013) Conclusions • Largest changes in community structure in the 1940s, 1950s, 1960s coincided with major hydroscape changes in South Florida • Changes in community structure in the mid-1950s, & early 1960s, 1970s coincided with severe drought events followed by period of increased precipitation • The early 1960s shits also coincided with 3 major hurricanes • The mechanisms of rising salinity levels at Ninemile Bank & No Name Bank since 1900 are unclear (precipitation was actually above aver. then….; links to sea level rise?) ACKNOWLEDGMENTS • Project Sponsors & Collaborators: USGS, NOAA, NSF, NCS, NRC, Biscayne National Park, SERC, FCE LTER, University of Miami, Florida Atlantic University, Mariners Hospital in Tavernier Key • Technical Assistance: graduate and undergraduate students, technicians, volunteers .