P1252108902wlbZa - PowerPoint PPT Presentation

Title: P1252108902wlbZa


1
Climate Change and Zooplankton Predator-Prey
Dynamics
Copepods
Comb-jelly
Barbara K. Sullivan, Donna Van Keuren,
University of Rhode Island Supported by
2
Temperatures in Narragansett Bay since 1950
increases are evident
NOAA data from Newport RI to 1994 URI Fish Trawl
1995-1999
3
Changes in Mnemiopsis spp. distribution in North
America
1950-1979 vs 1999-2002
geographic range expansion
temporal range expansion in Narragansett Bay
4
Mnemiopsis gt1 cm appeared earlier and were more
abundant in 1999 than in 1971
0 20 40
Jan Mar May Jul Sep
Nov Dec
Number/m3
1999
0 200 400
1999
Jan Mar May Jul
Sep Nov Dec
5
Consequences?
Comb jellies, fish larvae
Zooplankton Phytoplankton

• Increased predation on fish eggs and larvae?
• Depletion of zooplankton stocks in 2000 that fish
  eat?
• Keller et al. 1999 reported 2 to 4 fold
  reductions in fish eggs and larvae since 1972-73
  (p lt .05).

6
Can we predict the consequences of climate change?

• One species near northern edge of its range has
  expanded its seasonal range
• With warming will all species simply shift
  distribution to earlier in the season?
• Will there be a more complicated community
  response by zooplankton and phytoplankton?

7

What do the data say? Zooplankton and Comb
jellies no one was keeping track of
zooplankton in the Bay until Sullivan et al.
1999-2002 Could there be big changes being missed
that have important consequences on the rest of
the system?
8
Dominant zooplankton and comb jellies -PAST
9
Dominant summer zooplankton severely reduced in
2000 and 2001
10
And in 2002 and 2003 at multiple stations
11
Date of data collection Ratio summer copepod winter copepod Ratio summer copepod winter copepod
Date of data collection Max. abundance Average abundance
1951 Frolander 1.13 0.86
1973 Hulsizer 1.15 0.4
1976 Durbin Durbin 0.99 0.80
2002 Sullivan et al. 0.05 0.03
2003 Sullivan et al. 0.18 0.07
12

• Consequences?
• Keller et al. 1999 report 2-4 fold fewer fish
  larvae.
• Chlorophyll a in summer?
• Less consumed
• More arrive at the bottom?